[Collins] 75S-1 Problem

[Jim Brannigan]

Glenn,

I was just trying to give the fellow a benchmark.

If his calibrator "pinned" his S-meter, then the problem "might" not be with
the URM-25.
If the calibrator produced no S-meter indication, then the RX sensitivity
"might" be too low and the URM-25 "might" be producing much more output than
the RF output meter indicates.

I used "DB" in a generic sense.

BTW, my calibrated 75S-3B S-meter reads "80" at 14.100khz..........

Jim

> None of my S-Line receivers produce anything like S-9
> +20dB on 20 meters (note the large "B" on "dB" which
> indicates a "Bell", a lower case "b" doesn't mean
> anything in terms of signal relationships) and all
> have S-9 set for 50 microvolts using a well calibrated
> service monitor.  That includes two 75S-1 receivers
> and a 75S-3A receiver.  I have worked on numerous
> S-Line receivers over the years and very few, if any,
> have had the calibrator run that high of an "S" meter
> reading on 20 meters.
>
> Frankly, the output of the crystal calibrators vary
> all over the place.  You can do a rough alignment on
> the receivers using just the calibrator.  But, as to
> knowing just what the actual sensitivity is, you won't
> have a "clue" using the crystal calibrator.
>
> Glen, K9STH
>
>
> --- Jim Brannigan <jbrannig at optonline.net> wrote:
>
> As a benchmark, subject to a lot of variables,  the
> 100kc calibrator should produce a S9+ 20db response on
> 20M.