[ARC5] Command Sets Manuals

[Robert Downs]

Group,

 

For the record, I also do the LF/MF/HF AN/ARC-5 Operators and Maintenance manuals, the ATA/ARA manual, the RAT & RAT-1 manual, the RAV manual, and will eventually finish the AN/ARC-5 VHF manual.  If anything more was ever done on the test sets or the dynamotors beyond what’s in the maintenance manuals, I’ve never found it.  And if there was ever a manual on the SCR-274-N VHF set, I’ve never seen it.

 

Robert Downs

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On Behalf Of Mike Morrow
Sent: Saturday, June 22, 2019 01:56
To: arc5 at mailman.qth.net
Subject: Re: [ARC5] Command Sets Manuals

 

FWIW, Rich, there are three major so-called "command set" systems that were used throughout WWII:

 

1.  USN ARA/ATA (1940) - Five receivers (0.19 to 9.05 MHz), five transmitters (2.1 to 9.05 MHz), series-fed PA with screen modulation, uses lo-Z AF.

 

2.  USAAF SCR-274-N (1941) - Similar to ARA/ATA except no 1.5 to 3.0 MHz receiver, no 2.1 to 3.0 MHz transmitter, uses hi-Z or hi/lo-Z AF.

 

3.  USN AN/ARC-5 (1943) - Improved ARA/ATA.  Receivers have AVC, navigation receivers have loop connections and circuitry to support the subsequently-discarded AN/ARR-1 VHF homing adapter or AN/ARN-9 "Air-Trak" ILS.  Transmitters have shunt-fed PA with plate modulation.  Three transmitters were added to cover 0.5 to 2.1 MHz.  A four-channel VHF receiver and transmitter were made to cover 100 to 156 MHz.  The AN/ARR-2 VHF homing receiver was integrated with the AN/ARC-5 system.

 

The transmitter components in the ARA/ATA set are identical to those in the SCR-274-N except for sidetone AF impedance.  In contrast, the transmitting components of the AN/ARC-5 have very significant differences from the two earlier sets.  The ONLY **transmitting** components (including plugs and control boxes) that are interchangeable electrically between AN/ARC-5 and the earlier sets are the modulator dynamotor and the antenna relay.

 

Usually the best source for manuals and units of these three sets is ebay.  SCR-274-N components are much much easier to find than components of the other two systems.  The maintenance manual for the SCR-274-N is here:

 

  http://bama.edebris.com/download/military/scr274/TO%2012R2-3SCR274-2.pdf

 

You will find links to the AN/ARC-5 maintenance manuals at the wikipedia article for ARC-5.

 

Robert/WA5CAB reprints the SCR-274-N operating and maintenance manuals.

 

 

Mike / KK5F

 

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