[ARC5] Stinson L-5 Radios

[Mike Morrow]

> May have been the RCA AVT-112 transmitter and whatever its companion receiver
> was.

The standard radio sets shown in L-5 manual were:
MF/HF - 
     RCA AVT-112 single channel crystal control transmitter
     RCA AVR-20-A1 2.3 to 6.7 MHz receiver, made by Continental Radio
     RCA AVA-126 12vdc vibrator power supply
LF/MF -
     R-76/ARR-13 (Setchel-Carlson Model 512) with 278 kHz pre-set.
                 12vdc, B+ supplied by the AVA-126 above.
                 NB-This is NOT a BC-1206-C, -CM, or CM2!
                 Those won't work in 12vdc aircraft like most L-5's were.

Taigh Ramey's recent postings about phone plugs show pictures of part of this radio installation in an L-5.

> I think the receiver may have had both an LF band and a 2.5-6.5 mc HF range
> to match the transmitter, but am not positive.

See above.

> Never before heard of a BC-1335, BC-659 or BC-620 in an a/c but would not
> doubt it.

It is easy to find system diagrams of the post-WWII A.R.C. Type 12 VHF-AM aircraft set that show connection to the SCR-619 (BC-1335).  The A.R.C. C-37 control box for these systems had an FM position on the transmitter channel selector switch.  The BC-1335 receiver has no squelch, so that noise would be fun to have in the headset all the time.  The BC-1335 in these installations got 12vdc from the aircraft's 24vdc bus through a voltage-dropping resistor.

> A BC-1000/SCR-300 would have made a lot of sense because they could
> communicate directly with the infantry.  US Army and USMC both used
> the SCR-300.

I suspect the need was greater for observation aircraft to communicate with artillery or armor.  The SCR-300-A's 40 to 48 MHz coverage would not be very useful for that.  But at least its receiver has squelch!

Alongside their SCR-508-*, a lot of US Army armor units employed the AN/VRC-3 for direct communication with the infantry.  The AN/VRC-3 is the BC-1000-* with PP-114/VRC-3 vibrator power supply.  

Mike / KK5F

>73
>Mike
>WA4DLF