Re: Urban Stealth
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Good thinking, Grant. How about the metal frame for a backpack? Unobtrusive, lightweight, and an intregal part of the backpack. Brilliant!
Cheers Norm vk5gi McLaren Vale South Australia Sent from my iPad > On 23 Jan 2019, at 12:21 pm, [hidden email] wrote: > > Send Elecraft mailing list submissions to > [hidden email] > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.qth.net/mailman/listinfo/elecraft > or, via email, send a message with subject or body 'help' to > [hidden email] > > You can reach the person managing the list at > [hidden email] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Elecraft digest..." > > > Today's Topics: > > 1. Re: Urban stealth HF: Inside-the-backpack loop antenna? > (Grant Youngman) > 2. Re: Urban stealth HF: Inside-the-backpack loop antenna? (K9MA) > 3. Re: Urban stealth HF: Inside-the-backpack loop antenna? > (Clay Autery) > 4. Re: Urban stealth HF: Inside-the-backpack loop antenna? > (Grant Youngman) > 5. Re: Urban stealth HF: Inside-the-backpack loop antenna? (K9MA) > 6. Re: Urban stealth HF: Inside-the-backpack loop antenna? (turnbull) > 7. Ferrite Rod? (was: Urban stealth HF...) (Steve Sergeant) > 8. Re: [KX3] Urban stealth HF: Inside-the-backpack loop antenna? > (Rich Arland) > 9. Re: Elecraft Digest, Vol 177, Issue 36 (Thaire Bryant) > 10. Re: Auto-spot, tuning aids, and the arcane history of CW > pitch-matching (Robert Rennard) > 11. Re: Auto-spot, tuning aids, and the arcane history of CW > pitch-matching (Bill Frantz) > 12. Re: Urban stealth HF: Inside-the-backpack loop antenna? (kevinr) > 13. Re: Auto-spot, tuning aids, and the arcane history of CW > pitch-matching (Joan) > 14. Re: Urban stealth HF: Inside-the-backpack loop antenna? > (Michael Chowning) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 22 Jan 2019 16:46:03 -0500 > From: Grant Youngman <[hidden email]> > To: Wayne Burdick <[hidden email]> > Cc: Elecraft <[hidden email]>, KX3 <[hidden email]> > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > The problem is loop diameter. Efficiency on 20m of a 12? diameter loop would be on the order of 5%. Forget it entirely on 40m .. essentially a dummy load that would take around 1200 pf to resonate. On 17m efficiency would go up to around 11%. > > I use a loop portable all the time (Alexloop, W4OP) and they work well. They?re both about 3 ft in diameter. The Alexloop is light enough to be carried around hand held ... the W4OP needs a table top or tripod. > > Grant NQ5T > > Sent from my iPhone > >> On Jan 22, 2019, at 3:57 PM, Wayne Burdick <[hidden email]> wrote: >> >> >> >> So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course. OTOH, we?re talking about HF. A cellphone by your ear is probably worse. >> >> Any other antenna suggestions? >> >> Wayne >> > > > ------------------------------ > > Message: 2 > Date: Tue, 22 Jan 2019 15:51:00 -0600 > From: K9MA <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > >> On 1/22/2019 15:46, Grant Youngman wrote: >> The problem is loop diameter. > > It doesn't have to be round. > > 73, > > Scott K9MA > > > -- > Scott K9MA > > [hidden email] > > > > ------------------------------ > > Message: 3 > Date: Tue, 22 Jan 2019 16:01:56 -0600 > From: Clay Autery <[hidden email]> > To: Elecraft <[hidden email]> > Cc: KX3 <[hidden email]> > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Consider integrating the loop into a purpose built/modified backpack...? or the frame. > You can get a larger enclosed area, maintain easier use of the pack's volume without jacking up the loop, and better insure the loop geometry doesn't change as you pack/move/use it. > With a little creativity, yiu could also integrate some variable tuning into the design with access by hand if you place the adjusrable parts in the right location... > If you do switch in/out parts, it could be just a switch setup on the torso strap... > If QRP, I'd try to use the frame or an extension thereof... > Even the flexible plastic stiffeners in some frames could be used to carry a loop wire. > Good luck! > 73, > ClayKY5G > > > Sent from my Verizon, Samsung Galaxy smartphone > -------- Original message --------From: Wayne Burdick <[hidden email]> Date: 1/22/19 14:57 (GMT-06:00) To: Elecraft <[hidden email]> Cc: KX3 <[hidden email]> Subject: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna? > I?ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 antenna and a dragged counterpoise. In wide open spaces it?s a blast. But urban settings with dogs, wire-eating cacti and overzealous Neighborhood Watchers can distract from one?s radio experience. > > So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have? modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. > > The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course.? OTOH, we?re talking about HF. A cellphone by your ear is probably worse. > > Any other antenna suggestions? > > Wayne > N6KR > > > > ---- > elecraft.com > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > ------------------------------ > > Message: 4 > Date: Tue, 22 Jan 2019 17:09:56 -0500 > From: Grant Youngman <[hidden email]> > To: K9MA <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Yes, it does not have to be round. The actual measurement of interest is Circumference of whatever shape it is (e.g, the total length of the radiator). A 12? loop or square, or whatever, is still going to have a very low efficiency at this size point. But closer to rounder is better ? > > Grant NQ5T > K3 #2091 KX3 #8342 > >> On Jan 22, 2019, at 4:51 PM, K9MA <[hidden email]> wrote: >> >> On 1/22/2019 15:46, Grant Youngman wrote: >>> The problem is loop diameter. >> >> It doesn't have to be round. >> >> 73, >> >> Scott K9MA >> >> >> -- > > > > ------------------------------ > > Message: 5 > Date: Tue, 22 Jan 2019 16:17:12 -0600 > From: K9MA <[hidden email]> > To: Grant Youngman <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > There's undoubtedly a trade-off between rounder and longer. I was > thinking of a typical more or less rectangular backpack, which would > have a circumference much larger than a 12 inch circle. A typical > backpacking pack could accommodate a circumference of about 88 inches, > more than twice that of a 12 inch round loop. Granted, such a large pack > wouldn't exactly be inconspicuous on an urban hiking trail, but you > could always put some rocks in it, and pretend you're training for a > Grand Canyon hike. > > 73, > Scott K9MA > >> On 1/22/2019 16:09, Grant Youngman wrote: >> Yes, it does not have to be round. ?The actual measurement of interest >> is Circumference of whatever shape it is (e.g, the total length of the >> radiator). ?A 12? loop or square, or whatever, ?is still going to have >> a very low efficiency at this size point. ?But closer to rounder is >> better ? >> >> Grant NQ5T >> K3 #2091 KX3 #8342 >> >>> On Jan 22, 2019, at 4:51 PM, K9MA <[hidden email] >>> <mailto:[hidden email]>> wrote: >>> >>>> On 1/22/2019 15:46, Grant Youngman wrote: >>>> The problem is loop diameter. >>> >>> It doesn't have to be round. >>> >>> 73, >>> >>> Scott K9MA >>> >>> >>> -- >> > > -- > Scott K9MA > > [hidden email] > > > > ------------------------------ > > Message: 6 > Date: Tue, 22 Jan 2019 22:24:49 +0000 > From: turnbull <[hidden email]> > To: Grant Youngman <[hidden email]>, K9MA <[hidden email]> > Cc: [hidden email] > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Why not a collapsible Alexloop mag loop which fits in your back pack and will be nore efficient.? ? 73 Doug EI2CN > > > Sent from my Samsung Galaxy smartphone. > -------- Original message --------From: Grant Youngman <[hidden email]> Date: 22/01/2019 22:09 (GMT+00:00) To: K9MA <[hidden email]> Cc: [hidden email] Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna? > Yes, it does not have to be round.? The actual measurement of interest is Circumference of whatever shape it is (e.g, the total length of the radiator).? A 12? loop or square, or whatever,? is still going to have a very low efficiency at this size point.? But closer to rounder is better ? > > Grant NQ5T > K3 #2091 KX3 #8342 > >> On Jan 22, 2019, at 4:51 PM, K9MA <[hidden email]> wrote: >> >> On 1/22/2019 15:46, Grant Youngman wrote: >>> The problem is loop diameter. >> >> It doesn't have to be round. >> >> 73, >> >> Scott K9MA >> >> >> -- > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > ------------------------------ > > Message: 7 > Date: Tue, 22 Jan 2019 14:26:34 -0800 > From: Steve Sergeant <[hidden email]> > To: [hidden email] > Subject: [Elecraft] Ferrite Rod? (was: Urban stealth HF...) > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Just as a way-out idea: How about a large ferrite rod on the end of a > walking staff, on top of a backpack, or hidden inside a top-hat? > > [ https://sites.google.com/site/g3xbmqrp3/antennas/ferrite_tx ] > >> On 1/22/19 12:57 PM, Wayne Burdick wrote: >> So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course. OTOH, we?re talking about HF. A cellphone by your ear is probably worse. >> >> Any other antenna suggestions? >> >> Wayne >> N6KR > > > > ------------------------------ > > Message: 8 > Date: Tue, 22 Jan 2019 22:59:32 +0000 > From: Rich Arland <[hidden email]> > To: Mark Goldberg <[hidden email]>, Michael Blake > <[hidden email]> > Cc: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack > loop antenna? > Message-ID: > <[hidden email]> > > Content-Type: text/plain; charset="iso-8859-1" > > Ref: Homless......let's not forget the ever present shopping cart! Get a BIG one. It can be used as