[ARC5] RF ammeter

[WA5CAB--- via ARC5]

All of the TCS RFA's are mounted directly to the front panels. As are the 
meters in the majority of low and medium power military sets. 

Electrically, in most of the NT-52245 (TCS transmitter) the meter is in the 
low side of the circuit, between the bottom of the variometer secondary and 
chassis. During production of TCS-12, 13 and 14, and in TCS-15, it was 
moved electrically to the high side, connected between the T/R relay and the 
antenna post. None of the documentation says whether or not this coincided with 
the addition of the "A" suffix to the Navy Type Number (52245A or 52245-A).

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 08/08/2014 10:07:55 AM Central Daylight Time, 
arc5 at mailman.qth.net writes: 
> The ARC-5 meter has an external thermocouple. The ART-13 meter has an 
> external pickup loop (current transformer), which keeps the high RF voltage 
> out of the meter itself. And, the ARC-5 meter has a current transformer to 
> feed the thermocouple.
> 
> It's been a while since I looked at the TCS schematic to see how those 
> meters are configured; but if I remember right the RF goes directly through 
> them. Are they mounted directly to a metal panel, or to some kind of 
> insulating material? I used two in a home brew balanced line antenna tuner back in 
> the 1970s, and mounted them on a piece of plexiglas behind an aluminum 
> panel with over-size holes for the meter case flanges.
> 
> 73
> 
> Mike
> WA4DLF