[ARC5] Re: SCR-274-N Transmitter Dial Accuracy

Tue Jul 8 16:51:18 EDT 2008

I was in the USAF from 1952 to 1958. The VHF ARC-5 equipment was in use
during that period.

I was in Korea in 53/54. Our F-84s and F-86s used ARC-3s. But we had the
ARC-5 VHF sets in non combat aircraft. C-45, T-6, and T-33. They were used
between the aircraft and the towers.

In 1954 I was assigned to a SAC wing. The F-84Gs in 54 had ARC-27 radios.
When we got the F-84Fs in 1955 they had ARC-33 radios. But we still had the
ARC-5 VHF equipment in use in non combat aircraft.

In 1955 I was the Test Equipment NCO in the 31st SFW.

Bob Macklin
K5MYJ
Seattle, Wa,
"Real Radios Glow in the Dark"
----- Original Message ----- 
From: "Mike Morrow" <kk5f at earthlink.net>
To: "Michael Tauson" <wh7hg.hi at gmail.com>; "arc5" <arc5 at mailman.qth.net>;
"milsurplus" <milsurplus at mailman.qth.net>
Sent: Tuesday, July 08, 2008 1:35 PM
Subject: [ARC5] Re: SCR-274-N Transmitter Dial Accuracy

> I wrote:
>
> > I'm not considering the SCR-274-N made by WE and others to be A.R.C.
> > gear.
>
> Michael wrote:
>
> >Okay, here's where our points of view differ.  I look at the design
> >source otherwise it gets confusing.  For example, Colonial built the
> >SCR-522, SCR-274-N and ARC-3 (and probably other equipment) under
> >subcontract so who gets credit for them?
>
> In my view, I choose whoever made the majority of any particular item.
>
> For ARA/ATA and AN/ARC-5, I'd say A.R.C. has the edge over S.C.
>
> For SCR-274-N, W.E. has the lion share over anyone else.
>
> >...a goodly number of the T-47As were made by Stewart-Warner
> >(among others) yet I've never heard anyone call it anything but a
> >Collins transmitter.
>
> I would not.  I believe that Collins made fewer T-47A/ART-13 units than
> Stewart-Warner.  In fact, I don't ever recall seeing a Collins T-47A.
> (I like the T-47A better than any other model of the "Collins ART-13"
> transmitters.)
>
> >The ARR-1s and ARR-2s I have on hand here are split pretty evenly
> >between WE and Zenith...
>
> It appears to me from the ones I've seen that Zenith made more of the
> AN/ARR-1 sets, while WE made more of the AN/ARR-2 sets.
>
> I wrote:
>
> > Once one removes the command set gear, what else did A.R.C. contribute?
>
> Michael wrote:
>
> >Wasn't this enough?  Every combatant that flew as well as a fat number
> >of transports et al carried command equipment, whether it be HF or
> >VHF...
>
> That's the rub for A.R.C., because they built no successful VHF command
> sets.  I don't wish to start up the HF vs. VHF command set use
controversy,
> but clearly, overall, VHF command sets won out over HF by war's end.
A.R.C.
> played no part in the development of a usable war-time VHF set.  The
> war could likely have been better prosecuted had no HF command set ever
> been accepted by US forces during the war.
>
> >... On the other hand, not all Navy and not that many USAAF
> >aircraft carried the ZB or ARR-1 or the later ARR-2, and the SCR-274-N
> >and ARC-5 VHF components weren't built in any huge quantities - 1000 &
> >20,000 respectively.
>
> I consider the SCR-274-N VHF components to have never really survived
> the development phase.  I know of no edition of any SCR-274-N manual
> (I've got four, from the first 1941 version, to thee last in 1956, IIRC)
> that even hints of the VHF components, nor have I seen any other official
> documentation.
>
> >As a sidenote, my T-23 was built on a BC-950 chassis, complete with
> >the hole for the 815(?) socket.
>
> I recently traded off a R-28 that had an old-style channel selector and
> a tube cover with a diagram showing tubes designated by Signal Corps "VT"
> numbers and showing the dynamotor as a DM-32-A.  Very possibly, that unit
