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Alverson, Tom \(Xetron\)
开云体育Chris:
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I put my softrock on a calibrated? HP siggen and got a
very accurate reading with a -80 dBm input.? You may have a problem with
your? input filtering? (got the 2 inductors switched maybe?).? I
don't know if the soundcard levels affect the s-meter or not.? I also got
the "popping" effect on the PC I used that? was near the signal
generator.? (an IBM with built in sound).?? My Dell Dimension
4600 with built in sound does not have this popping problem (every few seconds,
there is a popping sound, and the spectrum display jumps at the same
time).? Maybe some tweaking of the sound card/drivers would help (or a
different sound card).
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73 de Tom NU8D From: softrock40@... [mailto:softrock40@...] On Behalf Of Chris Waldrup Sent: Wednesday, October 05, 2005 10:32 PM To: softrock40@... Subject: [softrock40] Softrock up and running but need a little guidance Hi All,
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I finally got my Softrock up tonight after playing
with it last night with no luck.? Tonight I can hear stations!!? I had
a SDR program operator error last night.
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I took it into work and during lunch plugged it
into a USB port and verified with a scope that the timing signals were
present.? A little overshoot and undershoot on the output of the buffer amp
U1, but the signal is present.? I did the initial soldering under my
microscope but checked over it again today to make sure all was
fine.
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Tonight I hooked it up to my 8640 generator and
hear the tone fine, but every few seconds there is a rapid succession of a few
clicks where the signal dies and then comes back.? The signal strength goes
up from about -140 dBm to mid -50's.? The LED does not flicker at all
during this (I had thought that the USB connector may be loose) and I tried
connecting the USB connector up to my wife's new laptop and I get the same
result.? I also connected the radio up to my antenna to rule out the
generator acting funny and I get the same result.?
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How accurate is the signal strength meter?? I
set my generator for 7.040 Mhz at -73 dbm and the signal strength meter read
-109 dBm.? I checked the output of my generator last year with a commercial
power meter and it was about 2 dBm off, not 36 dBm off.
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I have one last question.? I was going through
the "Configure and Use" section of the assembly manual and?item #4 made me
pause. Do I have to null the receiver to below -50 dBm on the?panadapter
display ?or am I supposed to have a difference before and after nulling of
50 dBm.? I can get the receiver to null by about 5 dBm on the screen (from
-108 dBm to -103 dBm).
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Thanks in advance for any help that can be
provided.
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Chris Waldrup
KD4PBJ |