a counter poise in place of a set of radials or a drag wire. One could also try loading the shopping cart and using it as an antenna since the wheels are composed of a non-conductive set of wheels so the cart would be above ground. > > Just sayin' > > Vy 73 es gud DX! > > Rich Arland K7SZ WPE7BYR > Radio/electronics archaeologist > Author: The ARRL's Low Power Communicatoions > Bent Dipole Ranch, Dacula, GA > http://commobunker.blogspot.com/ > > > > ________________________________ > From: [hidden email] <[hidden email]> on behalf of Michael Blake via Elecraft <[hidden email]> > Sent: Tuesday, January 22, 2019 4:40 PM > To: Mark Goldberg > Cc: Elecraft Reflector; KX3 > Subject: Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna? > > Mark (W7MLG), It is scary how perfectly sane and normal your suggestions sound to me :) > > Very 73 - Mike - K9JRI > > > > > > > >> On Jan 22, 2019, at 4:32 PM, Mark Goldberg <[hidden email]> wrote: >> >> I would expect any high Q antenna like a loop would be detuned by any >> movement or any metal you pass by. One more reason to support automatic >> mobile screwdriver / mag loop antenna tuning on the KX series. >> A flag on a backpack would be more or less ignored. Just put a flag on the >> top of the AX1. Counterpoise is an issue though. Maybe a short one down >> your leg? >> >> Now, if you dressed as a homeless or otherwise distressed person, lots of >> weird things are possible, tinfoil hat with a big flag, dragged wire >> disguised as one of those fake animals on a leash, etc. The weirder, the >> more people will ignore you. >> >> Hopefully taken in the spirit of which it is posted. >> >> 73, >> >> Mark >> W7MLG >> >> >> On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick [hidden email] [KX3] < >> [hidden email]> wrote: >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > > ------------------------------ > > Message: 9 > Date: Tue, 22 Jan 2019 18:11:18 -0500 > From: Thaire Bryant <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Elecraft Digest, Vol 177, Issue 36 > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Ed, I?d like the K1. > > Thaire. W2APF > >> On Jan 22, 2019, at 16:41, [hidden email] wrote: >> >> Send Elecraft mailing list submissions to >> [hidden email] >> >> To subscribe or unsubscribe via the World Wide Web, visit >> http://mailman.qth.net/mailman/listinfo/elecraft >> or, via email, send a message with subject or body 'help' to >> [hidden email] >> >> You can reach the person managing the list at >> [hidden email] >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of Elecraft digest..." >> >> >> Today's Topics: >> >> 1. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Mike Harris) >> 2. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (David Gilbert) >> 3. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (K9MA) >> 4. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (K9MA) >> 5. Re: K3 SWR Anomaly (N8LP) >> 6. K2, K1, W1, and other stuff for Sale (Dauer, Edward) >> 7. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Chris Cox, N0UK) >> 8. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Chris Cox, N0UK) >> 9. Zero Beat / CWT / Auto Spot (Jim Clymer) >> 10. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Bob McGraw K4TAX) >> 11. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Don Wilhelm) >> 12. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (rv6amark) >> 13. Re: [KX3] Auto-spot, tuning aids, and the arcane history of >> CW pitch-matching (Howard Hoyt) >> 14. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Dave New, N8SBE) >> 15. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Dave New, N8SBE) >> 16. Urban stealth HF: Inside-the-backpack loop antenna? >> (Wayne Burdick) >> 17. Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Andy Durbin) >> 18. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (Wes) >> 19. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (ab2tc) >> 20. Re: [KX3] Urban stealth HF: Inside-the-backpack loop antenna? >> (Mark Goldberg) >> 21. Re: Urban stealth HF: Inside-the-backpack loop antenna? >> (Steve Sergeant) >> 22. Re: [KX3] Urban stealth HF: Inside-the-backpack loop antenna? >> (Michael Blake) >> 23. Re: Auto-spot, tuning aids, and the arcane history of CW >> pitch-matching (K9MA) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Tue, 22 Jan 2019 13:28:28 -0300 >> From: Mike Harris <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Yet another trick learnt by hard experience given away for free :-( >> >> Regards, >> >> Mike VP8NO >> >>> On 22/01/2019 11:14, Nr4c wrote: >>> Now, one thing you missed... when you?re working a big pileup and you feel you just can?t get through, it may be that all your ?buddies? are doing the same thing, using Auto-Spot! >>> >>> Now turn on XIT and set it to 12-20 Hz either way. Now your signal will be just a little different from all the others and you have a better chance of being heard. >>> >>> Sent from my iPhone >>> ...nr4c. bill >> >> >> ------------------------------ >> >> Message: 2 >> Date: Tue, 22 Jan 2019 09:59:04 -0700 >> From: David Gilbert <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> >> Wayne, you forgot clicking on the DX Cluster spot.? ;) >> >> I'm being facetious, of course, but the practice of simply clicking on a >> cluster spot does point out a problem with zero beating by any means ... >> if every calling station is zero beat the station calling CQ isn't going >> to copy anyone. >> >> Zero beat isn't always a good thing. >> >> 73, >> Dave? AB7E >> >> >>> On 1/21/2019 10:09 PM, Wayne Burdick wrote: >>> Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. >>> >>> >>> CW Spotting History >>> >>> When a station finishes a CQ in CW mode, the operator faces the challenge of copying someone who's calling back. Callers may be weak or obscured by QRM; the op can usually deal with both problems by narrowing the filter passband. However, callers may also be off frequency. A calling station may be using a wide filter passband themselves, not attempting to carefully match their VFO frequency to that of the CQing station. The result may be no QSO, even when propagation is excellent. >>> >>> In the Days of Yore, a frequency offset between stations didn't always matter. Sometimes both stations used crystal-controlled transmitters, so operators had to patient tune around after calling CQ. >>> >>> As a 14-year-old novice I embraced this operating style for a year or so, armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly wore out the socket swapping them in and out. After calling CQ, it was not unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly answered question, as my Hallicrafters receiver dial wasn't exactly digital.) >>> >>> Fortunately I soon acquired an outboard VFO, a life-changing addition to my station. Jealous friends doubled up on their paper routes to pay for their own. Girls suddenly paid more attention to me. >>> >>> These days virtually everyone has a VFO, along with the expectation that they won't have to tune theirs very far, if at all, to tune you in. Not only that, they're stable and well calibrated, not like the beasts we had to skillfully tame. Progress! >>> >>> >>> Manual Spotting (SPOT switch) >>> >>> Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs did't provide a way to do that explicitly, so you'd improvise. Basically, you had to coerce a very weak signal out of your own transmitter, say by turning on only the driver, then tune the transmit VFO until you could hear your signal on your own receiver -- superimposed on the calling station, at the same pitch. This is what we call spotting. >>> >>> Of course spotting is a lot more convenient these days, as many rigs include a SPOT switch. This function is easy for a modern transceiver designer to add, because the radio's firmware is quite capable of turning on only the CW sidetone without transmitting. >>> >>> That is the purpose of the SPOT switch on all Elecraft transceivers. Tap SPOT, and you'll hear your sidetone pitch. Most people can do a good job of adjusting the VFO such that the CQing station's pitch matches that of the SPOT tone. This ensures that when you call them, you'll be close to their own frequency. >>> >>> >>> Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) >>> >>> Since not everyone has an inherent musical ear, various hardware-enhanced means of tuning in CW signals have been developed. >>> >>> The simplest method is to just narrow your receiver passband so much that, if you can hear a station calling CQ at all, you're guaranteed to be "right on top of him." This assumes that your transceiver enforces alignment between its transmit and receive pitch...true of all Elecraft gear. >>> >>> Narrow filtering has gone through decades of evolution. Some filters were based on op-amps (active filters), while others were based on LC filtering, conscripting humongous toroidal cores scavenged from telco equipment. I acquired my stash of these from a haphazard mound of old switching racks, decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That irresistible junk pile was also a mother load of TO5 transistors, multi-pound electrolytic capacitors, and tetanus, but that's another story.) Typically the toroids were 88 millihenries -- a huge value for a high-Q inductor, permitting resonance in the low audio range. >>> >>> Later, such filters migrated to digital signal processing, in the form of switched-capacitor ICs or DSPs. You can still buy these switched-capacitor chips, like the MF10, from various sources. It's instructive to roll your own tunable filter, just for