[K2] Using the K2 above 29 MHz
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[K2] Using the K2 above 29 MHz
 
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The K2 is specified to operate on 10m only up to 28.8 MHz. While contemplating possible future VHF rigs for a multi-operator multi-band environment, I have wondered about using a K2 as an IF for VHF transverters at around 29-29.4 MHz (to avoid interference with bands using 28 MHz IF).
Both of my K2s seem to operate (VFO synthesizer works) up to 30 MHz. At 29.5 MHz the available transmit power (QRP) is starting to drop off and this is quite noticeable at 30 MHz. The QRP PA efficiency drops off somewhat as well. There are a few receive birdies on the 100 watt radio, but the QRP one is pretty quiet - nothing that should be noticeable under the extra noise coming from a transverter. Turning the preamp on makes extra noise as it should (but it is after the bandpass filters so that doesn't mean a whole lot). But it seems that it should work ok as long as I don't want more than 4-5 watts (most likely I'd use a K60XV), perhaps with a bit of bandpass filter tweaking. Are there any caveats that I am unaware of? Spurious emissions, perhaps? Has anyone tried using their K2 above 29 MHz? 73, Steve VE3SMA ______________________________________________________________ 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: [K2] Using the K2 above 29 MHz
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I have used my K2 with a DEMI 2M transverter board in it to drive
transverters from 902 through 10368 MHz for many years. When I used it to drive both 902 and 903 MHz portions of that band, the output was very much lower when 29MHz was in use for 903. I can't say whether it was due to the 29 MHz IF or the 144MHz transverter output. I didn't pay much attention to spurs as 902/903 is a trashy band anyway. I have made many nice QSOs with the setup. 73, Dave, K4TO On Sat, May 19, 2018 at 1:18 PM Steve Kavanagh via Elecraft < [hidden email]> wrote: > The K2 is specified to operate on 10m only up to 28.8 MHz. While > contemplating possible future VHF rigs for a multi-operator multi-band > environment, I have wondered about using a K2 as an IF for VHF transverters > at around 29-29.4 MHz (to avoid interference with bands using 28 MHz IF). > > Both of my K2s seem to operate (VFO synthesizer works) up to 30 MHz. At > 29.5 MHz the available transmit power (QRP) is starting to drop off and > this is quite noticeable at 30 MHz. The QRP PA efficiency drops off > somewhat as well. There are a few receive birdies on the 100 watt radio, > but the QRP one is pretty quiet - nothing that should be noticeable under > the extra noise coming from a transverter. Turning the preamp on makes > extra noise as it should (but it is after the bandpass filters so that > doesn't mean a whole lot). But it seems that it should work ok as long as > I don't want more than 4-5 watts (most likely I'd use a K60XV), perhaps > with a bit of bandpass filter tweaking. > > Are there any caveats that I am unaware of? Spurious emissions, perhaps? > Has anyone tried using their K2 above 29 MHz? > > 73, > Steve VE3SMA > ______________________________________________________________ > 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: [K2] Using the K2 above 29 MHz
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In reply to this post by Elecraft mailing list
Thanks, Dave.
Were you using a K60XV transverter interface or the QRP antenna jack for transmit output (and if the latter, at what power level) ? 73, Steve VE3SMA -------------------------------------------- On Sat, 5/19/18, Dave Sublette <[hidden email]> wrote: Subject: Re: [Elecraft] [K2] Using the K2 above 29 MHz To: "Steve Kavanagh" <[hidden email]> Cc: "Elecraft Discussion List" <[hidden email]> Received: Saturday, May 19, 2018, 2:12 PM I have used my K2 with a DEMI 2M transverter board in it to drive transverters from 902 through 10368 MHz for many years. When I used it to drive both 902 and 903 MHz portions of that band, the output was very much lower when 29MHz was in use for 903. I can't say whether it was due to the 29 MHz IF or the 144MHz transverter output. I didn't pay much attention to spurs as 902/903 is a trashy band anyway. I have made many nice QSOs with the setup. 73, Dave, K4TO On Sat, May 19, 2018 at 1:18 PM Steve Kavanagh via Elecraft <[hidden email]> wrote: The K2 is specified to operate on 10m only up to 28.8 MHz. While contemplating possible future VHF rigs for a multi-operator multi-band environment, I have wondered about using a K2 as an IF for VHF transverters at around 29-29.4 MHz (to avoid interference with bands using 28 MHz IF). Both of my K2s seem to operate (VFO synthesizer works) up to 30 MHz. At 29.5 MHz the available transmit power (QRP) is starting to drop off and this is quite noticeable at 30 MHz. The QRP PA efficiency drops off somewhat as well. There are a few receive birdies on the 100 watt radio, but the QRP one is pretty quiet - nothing that should be noticeable under the extra noise coming from a transverter. Turning the preamp on makes extra noise as it should (but it is after the bandpass filters so that doesn't mean a whole lot). But it seems that it should work ok as long as I don't want more than 4-5 watts (most likely I'd use a K60XV), perhaps with a bit of bandpass filter tweaking. Are there any caveats that I am unaware of? Spurious emissions, perhaps? Has anyone tried using their K2 above 29 MHz? 73, Steve VE3SMA ______________________________________________________________ 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: [K2] Using the K2 above 29 MHz
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In reply to this post by Elecraft mailing list
OK, Dave. Yes, I am somewhat familiar with DEMI's predecessor of the K60XV. It had no Elecraft-style power control, so it wouldn't surprise me if the power fell off with frequency above 29 MHz. I guess I should test the 29+ MHz output level of the K60XV in the K2 I have with one installed.
