[Milsurplus] Re: [ARC5] SCR-274-N Transmitter Dial Accuracy
Mike Morrow
kk5f at earthlink.net
Sun Jul 6 10:46:12 EDT 2008
Michael wrote:
>I'm trying hard to think of a case of an airplane that flew during the
>war that had WE equipment in it but no A.R.C. equipment.
I doubt there was much A.R.C. gear in any USAAF aircraft in WWII. Of
course, I'm not considering the SCR-274-N made by WE and others to
be A.R.C. gear. Once one removes the command set gear, what else did
A.R.C. contribute?
>This was later addressed with the variation on a theme called the T-126.
The T-126 appears to have been made in very limited quantities compared
to the T-23.
>The ARC-2, ARC-39 and HF elements (plus the T-23) of the ARC-5 sets
>continued in service into the 1960s for local air-air and air-ground
>communications.
These sets were always installed with a VHF, or later UHF, command set.
Even though low-powered, they appear to have served a liason function
more than a command function.
The AN/ARC-39 seems to have been made in very small quantities. Maybe
a few hundred total? I've got two, and I've seen several others, and
I don't recall a serial greater than low three digits.
>In the mixed ARC-5/Type 12 system I'm assembling, the T-19/R-26
>pair is being set up for 3105 KCs which seems as good a frequency to
>use as any other.
I have a handbook for a USN training aircraft that shows the radio
installation, which sounds similar to what you are creating:
R-23 for beacon band and LF/MF (278 kHz) airport reception
R-26 for 3105 kHz (air-to-air) reception
T-19 for 3105 kHz (air-to-ground and air-to-air) transmission
C-125 to tune the R-23
C-125 to tune the R-26 (not lock tuned!)
MD-7 transmitter modulator
RE-2 antenna relay (picture actually clearly shows a BC-442-A!)
Plus associated mountings. But note:
There is NO transmitter control box. In a single transmitter installation,
the transmitter control box is superfluous, since there are no transmitters
or transmitter modes to be selected. The necessary connections would have
been made at the connecting plugs. The only transmitter control was
a microphone jack and a toggle switch to swap the mic to RADIO or ICS.
What part is played by A.R.C. type 12 components in your system?
>On the other talon, the R-23A was, as you noted, in service for quite
>a while - into the 70s at least. Not bad for a receiver originally
>conceived isn 1935.
Yes, I've flown on USN aircraft in 1972 that had an R-23 installed.
But my best candidate for a radio system in long use is completely
different: The AN/VRC-12 series (RT-246, RT-524, R-442/VRC) low band
VHF FM gear that first appeared in the early 1960s, continued in US
service to the 1990s, and no doubt is still in use in many corners of
the world. Fourty-five-plus years in common service isn't bad. It's much
longer than the R-23, which was found only in backwaters after the 1960s!
Mike / KK5F
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