fun. >>> >>> Whether passive or active, the goal of filtering is typically to achieve a narrow passband, say 250 Hz or less. With DSP, nearly perfect filters with "brick wall" passbands can be created. But these have the disadvantage of ringing like a bell when pinged by a CW signal or noise, making copy difficult. >>> >>> One solution incorporated into the K-line and KX-line is the Audio Peaking Filter (APF), which provides a 30-Hz bandwidth at -3 dB, but broad skirts, preventing ringing from occurring. As our customers will attest, APF works like magic on weak signals obscured by noise. >>> >>> Another forerunner to DSP techniques was the audio phase-locked-loop, using inexpensive ICs like the legendary LM567. When locked on a signal that matched its center frequency, the circuit would turn on an LED, alerting the operator that the VFO was now properly tuned. >>> >>> With the DSPs in our K-line and KX-line radios, we can provide a much more powerful tool: CWT, or "CW Tuning Aid." When enabled, CWT turns the upper portion of the rig's S-meter into something of a mini spectrum analyzer. The pitch of the strongest signal in the passband is analyzed by the DSP, then represented as a single segment of the bar graph. For CWT-enhanced manual spotting, the operator simply tunes the VFO slowly until the center CWT segment is flashing along with the keyed signal. >>> >>> Manual tuning with CWT can also be used in FSK-D and PSK-D modes as described in the owner's manual. >>> >>> >>> Closing the Loop: Auto-Spotting (SPOT + CWT) >>> >>> The Elecraft K3/K3S/KX2/KX3 take CW tuning another step forward by providing a way to *automatically* retune the VFO frequency to match that of a received signal. How does this work? >>> >>> When CWT is turned on, firmware treats the SPOT switch as AUTO-SPOT. The DSP analyzes the incoming signal, and with a bit of processing, determines its exact audio pitch. From there all that's needed is a bit of math to offset the VFO to match this pitch to the CW sidetone. >>> >>> There's another subtlety, though. Since a CW signal is generally being keyed on and off, the CWT algorithm has to ensure that it doesn't "take off," chasing a signal that's not there. To avoid this, we keep track of the energy in the passband, and slew the VFO incrementally over an average of about 0.5 second, moving only when the target signal is present. >>> >>> >>> How to Use Auto-Spot >>> >>> I encourage you to give the auto-spot feature a try. It's best to start with a fairly narrow passband, say 400-600 Hz; narrower if there's a lot of QRM. Find a signal, turn on CWT, then tap SPOT to tune it in. A second tap of SPOT may get even closer, especially if there's a lot of band noise. >>> >>> Auto-spot can also be used in Elecraft's PSK-D mode, i.e. for PSK31/PSK63. As with CW mode, just turn on CWT, tune in a prospective signal, and tap SPOT. Since PSK auto-decoding requires very accurate tuning, it's best to set the filter bandwidth to 50 Hz, then let auto-spot dial things in down to the last 2 or 3 Hz. If you have text decode turned on, you should start seeing text characters scroll by after auto-tuning has completed. Tapping a second time or fine-tuning the VFO a bit in 1 Hz steps may improve copy. >>> >>> 73, >>> Wayne >>> N6KR >>> >>> >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >>> >> >> >> >> ------------------------------ >> >> Message: 3 >> Date: Tue, 22 Jan 2019 11:11:30 -0600 >> From: K9MA <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Back in my college days at W9YT, we had a Drake line, separate >> transmitter and receivers. When searching and pouncing in a contest, you >> had to spot the transmitter before every contact. Spotting required >> turning one of the rotary switches on the transmitter, a cumbersome >> process. Imagine doing that a couple thousand times in a weekend. At >> some point, we came up with the idea to hook a foot switch up to do the >> spotting, which made it much easier, and save a lot of wear and tear on >> the rotary switch, not to mention the operator's wrist. >> >> In those days, 40-50 years ago, transceivers just didn't work well on >> CW, so almost all CW operators used separate transmitters and receivers. >> Some, like the Drake line, could transceive, but had the same problem on >> CW. Transceivers didn't account for the BFO offset, and there was no RIT >> or XIT. If you called another station in transceive mode, you would be >> 700 Hz or so off frequency. Two transceivers pretty much couldn't work >> each other at all. Sometime while I was inactive in the late 70's and >> 80's, that problem was solved, and we no longer had to spot before every >> contact. I think that solution had to wait for frequency synthesis, as >> it otherwise would have required additional (expensive) crystals. Does >> anyone know of a non-synthesized transceiver that didn't have the CW >> offset problem? >> >> 73, >> Scott K9MA >> >> >>> On 1/21/2019 23:09, Wayne Burdick wrote: >>> Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. >> >> >> -- >> Scott K9MA >> >> [hidden email] >> >> >> >> ------------------------------ >> >> Message: 4 >> Date: Tue, 22 Jan 2019 11:14:27 -0600 >> From: K9MA <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >>> On 1/22/2019 10:59, David Gilbert wrote: >>> >>> Wayne, you forgot clicking on the DX Cluster spot. ;) >> >> Everyone zero beat was, I think, a bigger problem before skimmers. >> Skimmer spots often seem to be quite a ways off frequency, probably >> because their SDR receivers aren't all that stable. Some may be in >> unheated buildings, too. >> >> 73, >> >> Scott K9MA >> >> -- >> Scott K9MA >> >> [hidden email] >> >> >> >> ------------------------------ >> >> Message: 5 >> Date: Tue, 22 Jan 2019 11:13:25 -0700 (MST) >> From: N8LP <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] K3 SWR Anomaly >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=us-ascii >> >> This may be out of left field, but I seem to recall from the deep recesses of >> my memory that there were some issues regarding an IF trap in the output of >> the K3. It could be that one of the components in the trap has changed and >> it now affects 40m. I don't know if newer K3s even have this circuit. Just >> thinking out loud. >> >> Larry N8LP >> >> >> >> >> >> -- >> Sent from: http://elecraft.365791.n2.nabble.com/ >> >> >> ------------------------------ >> >> Message: 6 >> Date: Tue, 22 Jan 2019 18:15:19 +0000 >> From: "Dauer, Edward" <[hidden email]> >> To: "[hidden email]" <[hidden email]> >> Subject: [Elecraft] K2, K1, W1, and other stuff for Sale >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset="utf-8" >> >> Selling principal home, no further need for seven HF transceivers. So the following are for sale. Terms for each are: No pay Pal, shipment on receipt of payment, seller packs, and buyer pays actual shipment cost from Denver, CONUS only and selling to licensed hams only. All items unless otherwise noted are in excellent cosmetic and electrical condition. Nonsmoking environment, never used out of doors or in mobile / portable operations. >> >> I have two heavy dimpled main tuning knobs for the K2s. Original cost $90 (as I remember it), option to buy for $50 each with purchase of a K2. Most interconnecting cables for K2s are also available at no additional cost. >> >> K2/10 (s/n 7637) with KNB2, KAF2, KAT2, KIO2, KBT2 (with battery), and optional heavy dimple knob. $900. >> >> K2/10 (s/n 7687) with KNB2, KSB2, KAF2, KPA100, and KAT100-1 in matching low profile enclosure, with tilt stand. $1,300. >> >> K2/10 (s/n 7739) and KAT100/KPA100 in EC-2 enclosure (?twins? configuration). K2 includes KNB2, KSB2, KAT2, KAF2, KIO2. $1,550. >> >> K1 (s/n 3440) 17 and 30 meters, with KAT1 internal ATU, KNB1 noise blanker, and KBT1 internal battery adapter. Includes extra cover and speaker (not used when cover with ATU is installed.) Tuned and aligned by Alan Wilcox. $350. >> >> Elecraft W1 Power Meter in acrylic case w/stand. $70 >> >> KD1JV Triband Transceiver and external ATU (Kit built, never tested.) $100 >> >> Pico Keyer condition unknown. Free to whomever buys the first K2 or K1. >> >> >> Ted, KN1CBR >> >> >> >> Edward A. Dauer >> Dean Emeritus and Professor Emeritus of Law >> University of Denver >> >> >> ------------------------------ >> >> Message: 7 >> Date: Tue, 22 Jan 2019 12:54:36 -0600 (CST) >> From: "Chris Cox, N0UK" <[hidden email]> >> To: K9MA <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: TEXT/PLAIN; charset=US-ASCII >> >> The transceive problem didn't seem to exist on any older non-synthesized >> transceiver that I have used, including FT-101 series, TS-520/820 and >> later, KW Electronics KW-2000E. these were all '70s era transceivers. >> >> -- >> 73 Chris Cox, N0UK, G4JEC >> [hidden email] >> >> >> >> ------------------------------ >> >> Message: 8 >> Date: Tue, 22 Jan 2019 12:51:50 -0600 (CST) >> From: "Chris Cox, N0UK" <[hidden email]> >> To: K9MA <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: TEXT/PLAIN; charset=US-ASCII >> >> >> >> -- >> 73 Chris Cox, N0UK, G4JEC >> [hidden email] >> >>> On Tue, 22 Jan 2019, K9MA wrote: >>> >>> transmitter before every contact. Spotting required turning one of the rotary >>> switches on the transmitter, a cumbersome process. Imagine doing that a couple >>> thousand times in a weekend. At some point, we came up with the idea to hook a >>> foot switch up to do the spotting, which made it much easier, and save a lot >>> of wear and tear on the rotary switch, not to mention the operator's wrist. >>> >>> In those days, 40-50 years ago, transceivers just didn't