Re: [Elecraft] 75 ohm coax
On 4/1/2020 6:37 PM, Don Wilhelm wrote: Even RG-6 will withstand 1500 watts with no problems. RG6 is a VERY generic description of coax, and there are probably 100 very different cables carrying that designation. We are most familiar with those manufactured for the CATV industry, all optimized for low weight, low cost, low loss at VHF/UHF, and very low power. But these cables mostly have CCS center (copper coated steel), Al foil, Al braid shields. This causes them to be rather lossy at low RF. There ARE a few more far more robust RG6 cables designed for transmitting and for analog video (remember that?). I have some -- double copper braid, solid copper center. What I have is labeled Pasternak, but I've seen a very similar RG6 in the Belden catalog. 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] WTB KDVR3
I received a response to this query and have been able to secure a KDVR3. Great list! 73 de Carl N8VZ Sent from my iPhone Carl Jón Denbow, N8VZ 17 Coventry Lane Athens, Ohio 45701-3718 c...@n8vz.com www.n8vz.com EM89wh IRLP 4533 Echolink 116070 PSK and JT65 Forever! > On Mar 31, 2020, at 8:41 PM, Carl Jón Denbow wrote: > > I would like to buy a KDVR3 for my K3. Elecraft is not selling them > anymore. If anyone has one that they would sell, please contact me off list. > Thanks. 73 de Carl N8VZ > > > __ > 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 n...@qth.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] 75 ohm coax
The voltage allowable on 75 ohm 1/2 inch hardline far exceeds the voltage allowable for RG-213. No problem at the limit of 1500 watts for the ham bands. Even RG-6 will withstand 1500 watts with no problems. 73, Don W3FPR On 4/1/2020 4:38 PM, Gmail wrote: Careful, 75 ohms was picked for cable TV receiving Coax because it was lower loss then 50 ohms but it could not handle high power as 50 ohms could. 50 ohms is a power, loss compromise. 35 ohms For high power high loss, 50 ohms compromise, 75 ohms low loss low power. Ray W8LYJ __ 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] VF Varies With Frequency
Hi Mark, Whoever you talked to needs to go back to school and study Maxwell's equations. He is WRONG! http://k9yc.com/TransLines-LowFreq.pdf http://k9yc.com/Coax-Stubs.pdf 73, Jim K9YC On 4/1/2020 2:45 PM, Mpridesti wrote: Requested technical comment from a long established coaxial cable manufacturer on this topic. This was the response: The Vp is not measured at any frequency and is independent of frequency. The only variable in play is the dielectric constant. The Vp represents the speed at which a signal transmits along the cable as a % of the speed of air. Air/vacuum will be the fasted medium to use to transmit an RF signal. The thing is, air is usually not practical since there is nothing to support the center conductor, can be easily crushed and is susceptible to the ingress of moisture. We use foamed dielectrics and expanded tapes to get as close to air as possible. Vp will vary based on the specific dielectric used. The vast majority of our cables range in velocity of propagation from 76% to 86%. For a given cable, the Vp will likely not vary more that +/- 1% over it’s length but as I mentioned earlier, it would be best to use +/-2% for planning purposes. End response Regards, Mark, K1RX On Apr 1, 2020, at 1:43 PM, Jim Brown wrote: On 4/1/2020 7:58 AM, Don Wilhelm wrote: When dealing with a length of transmission line, the use of the '468' factor should not be used - compute the actual wavelength and then apply the velocity factor. There is yet another variable -- VF varies with frequency. At low frequencies, it is lower (slower), increasing until it converges to the published value at VHF. For this reason, matching sections and stubs must be measured at or near the operating frequency with an analyzer or as a stub placed in line with a generator and receiver. They should be cut long, then trimmed so that the null in that generator/receiver circuit is heard, or the analzyer reads a short or open. How much is this variation? For typical transmission lines, it's on the order of 1% from 80M, a bit more for 160M as compared to the published value. If what you're building is a stub to kill harmonics, it's the difference between the CW and phone bands on 80M. 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 mpride...@yahoo.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] VF Varies With Frequency
I would not be buying any cable from them. Wes N7WS On 4/1/2020 2:45 PM, Mpridesti via Elecraft wrote: Requested technical comment from a long established coaxial cable manufacturer on this topic. This was the response: The Vp is not measured at any frequency and is independent of frequency. The only variable in play is the dielectric constant. The Vp represents the speed at which a signal transmits along the cable as a % of the speed of air. Air/vacuum will be the fasted medium to use to transmit an RF signal. The thing is, air is usually not practical since there is nothing to support the center conductor, can be easily crushed and is susceptible to the ingress of moisture. We use foamed dielectrics and expanded tapes to get as close to air as possible. Vp will vary based on the specific dielectric used. The vast majority of our cables range in velocity of propagation from 76% to 86%. For a given cable, the Vp will likely not vary more that +/- 1% over it’s length but as I mentioned earlier, it would be best to use +/-2% for planning purposes. End response Regards, Mark, K1RX __ 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] 75 ohm coax
