[Hammarlund] HX-50??

[Glen Zook]

The HX-50A is VERY low power on AM (under 10 watts). 
It puts out about 80 watts on CW and peak on SSB.  I
have owned an HX-50A for several years and use it all
the time on 160 meter SSB and CW (along with a Collins
75A4 for the receiver).  Although my 160 meter
antennas are "full sized", neither one runs in a
straight line (my lot is 70 X 130 feet and the front
yard takes in about 30% of the space so no antennas
there!).  I do get accused of running a linear with
better antennas because my signal is usually right up
there with those who are running considerably more
power and who definitely have "better" antennas.

The wide-range "Pi-network" matches any of my antennas
without any problems.  Also, the HX-50A has a built-in
antenna change-over relay.  You can control it with an
external VFO as well as 3 crystals.  However, the
crystals and VFO are not the "normal" amateur band
frequencies.

Although the bandswitch has 160 meters on it, very few
of the HX-50 and HX-50A came with the optional 160
meter kit installed.  Luckily I found an original 160
meter kit for mine.  There was one problem with the
160 meter kit and that was the fact that there was not
enough "coupling" between two added coils.  I only got
enough drive for about 3 watts output on 160!  Finally
I added a 33 pf capacitor to couple between the two
coils and the output went right up to 80 watts.  The
circuitry is not quite "factory standard", but it
works fine on all bands 160 through 10 meters.

You have to let the rig warm up for at least an hour
before the VFO gets stable.  After that, it stays
pretty much on frequency, only needing a slight "touch
up" of about 100 Hz every half-hour or so.

When I turn my HX-50A on, often there is a "bit" of a
"twang" from the power transformer.  This depends on
just where in the "cycle" of the AC power that I turn
the rig on.  Sometimes there is no sound, but usually
there is!

The audio quality is excellent on SSB, the carrier
supression is very good, and the unwanted sideband
supression is also very good.

Since I only paid $75 for mine and another $50 for the
160 meter kit, it was an excellent buy.  Supposedly
the transmitter was not working when I bought it (that
is why the low price).  I removed the cabinet, put the
plate cap back on the final amplifier tube, and the
transmitter worked fine!  The only thing wrong was
that the plate cap had come unplugged!

The transmitter is pretty well constructed, but
definitely is not Collins "quality"!  However, if you
can get one for a good price, then they are worth the
money.

You can see a photograph of my HX-50A on the K9STH
website that is listed at the end of this message. 
The "link" is towards the bottom of the list and is
"shack photos" in description.

Glen, K9STH


--- ARDUJENSKI@aol.com wrote:

I have not found much information discussing the
Hammarlund HX-50 or 50A transmillter. Can someone
either share some background info or point me to a
website? Maybe sharing some pros and cons on the unit.
I would use it primarily for CW and som AM operations.

=====
Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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