[ARC5] HF/MF Mission Speculations (was ARC-39)

[David Stinson]

On 5/2/2020 11:13 PM, Hubert Miller wrote:
> That sounds like the best guess so far, and completely believable.

I've often wondered (since speculation is all we're ever likely to have 
on the subject) if this was the "mission" of the AN/ARC-5 MF sets like 
the T-15:  many vessels belonging to tertiary powers one might encounter 
when patrolling places like the eastern Mediterranean and western 
Caribbean were complying with the international radio accords of the 
1920s.  They were likely equipped with 600 Meter CW and, if they had any 
ground-to-air phone capacity,  it would likely be bases on Uncle Scam's 
"hand-me-downs-"  sets similar to SCR-134 and -135, operating in what is 
now the AM Broadcast band.   A couple of our early members with pre-WWII 
Navy service- now gone on to glory- recounted listening to Navy comms 
still using BCB frequencies even at that late time.

The design of the AN/ARC-5 MF set seems designed to "shoe-horn" into a 
small aircraft without a Liaison set.  The TN-6 external tuner was 
necessary to make it work on existing small HF antennas (trailing 
antenna was still required below a certain freq, IIRC) Otherwise, a 
simple trailing antenna with calibration marks would have worked.  This 
results in very low ERP and short range, which is adequate to 
communicate with an unknown vessel one's patrol is orbiting, or to 
contact BingoBongo Field, El Salvador's controller hut on 835 KC.  This 
very low ERP- less than a Watt in most cases- witnesses against use as a 
"portable ADF transmitter" as has been proposed.   I can think of no 
other plausible use for the AN/ARC-5 MF sets than short-range comm with 
units on BCB frequencies.

I was once told by a WWII Navy radio op that aircraft would orbit 
isolated Japanese garrisons, broadcasting "give up" messages on BCB 
frequencies, but if it was done (and I'm not inclined to doubt this 
gentleman's word), it would seem a job for AN/ARC-8 or SCR-287, which 
could do the mission outside Anti-Aircraft range. A Hellcat with the 
puny QRP ARC-5 MF set, close enough to be heard, would be in great danger.

Again- this is all speculation.  But I think it's a good one.
GL OM ES 73 DE Dave AB5S


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