In old days hams fed 10:1 antennas with ladder line and did well. Just keep feedline loss to a minimum. I feed my apex high delta loops direct with a good toroid coax choke at feedpoint at bottom corner (low impedance) near the shack. Coax is short and lmr240, works great. I tested 2:1 & 4:1 baluns etc on previous advice and the result was not as good as a good direct feed with high impedance choke. Look out for vk4tux on FT8. On 2/4/20 9:32 am, Josh Fiden wrote: This all reminds me of the difference between when I was a young teen getting started as a ham vs now. As a kid I would put things together or throw em up. Only worried about it after it didn’t work. Nowadays, I plan & overthink things to death before getting anything accomplished. I prefer the old way. 73, Josh W6XU Sent from my mobile device On Apr 1, 2020, at 4:20 PM, Frederick Dwight wrote: If you have 75 ohm coax, I would just try it. If the Z of the antenna is in fact around 35 ohms, the Z at the shack end may be close to 35 ohms on some bands, but on others the Z will be transposed to well over 100 ohms with an SWR probably over 3 to one. One of my dipoles has a SWR at the top of 75 meters of approximately 4:1, and I occasionally venture up there, but my K3S with internal tuner does not complain and quickly matches it to about 1:1. Not ideal and this is not the way I usually build my antennas, but the loss is not too bad. If you can build a unun with approximately a 1:2 ratio this should solve your problem. If it does not cover all the way from 80 to 10 with low loss, I would not worry too __ 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 vk4...@gmail.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] VF Varies With Frequency
H I'm seeing great variability in the Vf does/does not vary with F. This link says yes: https://owenduffy.net/transmissionline/concept/mvf/index.htm Other's say no... My "gut" says yes. Yea! Now I have something to research in order to figure out how/why! My favorite kind of puzzle! I'm guessing that not only can this be demonstrated mathematically one way or another, but also experimentally using say, my VNWA, sig generator, et al. 73, __ Clay Autery, KY5G (318) 518-1389 On 04/01/20 16:45, Mpridesti via Elecraft wrote: Requested technical comment from a long established coaxial cable manufacturer on this topic. This was the response: The Vp is not measured at any frequency and is independent of frequency. The only variable in play is the dielectric constant. The Vp represents the speed at which a signal transmits along the cable as a % of the speed of air. Air/vacuum will be the fasted medium to use to transmit an RF signal. The thing is, air is usually not practical since there is nothing to support the center conductor, can be easily crushed and is susceptible to the ingress of moisture. We use foamed dielectrics and expanded tapes to get as close to air as possible. Vp will vary based on the specific dielectric used. The vast majority of our cables range in velocity of propagation from 76% to 86%. For a given cable, the Vp will likely not vary more that +/- 1% over it’s length but as I mentioned earlier, it would be best to use +/-2% for planning purposes. End response Regards, Mark, K1RX On Apr 1, 2020, at 1:43 PM, Jim Brown wrote: On 4/1/2020 7:58 AM, Don Wilhelm wrote: When dealing with a length of transmission line, the use of the '468' factor should not be used - compute the actual wavelength and then apply the velocity factor. There is yet another variable -- VF varies with frequency. At low frequencies, it is lower (slower), increasing until it converges to the published value at VHF. For this reason, matching sections and stubs must be measured at or near the operating frequency with an analyzer or as a stub placed in line with a generator and receiver. They should be cut long, then trimmed so that the null in that generator/receiver circuit is heard, or the analzyer reads a short or open. How much is this variation? For typical transmission lines, it's on the order of 1% from 80M, a bit more for 160M as compared to the published value. If what you're building is a stub to kill harmonics, it's the difference between the CW and phone bands on 80M. 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] 75 ohm coax
This all reminds me of the difference between when I was a young teen getting started as a ham vs now. As a kid I would put things together or throw em up. Only worried about it after it didn’t work. Nowadays, I plan & overthink things to death before getting anything accomplished. I prefer the old way. 73, Josh W6XU Sent from my mobile device > On Apr 1, 2020, at 4:20 PM, Frederick Dwight wrote: > > If you have 75 ohm coax, I would just try it. If the Z of the antenna is in > fact around 35 ohms, the Z at the shack end may be close to 35 ohms on some > bands, but on others the Z will be transposed to well over 100 ohms with an > SWR probably over 3 to one. One of my dipoles has a SWR at the top of 75 > meters of approximately 4:1, and I occasionally venture up there, but my K3S > with internal tuner does not complain and quickly matches it to about 1:1. > Not ideal and this is not the way I usually build my antennas, but the loss > is not too bad. If you can build a unun with approximately a 1:2 ratio this > should solve your problem. If it does not cover all the way from 80 to 10 > with low loss, I would not worry too __ 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] 75 ohm coax