work well on CW, so >>> almost all CW operators used separate transmitters and receivers. Some, like >>> the Drake line, could transceive, but had the same problem on CW. Transceivers >>> didn't account for the BFO offset, and there was no RIT or XIT. If you called >>> another station in transceive mode, you would be 700 Hz or so off frequency. >>> Two transceivers pretty much couldn't work each other at all. Sometime while I >>> was inactive in the late 70's and 80's, that problem was solved, and we no >>> longer had to spot before every contact. I think that solution had to wait for >>> frequency synthesis, as it otherwise would have required additional >>> (expensive) crystals. Does anyone know of a non-synthesized transceiver that >>> didn't have the CW offset problem? >>> >>> 73, >>> Scott K9MA >>> >>> >>>> On 1/21/2019 23:09, Wayne Burdick wrote: >>>> Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- >>>> are very useful tools for CW operators, especially those not experienced in >>>> pitch-matching. Here's a bit of history on where these features came from >>>> and how they work. >>> >>> >>> -- >>> Scott K9MA >>> >>> [hidden email] >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >>> >> >> >> ------------------------------ >> >> Message: 9 >> Date: Tue, 22 Jan 2019 14:27:25 -0500 >> From: Jim Clymer <[hidden email]> >> To: [hidden email] >> Subject: [Elecraft] Zero Beat / CWT / Auto Spot >> Message-ID: >> <CAENrfz=2XpPoe8T9iJNbq2PwQUun3yPQ6r+DrGRA2B7=[hidden email]> >> Content-Type: text/plain; charset="UTF-8" >> >>> >>> Anyone who has ever had the privilege of being on the receiving end of a >>> huge CW pileup has a new appreciation for the tone deaf and those who never >>> learned to use CWT. (And the savvy pileup busters who >> >> intentionally avoid zero beat.) Of course there is always the W5 - dead >>> zero beat - who is so loud you don't hear anyone else no matter how far off >>> frequency! >> >> Jim - WS6X >> >>> >> Date: Mon, 21 Jan 2019 21:09:44 -0800 >>> From: Wayne Burdick <[hidden email]> >>> To: Elecraft Reflector <[hidden email]> >>> Subject: [Elecraft] Auto-spot, tuning aids, and the arcane history >>> of CW pitch-matching >>> >>> CW Spotting History >>> Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) >>> How to Use Auto-Spot >>> >>> >> >> >> ------------------------------ >> >> Message: 10 >> Date: Tue, 22 Jan 2019 14:14:00 -0600 >> From: Bob McGraw K4TAX <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Another trick which works well.?? Tune to a WWV frequency in CW mode.? >> Press SPOT and the radio will jump on the exact carrier frequency.?? The >> SPOT function can pull on to the WWV frequency as far away as about 100 >> Hz.? Once the radio has? resolved SPOT, the readout / display is the >> frequency of WWV +/- the error in Hz. Thus the readout of 9.999.992 is >> indicating being 8 Hz low. >> >> From a cold start, FP being 19?C, I find? -8 Hz error on 10 MHz WWV.? >> After about 15 minutes the FP is 25?C and the error is -1 Hz.? I've >> tweaked the REF CAL such that after 1/2 hr. in receive tuning to WWV >> from both higher and lower will produce a reading of 10.000.000.?? Will >> all stations pse QNZ? QNN. >> >> 73 >> >> Bob, K4TAX >> >> >> >> >> ------------------------------ >> >> Message: 11 >> Date: Tue, 22 Jan 2019 15:19:54 -0500 >> From: Don Wilhelm <[hidden email]> >> To: "Chris Cox, N0UK" <[hidden email]> >> Cc: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> In that era, SSB capable transceivers often offset the BFO by using a >> different BFO crystal for CW transmit or CW receive - but that technique >> slaved you to one sideband and one CW pitch. >> There were other ways of doing the offset as well, but it was usually >> done by shifting the BFO frequency. >> >> 73, >> Don W3FPR >> >>> On 1/22/2019 1:54 PM, Chris Cox, N0UK wrote: >>> The transceive problem didn't seem to exist on any older non-synthesized >>> transceiver that I have used, including FT-101 series, TS-520/820 and >>> later, KW Electronics KW-2000E. these were all '70s era transceivers. >>> >>> -- >>> 73 Chris Cox, N0UK, G4JEC >>> [hidden email] >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >>> >> >> >> ------------------------------ >> >> Message: 12 >> Date: Tue, 22 Jan 2019 12:26:40 -0800 >> From: rv6amark <[hidden email]> >> To: K9MA <[hidden email]>, [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >> Re:? "Does anyone know of a non-synthesized transceiver that didn't have the CW offset problem?" >> >> My TenTec 540 doesn't have that problem, but my much older TenTec PM-3A does.? If my memory is correct, the Heathkit HW8 has the problem, but they fixed it in the HW9 with a small capacitor that switches in and out for RX/TX to shift the VFO. >> >> There are others. >> >> Mark >> KE6BB >> >> >> >> Sent via the Samsung Galaxy Tab E, an AT&T 4G LTE tablet >> -------- Original message --------From: K9MA <[hidden email]> Date: 1/22/19 9:11 AM (GMT-08:00) To: [hidden email] Subject: Re: [Elecraft] Auto-spot, tuning aids, >> ? and the arcane history of CW pitch-matching >> Back in my college days at W9YT, we had a Drake line, separate >> transmitter and receivers. When searching and pouncing in a contest, you >> had to spot the transmitter before every contact. Spotting required >> turning one of the rotary switches on the transmitter, a cumbersome >> process. Imagine doing that a couple thousand times in a weekend. At >> some point, we came up with the idea to hook a foot switch up to do the >> spotting, which made it much easier, and save a lot of wear and tear on >> the rotary switch, not to mention the operator's wrist. >> >> In those days, 40-50 years ago, transceivers just didn't work well on >> CW, so almost all CW operators used separate transmitters and receivers. >> Some, like the Drake line, could transceive, but had the same problem on >> CW. Transceivers didn't account for the BFO offset, and there was no RIT >> or XIT. If you called another station in transceive mode, you would be >> 700 Hz or so off frequency. Two transceivers pretty much couldn't work >> each other at all. Sometime while I was inactive in the late 70's and >> 80's, that problem was solved, and we no longer had to spot before every >> contact. I think that solution had to wait for frequency synthesis, as >> it otherwise would have required additional (expensive) crystals. Does >> anyone know of a non-synthesized transceiver that didn't have the CW >> offset problem? >> >> 73, >> Scott K9MA >> >> >>> On 1/21/2019 23:09, Wayne Burdick wrote: >>> Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. >> >> >> -- >> Scott? K9MA >> >> [hidden email] >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] >> >> ------------------------------ >> >> Message: 13 >> Date: Tue, 22 Jan 2019 15:27:03 -0500 >> From: Howard Hoyt <[hidden email]> >> To: Mel Snyder <[hidden email]>, Wayne Burdick >> <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]>, >> "[hidden email]" <[hidden email]> >> Subject: Re: [Elecraft] [KX3] Auto-spot, tuning aids, and the arcane >> history of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Hi Mel, >> >> I experienced the same reading Wayne's highly informative post!! >> >> I started off in 1970 with a homebrew 6L6/807 xtal xmtr with maybe 12 >> xtals and a Hallicrafters S-38 which gave me hundreds of mesmerizing >> hours in my parents basement.? That rig gave me my first huge shock as >> well, so it is indeed memorable.? What idiot thought it was a good idea >> to put the 500 V B+ connection on an unguarded terminal strip on the >> back panel?? Wait, that was me... >> >> Still, I thought I was in heaven until my high school club bought a >> Drake R-4B/T-4XB which blew me away and I ended up owning a pair in the >> early 1980s and still love the Drake twins to this day. However they >> have been gathering dust since I got my K3, which is the best rig >> overall I have used to date, and love my KX3 in the car and on travel. >> >> Although it works well, I don't use Auto Spot is because it scrambles my >> feeble brain as to where I am tuned; I am just not used to a rig >> changing frequency without me intentionally doing it.? Perhaps this is a >> mental artifact of heavy contesting, where I am loathe to leave a good >> RUN frequency, indeed I often lock VFO A so I don't accidentally bump >> the VFO A knob. >> >> Cheers & 73, >> Howie / WA4PSC >> >> >>> On 1/22/2019 1:51 PM, Mel Snyder [hidden email] [KX3] wrote: >>> >>> Wow, this is *great,* Wayne! Thanks. I am away from home, but will be >>> interested to test the auto-spot when I get home. >>> >>> >>> A wonderful trip down memory lane. While you were swapping crystals >>> with your HW-16, I was a few years ahead of you as KN3AFW, swapping >>> them first into my home-brew 6AG7-6L6 rig, and then, a borrowed Eico 720. >>> >>> I still own a lovely Johnson Ranger II, and an SB-301 Heathkit >>> receiver with the original 500Hz filter, the combination of which >>> require your explained tuning the VFO to the note of the received >>> signal. But both are on my list to sell, along with my HW-9 and >>> FT-707, inasmuch with my KX3 for good band conditions and my >>> inherited/restored TS-940S when they?re poor, they are all surplus >>> space-consumers. >>> >>> Every time I turn on my KX3, I am in awe of how far ham radio has >>> progressed in the past 61 years since I was licensed. Like taking a >>> cell call on my Apple Watch, it?s beyond anything I dreamed of as a >>> kid back then. So glad I stopped by the Elecraft exhibit at the 2014 >>> Hartford ARRL convention, and was taken