OCF antennas
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I have found the easiest single antenna to utilize is the OCF - it is
coax fed, making easy routing of the feedline. The K3's ATU handles it fine (as does my TS-480 SAT). Dimensions for the version I use: 88' on one leg and 44 ' on the other leg. For a center insulator/balun I use the http://www.balundesigns.com/servlet/the-75/OCF-balun-4-cln-1/Detail I use #12 stranded insulated wire (not house wire) available from any of several ham distributors. Works FB for what I do with it, which is mostly rag chew on 40 and 75 SSB. However, I have used on the higher bands with good success also. The pattern does get somewhat directional as you move up from the primary design frequency. If you have room for a couple of them at right angles - that might be of an advantage. Bill W2BLC ______________________________________________________________ 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 |
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On Fri, Mar 9, 2012 at 3:50 PM, Bill <[hidden email]> wrote:
> I have found the easiest single antenna to utilize is the OCF... ============ The OCF has advantages and can work very well. I have had good success with several versions, and in fact published an article in QST about one such setup (March 2006). It's important to note that any OCF antenna will have common-mode current flowing on the feedline, which will produce RF in the shack. With modest power this is usually not a problem, but as power goes up, the effects get worse. If the antenna is coax-fed, the common-mode RF can be choked off with a 1:1 balun or an isolator. If it's fed with balanced line, it should go to a balun and thence to a coax link to the transmitter, and that coax should have provisions for choking the RF. The cold side of the isolator should be grounded to a good RF ground (i.e. not just a ground rod or water pipe -- ideally, a counterpoise or radial system, or other really good RF sink). The feedline will radiate, and this should be included in your EZNEC or other model when determining the radiation pattern. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 ______________________________________________________________ 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 |
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In reply to this post by Bill Clarke
When I got on the air at this QTH in 2006 I installed a Carolina Windom from Radio Works. It is about 40 feet high and fed with a short piece of RG8X. I thought it a great antenna and worked some contests and a lot of DX. Later, I installed a 30 foot vertical with one radial and found it much superior on 40 and 15. Then I installed a 65 ft tower with a 3 element SteppIR 30/40 and worked DXCC in 31 days. Then I installed a 40 and 80 inverted Vee fed with a common coax. Then I installed an Inverted L with an 80 meter trap for 80 and 160. The Carolina Windom is still up, but it is not the preferred antenna for any band at any distance. I find that the OCF is the best antenna only if it is your only antenna, but I have not compared it to a Buddy Pole.
Willis 'Cookie' Cooke K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart ________________________________ From: Bill <[hidden email]> To: [hidden email] Sent: Friday, March 9, 2012 3:50 PM Subject: [Elecraft] OCF antennas I have found the easiest single antenna to utilize is the OCF - it is coax fed, making easy routing of the feedline. The K3's ATU handles it fine (as does my TS-480 SAT). Dimensions for the version I use: 88' on one leg and 44 ' on the other leg. For a center insulator/balun I use the http://www.balundesigns.com/servlet/the-75/OCF-balun-4-cln-1/Detail I use #12 stranded insulated wire (not house wire) available from any of several ham distributors. Works FB for what I do with it, which is mostly rag chew on 40 and 75 SSB. However, I have used on the higher bands with good success also. The pattern does get somewhat directional as you move up from the primary design frequency. If you have room for a couple of them at right angles - that might be of an advantage. Bill W2BLC ______________________________________________________________ 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 ______________________________________________________________ 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 |
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In reply to this post by Tony Estep
I didn't mention the RF on the feedline, as I am in the habit of choking
all feedlines coming into the house. Easy: 10 turns of coax 6 or 8 inches diameter and cable tied just outside the wall - prior to the grounding panels. Use one of the "flex" type cables and it will be easy. Bill W2BLC ______________________________________________________________ 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 |
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In reply to this post by Bill Clarke
On 3/9/2012 1:50 PM, Bill wrote:
> I have found the easiest single antenna to utilize is the OCF Off center fed antennas are a recipe for noise pickup on the feedline. While a good common mode choke can help, off-center feed can also burn up a common mode choke if you're running much power. Bottom line -- off-center-fed antennas are a bad idea. 73, Jim Brown K9YC ______________________________________________________________ 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 |
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In reply to this post by Cookie