Thanks for your info. 73, Steve VE3SMA -------------------------------------------- On Sat, 5/19/18, Dave Sublette <[hidden email]> wrote: Subject: Re: [Elecraft] [K2] Using the K2 above 29 MHz To: "Steve Kavanagh" <[hidden email]> Received: Saturday, May 19, 2018, 4:54 PM Well now -- I don't think I was using the K60XV. When Steve Kostro developed the DEMI board, it just was wired into some point on the output chain. He changed the ON/OFF Power switch on the back to select either the HF QRP signal or the output of the transverter board at the BNC connector. The output of the transverter was about 22 dBm or 220 mw. Dave On Sat, May 19, 2018 at 3:39 PM Steve Kavanagh <[hidden email]> wrote: Thanks, Dave. Were you using a K60XV transverter interface or the QRP antenna jack for transmit output (and if the latter, at what power level) ? 73, Steve VE3SMA -------------------------------------------- On Sat, 5/19/18, Dave Sublette <[hidden email]> wrote: Subject: Re: [Elecraft] [K2] Using the K2 above 29 MHz To: "Steve Kavanagh" <[hidden email]> Cc: "Elecraft Discussion List" <[hidden email]> Received: Saturday, May 19, 2018, 2:12 PM I have used my K2 with a DEMI 2M transverter board in it to drive transverters from 902 through 10368 MHz for many years. When I used it to drive both 902 and 903 MHz portions of that band, the output was very much lower when 29MHz was in use for 903. I can't say whether it was due to the 29 MHz IF or the 144MHz transverter output. I didn't pay much attention to spurs as 902/903 is a trashy band anyway. I have made many nice QSOs with the setup. 73, Dave, K4TO On Sat, May 19, 2018 at 1:18 PM Steve Kavanagh via Elecraft <[hidden email]> wrote: The K2 is specified to operate on 10m only up to 28.8 MHz. While contemplating possible future VHF rigs for a multi-operator multi-band environment, I have wondered about using a K2 as an IF for VHF transverters at around 29-29.4 MHz (to avoid interference with bands using 28 MHz IF). Both of my K2s seem to operate (VFO synthesizer works) up to 30 MHz. At 29.5 MHz the available transmit power (QRP) is starting to drop off and this is quite noticeable at 30 MHz. The QRP PA efficiency drops off somewhat as well. There are a few receive birdies on the 100 watt radio, but the QRP one is pretty quiet - nothing that should be noticeable under the extra noise coming from a transverter. Turning the preamp on makes extra noise as it should (but it is after the bandpass filters so that doesn't mean a whole lot). But it seems that it should work ok as long as I don't want more than 4-5 watts (most likely I'd use a K60XV), perhaps with a bit of bandpass filter tweaking. Are there any caveats that I am unaware of? Spurious emissions, perhaps? Has anyone tried using their K2 above 29 MHz? 73, Steve VE3SMA ______________________________________________________________ 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: [K2] Using the K2 above 29 MHz
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In reply to this post by Elecraft mailing list
Steve - VE3SMA,
I see the same thing on 2m using my K3 with a DEMI transverter. The K3 will tune 28-32 MHz in transverter mode but there is not enough drive above 30 MHz. My 25w transverter drops to 7w at 146.52 (30.52 MHz IF). So its not usable at the FM end of 2m band. Whether this a limitation of the DEMI unit or K3 is debatable. Result is unusable. Rather than get upset, I just use a 2m-FM radio at frequencies >146 MHz. But I see your conundrum as you would like to use a higher freq. for IF on mw. KX3-2M works fine over full band, and the KX3-2M is my mw IF radio. 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: [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: [K2] Using the K2 above 29 MHz
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In reply to this post by Elecraft mailing list
I made some measurements on my K2/K60XV. It seems the bandpass filter does cut off just above 28.8 MHz and the available 1 mW output from the K60XV drops markedly starting around 29 MHz. It would not be practical to use this output unless the bandpass filter were retuned.
At the QRP antenna jack, using WSJT (and therefore presumably SSB) the power remains constant (when set for 2 watts) up to at least 29.4, so it seems the power control algorithm is doing its job. On CW, however, when raising the frequency the power drops. When starting at 29.4 MHz and going down, the power goes up well above 2 W. It can be reset to 2 W by moving the power knob off the 2 watt setting and back again. This isn't very practical in real operation, so once again, the conclusion is that to operate above 29 MHz the bandpass filter would need to be retuned. 73, Steve VE3SMA ______________________________________________________________ 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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