IMD and supply voltage
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On Thu, 29 Oct 2015 15:21:05 -0700
Wayne Burdick <[hidden email]> wrote: > Yes, we made sure compression was off. We gave the unit every opportunity to exhibit magic properties. Alas, it did not. > > Wayne > N6KR > Sounds like all solid state amps offering more than about 50 watts are having growing pains. It does not make much sense investing in something you might need to trash in a few years when someone decides to design a decent solid state amp or the chip designers create a magic power device. For my money its a K3S/10 and a homebrew 6146 run off a mobile power supply. ______________________________________________________________ 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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Frank,
Maybe when the devices come out Elecraft will bring out a new power amplifier module to replace the older module for both K3 and KX3. Meanwhile run the K3 at lower power and drive an external vacuum tube or solid state power amplifier. My experience of an Acom 2000A, a tube amp and an SPE Expert 2K-FA, a solid state amp is that: 1) Solid State amps are instant on and this is a big plus. 2) Solid State amps do not heat the shack to the same degree. 3) Solid State amps are much more particular as to load and if the SWR is at all high without being tuned out by matching the load then distortion is horrific. 4) The Acom 2000A is much more tolerant of operating for long periods flat out at 1500 Watts. Of course this is a comparison of these two amps. Please note that 1500 Watts is only used for contests which we are allowed to use for some contests in EI but not for regular operating where our power limit is 400W output. 73 Doug EI2CN -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of frank Sent: 29 October 2015 23:42 To: [hidden email] Subject: Re: [Elecraft] IMD and supply voltage On Thu, 29 Oct 2015 15:21:05 -0700 Wayne Burdick <[hidden email]> wrote: > Yes, we made sure compression was off. We gave the unit every opportunity to exhibit magic properties. Alas, it did not. > > Wayne > N6KR > Sounds like all solid state amps offering more than about 50 watts are having growing pains. It does not make much sense investing in something you might need to trash in a few years when someone decides to design a decent solid state amp or the chip designers create a magic power device. For my money its a K3S/10 and a homebrew 6146 run off a mobile power supply. ______________________________________________________________ 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 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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In reply to this post by frank-2
Frank,
Actually No. You can build solid state 125Wpep HF amplifiers with TX IMD figures better than -42dBc that operate quite happily at full power with only 11V. Unfortunately they are typically designed and built by Military and Commercial HF manufacturers who then have to recover their development costs with very high transceiver prices. I don't think most Hamsters will want to pay for the amortised development costs, they are not insignificant. The last commercial BJT HF amplifier design that I was involved with required ~6 man years of development work and easily made the above specs/grade, this was done 9 years ago. However while the FCC and other regulatory bodies don't make the specifications for Amateur gear better, then there wont really be any serious developments in this area why would you? However there are an equal amount of poorly designed tube amplifiers c.f solid state amplifiers on the air waves, so this phenomenon is not uncommon. Oh the K3/K3s 100W power amplifier is certainly well above par, especially when kept around 30Wpep; just the right amount of power to feed the KPA500 or well designed QRO tube amp. 73 Matthew VK5ZM On 30 October 2015 at 10:11, frank <[hidden email]> wrote: > On Thu, 29 Oct 2015 15:21:05 -0700 > Wayne Burdick <[hidden email]> wrote: > > > Yes, we made sure compression was off. We gave the unit every > opportunity to exhibit magic properties. Alas, it did not. > > > > Wayne > > N6KR > > > > > Sounds like all solid state amps offering more than about 50 watts are > having growing pains. It does not make much sense investing in something > you might need to trash in a few years when someone decides to design a > decent solid state amp or the chip designers create a magic power device. > > For my money its a K3S/10 and a homebrew 6146 run off a mobile power > supply. > > ______________________________________________________________ > 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 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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In reply to this post by Lu Romero - W4LT
It looks like there might be a business opportunity for an
