"Jim Higgins" wrote in message
...
On Wed, 10 Aug 2011 02:39:47 -0700 (PDT), DrYattz
wrote:

THANKS, everyone, for the very thoughtful and thorough responses!
________________________________

John KD5YI wrote:

Check for a slide switch on the back that switches from internal to
external antenna.

Would that be the ATT 0dB - 20dB switch? They show it in a figure,
but don't say what it's for. I'll try it.


No, that's an attenuator. 0dB gives full signal strength and 20dB
reduces it by 20dB. Very basically it's used when signals are too
strong. Play with it as you receive signals of various strengths and
with various strength signals interfering and you'll discover where it
can help.

On the schematic diagram that I retreived, the attenuator is only in the
path of the LO-Z antenna, the SO-239 jack -- the one with the threads on it.

The telescoping whip and the High-Z jack are electically almost the same
place, separated only by a single capacitor which couples signals from the
HI-Z jack into the path from the telescoping whip. No attenuator in that
path.