[K3] ...and then there was silence (well almost)
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Greetings fellow Elecrafters--
I was chasing RF in the shack, which had been causing cqrlog to lock up. I was using the loudness of the hum coming out of my PC's outboard stereo speakers to gauge how much raw RF there might be. Well at one point the shack got very quiet and I thought that I might have blown out the speakers. No...not the case. Here are the bottom line symptoms: Any change of band and the swr goes sky high upon keying. I hit the "ATU Tune" and the ATU quickly reduces the swr from ohmigawd to less than 2:1. The output power, which had taken a dive when the swr was high, comes back to a dialed 100W. However, the Diamond SX-100 watt/swr meter I keep in the line indicates that I'm transmitting almost 300W! Naw...can't be. Next major symptom: sensitivity is gone. Even the Boston big gun 50000 Watt WBZ, up the road, is in the noise. I use MW to chase baseball games. I have removed the wattmeter and my B&W LP filter as well as the surge suppressor from the line so that nothing stands in the way of my path to my Titan-DX vertical and the symptoms remain the same. The symptoms barely change if I bypass the ATU. I have a sneaking suspicion that I've blown the ATU and opened one side of the signal path. That would explain the loss of sensitivity and possibly the ridiculously high output power as indicated by the external wattmeter. The on-board meters shows a proper 100W out. I figured I'd throw this out there to the Elecraft Knowledge Base before tearing the rig apart. K3>>>Diamond SX-100 wattmeter>>>B&W Low Pass Filter>>>surge suppressor>>>antenna feed to the world. -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ______________________________________________________________ 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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Here's a gut guess...
Something in the Titan has gone sour. You read 300 watts on the Diamond because the line SWR is so high. Whatever is causing the high SWR from the antenna is causing all kinds of problems with RF in the shack. There is something the matter with the Diamond read on reflected power, so it's telling you everything is fine out the line, except it isn't. I have a Titan I now use as an alternate listen antenna, and if it gets water inside, or that 80 meter cap at the top goes bad, the whole thing behaves poorly. It's very touchy. The K3 is the last place I'd look until the above ruled out. 73, Guy. On Mon, Mar 22, 2010 at 8:50 PM, Dick Roth, KA1OZ <[hidden email]> wrote: > Greetings fellow Elecrafters-- > > I was chasing RF in the shack, which had been causing cqrlog to lock up. > I was using the loudness of the hum coming out of my PC's outboard > stereo speakers to gauge how much raw RF there might be. > > Well at one point the shack got very quiet and I thought that I might > have blown out the speakers. No...not the case. Here are the bottom > line symptoms: > > Any change of band and the swr goes sky high upon keying. I hit the > "ATU Tune" and the ATU quickly reduces the swr from ohmigawd to less > than 2:1. The output power, which had taken a dive when the swr was > high, comes back to a dialed 100W. However, the Diamond SX-100 watt/swr > meter I keep in the line indicates that I'm transmitting almost 300W! > Naw...can't be. > > Next major symptom: sensitivity is gone. Even the Boston big gun 50000 > Watt WBZ, up the road, is in the noise. I use MW to chase baseball games. > > I have removed the wattmeter and my B&W LP filter as well as the surge > suppressor from the line so that nothing stands in the way of my path to > my Titan-DX vertical and the symptoms remain the same. > > The symptoms barely change if I bypass the ATU. I have a sneaking > suspicion that I've blown the ATU and opened one side of the signal > path. That would explain the loss of sensitivity and possibly the > ridiculously high output power as indicated by the external wattmeter. > The on-board meters shows a proper 100W out. > > I figured I'd throw this out there to the Elecraft Knowledge Base before > tearing the rig apart. > > K3>>>Diamond SX-100 wattmeter>>>B&W Low Pass Filter>>>surge > suppressor>>>antenna feed to the world. > > -- > 73, > Dick ka1oz > Middleborough, MA > > Radio: Elecraft K3/100(Kit) SN 859 > Antenna: Titan-DX > ______________________________________________________________ > 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 > 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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Guy Olinger K2AV wrote:
> Here's a gut guess... > > Something in the Titan has gone sour. You read 300 watts on the > Diamond because the line SWR is so high. Whatever is causing the high > SWR from the antenna is causing all kinds of problems with RF in the > shack. There is something the matter with the Diamond read on > reflected power, so it's telling you everything is fine out the line, > except it isn't. > > I have a Titan I now use as an alternate listen antenna, and if it > gets water inside, or that 80 meter cap at the top goes bad, the whole > thing behaves poorly. It's very touchy. > > The K3 is the last place I'd look until the above ruled out. > > 73, Guy. > > On Mon, Mar 22, 2010 at 8:50 PM, Dick Roth, KA1OZ<[hidden email]> wrote: >> Greetings fellow Elecrafters-- >> >> I was chasing RF in the shack, which had been causing cqrlog to lock up. >> I was using the loudness of the hum coming out of my PC's outboard >> stereo speakers to gauge how much raw RF there might be. >> >> Well at one point the shack got very quiet and I thought that I might >> have blown out the speakers. No...not the case. Here are the bottom >> line symptoms: >> >> Any change of band and the swr goes sky high upon keying. I hit the >> "ATU Tune" and the ATU quickly reduces the swr from ohmigawd to less >> than 2:1. The output power, which had taken a dive when the swr was >> high, comes back to a dialed 100W. However, the Diamond SX-100 watt/swr >> meter I keep in the line indicates that I'm transmitting almost 300W! >> Naw...can't be. >> >> Next major symptom: sensitivity is gone. Even the Boston big gun 50000 >> Watt WBZ, up the road, is in the noise. I use MW to chase baseball games. >> >> I have removed the wattmeter and my B&W LP filter as well as the surge >> suppressor from the line so that nothing stands in the way of my path to >> my Titan-DX vertical and the symptoms remain the same. >> >> The symptoms barely change if I bypass the ATU. I have a sneaking >> suspicion that I've blown the ATU and opened one side of the signal >> path. That would explain the loss of sensitivity and possibly the >> ridiculously high output power as indicated by the external wattmeter. >> The on-board meters shows a proper 100W out. >> >> I figured I'd throw this out there to the Elecraft Knowledge Base before >> tearing the rig apart. >> >> K3>>>Diamond SX-100 wattmeter>>>B&W Low Pass Filter>>>surge >> suppressor>>>antenna feed to the world. >> >> -- >> 73, >> Dick ka1oz >> Middleborough, MA >> >> Radio: Elecraft K3/100(Kit) SN 859 >> Antenna: Titan-DX >> ______________________________________________________________ >> 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 >> > -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ______________________________________________________________ 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 |
Re: [K3] ...and then there was silence (well almost)
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In reply to this post by raroth7
I would check very carefully for a Coax failure or other short/Open in
the signal path. I would then check the antenna with a second rig or receiver , if you have one available Next check the k3 carefully to ensure that you have not inadvertently selected the wrong antenna port, RX antenna input input etc. If you have the transverter interface check to see if you can hear ok on the RX antenna input, this would help rule out the ATU Your wattmeter will not give meaningful power measurement results without a dummy load, even then the results will be a bit of a 'ballpark figure' Until you resolve other issues carry out your tests at a low power level (20W or less than 2W might be good choices) Also both the Low pass filter and the Surge arrestor expect to operate in a (near) 50Ohm environment but presumably the system is relatively close to this when functioning correctly ? On Mon, 2010-03-22 at 20:50 -0400, Dick Roth, KA1OZ wrote: > Next major symptom: sensitivity is gone. Even the Boston big gun 50000 > Watt WBZ, up the road, is in the noise. I use MW to chase baseball games. > > I have removed the wattmeter and my B&W LP filter as well as the surge > suppressor from the line so that nothing stands in the way of my path to > my Titan-DX vertical and the symptoms remain the same. -- 73 Brendan EI6IZ ______________________________________________________________ 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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