by the enthusiasm of KX3 users >>> that gathered there - and decided to join the cult. >>> >>> Mel, W3PYF >>> >>> >>> >>>> On Jan 22, 2019, at 12:09 AM, Wayne Burdick [hidden email] >>>> <mailto:[hidden email]> [KX3] <[hidden email] >>>> <mailto:[hidden email]>> wrote: >>>> >>>> Elecraft's auto-spot and CWT features -- available on the >>>> K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially >>>> those not experienced in pitch-matching. Here's a bit of history on >>>> where these features came from and how they work. >>>> >>>> CW Spotting History >>>> >>>> When a station finishes a CQ in CW mode, the operator faces the >>>> challenge of copying someone who's calling back. Callers may be weak >>>> or obscured by QRM; the op can usually deal with both problems by >>>> narrowing the filter passband. However, callers may also be off >>>> frequency. A calling station may be using a wide filter passband >>>> themselves, not attempting to carefully match their VFO frequency to >>>> that of the CQing station. The result may be no QSO, even when >>>> propagation is excellent. >>>> >>>> In the Days of Yore, a frequency offset between stations didn't >>>> always matter. Sometimes both stations used crystal-controlled >>>> transmitters, so operators had to patient tune around after calling CQ. >>>> >>>> As a 14-year-old novice I embraced this operating style for a year or >>>> so, armed with a dozen or so crusty FT-243 crystals for my Heath >>>> HW-16. I nearly wore out the socket swapping them in and out. After >>>> calling CQ, it was not unusual to find a caller 30 or more kHz away! >>>> (Away from "where" was a poorly answered question, as my >>>> Hallicrafters receiver dial wasn't exactly digital.) >>>> >>>> Fortunately I soon acquired an outboard VFO, a life-changing addition >>>> to my station. Jealous friends doubled up on their paper routes to >>>> pay for their own. Girls suddenly paid more attention to me. >>>> >>>> These days virtually everyone has a VFO, along with the expectation >>>> that they won't have to tune theirs very far, if at all, to tune you >>>> in. Not only that, they're stable and well calibrated, not like the >>>> beasts we had to skillfully tame. Progress! >>>> >>>> Manual Spotting (SPOT switch) >>>> >>>> Once I had a VFO I quickly learned to do *manual* pitch matching. >>>> Older rigs did't provide a way to do that explicitly, so you'd >>>> improvise. Basically, you had to coerce a very weak signal out of >>>> your own transmitter, say by turning on only the driver, then tune >>>> the transmit VFO until you could hear your signal on your own >>>> receiver -- superimposed on the calling station, at the same pitch. >>>> This is what we call spotting. >>>> >>>> Of course spotting is a lot more convenient these days, as many rigs >>>> include a SPOT switch. This function is easy for a modern transceiver >>>> designer to add, because the radio's firmware is quite capable of >>>> turning on only the CW sidetone without transmitting. >>>> >>>> That is the purpose of the SPOT switch on all Elecraft transceivers. >>>> Tap SPOT, and you'll hear your sidetone pitch. Most people can do a >>>> good job of adjusting the VFO such that the CQing station's pitch >>>> matches that of the SPOT tone. This ensures that when you call them, >>>> you'll be close to their own frequency. >>>> >>>> Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) >>>> >>>> Since not everyone has an inherent musical ear, various >>>> hardware-enhanced means of tuning in CW signals have been developed. >>>> >>>> The simplest method is to just narrow your receiver passband so much >>>> that, if you can hear a station calling CQ at all, you're guaranteed >>>> to be "right on top of him." This assumes that your transceiver >>>> enforces alignment between its transmit and receive pitch...true of >>>> all Elecraft gear. >>>> >>>> Narrow filtering has gone through decades of evolution. Some filters >>>> were based on op-amps (active filters), while others were based on LC >>>> filtering, conscripting humongous toroidal cores scavenged from telco >>>> equipment. I acquired my stash of these from a haphazard mound of old >>>> switching racks, decaying in an abandoned aircraft hanger on the >>>> Bermuda U.S. Navy base. (That irresistible junk pile was also a >>>> mother load of TO5 transistors, multi-pound electrolytic capacitors, >>>> and tetanus, but that's another story.) Typically the toroids were 88 >>>> millihenries -- a huge value for a high-Q inductor, permitting >>>> resonance in the low audio range. >>>> >>>> Later, such filters migrated to digital signal processing, in the >>>> form of switched-capacitor ICs or DSPs. You can still buy these >>>> switched-capacitor chips, like the MF10, from various sources. It's >>>> instructive to roll your own tunable filter, just for fun. >>>> >>>> Whether passive or active, the goal of filtering is typically to >>>> achieve a narrow passband, say 250 Hz or less. With DSP, nearly >>>> perfect filters with "brick wall" passbands can be created. But these >>>> have the disadvantage of ringing like a bell when pinged by a CW >>>> signal or noise, making copy difficult. >>>> >>>> One solution incorporated into the K-line and KX-line is the Audio >>>> Peaking Filter (APF), which provides a 30-Hz bandwidth at -3 dB, but >>>> broad skirts, preventing ringing from occurring. As our customers >>>> will attest, APF works like magic on weak signals obscured by noise. >>>> >>>> Another forerunner to DSP techniques was the audio phase-locked-loop, >>>> using inexpensive ICs like the legendary LM567. When locked on a >>>> signal that matched its center frequency, the circuit would turn on >>>> an LED, alerting the operator that the VFO was now properly tuned. >>>> >>>> With the DSPs in our K-line and KX-line radios, we can provide a much >>>> more powerful tool: CWT, or "CW Tuning Aid." When enabled, CWT turns >>>> the upper portion of the rig's S-meter into something of a mini >>>> spectrum analyzer. The pitch of the strongest signal in the passband >>>> is analyzed by the DSP, then represented as a single segment of the >>>> bar graph. For CWT-enhanced manual spotting, the operator simply >>>> tunes the VFO slowly until the center CWT segment is flashing along >>>> with the keyed signal. >>>> >>>> Manual tuning with CWT can also be used in FSK-D and PSK-D modes as >>>> described in the owner's manual.. >>>> >>>> Closing the Loop: Auto-Spotting (SPOT + CWT) >>>> >>>> The Elecraft K3/K3S/KX2/KX3 take CW tuning another step forward by >>>> providing a way to *automatically* retune the VFO frequency to match >>>> that of a received signal. How does this work? >>>> >>>> When CWT is turned on, firmware treats the SPOT switch as AUTO-SPOT. >>>> The DSP analyzes the incoming signal, and with a bit of processing, >>>> determines its exact audio pitch. From there all that's needed is a >>>> bit of math to offset the VFO to match this pitch to the CW sidetone. >>>> >>>> There's another subtlety, though. Since a CW signal is generally >>>> being keyed on and off, the CWT algorithm has to ensure that it >>>> doesn't "take off," chasing a signal that's not there. To avoid this, >>>> we keep track of the energy in the passband, and slew the VFO >>>> incrementally over an average of about 0.5 second, moving only when >>>> the target signal is present. >>>> >>>> How to Use Auto-Spot >>>> >>>> I encourage you to give the auto-spot feature a try. It's best to >>>> start with a fairly narrow passband, say 400-600 Hz; narrower if >>>> there's a lot of QRM. Find a signal, turn on CWT, then tap SPOT to >>>> tune it in. A second tap of SPOT may get even closer, especially if >>>> there's a lot of band noise. >>>> >>>> Auto-spot can also be used in Elecraft's PSK-D mode, i.e. for >>>> PSK31/PSK63. As with CW mode, just turn on CWT, tune in a prospective >>>> signal, and tap SPOT. Since PSK auto-decoding requires very accurate >>>> tuning, it's best to set the filter bandwidth to 50 Hz, then let >>>> auto-spot dial things in down to the last 2 or 3 Hz. If you have text >>>> decode turned on, you should start seeing text characters scroll by >>>> after auto-tuning has completed. Tapping a second time or fine-tuning >>>> the VFO a bit in 1 Hz steps may improve copy. >>>> >>>> 73, >>>> Wayne >>>> N6KR >>>> >>> >>> __._,_.___ >>> ------------------------------------------------------------------------ >>> Posted by: Mel Snyder <[hidden email]> >>> ------------------------------------------------------------------------ >>> Reply via web post >>> <https://groups.yahoo.com/neo/groups/KX3/conversations/messages/65003;_ylc=X3oDMTJyOGZ0NTd0BF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2NTAwMwRzZWMDZnRyBHNsawNycGx5BHN0aW1lAzE1NDgxODMyMDE-?act=reply&messageNum=65003> >>> ? Reply to sender >>> <mailto:[hidden email]?subject=Re%3A%20%5BKX3%5D%20Auto-spot%2C%20tuning%20aids%2C%20and%20the%20arcane%20history%20of%20CW%20pitch-matching> >>> ? Reply to group >>> <mailto:[hidden email]?subject=Re%3A%20%5BKX3%5D%20Auto-spot%2C%20tuning%20aids%2C%20and%20the%20arcane%20history%20of%20CW%20pitch-matching> >>> ? 