SB 310 Shortwave Rcvr Question

[Eddy Swynar]

Hi Mark...

Sounds like your RF amplifier is "taking off" on you...

I have two SB-301's here that I'm always fooling with...one of my favourite
tricks with these rigs is to replace the first tube in the line-up (RF amp
6BZ6) with a "hotter" tube, like the 6DK6, I believe (or was it the 6KD6...?
In any event, it's the same size as, & is a direct replacement for,  the
6BZ6, but with a higher transconductance)...

Anyway, BOTH rigs benefitted from substantially higher sensitivity, but one
of the '301s would oscillate at the front end, dependent upon the
pre-selector setting, on 80-meters only. I tried shielding the grid from the
plate below chassis, different tubes, etc.---but this one '301 only became
"tame" again when a 6BZ6 was placed back into the RF amp socket...

If you ever figure out the answer to your dilema with the '310s, please let
me know.

Tnx & vy

~73~ Eddy VE3CUI - VE3XZ





-----Original Message-----
From: Mark V. Johnson VE3DJU <mjohnson at CA.IBM.COM>
To: HEATH at LISTSERV.TEMPE.GOV <HEATH at LISTSERV.TEMPE.GOV>
Date: Sunday, June 11, 2000 8:14 AM
Subject: SB 310 Shortwave Rcvr Question


>Hello all;
>I own 2 of these units and both exhibit a  characteristic (I won't call it
>a problem)  that is a bit annoying. On the 9.5mhz band, and the 17.5 mhz
>band, the setting of the preselector is very very touchy. You have to have
>the RF gain set back or the preselector setting will cause an oscillation
>and an actual frequency change. Very "tight" adjustment!
>
>I was wondering if this is a "working as designed" or if I have a problem??
>
>Advice always appreciated! Thanks!!
>
>
>Mark V. Johnson
>VE3DJU
>