40600Re: [softrock40] Re: Si570 desoldering tips - SOLVED
- Feb 8, 2010So, it wasn't the Si570... Turns out it was my sound card! Stupid me,
I never thought about what damage the original event would have done to
the sound card that was connected.
When I first built the RXTX, I could leave the 80M/40M filter in place
and tune 160-10 in search of something interesting. I could see signals
no matter where I went. If I found something, I 'd swap out the filter
and get a stronger signal. Now, there's noise everywhere when the
antenna isn't connected. With the antenna hooked up and the 80M/40M
filter in place, everything under 30M shows up fine. But, even with the
30M/20M/17M filter in place, all I get is noise above about 10.1Mhz.
Last night, I was messing with my old TS-520 and using the RXTX as a
tuning tool (TX low power on the TS-520 and tune the carrier until it
showed up in the right spot in Rocky). With the antenna disconnected on
the RXTX and noise all over the waterfall, as soon as I transmitted with
the TS-520, all the noise went away and I could see my signal clearly.
it got me thinking about the sound card. Maybe, now that it is damaged,
it needs a minimum signal level to overcome the noise.
I've connected it to my laptop and all bands are working. This old
laptop can't process 96kbps, but 48 is ok. I'm WSPRing on 30M now (RX
only). Guess it's time to buy a new sound card and this time install
some isolation to protect it...
Barry - KE4JUC
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