Re: [Elecraft] KX3 and KPA1500 compatibility
From: Jim Brown mailto:j...@audiosystemsgroup.com> > I think one of the the half-wave designed verticals Jim is thinking of is the Cushcraft R8 and/or R9. MFJ now manufactures these antennas, but I have one of the "original" models, and it worked very well for me -considering it was something of a compromise. As Jim noted, years ago Ward Silver, N0AX, and K7LXC, put together a very substantial review of various verticals, and he gave the R8 (the R9 wasn't born yet) very good maks! That info may seem somewhat dated, but still has serious relevance! Besides, it isn't just a review of various antennas, it is an analysis of each antenna's performance! I'd be using my R8 right now except when we moved from Tucson to Portland some of the pieces went missing, and I haven't had a chance to resolved the problem!!! I also echo Jim's comments about Tom, N6BT, are also very appropriate. I've seen Tom give marvelous presentations at at Pacificon, Yuma, and most recently to one of our ham clubs here in Portland via Zoom! Tom has created some of the most interesting and effective antennas around! For that matter, I've also seen Jim, K9YC, do presentations at Pacificon, and they were excellent as well. His website is like another handbook! If Jim says it is good, it's good! Cheers, Dave W7AQK __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 and KPA1500 compatibility
> Regarding the question about KX3-->KXPA100-->KPA1500: Be careful. All > amplifiers generate some distortion that wasn't present at the input. Each > succeeding amplifier amplifies that distortion. There are a couple of interesting articles here that discuss the design, construction and use of filters between transmitter and amplifier designed to prevent the amplification of the “junk” - unwanted harmonics and phase noise from the transmitter: https://kitsandparts.com/W3NQN_filter.php I've seen several QST reviews recently with lab notes to the effect “not recommended for use with an amplifier” because of the uncleanliness of the transmitted signal. This is an issue of increasing concern given some of the dirty signals we’ve all heard on the air. Steve AA8AF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 and KPA1500 compatibility
AF5LQ wrote, "Unable to call anyone, especially on Elecraft 80 m Sunday nets." In mild dissent to several of the replies ... from very savvy folks ... one of the truly enlightening things that J. C. Maxwell worked out back in the 19th century was, "If you can get alternating current to flow in a non-buried, non-submerged conductor, it will radiate." Many years ago, in a far away land, while installing and operating a heavy mobile troposcatter system on a sand dune about 180 m AMSL, we just laid the dipole for our HF SSB intra-unit net [KWM-2A's] out on the sand. It worked fine. We finally found the masts in our pallets of gear and strung the dipole up. There was no appreciable difference in how it worked. Today, we're HOA dwellers [by choice], my antenna at home is a 43 m wire strung on a wooden fence on plastic electric fence insulators. It is about 2 m high with a 90 deg "corner," and is end-fed through what I believe is an 8:1 transformer. It works ... on all HF bands. It is a compromise of course, a Sterba curtain would work better, but I make lots of Q's with it including DX. I suggest a high likelihood that you aren't managing to get enough alternating current to flow in any of the antennas you've tried, and that's where I'd start. Regarding the question about KX3-->KXPA100-->KPA1500: Be careful. All amplifiers generate some distortion that wasn't present at the input. Each succeeding amplifier amplifies that distortion. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County j...@kk9a.com wrote on 3/6/2023 4:58 PM: Your questions regarding if you can use a KPA100 and KPA1500 together has been recently asked on this list and the answer was YES. I suspect, as K9YC noted, that the real issue is with your antenna. You did not specify exactly what you have tried. A 1/4 vertical with a decent counterpoise will work very well but I suspect that the vertical you tried was something else. A simple center fed 1/2 WL dipole with the center as high as possible should also get you into the net with your 100 watts amp, no tuner needed. John KK9A Karl AF5LQ wrote: I have a KX3 and a KPA100 amplifier but despite various attempts at verticals, end feds, OCFs, and loops, am unable to call anyone, especially on Elecraft 80 m Sunday nets on 3.784 or 3.786. Reception is adequate with most 5/8 or 5/9 and verify against the call- in list. A lot of people seem to get by with a KPA 500 but reception is not as solid as those running the legal limit. My understanding is that the KX3 is compatible with the KPA 500. What about the KPA1500? Question: Is it possible / practical/ safe to daisy-chain a KX3 to a KPA100 and drive a KPA1500? Thanks and 73, Karl AF5LQ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k6dg...@gmail.com -- This email has been checked for viruses by AVG antivirus software. www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 and KPA1500 compatibility