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Terms >>> of Use <https://info.yahoo.com/legal/us/yahoo/utos/terms/> >>> >>> SPONSORED LINKS >>> . >>> >>> __,_._,___ >> >> >> ------------------------------ >> >> Message: 14 >> Date: Tue, 22 Jan 2019 13:45:13 -0700 >> From: "Dave New, N8SBE" <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: >> <[hidden email]> >> >> Content-Type: text/plain; charset="utf-8" >> >> When I upgraded from my K3 to a K3s, I took the opportunity to order a >> 10 MHz Ref In option. >> >> I finally got around to hooking it up to a Leo Bodnar GPS receiver I >> picked up at Dayton a year ago, and now the K3s is rock solid spot on >> frequency. >> >> Don't know how i did without it all these years... >> >> 73, >> >> -- Dave, N8SBE >> >> -------- Original Message -------- >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> From: Bob McGraw K4TAX <[hidden email]> >> Date: Tue, January 22, 2019 3:14 pm >> To: [hidden email] >> >> Another trick which works well. Tune to a WWV frequency in CW mode. >> Press SPOT and the radio will jump on the exact carrier frequency. The >> SPOT function can pull on to the WWV frequency as far away as about 100 >> Hz. Once the radio has resolved SPOT, the readout / display is the >> frequency of WWV +/- the error in Hz. Thus the readout of 9.999.992 is >> indicating being 8 Hz low. >> >> From a cold start, FP being 19?C, I find -8 Hz error on 10 MHz WWV. >> After about 15 minutes the FP is 25?C and the error is -1 Hz. I've >> tweaked the REF CAL such that after 1/2 hr. in receive tuning to WWV >> from both higher and lower will produce a reading of 10.000.000. Will >> all stations pse QNZ QNN. >> >> 73 >> >> Bob, K4TAX >> >> >> >> >> >> ------------------------------ >> >> Message: 15 >> Date: Tue, 22 Jan 2019 13:47:04 -0700 >> From: "Dave New, N8SBE" <[hidden email]> >> To: "Elecraft Reflector" <[hidden email]> >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: >> <[hidden email]> >> >> Content-Type: text/plain; charset="utf-8" >> >> I'm a great fan of using the auto-spot feature, and love to show it off >> to all shack visitors, as an example of yet another reason they need to >> upgrade to Elecraft, from whatever boat anchor they are still using... >> >> 73, >> >> -- Dave, N8SBE >> >> >> ------------------------------ >> >> Message: 16 >> Date: Tue, 22 Jan 2019 12:57:16 -0800 >> From: Wayne Burdick <[hidden email]> >> To: Elecraft <[hidden email]> >> Cc: KX3 <[hidden email]> >> Subject: [Elecraft] Urban stealth HF: Inside-the-backpack loop >> antenna? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >> I?ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 antenna and a dragged counterpoise. In wide open spaces it?s a blast. But urban settings with dogs, wire-eating cacti and overzealous Neighborhood Watchers can distract from one?s radio experience. >> >> So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course. OTOH, we?re talking about HF. A cellphone by your ear is probably worse. >> >> Any other antenna suggestions? >> >> Wayne >> N6KR >> >> >> >> ---- >> elecraft.com >> >> ------------------------------ >> >> Message: 17 >> Date: Tue, 22 Jan 2019 20:57:26 +0000 >> From: Andy Durbin <[hidden email]> >> To: "[hidden email]" <[hidden email]> >> Subject: [Elecraft] Auto-spot, tuning aids, and the arcane history of >> CW pitch-matching >> Message-ID: >> <[hidden email]> >> >> Content-Type: text/plain; charset="iso-8859-1" >> >> "Find a signal, turn on CWT, then tap SPOT to tune it in. A second tap of SPOT may get even closer, especially if there's a lot of band noise." >> >> and >> >> "I'm a great fan of using the auto-spot feature, and love to show it off to all shack visitors, as an example of yet another reason they need to upgrade to Elecraft," >> >> I must be missing something. How is this 2 step activated spot feature better than a single press of Kenwood's CWT? I often use CWT on my TS-590S but almost always with a spit or XIT offset (I didn't know that was a secret). >> >> Andy, k3wyc >> >> >> ------------------------------ >> >> Message: 18 >> Date: Tue, 22 Jan 2019 14:01:33 -0700 >> From: Wes <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >> Are you serious? >> >> Wes? N7WS >> >>> On 1/22/2019 1:45 PM, Dave New, N8SBE wrote: >>> Don't know how i did without it all these years... >>> >>> 73, >>> >>> -- Dave, N8SBE >>> >> >> >> >> ------------------------------ >> >> Message: 19 >> Date: Tue, 22 Jan 2019 14:01:52 -0700 (MST) >> From: ab2tc <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=us-ascii >> >> Hi all, >> >> Agreed; the problem can easily be solved in analog radios without frequency >> synthesis by offsetting the BFO frequency by those 700Hz or so in transmit. >> In down conversion machines with a single IF in the 8-9MHz range that could >> easily be done by pulling the BFO crystal. The Drake TR4 undoubtedly worked >> this way. I bought my first transceiver in 1969 (I think), a Yaesu FT-200, I >> think it was called in the US. In Europe it was sold as Sommerkamp FT-250. >> As the Drake TR4 it was down conversion with a single 9MHz IF and worked CW >> by pulling the BFO crystal into the passband of the 9MHz crystal filter on >> transmit. >> >> Another technical solution, which was used in the Collins KWM2 (and probably >> KWM1) was to keep the balanced (de)modulator balanced and inject an audio >> tone into it on transmit. Clearly the spectral purity of the CW signal would >> be less than ideal in this case, but I am not sure if FCC type approval was >> needed in those days. Nor am I sure what the the FCC spec for "inband" (read >> close in) spurs would be. >> >> AB2TC - Knut >> >> >> n0uk wrote >>> The transceive problem didn't seem to exist on any older non-synthesized >>> transceiver that I have used, including FT-101 series, TS-520/820 and >>> later, KW Electronics KW-2000E. these were all '70s era transceivers. >>> >>> >>> >>> -- >>> 73 Chris Cox, N0UK, G4JEC >> >>> chrisc@ >> >>> >>> _ >>> <snip> >> >> >> >> >> >> -- >> Sent from: http://elecraft.365791.n2.nabble.com/ >> >> >> ------------------------------ >> >> Message: 20 >> Date: Tue, 22 Jan 2019 14:32:47 -0700 >> From: Mark Goldberg <[hidden email]> >> To: Wayne Burdick <[hidden email]> >> Cc: Elecraft <[hidden email]>, KX3 <[hidden email]> >> Subject: Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack >> loop antenna? >> Message-ID: >> <CAKn+a3tdcK4Gk+SLSuyEP+2CR+nFK+qRtnVZWecrf0qDoh=[hidden email]> >> Content-Type: text/plain; charset="UTF-8" >> >> I would expect any high Q antenna like a loop would be detuned by any >> movement or any metal you pass by. One more reason to support automatic >> mobile screwdriver / mag loop antenna tuning on the KX series. >> A flag on a backpack would be more or less ignored. Just put a flag on the >> top of the AX1. Counterpoise is an issue though. Maybe a short one down >> your leg? >> >> Now, if you dressed as a homeless or otherwise distressed person, lots of >> weird things are possible, tinfoil hat with a big flag, dragged wire >> disguised as one of those fake animals on a leash, etc. The weirder, the >> more people will ignore you. >> >> Hopefully taken in the spirit of which it is posted. >> >> 73, >> >> Mark >> W7MLG >> >> >> On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick [hidden email] [KX3] < >> [hidden email]> wrote: >> >>> >>> >>> I?ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 >>> antenna and a dragged counterpoise. In wide open spaces it?s a blast. But >>> urban settings with dogs, wire-eating cacti and overzealous Neighborhood >>> Watchers can distract from one?s radio experience. >>> >>> So, just for grins, I?d like to try something completely incognerdo: no >>> visible antenna. A small remotely tuned loop (say 12? diameter) would seem >>> to be the best choice, as it would fit entirely inside a small backpack. It >>> could have modest efficiency while not requiring a counterpoise wire. >>> Rigid 1? copper pipe formed in a square would be convenient to deploy. >>> >>> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, >>> of course. OTOH, we?re talking about HF. A cellphone by your ear is >>> probably worse. >>> >>> Any other antenna suggestions? >>> >>> Wayne >>> N6KR >>> >>> >>> >>> ---- >>> elecraft.com >>> >>> __._,_.___ >>> ------------------------------ >>> Posted by: Wayne Burdick <[hidden email]> >>> ------------------------------ >>> Reply via web post >>> <https://groups.yahoo.com/neo/groups/KX3/conversations/messages/65005;_ylc=X3oDMTJyOWdpcW0yBF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2NTAwNQRzZWMDZnRyBHNsawNycGx5BHN0aW1lAzE1NDgxOTA2NDA-?act=reply&messageNum=65005> >>> ? Reply to sender >>> <[hidden email]?subject=Re%3A%20Urban%20stealth%20HF%3A%20Inside-the-backpack%20loop%20antenna%3F> >>> ? Reply to group >>> <[hidden email]?subject=Re%3A%20Urban%20stealth%20HF%3A%20Inside-the-backpack%20loop%20antenna%3F> >>> ? Start a New Topic >>> <https://groups.yahoo.com/neo/groups/KX3/conversations/newtopic;_ylc=X3oDMTJmZW4xYXF1BF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNudHBjBHN0aW1lAzE1NDgxOTA2NDA-> >>> ? Messages in this topic >>> <https://groups.yahoo.com/neo/groups/KX3/conversations/topics/65005;_ylc=X3oDMTM3cGU2OTN1BF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2NTAwNQRzZWMDZnRyBHNsawN2dHBjBHN0aW1lAzE1NDgxOTA2NDAEdHBjSWQDNjUwMDU-> >>> (1) >>> ------------------------------ >>> Have you tried the highest rated email app? <https://yho.com/1wwmgg> >>> With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email >>> app on the market. What are you waiting for? Now you can access all your >>> inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email >>> again with 1000GB of free cloud storage. >>> ------------------------------ >>> Visit Your Group >>> <https://groups.yahoo.com/neo/groups/KX3/info;_ylc=X3oDMTJmcmZybjN1BF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDdnRsBHNsawN2Z2hwBHN0aW1lAzE1NDgxOTA2NDA-> >>> >>> >>> [image: Yahoo! Groups] >>> <https://groups.yahoo.com/neo;_ylc=X3oDMTJlZDVicHB1BF9TAzk3NDc2NTkwBGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTU0ODE5MDY0MA--> >>> ? Privacy <https://info.yahoo.com/privacy/us/yahoo/groups/details.html> ? >>> Unsubscribe <[hidden email]?subject=Unsubscribe> ? Terms >>> of Use <https://info.yahoo.com/legal/us/yahoo/utos/terms/> >>> >>> SPONSORED LINKS >>> . >>> >>> __,_._,___ >>> >> >> >> ------------------------------ >> >> Message: 21 >> Date: Tue, 22 Jan 2019 13:38:35 -0800 >> From: Steve Sergeant <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop >> antenna? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8 >> >>> On 1/22/19 12:57 PM, Wayne Burdick wrote: >>> A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> [Deletia] >> >>> Any other antenna suggestions? >> >> I tried a 52ft 26ga wire J-pole/Zep on the line of a 5ft parafoil kite, >> with 50ft of kite line above the antenna, and another 50' of RG-174 >> between the antenna and the radio. >> >> I'll grant that this is not as invisible as your idea. But I felt >> reasonably inconspicuous working SSB with cell-phone type earbuds >> (w/mic), and the KX2 in an open waist-pack, out in an open field of a >> large city park. People just thought I was on a phone call while flying >> the kite. It helped that there were several other kite-fliers in the >> park that day. >> >> It was not a particularly good day for propagation, but I did work Las >> Vegas and Spokane from Silicon Valley with under 10W on 20m. >> >> >> >> >> ------------------------------ >> >> Message: 22 >> Date: Tue, 22 Jan 2019 16:40:04 -0500 >> From: Michael Blake <[hidden email]> >> To: Mark Goldberg <[hidden email]> >> Cc: Elecraft Reflector <[hidden email]>, KX3 >> <[hidden email]> >> Subject: Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack >> loop antenna? >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=us-ascii >> >> Mark (W7MLG), It is scary how perfectly sane and normal your suggestions sound to me :) >> >> Very 73 - Mike - K9JRI >> >> >> >> >> >> >> >>> On Jan 22, 2019, at 4:32 PM, Mark Goldberg <[hidden email]> wrote: >>> >>> I would expect any high Q antenna like a loop would be detuned by any >>> movement or any metal you pass by. One more reason to support automatic >>> mobile screwdriver / mag loop antenna tuning on the KX series. >>> A flag on a backpack would be more or less ignored. Just put a flag on the >>> top of the AX1. Counterpoise is an issue though. Maybe a short one down >>> your leg? >>> >>> Now, if you dressed as a homeless or otherwise distressed person, lots of >>> weird things are possible, tinfoil hat with a big flag, dragged wire >>> disguised as one of those fake animals on a leash, etc. The weirder, the >>> more people will ignore you. >>> >>> Hopefully taken in the spirit of which it is posted. >>> >>> 73, >>> >>> Mark >>> W7MLG >>> >>> >>> On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick [hidden email] [KX3] < >>> [hidden email]> wrote: >>> >> >> >> >> ------------------------------ >> >> Message: 23 >> Date: Tue, 22 Jan 2019 15:41:14 -0600 >> From: K9MA <[hidden email]> >> To: [hidden email] >> Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history >> of CW pitch-matching >> Message-ID: <[hidden email]> >> Content-Type: text/plain; charset=utf-8; format=flowed >> >>> On 1/22/2019 14:14, Bob McGraw K4TAX wrote: >>> Another trick which works well.?? Tune to a WWV frequency in CW mode. >>> Press SPOT and the radio will jump on the exact carrier frequency. >> >> You can do the same thing, of course, by listening to the beat between >> the sidetone and the carrier. I was able to get 3 Hz closer that way, >> within the 1 Hz tuning resolution. 3 Hz is close enough, though. >> >> When listening for the beats, you have to match the volume of the >> sidetone and carrier, or you won't hear them. You don't need a musical >> ear, just a functioning one. >> >> 73, >> >> Scott K9MA >> >> -- >> Scott K9MA >> >> [hidden email] >> >> >> >> ------------------------------ >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> http://mailman.qth.net/mailman/listinfo/elecraft >> You must be a subscriber to post. >> Elecraft web page: http://www.elecraft.com >> >> End of Elecraft Digest, Vol 177, Issue 36 >> ***************************************** >> > > > > ------------------------------ > > Message: 10 > Date: Tue, 22 Jan 2019 17:26:41 -0600 > From: Robert Rennard <[hidden email]> > To: "[hidden email]" <[hidden email]> > Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history > of CW pitch-matching > Message-ID: <[hidden email]> > Content-Type: text/plain; charset="utf-8" > > For N1MM, use the up and down arrow keys to get close in S&P operation and then press F11 to zero beat - > > F11 Z B,{CATA1ASC SWT42;} > > If it is a dense pile, a little XIT offset is a big help. > > 73, > > Bob R > > > ------------------------------ > > Message: 11 > Date: Tue, 22 Jan 2019 17:06:17 -0800 > From: Bill Frantz <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history > of CW pitch-matching > Message-ID: > <[hidden email]> > > Content-Type: text/plain; charset=UTF-8; format=flowed > > I must admit, most of my CW tuning is done with the P3/SVGA and > getting the pitch "right" in my earphones. (With RTTY, I can get > very close to the correct pitch by ear. Then I used the crossed > loop tuning aid for the final few Hz.) > > 73 Bill AE6JV > > --------------------------------------------------------------------------- > Bill Frantz | "I wish there was a knob on the TV to turn > up the > 408-356-8506 | intelligence. There's a knob called > "brightness", but > www.pwpconsult.com | it doesn't work. -- Gallagher > > > > ------------------------------ > > Message: 12 > Date: Tue, 22 Jan 2019 17:17:03 -0800 > From: kevinr <[hidden email]> > To: [hidden email] > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8; format=flowed > > There may be other options.? A serpentine pattern fed at the center > could give you enough length for a 10 m or larger dipole. I've seen > serpentine F antennas on printed circuit boards.? I've also seen spiral > patterns used so I know they work to some extent. > > If a dipole cut for 14 MHz is ~ 400 inches long it would take 11 up and > down segments of 36" each to stuff it inside your pack. I'm sure the > serpentine factor will change the length needed but with a bit of > tweaking this could work. > > Or feed it at one end for a 40 meter monopole (a counterpoise could be > woven into the pack). > > ?? 73 & GL, > > ?????? Kevin.? KD5ONS > > - > > >> On 1/22/19 12:57 PM, Wayne Burdick wrote: >> I?ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 antenna and a dragged counterpoise. In wide open spaces it?s a blast. But urban settings with dogs, wire-eating cacti and overzealous Neighborhood Watchers can distract from one?s radio experience. >> >> So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course. OTOH, we?re talking about HF. A cellphone by your ear is probably worse. >> >> Any other antenna suggestions? >> >> Wayne >> N6KR >> >> >> >> ---- >> elecraft.com >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ------------------------------ > > Message: 13 > Date: Tue, 22 Jan 2019 17:19:52 -0800 > From: Joan <[hidden email]> > To: Wayne Burdick <[hidden email]> > Cc: Elecraft Reflector <[hidden email]>, > "[hidden email]" <[hidden email]> > Subject: Re: [Elecraft] Auto-spot, tuning aids, and the arcane history > of CW pitch-matching > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Thanks, Wayne! This is one of the best entries into these threads I?ve ever read. And, yes, I've experimented with Auto Spot in CWT mode. > > And: > ?the Audio Peaking Filter (APF), ?provides a 30-Hz bandwidth at -3 dB, but broad skirts, preventing ringing from occurring. As our customers will attest, APF works like magic on weak signals obscured by noise?? To which I also attest! ^_^ > > And, the VFO and IF passband tracking exactly on the user setable CW sidetone (A 440, in my case) is one of the main things which made me fall in love with Elecraft. > > 72 de KX2CW .. > ~Joan > > Darmok and Jalad at Tanagra, said Piglet. > Shaka, when the walls fell, said Pooh. > >> On Jan 21, 2019, at 21:09, Wayne Burdick <[hidden email]> wrote: >> >> Elecraft's auto-spot and CWT features -- available on the K3/K3S/KX2/KX3 -- are very useful tools for CW operators, especially those not experienced in pitch-matching. Here's a bit of history on where these features came from and how they work. >> >> >> CW Spotting History >> >> When a station finishes a CQ in CW mode, the operator faces the challenge of copying someone who's calling back. Callers may be weak or obscured by QRM; the op can usually deal with both problems by narrowing the filter passband. However, callers may also be off frequency. A calling station may be using a wide filter passband themselves, not attempting to carefully match their VFO frequency to that of the CQing station. The result may be no QSO, even when propagation is excellent. >> >> In the Days of Yore, a frequency offset between stations didn't always matter. Sometimes both stations used crystal-controlled transmitters, so operators had to patient tune around after calling CQ. >> >> As a 14-year-old novice I embraced this operating style for a year or so, armed with a dozen or so crusty FT-243 crystals for my Heath HW-16. I nearly wore out the socket swapping them in and out. After calling CQ, it was not unusual to find a caller 30 or more kHz away! (Away from "where" was a poorly answered question, as my Hallicrafters receiver dial wasn't exactly digital.) >> >> Fortunately I soon acquired an outboard VFO, a life-changing addition to my