external 100W amp which has very low distortion. Via auxbus it could be slaved to a K3, K3S, or a KX3. How does the KXPA100 stack up? Re: Overdriving speech processors K1N team member Glenn Johnson, W0GJ, said, “It seems like everyone tries to turn up their microphone gain and speech processors to overdrive and it creates splatter and makes it almost impossible and if we could somehow magically eliminate all speech processors, we could probably double or triple our rate."[1] He also said that European stations were worse offenders than US stations. [1] Interview with Glenn Johnson WØGJ , K1N co-team leader by Wolf Harranth, OE1WHC of Dokumentationsarchiv Funk, a history of radio site <http://audioboom.com/boos/2875970-satphone-interview-with-glenn-johnson-w0gj-on-navassa-9-february-2015-13-00z> 73 Bill AE6JV ----------------------------------------------------------------------- Bill Frantz | Ham radio contesting is a | Periwinkle (408)356-8506 | contact sport. | 16345 Englewood Ave www.pwpconsult.com | - Ken Widelitz K6LA / VY2TT | Los Gatos, CA 95032 ______________________________________________________________ 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] |
Re: IMD and supply voltage
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In reply to this post by Matthew Cook
Folks - we're also hitting the posting limit for this topic. To avoid overload
for other readers, lets wind it down tonight and then close the thread.. 73 Eric List Moderation, LLC /elecraft.com/ --- On 10/29/2015 4:57 PM, Matthew Cook wrote: > Frank, > > Actually No. > > You can build solid state 125Wpep HF amplifiers with TX IMD figures better > than -42dBc that operate quite happily at full power with only 11V. > Unfortunately they are typically designed and built by Military and > Commercial HF manufacturers ______________________________________________________________ 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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Eric,
I have learnt a lot reading the posts, thanks for being tolerant. Gary -----Original Message----- From: "Eric Swartz - WA6HHQ, Elecraft" <[hidden email]> Sent: 30/10/2015 10:53 AM To: "Matthew Cook" <[hidden email]>; "frank" <[hidden email]> Cc: "Elecraft Reflector" <[hidden email]> Subject: Re: [Elecraft] IMD and supply voltage Folks - we're also hitting the posting limit for this topic. To avoid overload for other readers, lets wind it down tonight and then close the thread.. 73 Eric List Moderation, LLC /elecraft.com/ --- On 10/29/2015 4:57 PM, Matthew Cook wrote: > Frank, > > Actually No. > > You can build solid state 125Wpep HF amplifiers with TX IMD figures better > than -42dBc that operate quite happily at full power with only 11V. > Unfortunately they are typically designed and built by Military and > Commercial HF manufacturers ______________________________________________________________ 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 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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In reply to this post by frank-2
IMD is not a single number, even at a fixed supply voltage and power output.
Recent measurements that I have performed on my K3 show a significant variation in IMD vs. frequency. For example, at 30W (V+ 14.5V), the IMD of my K3, varied from -58 dB (relative to PEP*) at 3.8 MHz to -40 dB at 14 MHz. Both of these numbers are astoundingly good, but get worse at 100W, as expected, and get much worse at 10W, which is not. And you don't even want to think about it at 12W. I have it on excellent authority that no one understands this IMD variation with respect to frequency. As to a rule of thumb for IMD dB per volt, IMHO, there isn't one. A 1 volt change from 11 to 12 might be fairly significant; a change from 14 to 15, not so much. * Some words about the numbers. I believe, and a number of professional (Collins, EIMAC) and military specifications agree with me, that the IMD products should be compared to the level of one of the two fundamental spectral components. ARRL, Elecraft and every other ham equipment manufacturer compare the IMD products to the PEP of the two fundamental spectral components. So when they measure -24 dBc on a spectrum analyzer they add -6 dB and call the IMD -30 dBc. Your receiver is an unswept spectrum analyzer; it isn't fooled by the slight-of-hand. On 10/29/2015 8:09 AM, frank wrote: > This subject keeps cropping up. Is this a serious issue ? > > I have heard that IMD improves by 10db with a one volt increase in supply voltage. Is this really the case or just a measurement error? 10db is a large difference. One volt is a small variation. > > What is the minimum acceptable IMD? How linear does the amp need to be? If 36db is better than 26db is 100db even better or just overkill? > > Are other solid state amplifier products similarly effected? > > What is the IMD performance of the K3S at 10 watts over a supply voltage variation from 11 volts to 14.7 volts? I ask because I believe those ten watts are generated by Dmos devices as well. Do these devices only misbehave with varying supply voltage at higher (100w) power levels and lower supply voltages? > > Should I wait to purchase a K3S until this issue is resolved? (Assuming this is a valid issue) > > Back in the good old days we used to solve problems. Today we don't have problems, just issues. > ______________________________________________________________ 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] |
Re: IMD and supply voltage
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In reply to this post by Lu Romero - W4LT