On 3/6/2023 2:08 PM, Jim Brown wrote: Most (but not all) verticals need radials to transmit a decent signal. A vertical that needs radials is a lousy TX antenna without them. To expand on this -- the BTV-series, the Butternut and a few others use various forms of traps and resonators that essentially function as a quarter-wave (or odd multiple of quarter-waves) verticals. The DO need radials. Length on the ground is not critical, and more is better. The Hy-Gain AV-series, and another similar design by another designer (all currently mfd by MFJ) are loaded, center-fed half-wave antennas, and do NOT need radials (and work best without them). I could give you family name of the other design (also mfd by MFJ), but my copy of the N0AX/K7LXC review of them is currently out on loan to another ham. My 81-year-old brain can only remember so many details. N6BT (original Force 12 designer, VERY sharp engineer), designed a lot of excellent center-fed loaded designs for that company, which he owned, and brands after he sold Force 12. Tom is a far better designer than businessman, and I love him dearly. :) His self-published "Array Of Light" is a GREAT education, and includes many of his designs. N0AX/K7LXC very disciplined tests of both verticals and tri-banders showed Tom's designs to be leading both packs! Our 7QP/CQP/FD team owns three of his C3SS Yagis. Tom is also very sharing of what he has learned, zero ego, and I've learned a LOT from him. His measurements (using drones) on the effect of terrain (above a dropoff in the direction of DX) on the performance of verticals, first presented at Pacificon about six years ago, was ground-breaking! 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 and KPA1500 compatibility
Your questions regarding if you can use a KPA100 and KPA1500 together has been recently asked on this list and the answer was YES. I suspect, as K9YC noted, that the real issue is with your antenna. You did not specify exactly what you have tried. A 1/4 vertical with a decent counterpoise will work very well but I suspect that the vertical you tried was something else. A simple center fed 1/2 WL dipole with the center as high as possible should also get you into the net with your 100 watts amp, no tuner needed. John KK9A Karl AF5LQ wrote: I have a KX3 and a KPA100 amplifier but despite various attempts at verticals, end feds, OCFs, and loops, am unable to call anyone, especially on Elecraft 80 m Sunday nets on 3.784 or 3.786. Reception is adequate with most 5/8 or 5/9 and verify against the call- in list. A lot of people seem to get by with a KPA 500 but reception is not as solid as those running the legal limit. My understanding is that the KX3 is compatible with the KPA 500. What about the KPA1500? Question: Is it possible / practical/ safe to daisy-chain a KX3 to a KPA100 and drive a KPA1500? Thanks and 73, Karl AF5LQ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 and KPA1500 compatibility
Hi Karl, I suspect your problem may be the antennas you've tried, which are not wonderful for 75/80M. Almost any antenna will receive well if you don't have a lot of noise, but transmitting a strong signal needs a better one, and well installed. How far are you from the nets you're trying to work? How tall was that vertical? What model? Most (but not all) verticals need radials to transmit a decent signal. A vertical that needs radials is a lousy TX antenna without them. Most end-fed antennas need a counterpoise to transmit well. Did you have one? How high were those other antennas? Horizontal antennas work better if they're high. Do you have skyhooks positioned so that you could rig a 75M dipole (it's roughly 120 ft long)? They're easy to build and should be fed with coax. There are shortened dipoles with loading coils that can fit between closer supports. Have you studied the antenna section of the ARRL Handbook,or the ARRL Antenna Book? Most of the antennas you've described probably need a tuner to load efficiently. The KPA500 does NOT include a tuner, so the KAT500 would likely be needed. The KPA1500 includes an excellent tuner. 2-3W will yield 100W on most bands, about twice that for 200-250W. Yes, you can certainly daisy-chain the two amps to get legal limit with as little as 1W from the KX3. 73, Jim K9YC On 3/6/2023 1:01 PM, Karl W Hubbard via Elecraft wrote: I have a KX3 and a KPA100 amplifier but despite various attempts at verticals, end feds, OCFs, and loops, am unable to call anyone, especially on Elecraft 80 m Sunday nets on 3.784 or 3.786. Reception is adequate with most 5/8 or 5/9 and verify against the call- in list. A lot of people seem to get by with a KPA 500 but reception is not as solid as those running the legal limit. My understanding is that the KX3 is compatible with the KPA 500. What about the KPA1500? Question: Is it possible / practical/ safe to daisy-chain a KX3 to a KPA100 and drive a KPA1500? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] KX3 and KPA1500 compatibility
I have a KX3 and a KPA100 amplifier but despite various attempts at verticals, end feds, OCFs, and loops, am unable to call anyone, especially on Elecraft 80 m Sunday nets on 3.784 or 3.786. Reception is adequate with most 5/8 or 5/9 and verify against the call- in list. A lot of people seem to get by with a KPA 500 but reception is not as solid as those running the legal limit. My understanding is that the KX3 is compatible with the KPA 500. What about the KPA1500? Question: Is it possible / practical/ safe to daisy-chain a KX3 to a KPA100 and drive a KPA1500? Thanks and 73, Karl AF5LQ Sent from Yahoo Mail for iPhone __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