If you have 75 ohm coax, I would just try it. If the Z of the antenna is in fact around 35 ohms, the Z at the shack end may be close to 35 ohms on some bands, but on others the Z will be transposed to well over 100 ohms with an SWR probably over 3 to one. One of my dipoles has a SWR at the top of 75 meters of approximately 4:1, and I occasionally venture up there, but my K3S with internal tuner does not complain and quickly matches it to about 1:1. Not ideal and this is not the way I usually build my antennas, but the loss is not too bad. If you can build a unun with approximately a 1:2 ratio this should solve your problem. If it does not cover all the way from 80 to 10 with low loss, I would not worry too much about say 10 and 12 meters now, since some loss, and/or lower power output should not be a problem with our sunspot situation. If you happen to have lots of 75 ohm cable, you could parallel two runs of exactly the same length, the pair would have a Z of 37.5 ohms, so nearly perfect if your actual antenna Z is in the vicinity of say 25 to 45 ohms. Not suggesting you spend much money on the coax, but if it is cheap or free, you could do this. Later if you change antennas you would have an extra coax run already in place. The power handling of the dual coax runs would be at least the same as a single run, and the loss could be either slightly higher or lower with the dual run depending upon whether the loss is I squared R, or due to the dielectric characteristics, but I would be surprised if the loss differed much at the HF frequencies. Just another idea to think about, not necessarily a recommendation. Rick KL7CW Sent from Mail for Windows 10 __ 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] VF Varies With Frequency
A typical, Type RG-58A Vf measurement, as a function of frequency, is shown in second plot: https://www.kn5l.net/transMeasure/ Vf is frequency dependent. John KN5L On 4/1/20 4:45 PM, Mpridesti via Elecraft wrote: > Requested technical comment from a long established coaxial cable > manufacturer on this topic. > > This was the response: > >The Vp is not measured at any frequency and is independent of frequency. __ 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] VF Varies With Frequency
Requested technical comment from a long established coaxial cable manufacturer on this topic. This was the response: The Vp is not measured at any frequency and is independent of frequency. The only variable in play is the dielectric constant. The Vp represents the speed at which a signal transmits along the cable as a % of the speed of air. Air/vacuum will be the fasted medium to use to transmit an RF signal. The thing is, air is usually not practical since there is nothing to support the center conductor, can be easily crushed and is susceptible to the ingress of moisture. We use foamed dielectrics and expanded tapes to get as close to air as possible. Vp will vary based on the specific dielectric used. The vast majority of our cables range in velocity of propagation from 76% to 86%. For a given cable, the Vp will likely not vary more that +/- 1% over it’s length but as I mentioned earlier, it would be best to use +/-2% for planning purposes. End response Regards, Mark, K1RX > On Apr 1, 2020, at 1:43 PM, Jim Brown wrote: > > On 4/1/2020 7:58 AM, Don Wilhelm wrote: >> When dealing with a length of transmission line, the use of the '468' factor >> should not be used - compute the actual wavelength and then apply the >> velocity factor. > > There is yet another variable -- VF varies with frequency. At low > frequencies, it is lower (slower), increasing until it converges to the > published value at VHF. For this reason, matching sections and stubs must be > measured at or near the operating frequency with an analyzer or as a stub > placed in line with a generator and receiver. They should be cut long, then > trimmed so that the null in that generator/receiver circuit is heard, or the > analzyer reads a short or open. > > How much is this variation? For typical transmission lines, it's on the order > of 1% from 80M, a bit more for 160M as compared to the published value. If > what you're building is a stub to kill harmonics, it's the difference between > the CW and phone bands on 80M. > > 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 mpride...@yahoo.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
[Elecraft] 75 ohm coax
Careful, 75 ohms was picked for cable TV receiving Coax because it was lower loss then 50 ohms but it could not handle high power as 50 ohms could. 50 ohms is a power, loss compromise. 35 ohms For high power high loss, 50 ohms compromise, 75 ohms low loss low power. Ray W8LYJ Sent from my iPad __ 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] RemoteRig Fail
Not entirely clear of the remote configuration. Is it possible the IP address on the remote end has changed? Teamviewer doesn't care about this. -de John NI0K Richard Hayman wrote on 4/1/2020 2:38 PM: It worked yesterday. Cannot connect today. Any additional troubleshooting ideas? All testing looks good. I can get into both radio and control units’ web page by putting in the local IP address in my browser. Therefore both LAN and WAN connectivity are OK. DNS address is OK. Connection not made, shows SIP error and two/tone warning sounds. Radio does not turn on. All pings are normal. I can connect to radio station's PC using TeamViewer from control point. 73, Dick, WN3R wn3r...@gmail.com 202-497-2840 __ 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 jasimm...@pinewooddata.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
[Elecraft] RemoteRig Fail
It worked yesterday. Cannot connect today. Any additional troubleshooting ideas? All testing looks good. I can get into both radio and control units’ web page by putting in the local IP address in my browser. Therefore both LAN and WAN connectivity are OK. DNS address is OK. Connection not made, shows SIP error and two/tone warning sounds. Radio does not turn on. All pings are normal. I can connect to radio station's PC using TeamViewer from control point. 73, Dick, WN3R wn3r...@gmail.com 202-497-2840 __ 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] 75ohm Impedance question K3S and Antenna side.
