[Boatanchors] HQ-129X Info

[The Pollacks]

Follow up to my reply to Byron about this RX:  I recapped mine, a tedious
but not difficult task, and it is an amazingly stable, sensitive, and
selective receiver.  Just had it on the San Diego AM net last nite, paired
with my Viking I.  I did not make any mods, and probably won't, both because
I like to keep things original, and also because I don't think that any
reasonable mods would result in a great improvement.

This being said, a short search revealed only one article on the 129X in
QST, which is a "Hints and Kinks" from 1955.  This was a simple mod, but not
too useful.  The writer wanted to leave the filaments going for long periods
and turn off all the B+, so he replaced the RF Gain (Sensitivity) pot to one
with a switch, and grounded the center tap of the power transformer through
the switch.  When the RF gain was turned "on," the receiver came to life.
Not sure why he wanted to do this!

There is a more extensive mod in the April 1952 CQ, which involves changing
the 6K8 mixer to a 6X8 for better signal to noise figures.  Since the 6X8 is
a 9 pin miniature tube, and is replacing an octal tube, the author
recommends drilling out the old socket, bolting in a piece of aluminum
punched for the miniature socket, and making the mods, which, other than
changing the tube socket, are not too extensive.  The author even provides
step by step instructions.

The article is reproduced in the CQ Anthology II.

I probably won't bother, but if someone does or has done this mod, I'd like
to hear the results!

In conclusion, it is interesting that there are so few mods described for
this receiver in contemporary magazines, considering the great popularity it
enjoyed.  In contrast, there were many dozens of mods published for the
75A4, which was a much more advanced unit!  (Perhaps this is because an
HQ129X owner had the option of trading up during the mid to late 50s to a
receiver designed for better performance, while the A4 was the "ultimate!")

Hope all this rambling was helpful, or at least interesting, to someone!

Ron K2RP
K2RP at ARRL.NET

-----Original Message-----
From: boatanchors-bounces at mailman.qth.net
[mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Byron Tatum
Sent: Monday, March 09, 2009 6:53 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] HQ-129X Info

Hello-
    I picked up a restorable, working HQ-129X at a recent swapmeet. It
brings back fond memories of my novice days in late1960's. I was not
fortunate enough to have one myself, but I would tune around on my friend's.
I remember  he could work the VK's and ZL's when I barely could tell they
were there on my HR-10, and I had the better antenna!.
    I have ordered a new front panel and will repaint the case. My plans are
to mate this set with my DX-100B.
    I wonder if anyone recalls any improvements to the HQ-129X front end,
such as a less-noisy RF Amp or Mixer? I have been searching on the internet
and saw reference to a QST article about improving the HQ-129X.
    Anyway, just thought I would start gathering info ahead of restoration.
                                                                Thanks,
Byron WA5THJ.
______________________________________________________________
Boatanchors mailing list
Home: http://mailman.qth.net/mailman/listinfo/boatanchors
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Boatanchors at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html