On 10/29/2015 5:53 PM, Luis V. Romero wrote: > > Processing issues heard on the air today simply make the discussion of final > amplifier spectral purity moot. > > Comparing processing issues and transmitter IMD are mixing apple and oranges. Processing issues generally affect the quality of signal *on channel* - the ability to understand the audio - whilst IMD is the "off frequency" splatter up/down the band that interferes with everyone *except* your own QSO. While both are important it is the IMD that represents a "spurious" signal outside the bandwidth required for communication - typically fie to ten KHz above and below the desired RF. 73, ... Joe, W4TV ______________________________________________________________ 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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Guys,
This comment in no way is mean spirited, but truly a concern after reading all of this tech data. For those of us who do not have 100K in test equipment and a EE, I am starting to feel like I should not even get on the air. I get the concept, but the best I can do is make good clean connections, do not overdrive my audio and hope for the best. I have to have faith in the equipment builders or find a new hobby. Rich On 10/29/2015 10:52 PM, Joe Subich, W4TV wrote: > > On 10/29/2015 5:53 PM, Luis V. Romero wrote: >> >> Processing issues heard on the air today simply make the discussion >> of final >> amplifier spectral purity moot. >> >> > > Comparing processing issues and transmitter IMD are mixing apple and > oranges. Processing issues generally affect the quality of signal > *on channel* - the ability to understand the audio - whilst IMD is the > "off frequency" splatter up/down the band that interferes with everyone > *except* your own QSO. > > While both are important it is the IMD that represents a "spurious" > signal outside the bandwidth required for communication - typically > fie to ten KHz above and below the desired RF. > > 73, > > ... Joe, W4TV > ______________________________________________________________ > 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 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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In reply to this post by Doug Turnbull
As I think I remember, in California the limit was 1500 watts, unless you were calling an ATNO (all-time new one) in which case it was 5 kW.
Vic 4X6GP/K2VCO > On 30 Oct 2015, at 12:55 AM, Doug Turnbull <[hidden email]> wrote: > > Of course this is a comparison of these two amps. Please note that > 1500 Watts is only used for contests which we are allowed to use for some > contests in EI but not for regular operating where our power limit is 400W > output. ______________________________________________________________ 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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In reply to this post by Rich-4
Ham radio is a hobby for those who are willing to learn about how radio
works. To obtain a license, we must pass a test that shows we know the fundamentals of radio and electronics. Some don't bother to do that, but instead cram by memorizing answers to a lot multiple guess questions. I view that as cheating. If they don't know anything when they're done, that's their own fault. Last I looked, ARRL license study material taught the fundamentals of electronics and radio, and at least a third of the ARRL Handbook is specifically written for those just beginning to learn it. I'd bet that the vast majority of those who put us on the moon, and a generation later a lander on Mars, first learned electronics from the ARRL Handbook! As hams, we are responsible for producing a reasonably clean signal and operating within the FCC Rules. Operators in other services like CB, commercial 2-way, and so on are not permitted to modify equipment, but we are! I also do my best to produce tutorial materials to share what I've learned. I AM an EE, but I also taught for five years (at DeVry in Chicago), and my goal has always been to try to make complicated things easier to understand. Like many OTs on this reflector, I passed my General exam in my first year of high school, and the Extra exam the summer after high school. All that study (and on air activity) made me want to study EE. :) All of these study materials require STUDY, not casual reading. Some of the concepts take a while to sink in, and with my work on RFI and ferrites, took me a LONG time to figure out. It is a combination of my own research and work with colleagues on the AES Standards Committee's Working Group on EMC. I have some nice test gear, but nothing even close to the $100K range -- much of the work I've done on clean transmitters has been with a P3/SVGA, and I'm planning to increase my measurement capabilities next year with one of the new under $1K ANAN radios. My VNWA cost $769, with shipping and a calibration kit. You don't have to set this stuff up and measure it yourself -- there's plenty of data on my website you can download and study. There's an excellent Power Point, mostly by K6XX, an EE at Elecraft, that shows virtually everything that's been discussed here in the thread on transmitter distortion. I've posted these links several times. There's a