[Hammarlund] SP-600 JX-26

[Craig Roberts]

Dan Cotsirilos wrote:

"...what the heck kind of ant connecter that is on here supposed to be? 
it is nuts!"

It's not exactly nuts, but it is unusual these days.  It's a TWINAX" 
connector and, in days of yore, was used with balanced feedlines of the 
same name. Many users and restoration artits have substituted SO-239 
chassis connectors with right-angle adapters for the originals. I, 
however, have done just the opposite and retrofitted my set with the 
original connector and plug and built a ca. 1951-style doublet antenna 
as specified in my SP-600 Army manual for the set.  It makes absolutely 
no difference in the performance of the radio, but it was fun.

By the way, the antenna input impedance of the SP-600 is 100 ohms, not 
our "modern" standard 50 ohms. If you're a purist and want to match your 
receiver to a 50 ohm resonant antenna for a specific frequency, you can 
build an impedance transformer or, better yet, use an antenna tuner.  
It's too bad an antenna trimmer control wasn't built into the set.

This brings me to a question for the gurus. The RF alignment 
instructions for the SP-600 call for the signal generator output to be 
fed to the antenna terminal through a 100 ohm resistor. If a 50 ohm 
resistor is substituted, would the front end then be able to be tweaked 
to a 50 ohm input?

73,

Craig
W3CRR
www.aerialacts.com