Ummm ... not quite. A "perfect" half-wave transmission line will reproduce the impedance of the load [which has been alleged to be 35 ohms but this is an all-band antenna so that may vary some] at the source [TX] end. The real line will come close, its loss will have a small effect. His ATU will see whatever the feedpoint complex impedance is, not necessarily 50 ohms. I'd suggest a good common-mode choke at the feedpoint too which might mean a short pigtail of RG-8 ... not sure if there are ferrite toroids that will fit the CATV hardline. Jim, K9YC, has probably the best source of data on chokes, ferrites, et al at k9yc.com/Publish.htm 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 3/31/2020 8:52 PM, John K9UWA wrote: Cut the hardline to multiples of 1/2 wavelength and the swr will be 1 to 1 on both ends. 50 in 50 out. In this case the OP needs around 200 feet. Once your get the velocity factor for the 1/2" hardline... that is ballpark 80 to 83%. for 3.540 mhz is 265 feet x .8 = 212 feet. If you don't have a piece of test gear to get it cut correctly then put a 50 ohm dummy load at the far end keep cutting until your wattmeter says 1 to 1 swr. 1/2 wave multiples will hit most of the ham bands. A little high in the 30m band. Close enough. 73 John k9uwa __ 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] K3 SSB filters
You said: "In addition, when the DSP IF filters are set to about the same width as the roofing filters, the two filters "cascade" -- the rejection of adjacent signals is the sum of the rejection of the two filters. " There is no requirement that the widths be about the same. They could be widely different. If one passes an interfering signal with no attenuation and the other has 100 dB rejection then the sum is 0 + 100 = 100. Either could be first in the lineup. If the K3 second mixer was stronger, hardware AGC might not be necessary and the only need for a "roofing" filter would be to eliminate the image. A single 10-12 kHz filter would suffice and DSP would be the final filter. Sounds like a K4HD doesn't it? On 4/1/2020 10:23 AM, Jim Brown wrote: On 4/1/2020 7:17 AM, Wes wrote: Until you get down to the noise floor isn't it always the sum (in dB) of the rejection? Isn't that what I said? Perhaps I said it badly. 73, Jim __ 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] 75ohm Impedance question K3S and Antenna side.
I agree with those who say just try it with TV cable connected, direct. Tuner will keep the transmitter happy. If you can cut the run to integrals of half wave that might be marginally better on Tx. Back before WWII hams never worried about SWR and just maxed RF current. Open-wire transmission line was popular (and low loss). In 1980 I bought a TS-180S and a 4BTR with 80m coil-whip addition. I attached the base direct to the front bumper of my 4x4 and operated mobile with no radials or tuner. Heard Antarctica on 20m from Eagle, AK. Should have kept the antenna. Sold the radio after losing the finals (driver still output 10w). Before my K3 the best radio I owned was a FT-840. I traded it for a FT-847 which was great on VHF/UHF but nowhere as good on HF (and part of the reason for getting the K3). 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: dubus...@gmail.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
[Elecraft] VF Varies With Frequency
On 4/1/2020 7:58 AM, Don Wilhelm wrote: When dealing with a length of transmission line, the use of the '468' factor should not be used - compute the actual wavelength and then apply the velocity factor. There is yet another variable -- VF varies with frequency. At low frequencies, it is lower (slower), increasing until it converges to the published value at VHF. For this reason, matching sections and stubs must be measured at or near the operating frequency with an analyzer or as a stub placed in line with a generator and receiver. They should be cut long, then trimmed so that the null in that generator/receiver circuit is heard, or the analzyer reads a short or open. How much is this variation? For typical transmission lines, it's on the order of 1% from 80M, a bit more for 160M as compared to the published value. If what you're building is a stub to kill harmonics, it's the difference between the CW and phone bands on 80M. 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] K3 SSB filters
On 4/1/2020 7:17 AM, Wes wrote: Until you get down to the noise floor isn't it always the sum (in dB) of the rejection? Isn't that what I said? Perhaps I said it badly. 73, Jim __ 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] Shipping Status updates
Update: My KX2 was delivered to Elecraft today. Looks like the company is functioning as it can. Unless this is a nasty April Fool's joke from FedEx. Stay safe out there! 73 Lou, W0FK - St. Louis, MO "The difference between stupidity and genius is that genius has its limits." Albert Einstein -- Sent from: http://elecraft.365791.n2.nabble.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] axt1 tripod