summary of ARRL measurements on transmitters that makes it easy to compare them. You and others can learn a lot by downloading and studying them. I learned a lot by doing the work to prepare them! CAPS added for emphasis. :) 73, Jim K9YC On Thu,10/29/2015 8:35 PM, Rich wrote: > For those of us who do not have 100K in test equipment and a EE, I am > starting to feel like I should not even get on the air. I get the > concept, but the best I can do is make good clean connections, do not > overdrive my audio and hope for the best. I have to have faith in the > equipment builders or find a new hobby. ______________________________________________________________ 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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In reply to this post by frank-2
Joe and all:
> >Comparing processing issues and transmitter IMD are mixing apple and >oranges. Processing issues generally affect the quality of signal >*on channel* - the ability to understand the audio - whilst IMD is the >"off frequency" splatter up/down the band that interferes with everyone >*except* your own QSO. > >While both are important it is the IMD that represents a "spurious" >signal outside the bandwidth required for communication - typically fie >to ten KHz above and below the desired RF. > Yes, I understand completely. From a "Real World Practical" standpoint, if I have a really clean transmitter with lovely IMD specifications and I stuff over compressed, highly processed, all compressor-limiter knobs to the right audio into it I will get completely unintelligible audio with wonderful technical specifications and still bother my neighbors. And don't forget. Some contesters *WANT* the scenario you described above. No sense in sweeping that under the rug! That's my point. I'm being responsible in keeping my IMD products from raising the noise floor on the bands, but the OB down the street with his FT101E, "Power Mic" and 4 EL509 sweep tube amp promptly blasts me out of the pileup. I'm not saying that the pursuit of technical excellence in amateur transmitters is a bad thing, but life is a constant compromise between technical excellence and "good enough". Sometimes "close enough! Now ship it so we can make a profit!" is the true measure of excellence in the real world. That doesn't mean we should accept poor engineering, all it means is that excellence is always a tradeoff, and not only about "numbers". Will the OB down the street care enough to change? That's the ultimate variable in the equation, isn't it? -lu- ______________________________________________________________ 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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In reply to this post by frank-2
NO!!!!!! Us Californian's understand dB. If you ain't increasing power in 10 dB increments, don't bother.
Eimac made 4CX10000's based on market demand in California. Don't ask me how I know this........... JimW6AIM . -------- Original message -------- From: Vic Rosenthal <[hidden email]> Date: 10/29/2015 10:50 PM (GMT-08:00) To: Elecraft Reflector <[hidden email]> Subject: Re: [Elecraft] IMD and supply voltage As I think I remember, in California the limit was 1500 watts, unless you were calling an ATNO (all-time new one) in which case it was 5 kW. Vic 4X6GP/K2VCO > On 30 Oct 2015, at 12:55 AM, Doug Turnbull <[hidden email]> wrote: > > Of course this is a comparison of these two amps. Please note that > 1500 Watts is only used for contests which we are allowed to use for some > contests in EI but not for regular operating where our power limit is 400W > output. ______________________________________________________________ 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 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] |
Re: IMD and supply voltage
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Administrator
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This thread is now closed. We're drifting way off topic.(We asked that it be
would down last night.) 73, Eric /elecraft.com/ On 10/30/2015 7:19 AM, Jim Bolit wrote: > NO!!!!!! Us Californian's understand dB. If you ain't increasing power in 10 dB increments, don't bother. > Eimac made 4CX10000's based on market demand in California. > Don't ask me how I know this........... > JimW6AIM > > ______________________________________________________________ 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] |
Re: The Technical Side of Ham Radio
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In reply to this post by Jim Brown-10
It seems to me that a good basic knowledge of electronics is enough,
