[ARC5] Command Sets Manuals

Sat Jun 22 04:36:04 EDT 2019

I'm working on an unmodified T-23/ARC-5 transmitter. A heater power supply
of 25.5 VDC and B+ of 540 VDC @ 100mA is nearly finished. This transmitter
has 4 bands and by careful choice of crystal frequencies (8 MHz) it's
possible to put 3 channels on the 2m band using bands B and C (122-146 MHz)
and D (132-156). Band A (100-124) is useless. Its turret switching wire can
be lifted off its turret cam contact and you then have a wire from the
front panel connector that can be used for a volt or two of audio to drive
a varactor diode across the common crystal circuitry at the oscillator grid
for FM modulation. Otherwise, no modification should be needed. A superbly
comprehensive manual for this transmitter and its VHF receiver is available
at NJ7P's site.

Neil ZL1ANM

On Sat, Jun 22, 2019 at 6:56 PM Mike Morrow <kk5f at earthlink.net> wrote:

> 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.
>
> The assembly of a complete historically-accurate set is challenging and
> satisfying.
>
> I have a complete three-receiver two-transmitter SCR-274-N set consisting
> of BC-453-B, BC-454-B, and BC-455-B receivers plus BC-696-A and BC-459-A
> transmitters, plus all associated items.
>
> I have a complete three-receiver two-transmitter AN/ARC-5 + AN/ARR-2 set
> consisting of R-4A/ARR-2, R-26/ARC-5, and R-28/ARC-5 receivers plus
> T-20/ARC-5 and T-23/ARC-5 transmitters, plus all associated items.
>
> I continue work to assemble a three-receiver two-transmitter ARA/ATA with
> ZB-3 set consisting of CBY-46104, -46105, and -46145 receivers plus
> CBY-52209 and -52232 transmitters, plus ZB-3 CW-69076 homing adapter, plus
> all associated items.
>
> The sets above are interesting examples of how real-life military versions
> of the "command sets" were typically configured.  However, the search for
> all the necessary components for even the simple SCR-274-N can take many
> years.
>
> If one does not care to re-create a historically and technically accurate
> set, then it is better to use components that have already been
> ham-hacked.  They are usually plentiful on eBay.
>
> Mike / KK5F
>
> From: Rich Arland
> Sent: Jun 21, 2019 10:58 PM
> To: ARC-5
> Subject: [ARC5] Command Sets Manuals
>
> Man, thanks to all for the fantastic feedback on my little bunch of gear.
> Of course it will take me about 2 years to sift through the entire
> information bank!
>
> I have a burning desire to obtain the manual(s) on these receivers,
> dynamotors and "stuff". Although I have several of the CQ publications from
> the 1950/60s but they are in bad shape physically and the type face is
> rather small....very hard to read with my eyesight. SO......does anyone
> know of a source of TMs/TOs for the BC-453/454/455 receivers? Preferably
> copies that I won't have to mortgage the Bent Dipole Ranch!!
>
> Several list members had counseled me to keep the triple rack that the
> receivers are currently occupying. My main problem with the rack is the
> lack of space in/around the new shack. As it is I will probably use only
> one of the receivers at a time. I figure that I can hook the radio(s) up
> toe 24VDC and run them (one at a time) off of the dynamotors.
>
> Anyone have a SWAG as to what a T-19/T-22 (BC-696/459) currently cost
> (preferably without me giving up a kidney or part of my liver!!)
>
> Again, thanks to all who offered me info and comments. This is a GREAT
> group.
>
>
> *Vy 73 es gud DX!*
>
> *Rich Arland   K7SZ   WPE7BYR*
>
> *Bent Dipole Ranch, Dacula, GA *
>
> *"Faith is not about everything turning out ok.  It's about being ok, no
> matter how things turn out."*
>
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