station. Jealous friends doubled up on their paper routes to pay for their own. Girls suddenly paid more attention to me. >> >> These days virtually everyone has a VFO, along with the expectation that they won't have to tune theirs very far, if at all, to tune you in. Not only that, they're stable and well calibrated, not like the beasts we had to skillfully tame. Progress! >> >> >> Manual Spotting (SPOT switch) >> >> Once I had a VFO I quickly learned to do *manual* pitch matching. Older rigs did't provide a way to do that explicitly, so you'd improvise. Basically, you had to coerce a very weak signal out of your own transmitter, say by turning on only the driver, then tune the transmit VFO until you could hear your signal on your own receiver -- superimposed on the calling station, at the same pitch. This is what we call spotting. >> >> Of course spotting is a lot more convenient these days, as many rigs include a SPOT switch. This function is easy for a modern transceiver designer to add, because the radio's firmware is quite capable of turning on only the CW sidetone without transmitting. >> >> That is the purpose of the SPOT switch on all Elecraft transceivers. Tap SPOT, and you'll hear your sidetone pitch. Most people can do a good job of adjusting the VFO such that the CQing station's pitch matches that of the SPOT tone. This ensures that when you call them, you'll be close to their own frequency. >> >> >> Tuning Aids: Filtering (APF), PLL (NE567), and Spectral (CWT) >> >> Since not everyone has an inherent musical ear, various hardware-enhanced means of tuning in CW signals have been developed. >> >> The simplest method is to just narrow your receiver passband so much that, if you can hear a station calling CQ at all, you're guaranteed to be "right on top of him." This assumes that your transceiver enforces alignment between its transmit and receive pitch...true of all Elecraft gear. >> >> Narrow filtering has gone through decades of evolution. Some filters were based on op-amps (active filters), while others were based on LC filtering, conscripting humongous toroidal cores scavenged from telco equipment. I acquired my stash of these from a haphazard mound of old switching racks, decaying in an abandoned aircraft hanger on the Bermuda U.S. Navy base. (That irresistible junk pile was also a mother load of TO5 transistors, multi-pound electrolytic capacitors, and tetanus, but that's another story.) Typically the toroids were 88 millihenries -- a huge value for a high-Q inductor, permitting resonance in the low audio range. >> >> Later, such filters migrated to digital signal processing, in the form of switched-capacitor ICs or DSPs. You can still buy these switched-capacitor chips, like the MF10, from various sources. It's instructive to roll your own tunable filter, just for fun. >> >> Whether passive or active, the goal of filtering is typically to achieve a narrow passband, say 250 Hz or less. With DSP, nearly perfect filters with "brick wall" passbands can be created. But these have the disadvantage of ringing like a bell when pinged by a CW signal or noise, making copy difficult. >> >> One solution incorporated into the K-line and KX-line is the Audio Peaking Filter (APF), which provides a 30-Hz bandwidth at -3 dB, but broad skirts, preventing ringing from occurring. As our customers will attest, APF works like magic on weak signals obscured by noise. >> >> Another forerunner to DSP techniques was the audio phase-locked-loop, using inexpensive ICs like the legendary LM567. When locked on a signal that matched its center frequency, the circuit would turn on an LED, alerting the operator that the VFO was now properly tuned. >> >> With the DSPs in our K-line and KX-line radios, we can provide a much more powerful tool: CWT, or "CW Tuning Aid." When enabled, CWT turns the upper portion of the rig's S-meter into something of a mini spectrum analyzer. The pitch of the strongest signal in the passband is analyzed by the DSP, then represented as a single segment of the bar graph. For CWT-enhanced manual spotting, the operator simply tunes the VFO slowly until the center CWT segment is flashing along with the keyed signal. >> >> Manual tuning with CWT can also be used in FSK-D and PSK-D modes as described in the owner's manual. >> >> >> Closing the Loop: Auto-Spotting (SPOT + CWT) >> >> The Elecraft K3/K3S/KX2/KX3 take CW tuning another step forward by providing a way to *automatically* retune the VFO frequency to match that of a received signal. How does this work? >> >> When CWT is turned on, firmware treats the SPOT switch as AUTO-SPOT. The DSP analyzes the incoming signal, and with a bit of processing, determines its exact audio pitch. From there all that's needed is a bit of math to offset the VFO to match this pitch to the CW sidetone. >> >> There's another subtlety, though. Since a CW signal is generally being keyed on and off, the CWT algorithm has to ensure that it doesn't "take off," chasing a signal that's not there. To avoid this, we keep track of the energy in the passband, and slew the VFO incrementally over an average of about 0.5 second, moving only when the target signal is present. >> >> >> How to Use Auto-Spot >> >> I encourage you to give the auto-spot feature a try. It's best to start with a fairly narrow passband, say 400-600 Hz; narrower if there's a lot of QRM. Find a signal, turn on CWT, then tap SPOT to tune it in. A second tap of SPOT may get even closer, especially if there's a lot of band noise. >> >> Auto-spot can also be used in Elecraft's PSK-D mode, i.e. for PSK31/PSK63. As with CW mode, just turn on CWT, tune in a prospective signal, and tap SPOT. Since PSK auto-decoding requires very accurate tuning, it's best to set the filter bandwidth to 50 Hz, then let auto-spot dial things in down to the last 2 or 3 Hz. If you have text decode turned on, you should start seeing text characters scroll by after auto-tuning has completed. Tapping a second time or fine-tuning the VFO a bit in 1 Hz steps may improve copy. >> >> 73, >> Wayne >> N6KR >> >> >> >> >> > > > ------------------------------ > > Message: 14 > Date: Tue, 22 Jan 2019 19:51:01 -0600 > From: Michael Chowning <[hidden email]> > To: Wayne Burdick <[hidden email]> > Cc: Elecraft <[hidden email]>, KX3 <[hidden email]> > Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop > antenna? > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=utf-8 > > Just for grins, look into this link, from Ohio State University from back in 2011! > https://news.osu.edu/antennas-in-your-clothes--new-design-could-pave-the-way/ <https://news.osu.edu/antennas-in-your-clothes--new-design-could-pave-the-way/> > There are also articles more recently (2018) on electronics in one?s clothes, and computers in one?s clothes in this website?s news as well. > Mike, N8TTR > >> On Jan 22, 2019, at 2:57 PM, Wayne Burdick <[hidden email]> wrote: >> >> I?ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 antenna and a dragged counterpoise. In wide open spaces it?s a blast. But urban settings with dogs, wire-eating cacti and overzealous Neighborhood Watchers can distract from one?s radio experience. >> >> So, just for grins, I?d like to try something completely incognerdo: no visible antenna. A small remotely tuned loop (say 12? diameter) would seem to be the best choice, as it would fit entirely inside a small backpack. It could have modest efficiency while not requiring a counterpoise wire. Rigid 1? copper pipe formed in a square would be convenient to deploy. >> >> The loop would be only 6 to 8? from soft tissue, so you?d want to run QRP, of course. OTOH, we?re talking about HF. A cellphone by your ear is probably worse. >> >> Any other antenna suggestions? >> >> Wayne >> N6KR >> >> >> >> ---- >> elecraft.com >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > > ------------------------------ > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > http://mailman.qth.net/mailman/listinfo/elecraft > You must be a subscriber to post. > Elecraft web page: http://www.elecraft.com > > End of Elecraft Digest, Vol 177, Issue 37 > ***************************************** Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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This thread brings back memories of an antenna I once used mobile for a
weekend. I was headed to a hamfest in Phoenix from Tucson back when two-meter AM was still in vogue. Should give you and idea of time-frame. I owned a Heathkit "Twoer" and a 1956 Corvette (wish I had this back---the car---not the Heathkit). In those days BC stations still used "transcription discs" that could be obtained if you knew the right person at a station. These were 16" diameter aluminum discs, normally covered in lacquer that when stripped yielded a beautiful 2-meter ground plane. In the C1 Corvette the soft top was folded and stowed under a hinged hatch behind the seats. When it was up, a couple of toggle clamps secured the rear of the soft top, to the hatch. These clamps created a hole in the hatch through which the vertical whip could be passed. So the hatch could be opened, the disc placed in the storage compartment with the whip sticking through the hatch after it was closed. All of this was fiberglass so the antenna was mounted "in the clear" albeit pretty close to ground. With this rig, sitting in a friend's driveway in Tempe, I was able to work another friend back in Tucson over a path once described in QST's "World above 50 Mc" as "difficult." Wes N7WS ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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