without spending a fortune on test equipment -- unless that appeals to you. The recent threads on power supplies and voltage at the transceiver is a good example. Sure, you can measure the drop with a good voltmeter, either measured across the wire, or measured at the terminals. You can also find a good set of wire tables, and calculate the drop across a given length of wire. If the drop is going to be too high, go to a higher gauge. Back to the DVM, you can check the connectors (resistance) and calculate the voltage drop at 100% power out. If you aren't sure, look at the fuses. The current will be lower than the fuse rating, so that gives you extra margin, which is never bad. Then you test. Hook up your dummy load, transmit CW at 100w (or in my case, about 12w), and see what you've got at the transceiver. If it sags, grab your DVM and measure the power terminals on the power supply. It's not that hard, and the necessary equipment can be had for under $40 or so. I'm a software guy. I know how many programmers it takes to change a lightbulb (they can't, it's a hardware problem). I can do this. So can you. This list is a great place to ask simple questions (and sometimes watch them get beaten into the ground). 73 -- Lynn On 10/29/2015 11:39 PM, Jim Brown wrote: > Ham radio is a hobby for those who are willing to learn about how > radio works. To obtain a license, we must pass a test that shows we > know the fundamentals of radio and electronics. ______________________________________________________________ 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] |
Re: The Technical Side of Ham Radio
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In reply to this post by Jim Brown-10
On Fri,10/30/2015 4:35 AM, Harry White wrote:
> What new ANAN radio are you referring to? http://www.gigaparts.com/Product-Lines/HF-6M-Radios/Apache-Labs-ANAN-10E-SDR.html > How will it improve your measurement capabilities? I'll use the receiver as a spectrum analyzer. It has greater dynamic range (big signals to small ones) and frequency resolution (a few Hz) than anything else currently in my arsenal, and it costs less than $1,000. > What is a VNWA? A Vector Network Analyzer. It can 1) measure the complex impedance of anything from an antenna to a complicated network, swept over frequency. "Complex" means it can separate R and X, and give magnitude and phase. 2) measure the gain through a network (like a bandpass filter), again both magnitude and phase 3) measure the reflection coefficient of a network, which provides SWR 4) do Time Domain Reflectometry (TDR) to measure the electrical length of a feedline, and to look for damage to it 5) export data to modeling programs like SimSmith, which can be used to design matching networks for antennas VNWA refers to a specific model of VNA designed by a German EE professor and built by hams in the UK. It's a little box that connects to the USB port of a Windows computer. Good questions. Thanks for asking. 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 Message delivered to [hidden email] |
Re: The Technical Side of Ham Radio
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In reply to this post by Jim Brown-10
Hi Chris,
I have one. It is fine for looking at harmonics and standard IMD tests, but the ANAN 10e runs rings around it for spectrum analysis, and for $500 less. So does the VNWA for gain measurements, and for half the cost. Major limitation is that the frequency resolution isn't nearly fine enough to look at occupied bandwidth of ham gear. That's why I've been using P3/SVGA to look at ham rigs. Bottom line -- I wouldn't buy it again. 73, Jim K9YC On Fri,10/30/2015 6:10 AM, Chris Hallinan wrote: > Glad you keep posting, I keep learning. Can I ask, off list, what you > think of this? It's on my "wish list" at amazon. For my money, it > looks pretty good. > > http://www.amazon.com/dp/B00CLWJA38/ref=wl_it_dp_o_pd_S_ttl > > 73, > > K1AY > Chris in Punta Gorda, FL > > On Fri, Oct 30, 2015 at 2:39 AM, Jim Brown <[hidden email]> wrote: >> Ham radio is a hobby for those who are willing to learn about how radio >> works. To obtain a license, we must pass a test that shows we know the >> fundamentals of radio and electronics. Some don't bother to do that, but >> instead cram by memorizing answers to a lot multiple guess questions. I view >> that as cheating. If they don't know anything when they're done, that's >> their own fault. >> >> Last I looked, ARRL license study material taught the fundamentals of >> electronics and radio, and at least a third of the ARRL Handbook is >> specifically written for those just beginning to learn it. I'd bet that the >> vast majority of those who put us on the moon, and a generation later a >> lander on Mars, first learned electronics from the ARRL Handbook! >> >> As hams, we are responsible for producing a reasonably clean signal and >> operating within the FCC Rules. Operators in other services like CB, >> commercial 2-way, and so on are not permitted to modify equipment, but we >> are! >> >> I also do my best to produce tutorial materials to share what I've learned. >> I AM an EE, but I also taught for five years (at DeVry in Chicago), and my >> goal has always been to try to make complicated things easier to understand. >> Like many OTs on this reflector, I passed my General exam in my first year >> of high school, and the Extra exam the summer after high school. All that >> study (and on air activity) made me want to study EE. :) >> >> All of these study materials require STUDY, not casual reading. Some of the >> concepts take a while to sink in, and with my work on RFI and ferrites, took >> me a LONG time to figure out. It is a combination of my own research and >> work with colleagues on the AES Standards Committee's Working Group on EMC. >> >> I have some nice test gear, but nothing even close to the $100K range -- >> much of the work I've done