On 3/9/2012 2:14 PM, WILLIS COOKE wrote:
> When I got on the air at this QTH in 2006 I installed a Carolina > Windom from Radio Works. It is about 40 feet high and fed with a > short piece of RG8X. I thought it a great antenna and worked some > contests and a lot of DX. Later, I installed a 30 foot vertical with > one radial and found it much superior on 40 and 15. Then I installed > a 65 ft tower with a 3 element SteppIR 30/40 and worked DXCC in 31 > days. Then I installed a 40 and 80 inverted Vee fed with a common > coax. Then I installed an Inverted L with an 80 meter trap for 80 > and 160. The Carolina Windom is still up, but it is not the > preferred antenna for any band at any distance. I find that the OCF > is the best antenna only if it is your only antenna, but I have not > compared it to a Buddy Pole. If you keep installing antennas and don't take any down, will you ever have enough? The Buddipole, using the horizontal loaded dipole "recipe" in the documentation, is an OCF configuration to improve the match, and the line has current on it. Not a problem for my K2 or KX1 at 5 or 3W. Maybe not true for 100+ watts. I've been using a center-loaded "recipe" with radials made from the longer BP extendable elements. Seems to work better than the horizontal configs. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org ______________________________________________________________ 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 |
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In reply to this post by Jim Brown-10
Well said Jim,
There is no way to obtain equal and opposite currents on the feedline with an offset fed antenna - they are a sure recipe for RF-in-the-shack. As much acclaim as the Carolina Windom gets, that fact is still true, one just cannot run high power with such an antenna - at low power the RF levels may be tolerable, but at high power, they can wreak havoc in the shack with RF all over everything. 73, Don W3FPR On 3/9/2012 5:58 PM, Jim Brown wrote: > On 3/9/2012 1:50 PM, Bill wrote: >> I have found the easiest single antenna to utilize is the OCF > Off center fed antennas are a recipe for noise pickup on the feedline. > While a good common mode choke can help, off-center feed can also burn > up a common mode choke if you're running much power. > > Bottom line -- off-center-fed antennas are a bad idea. > > 73, Jim Brown K9YC > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > 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 |
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OCF antennas, under miscellaneous names, have been working fine, just fine,
just about as long as radio. We just have 50 ohm coax and SWR meters on the brain, and have a terrible time seeing outside the rather narrow 50 ohm coax/low SWR box. And we're boxing ourselves in further with single-Z transistor amps that fall off the table and go blurg off 50 ohm Z. (Whatever happened to I-don't-give-a-d*mn-about-SWR tetrode amps, like 807's, 6146's and 4CX1000A? I worked DXCC and had a BPL medallion before I ever had an SWR meter. Just can't understand how I managed. :>) Oops, forgot, Alpha's 8410 monster uses a pair of those 4CX1000A's, and it really doesn't give a d*mn about swr, either.) One famous (back in the day) OCF oldie is the ORIGINAL Windom, the single wire feed version Windom, decidedly an OCF. It's only a single band antenna, but you feed the single up wire with a 9:1 auto transformer at the ground against what can be minimal to almost non-existent radials since the Z is 400-450 ohms at the bottom of the feed wire, and it takes an absolute totally ugly resistive stinking ground connection to mess it up. Very useful on field days. It's supreme mechanical advantage is that the single wire feedline can be a single stranded #18 wire, even for QRO, far and away lighter than any other feedline. This means you can get what amounts to weird-fed 80 and 40 dipoles WAY up there, that are only supported at the ends, without all the weight issues. How does it work? It USES the common mode feedline induction from the long side of the OCF dipole, to work against the opposite phase coming from the feed (it's the same piece of wire). If you monkey with it a bit in a model, you can pick a connection point for the single wire feed where the current is flat all the way up, no standing waves, which means it is radiating very little from the feed. Or you can move it around a bit and PICK the amount of vertical radiation you would like to mix in. But that changes the feed Z. Disadvantage?, you can't buy the 9:1 autotransformer off the shelf any old where and you may have to roll your own. OCF antennas in general CAN be tamed at QRO, but one needs to know to do it. Just running a feedline to it and putting power on it WILL get you RF in the shack as others have opined. Using an isolation device at the antenna end only gets PART of the problem. The other part is that the now isolated feed line is STILL off center approaching the OCF antenna. This in and of itself will cause the "isolated" antenna to induce current on the feedline shield, because the long part of the antenna at right angles to the feed line induces more current to the feedline than the opposite phase current from the short part. This is not a problem in a dipole where ordinary (and fairly weak) devices pull off any needed isolation. "Weak" isolating devices will not cut it for OCF. A SECOND isolation device down the coax a bit, that breaks up the coax shield into a non-resonant length next to the antenna, will prevent the RF in the shack AND it will clean up the pattern to what the models say it should be, usually a performance plus. Care needs to be taken to the suitability of the isolation devices for the two uses. Some antennas use the second device as the ONLY device and deliberately use a length of the shield as a common mode radiator. No advertising needed. If you suspect that cleaning up all this tends to work against multiband use and makes doing OCF well a chess game, you suspect correctly. Portable use at 100 watts without all the isolators will work just fine. OCF's have been a mainstay of field day use as long as that has been going on. My K2/10, with the built-in ATU and the itty bitty balun love those antennas and never had the first problem. 