I have an XIT Photo XT57TRS tripod that I use with the AXT1 with the AX1. With the removable plate it seems to work well : https://imgur.com/a/dIaXvZl -eric On Tue, Mar 31, 2020 at 5:57 PM Walter Underwood wrote: > Tripod screws are 1/4-20, so an angle bracket and a screw and a wingnut > could help. Tilt the head over 90º. > > I did something similar to attach a Nagoya NMO base station mount to a > tripod. > > Photos and description here. I’ve since replaced the hex nut with a > wingnut. > > > https://observer.wunderwood.org/2018/07/08/using-a-mobile-antenna-as-a-temporary-base-antenna/ > > wunder > K6WRU > Walter Underwood > CM87wj > http://observer.wunderwood.org/ (my blog) > > > On Mar 31, 2020, at 5:49 PM, Jay Rutherford wrote: > > > > I raised this issue after getting my AX1 with tripod adaptor, since it > fit neither of my consumer tripods. You need either a really small tripod > head or a adjustable ball-type adapter that elevates the AX1 up enough to > use the BNC plug to the radio. > > > > Here is a link to one small ball head adapter from Amazon: > > > > AKOAK 1/4" Swivel Mini Ball Head Screw Tripod Mount for DSLR Camera > Camcorder Light Bracket > > 4.4 out of 5 stars > > > > I hope this helps. > > > > 73 Jay K3BH > > > > > > On Tue, Mar 31, 2020, at 18:16, rwwatson wrote: > >> Hello list, > >> I now almost have everything I need for my kx3 portable setup. I want > to use > >> the ax1 with an axt1 adapter and my tripod has a removable camera plate > >> which seems to prevent the coax from attaching to the axt1. any > suggestions > >> on a good tripod. > >> > >> > >> > >> -- > >> Sent from: http://elecraft.365791.n2.nabble.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 k...@arrl.net > >> > > __ > > 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 wun...@wunderwood.org > > __ > 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 garn...@gmail.com -- --Eric _ Eric Garner __ 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] Glad you are OK
Good to learn something from you today Don, Thanks 73, Leroy AB7CE -Original Message- From: Don Wilhelm Sent: Tuesday, March 31, 2020 9:36 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 SSB filters Hopefully that we will remember that the DSP filter skirts are steeper than the crystal filter skirts, so judicious use of the HiCut and LoCut will provide us with a better passband than narrow roofing filters. What the roofing filters will do is keep the receiver from reducing the hardware AGC for stations which are within the roofing filter passband. It takes adjacent signals in excess of S-9 +30 for the adjacent signal to activate the hardware AGC (which protects the front end DAC from overload). If the interfering station does not exceed that threshold, then the DSP filters will take care of it, and the need for more narrow roofing filters is superfluous. __ 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] 75ohm Impedance question K3S and Antenna side.
Try this link instead: https://www.dxengineering.com/parts/hsr-6btv 73 Lyn, W0LEN -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John K9UWA Sent: Wednesday, April 01, 2020 9:01 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] 75ohm Impedance question K3S and Antenna side. Supposedly the feedpoint impedance is 52 ohms ??? Yes, I question that a bit. Read all about it here. Sorry I doubled the 1/2 wave mults. https://www.dxengineering.com/search/department/antennas/section/hf-vertical -a ntennas/brand/hustler-antenna/product-line/hustle Hustler Antenna 6BTV - Hustler 6BTV 6-Band HF Vertical Antenna and DXE Installation Guide Packages Antenna, Vertical, HF, 6-Band, 80, 40, 30, 20, 15, 10 meters, 1.5 kW, 24 ft., + DXE BTV High Perf. Guide, Each $241.99 Performance provided by the Hustler 6BTVs is better than any other antenna of this type. Broad-banding is such that one measurement and setting permits both phone and CW operation. The antenna provides nominal 52-ohm base impedance when installed and tuned according to the instructions. The radiation efficiency is equal to, or greater than, other trap verticals. 73 John k9uwa On 1 Apr 2020 at 8:14, Bob McGraw K4TAX wrote: > Based on TLW calculations for 1/2" CATV 75 ohm hard line, 200 ft at 28 > MHz should show a 1.87:1 SWR at the transmitter. Assuming 35 ohms load > Z. This equates to 1.027 dB total loss with 0.207 dB being attributed > to the SWR on the line. Thus going through the efforts and matching > process would only net an improvement of 0.207 dB on 10 meters. Lower > frequencies would be less. > > Since this is a 5 or 6 band antenna, I doubt the Z at the feed point > will always be 35 ohms. In order to determine what is actually needed, > one would need measurements for each band. > > Conclusion: Feed it with 200 ft of 1/2" CATV 75 ohm hard line, use a > short jumper of RG6, or 8X or whatever to connect the hardline to the > radio and be done with it. > > > NOTE: I just noticed that the numbers below are somewhat in error. > > 468/3.540 = 132.2 which