on clean transmitters has been with a P3/SVGA, >> and I'm planning to increase my measurement capabilities next year with one >> of the new under $1K ANAN radios. My VNWA cost $769, with shipping and a >> calibration kit. >> >> You don't have to set this stuff up and measure it yourself -- there's >> plenty of data on my website you can download and study. There's an >> excellent Power Point, mostly by K6XX, an EE at Elecraft, that shows >> virtually everything that's been discussed here in the thread on transmitter >> distortion. I've posted these links several times. There's a summary of ARRL >> measurements on transmitters that makes it easy to compare them. You and >> others can learn a lot by downloading and studying them. I learned a lot by >> doing the work to prepare them! >> >> CAPS added for emphasis. :) >> >> 73, Jim K9YC >> >> On Thu,10/29/2015 8:35 PM, Rich wrote: >>> For those of us who do not have 100K in test equipment and a EE, I am >>> starting to feel like I should not even get on the air. I get the concept, >>> but the best I can do is make good clean connections, do not overdrive my >>> audio and hope for the best. I have to have faith in the equipment builders >>> or find a new hobby. >> >> ______________________________________________________________ >> 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 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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In reply to this post by Jim Bolit
Several years back I had obtained some excellent 4cx5 and
4cx10k tubes, they were a little more juice than my house mains power could handle, so I sold them .. the pair of 4cx10k went to a ham in CA who was "upgrading" his amp that used a pair of 4cx5K at the time, easy upgrade since the sockets are the same etc. There were several 4cx10K amps in the St Louis area at that time so its not just a CA option. THis was before Elecraft.. so OT I suspect. 73 Merv K9FD/KH6 > NO!!!!!! Us Californian's understand dB. If you ain't increasing power in 10 dB increments, don't bother. > Eimac made 4CX10000's based on market demand in California. > Don't ask me how I know this........... > JimW6AIM > > . > > -------- Original message -------- > From: Vic Rosenthal <[hidden email]> > Date: 10/29/2015 10:50 PM (GMT-08:00) > To: Elecraft Reflector <[hidden email]> > Subject: Re: [Elecraft] IMD and supply voltage > > As I think I remember, in California the limit was 1500 watts, unless you were calling an ATNO (all-time new one) in which case it was 5 kW. > > Vic 4X6GP/K2VCO > >> On 30 Oct 2015, at 12:55 AM, Doug Turnbull <[hidden email]> wrote: >> >> Of course this is a comparison of these two amps. Please note that >> 1500 Watts is only used for contests which we are allowed to use for some >> contests in EI but not for regular operating where our power limit is 400W >> output. > ______________________________________________________________ > 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 > 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 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] |
Re: The Technical Side of Ham Radio
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In reply to this post by Lynn W. Taylor, WB6UUT
Exactly right, Lynn!
73, Jim K9YC On Fri,10/30/2015 10:00 AM, Lynn W. Taylor, WB6UUT wrote: > It seems to me that a good basic knowledge of electronics is enough, > without spending a fortune on test equipment -- unless that appeals to > you. > > The recent threads on power supplies and voltage at the transceiver is > a good example. > > Sure, you can measure the drop with a good voltmeter, either measured > across the wire, or measured at the terminals. > > You can also find a good set of wire tables, and calculate the drop > across a given length of wire. If the drop is going to be too high, > go to a higher gauge. > > Back to the DVM, you can check the connectors (resistance) and > calculate the voltage drop at 100% power out. > > If you aren't sure, look at the fuses. The current will be lower than > the fuse rating, so that gives you extra margin, which is never bad. > > Then you test. Hook up your dummy load, transmit CW at 100w (or in my > case, about 12w), and see what you've got at the transceiver. > > If it sags, grab your DVM and measure the power terminals on the power > supply. > > It's not that hard, and the necessary equipment can be had for under > $40 or so. ______________________________________________________________ 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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In reply to this post by Jim Brown-10
I have been using the output on the KVX3 on the 475khz band
and it has worked great, can adjust it from .1 to 1.5mw, I have been running it at .4mw driving an amplifier, This morning I noticed that the power control no longer adjusts the power output, no matter the setting, its at some unknown power, maybe full power? but I cannot change the output any longer, Any ideas if there is something I could have changed or perhaps the KVX3 has gone south? Thanks 73 Merv K9FD/KH6 ______________________________________________________________ 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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