[Hammarlund] HQ-129 and 717A mod and SP-600

[jeremy-ca]

Not familiar with that particular application but a cascode pair mod was 
common fodder in the old mags. It was simply an update of the cascode 
6BQ7/6BZ7 mods of a few years earlier.

Carl
KM1H


----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at verizon.net>
To: "jeremy-ca" <km1h at jeremy.mv.com>
Cc: "Hammarlund List" <hammarlund at mailman.qth.net>
Sent: Wednesday, November 07, 2007 3:04 PM
Subject: Re: [Hammarlund] HQ-129 and 717A mod and SP-600


> On 7 Nov 2007 at 14:01, jeremy-ca wrote:
>
>> For that matter why not a pair of 6CW4's or 7586's ? The latter
>> especially are rather available.
>
> I suppose you are familiar with that mod in which two
> 6CW4s in cascode are substituted for the first RF amp tube
> in the SP-600? I think it was either a factory or a military
> mod. It was built on a small bit of board and simply plugged
> into the 1st RF amp socket. It increased the signal-to-noise
> ratio by between 3 and 9 db according to tests.
>
> I have that mod in PDF format up on the Glowbugs site.
>
> Ken Gordon W7EKB
>