is 1/2 wavelength. Thus 132.2 X 2 = 264 ft > which is 1 wavelength, not 2 wavelengths as stated. I didn't run the > math on the others. > > 73 > > Bob, K4TAX > > > On 4/1/2020 7:28 AM, John K9UWA wrote: > > Ah YES I noticed it is for a multi band antenna. > > > > 2 wavelengths 3540 = 265' > > 4 wavelengths 7080 = 265' > > 6 wavelengths 10600 = 265' > > 8 wavelengths 14160 = 265' > > 12 wavelngths 21240 = 265' > > 16 wavelengths 28320 = 265' > > > > Multiply the 265' by velocity factor of the coax and you will be someplace > > just a bit over 200 feet. > > > > the 10mhz band is off a bit. So OK... other than that 80, 40, 20, 15,10 are > > all harmonically related. As I said 50 in and 50 out. If the OP runs this > > vertical on 17 and 12m then yes he will have maybe a 1.5 / 1 mismatch caused > > by the coax. But the antenna isn't designed for 17 and 12. > > > > I cut all the 3/4" CATV in my system with a Hewlett Packard HP 4815A Vector > > Impedance Meter. Any 1/2 wave mult the the SWR is the same in as out. Any ODD > > 1/4 wavelength multiple creates a transformation With Multiple 4 hi stacks of > > yagi's I have many of those in the system as well. 75 ohm cable works well to > > put pairs or quads of yagi's together. > > > > The only thing that maybe won't be perfect is the actual vertical itself may > > not be a 50 ohm input. His vertical is a Hustler 6BTV. 73 John k9uwa > > > > > > __ > 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 j...@johnjeanantiqueradio.com John Goller, K9UWA & Jean Goller, N9PXF Antique Radio Restorations k9...@arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRadio.com 4836 Ranch Road Leo, IN 46765 USA 1-260-637-6426 __ 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 l...@lnainc.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
Re: [Elecraft] K160Rx protection
Hans, The K2 RX ANT is injected at the same point after the T/R switch and before the Low Pass Filter, so any energy from the transmit antenna will not harm the K2 during transmit, although it may add to the RF level going into the LPF and be amplified by the KPA100. 73, Don W3FPR On 4/1/2020 10:21 AM, Hans J Rasmusen via Elecraft wrote: Hello My K2/K100 complain and wants to get on the air. I plan to use the build-in K160RX antenna switch for a separate rx antenna, which is about 10m /30 feet from my tx antenna. Plan to run 100 W. Tx antenna is a vertical. Rx antenna is a low (1 m above grd) horizontal dipole. Do I have to install a rx protection curcuit on the rx antenna. I do not remember doing so earlier, but have forgotten and want to play safe. __ 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] 75ohm Impedance question K3S and Antenna side.
Bob and all, One problem is that you are using '468/fMhz' to compute the length of a half wavelength. That is the common 'cutting formula' which includes an end-effect factor of about 5% which reduces the length of a half wave radiator. An actual half wavelength is longer. The actual length (in feet) of a wavelength is 983.5712/fMhz which is considerably longer than that computed using 468/fMhz times 2. When dealing with a length of transmission line, the use of the '468' factor should not be used - compute the actual wavelength and then apply the velocity factor. For those who work in meters instead of feet, the factor is 299.7925/fMHz. See any antenna handbook which has essential characteristics of antennas for validation of my numbers. 73, Don W3FPR On 4/1/2020 9:14 AM, Bob McGraw K4TAX wrote: NOTE: I just noticed that the numbers below are somewhat in error. 468/3.540 = 132.2 which is 1/2 wavelength. Thus 132.2 X 2 = 264 ft which is 1 wavelength, not 2 wavelengths as stated. I didn't run the math on the others. __ 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] K3 SSB filters
Until you get down to the noise floor isn't it always the sum (in dB) of the rejection? Wes N7WS On 3/31/2020 8:52 PM, Jim Brown wrote: On 3/31/2020 8:36 PM, Don Wilhelm wrote: What the roofing filters will do is keep the receiver from reducing the hardware AGC for stations which are within the roofing filter passband. In addition, when the DSP IF filters are set to about the same width as the roofing filters, the two filters "cascade" -- the rejection of adjacent signals is the sum of the rejection of the two filters. 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
[Elecraft] K160Rx protection
Hello My K2/K100 complain and wants to get on the air. I plan to use the build-in K160RX antenna switch for a separate rx antenna, which is about 10m /30 feet from my tx antenna. Plan to run 100 W. Tx antenna is a vertical. Rx antenna is a low (1 m above grd) horizontal dipole. Do I have to install a rx protection curcuit on the rx antenna. I do not remember doing so earlier, but have forgotten and want to play safe. Thank you, stay safe and keep distance 73 Hans Jørgen (Joe) OZ7BQ Sendt fra min 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
Re: [Elecraft] 75ohm Impedance question K3S and Antenna side.
