[AMRadio] Ranger Audio


A.R.S. - W5AMI ars.w5ami at gmail.com
Wed Nov 15 08:21:09 EST 2006


On 11/15/06, Jack Schmidling <jack at schmidling.com> wrote:
> Rick Brashear wrote:
> > I know this is a dumb question, but are you sure the D-104 is of the
> > High Z variety?
>
> Not dumb at all.  How can I tell?  It puts out about 10mv ptp into a
> scope.  Did not measure the DC resistance because I am not sure I can
> apply voltage to it safely.
>

If it doesn't have the pre-amp built in the base, it's more than
likely high-Z.  Those crystal elements are usually very high
impedance, in the mega-ohms, which will do nicely on the Ranger.

If you don't have an audio generator, find a strong unmodulated
carrier, maybe a calibrator on your rx, hook your scope to the mic and
use some good headphones cupped over the d104 head.  Sweep your rx vfo
on ssb or cw from zero beat upwards away from the carrier and watch
the scope.  You should be able to tell if the crystal element is good
this way.  Should see a good sine wave except maybe at the very low
end where it may display a bit of phase distortion.  The d104 element
does have some bumps at certain points, but I don't remember where.



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