[Hallicrafters] HT37/SX111 muting/grounding

[Bill Gerhold]

I believe the HT-37 using the "Calibrate" position to zero in receiver
And xmitter on the same frequency.

K2WH

-----Original Message-----
From: hallicrafters-admin at mailman.qth.net
[mailto:hallicrafters-admin at mailman.qth.net] On Behalf Of W5HTW at att.net
Sent: Friday, October 31, 2003 8:39 PM
To: hallicrafters at mailman.qth.net
Subject: [Hallicrafters] HT37/SX111 muting/grounding

Does the HT37 have a "zero" or "spot" switch?  I've never used that
model so
don't know.  Normally all of the old separate transmitters had a spot
selection or zero selection for use in spotting the transmitter
frequency to
the receiver frequency.  The switch keyed the exciter stages but without
keying the final and without switching the relay.   Maybe the HT37
doesn't
have that capability. 

With the SX111 muted, no there will be no audio to use for spotting.
Unless
in 'muting' you simply short and ground the antenna but do not use the
receiver's "mute" terminals.  

While I believe in grounding, there are a good many hams who very
successfully
operate stations using nothing more for ground than the grounding pin of
the
three-wire receptacle in the wall socket.  Using RG8 coax and an antenna
tuner, this may be all the ground you will need.  In fact, adding a long
ground wire may actually bring out the problem of interference rather
than
eliminating it. Before being worried about it, I would try operating the
rig
using only the three wire AC outlet as your ground.  Be sure the
transmitter,
receiver and tuner are grounded together by the shortest possible means,
and
I'd recommend something in addition to the coax shield.  Perhaps a heavy
braid
or wire between the three units.  Use a surge protector strip.  If the
radios
have the two wire plug instead of a three wire, you may have to reverse
one or
the other, or both, to eliminate hum, as well as "hot chassis."   

Before operating, plug in both the receiver and the transmitter, into a
surger
protector or other three-wire outlet.  Disconnect all other wires,
including
the coax.  Using a VTVM, measure from the receiver chassis to the ground
pin
of the surger protector.  If you see line voltage, or substantial
voltage, on
the meter, reverse the receiver's plug.  Then do the same thing with the
transmitter.  Turn them on and measure again.  Plug them in
(independently)
the way that gives the lowest voltage (hopefully none!) on the chassis.


Then ground them together with the bonding wire, hook up your coax, and
get on
the air.  Keep the AC meter hooked up to one of the units and to ground
until
you know you are not going to have problems.  Then put the meter away
and
enjoy hamming. 

While on the air, observe your own TV, stereo, etc.  If you see
interference,
you might try retuning the tuner to see if you can eliminate it.
Otherwise
you may have to buy the artificial ground, like the one MFJ makes.  As I
said,
a lot of hams operate with only the house wiring as the ground.  I'd try
it
before worrying a lot. 

Congratulations on the new license!  Time to get on the air!

73
Ed
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