[Milsurplus] B25 Aircraft Maintenance Manual - Radio System

[WA5CAB at cs.com]

George,

The short answer is that command sets are short range and intended for plane 
to plane in a formation, and plane to ground during takeoff and landing.  
Generally.

Liaison sets are long range and used for communicating with base during 
missions.

Lot of overlap, of course, and the definition of short and long is loose, and 
subject to propagation.  It may be easier to remember if you remember that 
VHF and then UHF sets replaced all of the HF command sets, while liaison (long 
range) sets remained HF.  SCR-187, SCR-287, GO, GP, ATC, ATD, AN/ART-13, 
AN/ARC-38, AN/ARC-58, etc. were liaison sets over the years.  GF/RU, ATA/ARA, 
ATB/ARB, SCR-274N, SCR-522, AN/ARC-1, 3, 4, 5, 13, 27, 55 were command sets.  Of 
course, before someone jumps in, all of the Navy command set receivers were also 
used in liaison installations with different transmitters.

Of course, in the ETO, all of the fighter control was VHF later in the War.

In a message dated 11/2/2006 5:17:42 PM Central Standard Time, 
gl4d21a at juno.com writes: 
> It also contains sections that discuss some of the following 
> equipment:
> 
> Command Radio Equipment  SCR-274-N
> Liaison Radio Equipment
> Radio Compass Equipment
> Radio Marker Beacon Receiver
> Interphone Equipment
> Radio Frequency Meter
> Radio System Antennas
> ++++++++++++++++++++++++++++++++++++++++
> 
> Al, thanks for the scans.  It reawakens a question however, what are 
> the specific definitions of Command Radios and Liason Radios?  My 
> past understanding was the command was from the Base or Airdrome or 
> Command Staff wherever they were, to the aircraft, and Liason was a/c 
> to a/c.  But the choices of equipment and frequencies seem to often 
> be at odds with those descriptions.  What am I missing here?
> 

Robert Downs - Houston
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