K3 --- stopped XMIT during SSB QSO
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K3 --- stopped XMIT during SSB QSO
 
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Last evening I had an annoying problem with K3. It would stop transmitting any signal, even though the red xmit light was lit.
The K3 was driving a 30L1 linear with about 45 watts, a pretty safe level, and no ALC connection. I had LP-BRIDGE running, with HRD, SDR_IF and the nice little S-meter display application running. SDR_IF links direct to HRD.
I was running PTT mode, keying with the XMIT button. I would talk for about 30 seconds, and the signal would just quit. Happened many times, to the point I took the rig offline. Each time, the red light still glowing. Pressing XMIT twice to toggle PTT off/on would get my signal back. But the same symptom would recur a bit later.
I'd been running the K3+30L1 and HRD (no LP-BRIDGE) earlier in evening for about an hour in the same PTT fashion, so I know that setup worked FB. I will do some further experimentation, but I suspect that there might have been too heavy a load on the serial interface, causing some Ucode confusion in K3. The serial setup is using the Elecraft supplied USB-serial adapter cable, at 38Kbaud. Any thoughts ?
TNX -- Tom W6TJK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 --- stopped XMIT during SSB QSO
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Hi Tom,
I think you will find it is the "Nice little S-meter" that is causing your trouble. I had a similar experience with transmit lasting for 12 seconds and then being unresponsive until I switched VOX on and off. I sent my findings to Don WB8YQJ. In his reply he states: "As for the VOX, that's a new one to me, and I suspect it's because I am having to be aggressive with the threshold sets, due to the K3 firmware. Earler versions of the program that don't set the threshold probably don't suffer from this". I also had the odd DSP error to which he replied: "No worries about the DSP error, I am using an undocumented command to read the S-Meter and until a normal command is available that will pop up on rare occasions". Hope this helps 73 Tony VE3QF K3 #137 tom kenville wrote: > Last evening I had an annoying problem with K3. It would stop > transmitting any signal, even though the red xmit light was lit. > > The K3 was driving a 30L1 linear with about 45 watts, a pretty safe > level, and no ALC connection. I had LP-BRIDGE running, with HRD, SDR_IF > and the nice little S-meter display application running. SDR_IF links > direct to HRD. > > I was running PTT mode, keying with the XMIT button. > > I would talk for about 30 seconds, and the signal would just quit. > Happened many times, to the point I took the rig offline. Each time, > the red light still glowing. Pressing XMIT twice to toggle PTT off/on > would get my signal back. But the same symptom would recur a bit later. > > I'd been running the K3+30L1 and HRD (no LP-BRIDGE) earlier in evening > for about an hour in the same PTT fashion, so I know that setup worked FB. > > I will do some further experimentation, but I suspect that there might > have been too heavy a load on the serial interface, causing some Ucode > confusion in K3. > > The serial setup is using the Elecraft supplied USB-serial adapter > cable, at 38Kbaud. > > Any thoughts ? > > TNX -- Tom W6TJK > > > ------------------------------------------------------------------------ > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 --- stopped XMIT during SSB QSO
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In reply to this post by tom kenville
Hey Tom,
I suspect the S-Meter app is putting too much of a burden on the serial port. You could try using a lower poll rate, but you'll lose accuracy if you go below 10/sec. See if the problem occurs without the S-Meter running. Merry Christmas! David, W4SMT --- On Thu, 12/25/08, tom kenville <[hidden email]> wrote: > From: tom kenville <[hidden email]> > Subject: [Elecraft] K3 --- stopped XMIT during SSB QSO > To: [hidden email] > Date: Thursday, December 25, 2008, 10:53 AM > Last evening I had an annoying problem with K3. It would > stop transmitting > any signal, even though the red xmit light was lit. > The K3 was driving a 30L1 linear with about 45 watts, a > pretty safe level, > and no ALC connection. I had LP-BRIDGE running, with HRD, > SDR_IF and the > nice little S-meter display application running. SDR_IF > links direct to > HRD. > > I was running PTT mode, keying with the XMIT button. > > I would talk for about 30 seconds, and the signal would > just quit. Happened > many times, to the point I took the rig offline. Each > time, the red light > still glowing. Pressing XMIT twice to toggle PTT off/on > would get my signal > back. But the same symptom would recur a bit later. > > I'd been running the K3+30L1 and HRD (no LP-BRIDGE) > earlier in evening for > about an hour in the same PTT fashion, so I know that setup > worked FB. > > I will do some further experimentation, but I suspect that > there might have > been too heavy a load on the serial interface, causing some > Ucode confusion > in K3. > > The serial setup is using the Elecraft supplied USB-serial > adapter cable, at > 38Kbaud. > > Any thoughts ? > > TNX -- Tom W6TJK > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 --- stopped XMIT during SSB QSO
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In reply to this post by tom kenville
A FT-2000 user with a big hairy amp and a CAT cable
connected got so much RF into the CAT cable that he blew the UART in the FT-2000
and the serial port on the PC. This happened when the antenna was rotated to
point at the shack.
I wonder whether the CAT port on the radio has RF
decoupling?
Simon Brown, HB9DRV
www.ham-radio-deluxe.com
_______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 --- stopped XMIT during SSB QSO
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Simon,
The K3 has RF decoupling, but it also has a pin 1 problem. The "pin 1 problem" is the design error that connects a cable shield to a circuit board signal common rather than to the chassis. RF current then wanders around that common, and the IZ drops on common inject it into active circuitry at the whim of the PC board layout artist. Hams are surprisingly ignorant about the immunity of interconnect cables. The K2 shipped with a cable that was shielded but consisted of parallel wires. I had BAD RFI with it at only 12 watts out! We're also lazy -- preferring to run down to Radio Shack and buy a pre-made cable than to pull out a soldering iron and build a proper one. Since I work in pro audio and am an EMC specialist, I knew that twisted pair cable provides EXCELLENT immunity to noise and RF pickup, FAR more than straight wires inside a shield. I solved the problem by replacing the stock control cable with one made from ordinary unshielded CAT5 cable. I wired the cable using one pair for each signaling circuit used by the K2 and my computer, with the return conductor of each pair used as a signal return. That is, one pair for pin 2 and return, one pair for pin 3 and return, one pair for pin 4 (CW) and return, the fourth pair for pin 7 (PTT) and return. The second part of the solution was solving "the pin 1 problem." I did that by making the "return" connection on each end to the DB9 shell. Using that simple UNSHIELDED CAT5 cable I was able to run 1 kW into a long wire antenna on 160M and 80M that ended in the shack and ran only about 1 meter from that K2 control cable! 73, Jim Brown K9YC --Original Message Text--- From: Simon (HB9DRV) Date: Thu, 25 Dec 2008 20:07:44 +0100 A FT-2000 user with a big hairy amp and a CAT cable connected got so much RF into the CAT cable that he blew the UART in the FT-2000 and the serial port on the PC. This happened when the antenna was rotated to point at the shack. I wonder whether the CAT port on the radio has RF decoupling? Simon Brown, HB9DRV www.ham-radio-deluxe.com ----- Original Message ----- From: tom kenville Last evening I had an annoying problem with K3. It would stop transmitting any signal, even though the red xmit light was lit. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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