Supposedly the feedpoint impedance is 52 ohms ??? Yes, I question that a bit. Read all about it here. Sorry I doubled the 1/2 wave mults. https://www.dxengineering.com/search/department/antennas/section/hf-vertical-a ntennas/brand/hustler-antenna/product-line/hustle Hustler Antenna 6BTV - Hustler 6BTV 6-Band HF Vertical Antenna and DXE Installation Guide Packages Antenna, Vertical, HF, 6-Band, 80, 40, 30, 20, 15, 10 meters, 1.5 kW, 24 ft., + DXE BTV High Perf. Guide, Each $241.99 Performance provided by the Hustler 6BTVs is better than any other antenna of this type. Broad-banding is such that one measurement and setting permits both phone and CW operation. The antenna provides nominal 52-ohm base impedance when installed and tuned according to the instructions. The radiation efficiency is equal to, or greater than, other trap verticals. 73 John k9uwa On 1 Apr 2020 at 8:14, Bob McGraw K4TAX wrote: > Based on TLW calculations for 1/2" CATV 75 ohm hard line, 200 ft at 28 > MHz should show a 1.87:1 SWR at the transmitter. Assuming 35 ohms load > Z. This equates to 1.027 dB total loss with 0.207 dB being attributed > to the SWR on the line. Thus going through the efforts and matching > process would only net an improvement of 0.207 dB on 10 meters. Lower > frequencies would be less. > > Since this is a 5 or 6 band antenna, I doubt the Z at the feed point > will always be 35 ohms. In order to determine what is actually needed, > one would need measurements for each band. > > Conclusion: Feed it with 200 ft of 1/2" CATV 75 ohm hard line, use a > short jumper of RG6, or 8X or whatever to connect the hardline to the > radio and be done with it. > > > NOTE: I just noticed that the numbers below are somewhat in error. > > 468/3.540 = 132.2 which is 1/2 wavelength. Thus 132.2 X 2 = 264 ft > which is 1 wavelength, not 2 wavelengths as stated. I didn't run the > math on the others. > > 73 > > Bob, K4TAX > > > On 4/1/2020 7:28 AM, John K9UWA wrote: > > Ah YES I noticed it is for a multi band antenna. > > > > 2 wavelengths 3540 = 265' > > 4 wavelengths 7080 = 265' > > 6 wavelengths 10600 = 265' > > 8 wavelengths 14160 = 265' > > 12 wavelngths 21240 = 265' > > 16 wavelengths 28320 = 265' > > > > Multiply the 265' by velocity factor of the coax and you will be someplace > > just a bit over 200 feet. > > > > the 10mhz band is off a bit. So OK... other than that 80, 40, 20, 15,10 are > > all harmonically related. As I said 50 in and 50 out. If the OP runs this > > vertical on 17 and 12m then yes he will have maybe a 1.5 / 1 mismatch caused > > by the coax. But the antenna isn't designed for 17 and 12. > > > > I cut all the 3/4" CATV in my system with a Hewlett Packard HP 4815A Vector > > Impedance Meter. Any 1/2 wave mult the the SWR is the same in as out. Any > > ODD > > 1/4 wavelength multiple creates a transformation With Multiple 4 hi stacks > > of > > yagi's I have many of those in the system as well. 75 ohm cable works well > > to > > put pairs or quads of yagi's together. > > > > The only thing that maybe won't be perfect is the actual vertical itself may > > not be a 50 ohm input. His vertical is a Hustler 6BTV. 73 John k9uwa > > > > > > __ > 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 j...@johnjeanantiqueradio.com John Goller, K9UWA & Jean Goller, N9PXF Antique Radio Restorations k9...@arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRadio.com 4836 Ranch Road Leo, IN 46765 USA 1-260-637-6426 __ 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] 75ohm Impedance question K3S and Antenna side.
Based on TLW calculations for 1/2" CATV 75 ohm hard line, 200 ft at 28 MHz should show a 1.87:1 SWR at the transmitter. Assuming 35 ohms load Z. This equates to 1.027 dB total loss with 0.207 dB being attributed to the SWR on the line. Thus going through the efforts and matching process would only net an improvement of 0.207 dB on 10 meters. Lower frequencies would be less. Since this is a 5 or 6 band antenna, I doubt the Z at the feed point will always be 35 ohms. In order to determine what is actually needed, one would need measurements for each band. Conclusion: Feed it with 200 ft of 1/2" CATV 75 ohm hard line, use a short jumper of RG6, or 8X or whatever to connect the hardline to the radio and be done with it. NOTE: I just noticed that the numbers below are somewhat in error. 468/3.540 = 132.2 which is 1/2 wavelength. Thus 132.2 X 2 = 264 ft which is 1 wavelength, not 2 wavelengths as stated. I didn't run the math on the others. 73 Bob, K4TAX On 4/1/2020 7:28 AM, John K9UWA wrote: Ah YES I noticed it is for a multi band antenna. 2 wavelengths 3540 = 265' 4 wavelengths 7080 = 265' 6 wavelengths 10600 = 265' 8 wavelengths 14160 = 265' 12 wavelngths 21240 = 265' 16 wavelengths 28320 = 265' Multiply the 265' by velocity factor of the coax and you will be someplace just a bit over 200 feet. the 10mhz band is off a bit. So OK... other than that 80, 40, 20, 15,10 are all harmonically related. As I said 50 in and 50 out. If the OP runs this vertical on 17 and 12m then yes he will have maybe a 1.5 / 1 mismatch caused by the coax. But the antenna isn't designed for 17 and 12. I cut all the 3/4" CATV in my system with a Hewlett Packard HP 4815A Vector Impedance Meter. Any 1/2 wave mult the the SWR is the same in as out. Any ODD 1/4 wavelength multiple creates a transformation With Multiple 4 hi stacks of yagi's I have many of those in the system as well. 75 ohm cable works well to put pairs or quads of yagi's together. The only thing that maybe won't be perfect is the actual vertical itself may not be a 50 ohm input. His vertical is a Hustler 6BTV. 73 John k9uwa __ 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] 75ohm Impedance question K3S and Antenna side.
