472KHz/500KHz
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Dom, M1KTA, writes: "Anyone tried the K3 option with a KX3 on 472/500KHz yet?
http://www.elecraft.com/TechNotes/k3qtx_v2_pa3cw.pdf Will be trying but interested to hear anyone's success/failure stories. ------- Dom, I have been running my K3/10 on 495-510-KHz for over a year. I run in the TEST mode to produce 0.1mw drive to my converted 100w NDB aircraft beacon transmitter. I removed the xtal osc and drive the BP filter and 2N2222A driver. Details on my website: http://www.kl7uw.com/600m.htm I run either CW or WSPR near to 495-KHz. MY K3 will not tune below 490-KHz, so I am hopeful to use my KX3 on 472-478 KHz "630m" band when the FCC approves ham use. I am currently licensed with the ARRL Experimental Group WD2XSH to run up to 20w ERP. I achieve 4.125w ERP with 100W RF output on my 43x122 foot inverted-L. I usually monitor using my SDR-IQ, but receive with either it or the K3/10. 73, Ed - KL7UW/WD2XSH-45 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Did you read in that article how a KXV3 module is used in the K3 to
bypass the high pass filtering used to protect the T/R PIN diodes? The KX3 has the same filtering, but no possibility for a KXV3 module. Therefore, the KX3 is not really usable below around 1500kHz. If you want to get onto the 600m band with a KX3, you'll need to look at building a transverter. 73, Matt VK2ACL ----------- Matt and Dom, I have actually listened below 500-KHz with my KX3 and though lowered sensitivity it still hears at these frequencies. I think it will only require a Rx preamp to restore sensitivity. I have not tried to transmit down there with the KX3, but it is my hope that is will work. I can make a transverter (in fact I have one that I made with a SBL-1 mixer using my station 10-MHz REF OCXO as LO. This enables running 10.472-10.510 MHz on the K3 in TEST mode. 73, Ed - KL7UW/WD2XSH-45 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
I did an experiment with 600-meter transceive on the KX3 (around 500
kHz). With the ATU installed, which provides additional filtering for the broadcast band, the transmitter put out about 0.5 to 1.0 watts. But additional low-pass filtering would be required, and as noted above, receiver sensitivity is reduced in this band due to the high- pass filtering. 73, Wayne N6KR --------------- I tried keying the KX3 at 495 and 508 KHz and get BND END warning (probably because it is below edge of 160m). How do you defeat the out of band restriction? 0.5w output would work very nice for me as I currently only use 0.1mw to drive my 100w converted Southern Avionics Non Directional Beacon xmtr (used as a high-gain linear amp). The NDB is usable from 250 to 600 KHz by simply tuning a slug-tuned one-pole BP filter. Adding a preamp is an easy fix for receive as is a BP filter for 500-KHz. I currently have a three-pole LP filter for 600m. 73, Ed - KL7UW survived the 980mb massive storm last night (mostly affected Anchorage 70mi north of me). ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Edward R Cole wrote:
> I tried keying the KX3 at 495 and 508 KHz and get BND END warning > (probably because it is below edge of 160m). How do you defeat the > out of band restriction? Transmit is not presently allowed below 160 m since low-pass filtering would not be adequate. We'd have to provide an access code to allowing opening it up for experimental purposes. But even if we did allow transmit, I'm not sure receive sensitivity would be adequate for your purposes. Wouldn't a simple external transceive converter be a better approach? You could use 7 MHz an an I.F., for example, then use one of the KX3's transverter bands to show the actual operating frequency in kHz. Wayne N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
It would be even easier if one could use a 10MHz IF for LF. For this the K3
and KX3 (when the code is written) xverter settings could be set to XVRF=0MHz XVIF=10MHz. This way the accurate 10MHz reference, already applied to the reference input to the K3 could be used as the local oscillator in the external transverter Dave G4fre Date: Thu, 6 Sep 2012 08:02:50 -0700 From: Wayne Burdick <[hidden email]> Subject: Re: [Elecraft] 472KHz/500KHz To: Edward R Cole <[hidden email]> Cc: [hidden email] Transmit is not presently allowed below 160 m since low-pass filtering would not be adequate. We'd have to provide an access code to allowing opening it up for experimental purposes. But even if we did allow transmit, I'm not sure receive sensitivity would be adequate for your purposes. Wouldn't a simple external transceive converter be a better approach? You could use 7 MHz an an I.F., for example, then use one of the KX3's transverter bands to show the actual operating frequency in kHz. Wayne N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
It would be even easier if one could use a 10MHz IF for LF. For this the K3
