GRC-106(*) Experience, anyone?

Bob Miller bmiller at CALWEB.COM
Sun Sep 20 01:49:18 EDT 1998

    Good luck with the GRC106A.  'Tis a nifty radio but not without
problems of its own.  The PA is kind of a cranky devil on whip antennas,
but not too bad to tune on 50 ohm loads.  Don't drop it though as it is
as delicate as a fresh egg.  The turrent assembly can be a nightmare if
jarred and there are a lot of moving parts in the unit.  The turrent
unit is a collection of ferrite transformers organized in 1 mhz band
segments and they will and do burn out (wire spitzzzzz) etc.  The heat
exchanger system without external help is a joke in a hot environment
and an aux blower and plenum is needed to really get hot air out of the
thing---and I mean lots of air too.
You have not escaped the hoover completely with the GRC-106.
    The exciter (you mentioned GRC-106A) will have 100 hz tuning which
is a big improvement over the straight 106 with its 1khz tuning
increments.  The major down side is the USB only configuration and the
1.750Mhz filter is BIG and leaves no room to insert a complimentary
filter to get you LSB for 80 and 40 meters.
    The timing of the module switching can be a killer if you are not
carful.  Self aligning spring loaded index pins on the couplers usually
keep you out of trouble, but it's a good idea to recheck indexing when
you pull and replace modules.
    The Master Clocks are a common failure item according to other
fellows that I've talked with these past years and the synth modules for
Mhz and 100 Khz are also a source of dead bands.
    Overall my GRC106A exciter is a fairly nice radio and I use it by
itself w/o the amp  when I need a quiet Dead-On radio for listening to
HF stuff and rtty.  The amp is kind of a waste of energy given the
overall low effieciency DC input vs watts output and the thermal limits
of the sealed heat exchanger system used on the internal 4CX350s.  Most
I ever got out of the PA on CW was around 250 watts.  The manual coupler
system can be a nightmare to tune when working with random length
antennas and not too friendly when used with fairly resonant loads.  You
will definately miss your autotune GRC-19 in this catagory.
    When I was in the military using these units, our RATT link
reliability went down a great deal when we switched to the
GRC-106A/GRC-122 system from the GRC-19   GRC-46 RATT units.
    But as a home use Anchor in a military radio collection, everyone
should have at least two GRC-106s.  Heh!  But the big question is
whether or not you will be able to test the system before you spend you
dollars.  Be sure and get the dog bone and the primary DC cables and if
you are going to run the whip, make sure the high voltage feedline,
antenna mount, elements, and antenna HV condom come with the buy.  The
buy should also include the Termination Wattmeter and VSWR meter model
    Good luck and happy hoovers.

    Bob, KE6F

Tom Norris wrote:

> Am in the process of dealing for a GRC-106A. anyone with any
> experience care to comment or give me pointers to let me know
> just what I am getting myself into? :-)
> Less noisy than a GRC-19? Used to have one, liked it except
> for the "Runaway Hoover Shop Vac" sound effects. Great CW
> and AM TX. The 106 will also give me USB, and 400 watts.
> Looking at the specs, it appears to use about the same amount
>  of power @ 24 volts. ( more or less 40 amps ).Correct me if I
> am wrong.
> Thanks for your help and patience.
> Tom
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