73, Guy. On Fri, Mar 9, 2012 at 7:09 PM, Don Wilhelm <[hidden email]> wrote: > Well said Jim, > > There is no way to obtain equal and opposite currents on the feedline > with an offset fed antenna - they are a sure recipe for > RF-in-the-shack. As much acclaim as the Carolina Windom gets, that > fact is still true, one just cannot run high power with such an antenna > - at low power the RF levels may be tolerable, but at high power, they > can wreak havoc in the shack with RF all over everything. > > 73, > Don W3FPR > > On 3/9/2012 5:58 PM, Jim Brown wrote: > > On 3/9/2012 1:50 PM, Bill wrote: > >> I have found the easiest single antenna to utilize is the OCF > > Off center fed antennas are a recipe for noise pickup on the feedline. > > While a good common mode choke can help, off-center feed can also burn > > up a common mode choke if you're running much power. > > > > Bottom line -- off-center-fed antennas are a bad idea. > > > > 73, Jim Brown K9YC > > > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > ______________________________________________________________ > 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 > 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 |
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On Fri, Mar 9, 2012 at 7:48 PM, Guy Olinger K2AV <[hidden email]> wrote:
> OCF antennas, under miscellaneous names, have been working fine... ============= Of course. Please note that the Elecraft product line was originally designed to be used with an end-fed wire (the ultimate in off-center feed), or with a long wire fed against a short counterpoise. It's pretty far-fetched to say that OCF antenna are no good -- they radiate and they receive. I worked 260 countries in a year with an OCF antenna that I used on all bands 80-10. An OCF antenna may require more knowledge from its user than a coax-fed dipole, but that doesn't mean it won't work. If you set it up properly it will work. If you don't, RF will come into your shack and bite you, and you'll be unhappy. But there's a lot of ham gear that doesn't give good results when set up wrong. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 ______________________________________________________________ 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 |
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So let me say one thing I know about antennas:
PUT SOMETHING UP AND GET ON THE AIR. You can get perfect up, and you can get OK up. You an argue about what works better and what works worse. But when the bands are open, you might be able to work DX with a cantenna under your desk. (I've heard stories.) I used an untuned dipole with a LDG tuner to work my first (and only) DXCC back in the last sunspot cycle. So what I'm saying is put something up FIRST and then start the arguing, I mean, discussion. (But then again there are all sorts of aspects to the hobby and if you're here to argue you can if you want.) -- Hisashi T Fujinaka - [hidden email] BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte ______________________________________________________________ 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 |
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Right on!
Rick K6LE On 3/9/2012, at 8:49 , Hisashi T Fujinaka <[hidden email]> wrote: > So let me say one thing I know about antennas: > > PUT SOMETHING UP AND GET ON THE AIR. > ______________________________________________________________ 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 |
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In reply to this post by Hisashi T Fujinaka
Ham radio being a knowledge-based hobby, some people prefer to understand what they're doing. Apparently others don't seem to care. Dave AB7E On 3/9/2012 9:49 PM, Hisashi T Fujinaka wrote: > So let me say one thing I know about antennas: > > PUT SOMETHING UP AND GET ON THE AIR. > > You can get perfect up, and you can get OK up. You an argue about what > works better and what works worse. But when the bands are open, you > might be able to work DX with a cantenna under your desk. (I've heard > stories.) > > I used an untuned dipole with a LDG tuner to work my first (and only) > DXCC back in the last sunspot cycle. > > So what I'm saying is put something up FIRST and then start the arguing, > I mean, discussion. > > (But then again there are all sorts of aspects to the hobby and if you're > here to argue you can if you want.) > 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 |
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In reply to this post by Bill Clarke
K2AV wrote:
"We just have 50 ohm coax and SWR meters on the brain, and have a terrible time seeing outside the rather narrow 50 ohm coax/low SWR box. And we're boxing ourselves in further with single-Z transistor amps that fall off the table and go blurg off 50 ohm Z. (Whatever happened to I-don't-give-a-d*mn-about-SWR tetrode amps, like 807's, 6146's and 4CX1000A? I worked DXCC and had a BPL medallion before I ever had an SWR meter. Just can't understand how I managed. :>) Oops, forgot, Alpha's 8410 monster uses a pair of those 4CX1000A's, and it really doesn't give a d*mn about swr, either.)" ----------------------------------- Yes, but those "nice ole tube amps" almost universally used pi-net outputs which are tuners in-fact. Ferrites make wide-band transformation possible so solid-state no-tune amps are possible. Transistor impedances are so low it makes it critical to load them properly. But we seem to come full circle back to using tuners. I bought a small mobile MFJ-945E tuner for my station due to being on a budget. When I got the K3/10 it worked very nice with my array of 18 antennas. Later a friend was selling an old Drake QRO tuner so I bought it (MN2000) and it now tunes the output of my new 300w HF amp. Too bad it does not have 160m. It has two coax antenna outputs (direct or tuned) so I have one connected to a dummy load and the other to my 5-pos antenna switch (manual). I will eventually run the output of the K3/10 thru the MFJ to a 4-pos coax switch to chose either 6m, 6m-eme, or HF (with a spare position unused). The HF pos. goes to the 300w amp which has a bypass relay, so I can run QRP or with some power. The Drake tuner works really nice and has a power meter to monitor the HF amp so I do not have to commit my Bird43 to that. I sure like the big knobs for tuning and smooth operation of them. 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-? DUBUS Magazine USA Rep [hidden email] "Kits made by KL7UW" http://www.kl7uw.com/kits.htm ====================================== ______________________________________________________________ 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 |
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In reply to this post by Guy, K2AV
On 3/9/2012 5:48 PM, Guy Olinger K2AV wrote:
> OCF antennas, under miscellaneous names, have been working fine, just fine, > just about as long as radio. "Working fine" depends on your definition of "the big picture," and your ability to diagnose problems. The problem with OCF antennas is COMMON MODE FEEDLINE CURRENT, which causes the feedline to receive noise, make the shack hot with RF, and radiate RF to the TV and stereoand computer in our living room (and our neighbor's living room). Fifty years ago, there was relatively little man made noise to be picked up on the feedline of our antennas, the equipment in our living room did not have Pin One Problems that turned all of the wiring into receiving and transmitting antennas, and the equipment in our neighbors' living room was not full of noise generators (other than their TV set's horizontal flyback system). Equally important, we had not LEARNED about common mode current on feedlines, and its contribution to these problems. We lived in blissful ignorance. We called CQ, we got responses, we had fun, but we also had TVI! And when the electronics world changed, introducing Pin One Problems, digital equipment, and switching power supplies to create noise, COMMON MODE CURRENT on feedlines started biting us in the behind, WHETHER WE KNEW IT OR NOT. As Guy and I have both noted, we can get away with unbalanced antennas if we choke them to death, but we're going to fry chokes if we run power unless we use MULTIPLE chokes. And "choking them to death" means multiple turns around ferrite cores (multiple cores and multiple chokes for high power). A FAR better solution, if we can do it, is resonant antennas for each band, well choked. If you're limited on space that can be done with fan dipoles or traps or loading coils. And there is NO MAGIC to parallel wire feedline -- there can be just as much common mode current on parallel wire line as on coax if the antenna itself is unbalanced. Balance is determined by the entire circuit -- the antenna, the feedline, and the transmitter (including the tuner), not ONLY the feedline. That's why I object to the words "balanced feedline" -- they are are pure fiction. 73, Jim K9YC ______________________________________________________________ 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 |
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In reply to this post by Guy, K2AV
I have very fond memories of my Carolina Windom 80 strung between two
50' Sycamore trees. I won my section of the 1999 Nov Sweepstakes and the 2000 ARRL Int.DX contest with that antenna an MFJ 949E tuner and 100W from my hand-me-down TS-520. Not bad for an antenna that "can't work". -- R. Kevin Stover AC0H ______________________________________________________________ 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 |
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*Kevin,
I worked the world in 1999 on an IC-706MKIIG, an SS750 Henry amplifier and a Gary Stookey built GS3 screwdriver antenna mounted on my Kenworth 18 wheeler in the US..but they don't work either eh? Oh well...I Can Only Monitor must mean something after all..TIC 73 Gary The nice man in the white coat coat is calling me...again * On 10 March 2012 22:14, Kevin <[hidden email]> wrote: > I have very fond memories of my Carolina Windom 80 strung between two > 50' Sycamore trees. > I won my section of the 1999 Nov Sweepstakes and the 2000 ARRL Int.DX > contest with that antenna an MFJ 949E tuner and 100W from my > hand-me-down TS-520. > > Not bad for an antenna that "can't work". > > -- > R. Kevin Stover > AC0H > > ______________________________________________________________ > 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 > -- Gary VK4FD - Motorhome Mobile Elecraft Equipment K3 #679, KPA-500 #018 Living the dream!!! ______________________________________________________________ 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 |
