K2 "Aurora noice"
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Hi,
I have used my K2/10w a lot the last couple of years. Always a good performer on CW and very good audio reports on SSB. The KAT2 tunes any antenna I have tried an I have used it a lot portable. At one portable activity last summer the radio was exposed to direct sunlight for a while and got very hot. At that time the output power dropped sharply and receive appeared to listen to the whole band at once. This has happened a couple of times since then. The receive sounds like severe aurora noise covering almost all signals, the transmit on CW is just a low power very wide noise as well. It must be very early in the oscillator stage somewhere, the PLL or something stop working. If I change band it is the same thing on the higher bands. Then suddenly gone and the radio is OK for a moth. Very irritating on portable expeditions or when it happens in the middle of a QSO. I have no clue where to start. I have tried to find a bad connection or bad solder. Is there a PLL reference oscillatior that could make it act like this, or where should I look? Regards, Lennart - SM6KNL |
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Hi Lennart,
Oh dear, this sounds tricky to solve over an email reflector. The first thing do you have access to RF test equipment? As it would be useful to look at the LO on a spectrum analyser. Your description sounds like you have lost lock due to a component changing value with the excessive heat. I would start from scratch and re-align. Make sure you 4MHz oscillator and frequency counter is working correctly first. If it does not align or do the frequency cal does not work get back to me. I am away from home at the moment, but the more information you give me the more I can point you in the right direction. BR Andrew Lenton
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OK, I'll top-post.
Lennart, This exact thing happened to my K2 [#4398] about 18 months ago as I was getting set up outside for the Flight of the Bumblebees the end of July 2008. Weird, very wide band [like everywhere] noise on RX that sort of morphed as I tuned, equally noisy TX with nearly no power out. I got a # from Elecraft and sent the radio to Don. He found that the PLL chip was bad, fixed it, and then realigned my radio. Having it fixed was great. The realignment and improvements in how it worked were worth way more than what it cost me. Good luck, Fred K6DGW Auburn CA USA > Lennart wrote: >> Hi, >> >> I have used my K2/10w a lot the last couple of years. Always a good >> performer on CW and very good audio reports on SSB. The KAT2 tunes any >> antenna I have tried an I have used it a lot portable. At one portable >> activity last summer the radio was exposed to direct sunlight for a while >> and got very hot. At that time the output power dropped sharply and >> receive appeared to listen to the whole band at once. >> >> This has happened a couple of times since then. The receive sounds like >> severe aurora noise covering almost all signals, the transmit on CW is >> just a low power very wide noise as well. It must be very early in the >> oscillator stage somewhere, the PLL or something stop working. If I change >> band it is the same thing on the higher bands. Then suddenly gone and the >> radio is OK for a moth. >> >> Very irritating on portable expeditions or when it happens in the middle >> of a QSO. >> >> I have no clue where to start. I have tried to find a bad connection or >> bad solder. Is there a PLL reference oscillatior that could make it act >> like this, or where should I look? >> >> Regards, >> Lennart - SM6KNL >> > ______________________________________________________________ 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 Andrew UK
This is just feedback to the forum. Thanks to all good feedback I got I found resistor r25 in PLL without proper solder connection in just a few hours. As I was recommended towards the PLL area I looked around with a good lamp and a magnifying glass. I was able to "wiggle" the resistor and get the noise back. After resoldering R25 the radio has been performing very well.
Thanks everyone! 73 de SM6KNL |
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Well
there you have it, one way to test a product, is to heat it up and cool it
down again after a few cycles and all is well you have a good product. 73 Andrew From: Lennart [via Elecraft]
[mailto:[hidden email]] This is just feedback to the
forum. Thanks to all good feedback I got I found resistor r25 in PLL without
proper solder connection in just a few hours. As I was recommended towards the
PLL area I looked around with a good lamp and a magnifying glass. I was able to
"wiggle" the resistor and get the noise back. After resoldering R25
the radio has been performing very well. View message @ http://n2.nabble.com/K2-Aurora-noice-tp4134494p4183283.html
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