[Hammarlund] SP-600 IF mod, is it worthwhile? OTHER notes.

[James A. (Andy) Moorer]

----- Original Message ----- 
>
> ANYWAY, the question is this.  Is this "IF Gain Mod" that was designed to
> allow balancing of JX-17 receivers in a diversity setup, of any REAL use
> in a JX-14 that will obviously be used as a stand alone receiver?  It
> appears that about all it would do is reduce the overall IF gain (and AGC
> action?) of the set.
>

The "IF Gain" mod showed up in some Ham magazines (I'm not sure which) as
something fun to do to your SP-600. It is important on the JX-17 because the
RF stages are run at a very high gain. All the "DF" receivers also run the
RF stages at relatively high gain, expecially if the DF/N jumper is set to
DF mode - then the RF stages are run flat-out all the time. Then you do
really need the IF gain control.

The IF gain control is sometimes useful to prevent overload of the IF stages
in the presence of very powerful signals - especially in some of the
AGC-challenged receivers like the JX-17, and to a lesser extent, the JX-6,
JX-14, and JX-26 (and probably some others with the DF/N jumpers). Your
local MW station counts as very powerful.

P.S. - The DF/N jumper I am talking about is on E13. You can move the AGC
feed to the RF deck from the N (Normal) position to the DF
(Direction-Finder) position. If you have this, set it to N right now.

James A. (Andy) Moorer
www.jamminpower.com