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[Linrad] Re: Receiving sometimes stop
- Subject: [Linrad] Re: Receiving sometimes stop
- From: Leif Asbrink <sm5bsz.com; leif@xxxxxxxxxxxxxxxx>
- Date: Thu, 28 May 2009 01:10:48 +0200
> 3) Local oscillator testing with the spectrum analyzer
> - When had a problem, LO didn't work or maybe worked with
> incorrectly X'tal.
> - When had a problem, voltage of R4, R5, R6 and R10 were
> minus level. And all of X and Y at the U6/U7 were High.
When all X and Y on U6 and U7 are high, the voltage on R4, R5,
R6 and R10 must be high too. It is the same test point;-)
Anyway, the same voltage on all is an error. One, and one only
should be negative while the others have to be positive.
> But it seems to me that hardware test in Linrad was OK.
> - When had a problem, the X'tal selection occasionally
> changed if the coil was touched by my finger.
Touching the coil should not affect anything.
> - Changing normal/problem by D-sub on/off.
> - working normally at the start but will go problem and
> return to normal suddenly.
Do you really mean it will return to normal suddenly without
any activity on the computer from your side?
I could imagine a loose connection or a short in the control interface
between the computer and the WSE unit, but it seems unlikely that
the unit would go back to normal operation by itself.
If there is an intermittent error you might find that Linrad sometimes
can send a command sucessfully but that random pulses due to some
short or loose connection could store incorrect data in U3.
If something causes an error on the SELECT line to the RX10700 the data
in U2 will be transferred to U3 and that will likely cause an error.
U2 only has the correct data when Linrad uses the SELECT line to clock
in the new data.
Maybe you have some other software that writes to the parallel port
occasionally? Perhaps the parallel port is in some kind of unusual
mode that is not compatible with the way it is used in Linrad.
> I was aware after re-connecting 4 boxed that 143.975,
> 144.025-075, 125-175, 225-275, 325-375, 425-475 were NG and
> others were OK between 143.975 and 144.500 MHz. But all of QRG
> are NG now.
> I'm very confusing... What is no good in my systems? PC?
Connectors, cables or the PC. I think. Can you monitor the voltage
on the RX10700 SELECT line? Does it change by itself? It should
stay permanently low except when Linrad reprograms the RX10700
(Just be careful to not send +15V or -15V into the computer
parallel port if you measure on the d-sub. More safe to do
measurements on U4 in the WSE box.)
Leif / SM5BSZ
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