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In reply to this post by Jim Brown-10
This thread has a count of 15. I thought I would squeeze one more in
before the end of thread is called. Last year I performed some simple OCF Dipole investigations. My quest is to make a 15/20 trapped OCF dipole to place in an asymmetrical location in my attic. My rather incomplete notes can be found here: http://www.kn5l.net/ocfda/OCFDA.pdf My general finding for a OCF Dipole antenna are: EZNEC models, with accurate AGL parameters (including the Vee shape), are highly predictive within my ability to measure antenna parameters, Autek Model VA1 and KAT2 SWR meter. Best I can tell, a dual core 4:1 Balun does shunt coax shield currents. My observation is based on the EZNEC modeling versus actual measurements and noting that changing the feed-line length did not alter the measured antenna parameters. The off center ratio is highly dependent on antenna height for a relatively low antenna. So much so, that a single set of values will probably not be suitable for an application. If one wants to put up an optimal OCF Dipole, then you may want to use a modeling program or be prepared to perform a bunch of at location measurement and cuts to find the optimal values. A OCF Dipole does seem to work. I worked T32C using my K2/10 and the 15 meter OCF Dipole investigation antenna in my back yard. John, KN5L ______________________________________________________________ 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 |
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In reply to this post by Hisashi T Fujinaka
That's the most expensive latte I've ever seen. :-P
73, Mike NF4L On 3/9/2012 11:49 PM, Hisashi T Fujinaka wrote: > So let me say one thing I know about antennas: > > PUT SOMETHING UP AND GET ON THE AIR. > > You can get perfect up, and you can get OK up. You an argue about what > works better and what works worse. But when the bands are open, you > might be able to work DX with a cantenna under your desk. (I've heard > stories.) > > I used an untuned dipole with a LDG tuner to work my first (and only) > DXCC back in the last sunspot cycle. > > So what I'm saying is put something up FIRST and then start the arguing, > I mean, discussion. > > (But then again there are all sorts of aspects to the hobby and if you're > here to argue you can if you want.) > ______________________________________________________________ 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 |
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In reply to this post by Jim Brown-10
Probably the most elegant solution is to actually change the physical
length of the element(s). Mike, KK5F, does that with jumpers on his portable dipole, and SteppIR does it by spooling up the un-wanted portion of the element. There was a design in QST that used air pressure to operate relays that accomplished the same thing. Maybe, this could also be done with relays powered by the signal. 73, Rick K7MW > > A FAR better solution, if we can do it, is resonant antennas for each > band, well choked. If you're limited on space that can be done with > fan > dipoles or traps or loading coils. > > 73, Jim K9YC ______________________________________________________________ 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 |
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In reply to this post by David Gilbert
I'd put it this way: Some folks just want to get on the air and operate.
Others take greater joy in knowing they can get the most out of what is available. There's room for a variety of operators. EVERY station is a collection of compromises. There is no perfect station or even a perfect portion. Antennas are part of that compromise, since available space, height and ground conditions, (no) tree etc. can vary greatly within a very short distance. The only 'perfect' antenna is the isotropic, which is hard to build. :o) An example of compromise is the commonly used portable "rubber duck" (AKA the semi-radiating dummy load). One can be more/less efficient, but it works and nothing is perfect. Keeping that in mind, most do the best they can with what they have. Both ends of the operator spectrum (soggy noodle antenna -> every Pico watt out) make folks happy, so who's to complain? Some like QRP, some QRO, DX or not, ragchew or not, some are more technically minded and so on. While I tend to think it's wise to know WHY you're doing something and understanding what compromises you're accepting, I understand those that just want to get on the air and have fun. If you can afford heating the room (or hardware) with reasonable safety and you're having fun, have at it. Rick WA6NHC -----Original Message----- From: David Gilbert Ham radio being a knowledge-based hobby, some people prefer to understand what they're doing. Apparently others don't seem to care. Dave AB7E ______________________________________________________________ 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 |
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