> had once been a BC-942.
>
> I wrote:
>
> > The AN/ARC-39 seems to have been made in very small quantities.
>
> Michael wrote:
>
> >There were only 400 A.R.C.-built ones...
>
> >Some, though not all, wound up in places like the P-3 where it was
> >parked next to an ARC-94 and something VHF/UHF-ish.  The ARC-2, on the
> >other hand, went with the ARC-38 (the AM version) in the P-2 and P-5.
> >They also had something VHF/UHF-ish.
>
> I would think that the AN/ARC-39 would be very unsatisfactory for use
> in longe range Navy patrol aircraft.  I know some such aircraft in
> the 1960s carried an AN/ARC-38A along with the AN/ARC-94 (Collins 618T).
> I doubt there was much VHF command set gear on USN aircraft past the
> 1950s...the USN after all pioneered the use of the military UHF-AM band,
> with the RT-58/ARC-12 that directly replaced the RT-18/ARC-1 using all
> the mounting and control hardware of the AN/ARC-1, except antenna.  The
> classic UHF-AM command set of all time IMO is the AN/ARC-27, which
> replaced the AN/ARC-12.  I've been looking for a complete RT-58/ARC-12
> for years.  I couldn't afford them when I was in high school in the 1960s,
> when Fair Radio had them for sale.
>
> I wrote:
>
> > What part is played by A.R.C. type 12 components in your system?
>
> Michael wrote:
>
> >The system is built around the A.R.C. Type 12 C-40 control head,
> >although mine's a Stratocon R-2001 which is functionally the same but
> >made for panel installation in 1960.  Its a fairly conventional 3
> >receiver (VHF, HF and LF/MF), 2 transmitter (VHF/HF) setup with the
> >R-28 and R-23A/ARC-5 replaced by an A.R.C. R-19 and R-11 respectively.
>
> Interesting.  Did it use a MT-7/ARR-2 rack for a MF/HF receiver,
> and a MT-71 for a T-23 and some other MF/HF transmitter, thus requiring
> a MD-7 and RE-2 in the system?  Sounds bizarre, when a T-11 or T-13
> VHF transmitter could have beeen used for VHF.  None of my
> A.R.C. Type 12 manuals show anything similar.
>
> >There is also provision for an FM set ("like the SCR-619") but I
> >doubt that particular set would have still been operational in 1960.
>
> One of my A.R.C. Type 12 manuals shows a similar use of the SCR-619
> (BC-1335), in a 24 vdc system with C-37 control box, R-11, R-19, and
> two T-11 or -13 VHF transmitters.  A resistor is shown in the power
> lead to the BC-1335, which normally only runs from 6 or 12 vdc.  I've
> always wondered about the use of the BC-1335 in this function, because
> although the BC-1335 is a neat little two-channel VHF-FM set, for
> some unknown reason it has NO squelch circuit!  It wouldn't be fun
> to listen to FM noise continuously.
>
> >It came out of the 1952 edition of AN 16-45-122 which is the manual
> >for the Type 12 equipment.  It's not in the 1956 edition which, given
> >when the control head was made, is interesting.
>
> >While I didn't want to build a normal 3 Rx, 2 Tx, setup, this one
> >appealed to me because it's different.
>
> My favorite command set that I've assembled is a three-receiver (R-4,
> R-26, R-28), two-transmitter (T-23, T-20) AN/ARC-5 and AN/ARR-2 system.
>
> >The control head has a dial for the R-26 so that's why I selected 3105
> >KCs.  (Reflective thought: wasn't that changed to 3110 KCs later?)
>
> In the early 1950s the standard civil air-to-tower frequency changed
> to 3023.5 kHz.  That frequency today is officially assigned for search
> and rescue use.  I don't know why 3105 was changed, but 6210 kHz must have
> been lost at the same time, since most of the simple transmitters just
> doubled a 3105 crystal to get the 6210 frequency.  I don't know what
> 3105 kHz is assigned for today.
>
> Old radios...gotta love 'em!
>
> Mike / KK5F
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