Ah YES I noticed it is for a multi band antenna. 2 wavelengths 3540 = 265' 4 wavelengths 7080 = 265' 6 wavelengths 10600 = 265' 8 wavelengths 14160 = 265' 12 wavelngths 21240 = 265' 16 wavelengths 28320 = 265' Multiply the 265' by velocity factor of the coax and you will be someplace just a bit over 200 feet. the 10mhz band is off a bit. So OK... other than that 80, 40, 20, 15,10 are all harmonically related. As I said 50 in and 50 out. If the OP runs this vertical on 17 and 12m then yes he will have maybe a 1.5 / 1 mismatch caused by the coax. But the antenna isn't designed for 17 and 12. I cut all the 3/4" CATV in my system with a Hewlett Packard HP 4815A Vector Impedance Meter. Any 1/2 wave mult the the SWR is the same in as out. Any ODD 1/4 wavelength multiple creates a transformation With Multiple 4 hi stacks of yagi's I have many of those in the system as well. 75 ohm cable works well to put pairs or quads of yagi's together. The only thing that maybe won't be perfect is the actual vertical itself may not be a 50 ohm input. His vertical is a Hustler 6BTV. 73 John k9uwa On 31 Mar 2020 at 22:39, Jim Brown wrote: > On 3/31/2020 8:52 PM, John K9UWA wrote: > > Cut the hardline to multiples of 1/2 wavelength and the swr will be 1 to 1 > > on > > both ends. 50 in 50 out. > > Did you notice that this is for an all-band antenna? > > 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 j...@johnjeanantiqueradio.com > John Goller, K9UWA & Jean Goller, N9PXF Antique Radio Restorations k9...@arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRadio.com 4836 Ranch Road Leo, IN 46765 USA 1-260-637-6426 __ 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] K3 SSB Filters
John, I concur. When I am running them especially on 20M I find I have the LO Cut at .35 and the HI Cut at 2.25-2.35. Audio is good. Below 2.25 if the calling station is a little off freq or has terrible audio I may waste time trying to get the call. N2TK, Tony -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of j...@kk9a.com Sent: Wednesday, April 1, 2020 7:30 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 SSB Filters I concur. I have 2.8, 2.1 and 1.8 KHz 8 pole roofing filters in my K3S. I made over 8500 SSB QSOs last month and I used the 2.1 KHz roofing filter for all of them. John KK9A Jim Brown K9YC wrote: I tried that and didn't like the result. I prefer 2.1 kHz 8 pole 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 tony@verizon.net __ 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] 75ohm Impedance question K3S and Antenna side.
You can also use coax to make matching transformer however I don't know how either of these methods would work for AE4PB's 6 band vertical. John KK9A John K9UWA wrote: Cut the hardline to multiples of 1/2 wavelength and the swr will be 1 to 1 on both ends. 50 in 50 out. In this case the OP needs around 200 feet. Once your get the velocity factor for the 1/2" hardline... that is ballpark 80 to 83%. for 3.540 mhz is 265 feet x .8 = 212 feet. If you don't have a piece of test gear to get it cut correctly then put a 50 ohm dummy load at the far end keep cutting until your wattmeter says 1 to 1 swr. 1/2 wave multiples will hit most of the ham bands. A little high in the 30m band. Close enough. 73 John k9uwa John Goller, K9UWA & Jean Goller, N9PXF Antique Radio Restorations k9uwa at arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRadio.com 4836 Ranch Road Leo, IN 46765 USA 1-260-637-6426 __ 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] K3 SSB Filters
I concur. I have 2.8, 2.1 and 1.8 KHz 8 pole roofing filters in my K3S. I made over 8500 SSB QSOs last month and I used the 2.1 KHz roofing filter for all of them. John KK9A Jim Brown K9YC wrote: I tried that and didn't like the result. I prefer 2.1 kHz 8 pole 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] 75ohm Impedance question K3S and Antenna side.
Very true, and in fact due to those ground losses the feedpoint impedance might be higher ... and therefore provide a better "match" to the 75 CATV line than if it was 35 ohms. The loss just shows up in the ground instead of in the UNUN (they aren't lossless), on the line, or in the rig tuner. I agree with most of the comments here. I'd try it first without the 2:1 UNUN. 73, Dave AB7E On 3/31/2020 11:04 AM, Jim Brown wrote: Also, I suggest that you check the feedpoint Z with a good antenna analyzer right at the antenna. Depending on your soil conductivity, 35 ohms is pretty optimistic. 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] K3 SSB filters
No, the roofing filters aren't superfluous even with lower level signals. If you set the bandwidths similarly as I do all of the time, the rejection of the filter adds to the rejection from the DSP. I think this should be pretty obvious. Dave AB7E On 3/31/2020 8:36 PM, Don Wilhelm wrote: Hopefully that we will remember that the DSP filter skirts are steeper than the crystal filter skirts, so judicious use of the HiCut and LoCut will provide us with a better passband than narrow roofing filters. What the roofing filters will do is keep the receiver from reducing the hardware AGC for stations which are within the roofing filter passband. It takes adjacent signals in excess of S-9 +30 for the adjacent signal to activate the hardware AGC (which protects the front end DAC from overload). If the interfering station does not exceed that threshold, then the DSP filters will take care of it, and the need for more narrow roofing filters is superfluous. 73, Don W3FPR __ 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
