[1000mp] Inrad Front-end Mod

[WX5L]

A -73dbm from a signal generator should result in a S-9 reading on the
s-meter. If it reads higher possibly a slight reduction in the IF gain would
be in order. The IF mod increases the IF gain and reduction of the IF gain
in Menu 9 improves the signal to noise ratio.

I would guess that all rigs would not end of the same but my IF gain setting
with the mod installed and -73dbm to the antenna jack yelding an S-9 reading
was an 8.

73,
Randy




----- Original Message ----- 
From: "Thomas Beltran" <tbeltran@earthlink.net>
To: <1000mp@mailman.qth.net>
Sent: Sunday, January 18, 2004 12:05 PM
Subject: [1000mp] Inrad Front-end Mod


> I put the mod in yesterday, and it was quite easy.  I've been playing
around
> with the IF gain on different settings, currently it is at ten.   I read
> that Yaesu states that one should connect an RF signal generator to the
> antenna jack, and inject +8dbu, and adjust for 1 S unit on the meter.  Can
> anyone translate that into microvolts?  The only signal generator I have
is
> old HP 606A, but I also have a Timewave DSP 599zx that measures
microvolts.
>
>
> Another suggestion was to set the IF gain so that the S-meter reading was
> the same on the main as the sub-reciever.  On my radio, a Mark V (not
> Field), the sub-receiver always had a lower S-meter reading than the main
> receiver.  The IF gain was initially set at 13.  On CW, and at an IF gain
of
> 10, there was still a consistent difference, where the main receiver is 2
> S-units greater than the sub-reciever. I had to reduce the IF gain to 6,
to
> get the main and sub receivers to read the same S-meter readings for a
give
> CW signal.  Tuning around 17 meters right now, there are plenty of 20 db
> signals, so this low setting has not hurt the sensitivity.  What I am
> wondering though, is that the instructions show that one only reduces the
IF
> gain by 1 or 2 units.  Anyone else have similar experiences?  Tom W6EIJ
>
>
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