Can anyone help with this HQ-170 variation? mod?

[Kenneth D. Grimm, K4XL]

This fellow needs some help in identifying what he has.  Does anyone
recognize what he is describing?  The Hammarlund Historian's web page
seems to have disappeared and I can't find anything in any of my files
on this thing.  Sounds like it might be a noise blanker accessory, but I
can't recall whether there was such a thing available for the HQ-170A.

>First of all, I wish to thank you for running BAMA! Finally I managed
to get myself the >manual and schematics for my HQ170A. After the
initial enthusiasm, some frustration: my >receiver, S/N 9705, has a 3
tube sub-assembly that's not described in the manual. That >assembly
includes a 6BH6, a 6BE6, a 6AL5, and two RF coils or transformers. It is
>connected to a potentiometer coupled to the noise limiter pot, but
controlled separately, >and seems to be connected also to the 455KHz IF
amplifier stage. There's no panel >indication of the additional control.
The sub-assembly seems to have been factory >installed, in fact its
tubes have the Hammarlund name on.

What do you think?  Noise blanker?  Any hard info or off the wall ideas
will be appreciated!

73,
Ken K4XL
k4xl at arrl.net
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