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

[Kenneth G. Gordon]

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