[Boatanchors] HQ-129X Info

[Carl]

There have been several mods for that fine receiver, I bought my first 
one in 1957.

The May 1959 CQ has an excellent mixer conversion as long as you dont 
mind changing sockets; copy attached.  Or you can adapt a 6SB7Y for a 
noticable improvement.

For the RF stage the simplest is using the 717A mushroom tube.You can 
lift the ground off pin 3 and plug it in or get carried away and take it 
off the RF gain line and play with values to peak performance.

A 6AB7 should also work but may need the screen voltage resistor 
changed. If it is unstable install a 47-100 Ohm carbon resistor in the 
grid lead.

Depending on which mods you make a 717A in the first IF will mitigate 
the 6K8 mixer noise a bit above 20M.

The near ultimate RF stage is a 6GM6 which entails a socket change and 
juggling a few component values.

All tube specs are available here:  http://frank.yueksel.org/index.html

Im using a rebuilt stock 129X now with a Viking I which was my 1957-61 
station. Another one is on the bench getting ready for some serious 
mods. I have all the necessary test equipment to do a proper job and 
evaluation, something I didnt have in the 50's.

Carl
KM1H


----- Original Message ----- 
From: "Byron Tatum" <bjtatum1 at att.net>
To: <boatanchors at mailman.qth.net>
Sent: Monday, March 09, 2009 9:52 PM
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.
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