and KX3 (when the code is written) xverter settings could be set to XVRF=0MHz XVIF=10MHz. This way the accurate 10MHz reference, already applied to the reference input to the K3 could be used as the local oscillator in the external transverter Dave G4fre ------------ Dave, This is exactly what I am planning. I already have a low-level mixer that does this. My amplifier drives with 0.1 mw )-10 dBm) so basically all I need is to provide for Rx. I have a +/-5E-12 OCXO on 10-MHz with +10 dBm for LO injection. For the K3 running in TEST mode it is a natural. KX3 may not allow operation outside ham bands? 73, Ed - KL7uW ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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There is another caveat to keep in mind when using the K3 in
transverter mode. Sensitivity will be subject to the ham band BPFs, so a preamp may be needed if the "IF" freq. falls well outside the BPF passband unless a general coverage module (KBPF3) is installed. The KBPF3 works fine if the KXV3 is in TEST mode but the K3 is not setup with a transverter band, ie. you're parked on 10.500 MHz for 500 kHz conversion. However, when using a transverter band (ie. direct freq. readout using IF=10, RF=0), the KBPF3 is not switched in when it should be. I have brought this to the attention of support/development since it is clearly a bug and there should be no need for a preamp with the KBPF3 installed. In the meantime, I use IF=14 and RF=0 for a transverter band and get direct freq. readout. The 20M ham BPF is wide enough that there isn't a significant amount of attenuation at 14.500 MHz. Having both 3.5 MHz and 10 MHz would be good additions to the transverter IF selections. The former because there are numerous converter circuits published or were/are commercially available based on 3.5 MHz, the latter because it is a defacto reference freq. 73 - Eric NO3M (WD2XSH/46 - ARRL 600M Experimental Group) On 09/07/12 12:59, Edward R Cole wrote: > It would be even easier if one could use a 10MHz IF for LF. For this the K3 > and KX3 (when the code is written) xverter settings could be set to > XVRF=0MHz XVIF=10MHz. This way the accurate 10MHz reference, already applied > to the reference input to the K3 could be used as the local oscillator in > the external transverter > > Dave > > G4fre > > ------------ > Dave, > > This is exactly what I am planning. I already have a low-level mixer > that does this. My amplifier drives with 0.1 mw )-10 dBm) so > basically all I need is to provide for Rx. I have a +/-5E-12 OCXO on > 10-MHz with +10 dBm for LO injection. For the K3 running in TEST > mode it is a natural. KX3 may not allow operation outside ham bands? > > 73, Ed - KL7uW > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
There is another caveat to keep in mind when using the K3 in
transverter mode. Sensitivity will be subject to the ham band BPFs, so a preamp may be needed if the "IF" freq. falls well outside the BPF passband unless a general coverage module (KBPF3) is installed. The KBPF3 works fine if the KXV3 is in TEST mode but the K3 is not setup with a transverter band, ie. you're parked on 10.500 MHz for 500 kHz conversion. However, when using a transverter band (ie. direct freq. readout using IF=10, RF=0), the KBPF3 is not switched in when it should be. I have brought this to the attention of support/development since it is clearly a bug and there should be no need for a preamp with the KBPF3 installed. In the meantime, I use IF=14 and RF=0 for a transverter band and get direct freq. readout. The 20M ham BPF is wide enough that there isn't a significant amount of attenuation at 14.500 MHz. Having both 3.5 MHz and 10 MHz would be good additions to the transverter IF selections. The former because there are numerous converter circuits published or were/are commercially available based on 3.5 MHz, the latter because it is a defacto reference freq. 73 - Eric NO3M (WD2XSH/46 - ARRL 600M Experimental Group) ---------- Eric, Thanks for reminding that a KBPF3 is needed for general frequency use in TEST mode. I chose to install one when I bought my K3/10 because I was going to operate on 500-KHz with my K3. It is not operating in transverter mode but in TEST mode as RF output is at the transverter output RF jack and not at ANT. So there is no need to use transverter mode. Frequency would read 10.472 when on 472-KHz. I think that much easier than having to build a stable xtal LO on either 3.5 or 7.0 MHz. I bought my OCXO on e-bay for $42 and drifts about 1-Hz every 4-6 months. But that is just my opinion. 73, Ed My prototype transverter uses a SBL-1 mixer from mini-circuits and a 2N3906 buffer amp into a three-pole filter. That has enough RF to drive my 500-KHz linear amp. Others will need to come up with linear's to provide at least 25w to take advantage of the expected 1 ERP limitation on 630m. With my antenna efficiency 100w => 4.15w ERP on 500-KHz. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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