[Hammarlund] SP-600-JX-6

[D C _Mac_ Macdonald]

IIRC, the Hallicrafters SX-73 is the R-274 and the Hammarlund SP-600 is the R274B.


73 de Mac, K2GKK/5
(Since 30 Nov '53)
Oklahoma City, OK
USAF Retired 61-81
FAA Retired 94-10



________________________________
From: hammarlund-bounces at mailman.qth.net <hammarlund-bounces at mailman.qth.net> on behalf of wb3fau55 at neo.rr.com <wb3fau55 at neo.rr.com>
Sent: Sunday, March 11, 2018 18:41
To: hammarlund at mailman.qth.net
Subject: [Hammarlund] SP-600-JX-6

Folks, perhaps I have isolated oddball rig  here.  The designator  for service  use is R-274B,  checking with  the papers I have seen,  this should be a Halli-SX-73? [not].  So this unit  was  modded to run as diversity operation, with  added IF gain pot,  but not front panel installed.  The unit suffered from severe overload.   Removal of the pot  and return to stock setup, did not  help.
Not documented change in the RF section.  Screen resistors for the 2 RF amp tubes were  changed  from 33k to 3.3k.  Changing these fixed the overload issues.  Anyone else ever  come across this modification?  Now  working much better.  73s Russ-wb3fau.