[ARC5] Why is the ARC-5 Tx rack so hard to find?

[WA5CAB at cs.com]

I'll add two further comments (not actually prompted by any particular 
post) to all of this related to differences between the AN/ARC-5 and the ATA and 
SCR-274-N transmitter components.

First, the connectors in the transmitter mounts (racks) that the 
transmitters plug into are also different, to keep anyone from plugging in the "wrong" 
family transmitter.

Second, it is actually possible, if you through luck or hard work and much 
money have all of the other necessary components, to utilize a PL-153 or a 
PL-153-A at the MD-7 and at whatever control box you have.  To do this, first 
you have to plug socket contact #1 in the PL-153 for connector keying 
purposes.  Then you drill a clearanance hole for Pin #1 in the face of the 
connector so that you can physically plug it in.  Second, by default all MT-71 are 
strapped such that the two transmitters are #1 and #2.  You must re-strap 
J-75 and J-76 in the mount such that the two transmitters are either #2 and 
#3 or #3 and #4.  Then you wire the PL-153 per the schematic in AN 
16-30ARC5-2 but omitting the wire for SEL #1.  And of course you cannot have four 
transmitters in the system.

A bit of trivia, apropos of nothing in particular, but some combined 
installations that include AN/ARC-5 did actually use a pair of PL-153.  Just not 
between the modulator and control box.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20160313/3bf9e82d/attachment.html>