[ARC5] BC-453 in the SCR-274N Configuration

Fri Feb 24 18:53:27 EST 2023

Well, the ZB units were used with the R-24/ARC-5 and the BC-946B both of which covered 
the 520 to 1500 kHz frequency range. The R-23/ARC-5 and BC-453 did not cover the 
required frequency range and so were never used with the ZB units.

Both the R-23/ARC-5 and the R-24/ARC-5, and the BC-453 were listed as "navigation" 
receivers. I don't know if the BC-946B was ever so included.

Ken W7EKB

On 24 Feb 2023 at 15:51, MARK DORNEY via ARC5 wrote:

> 
> The USN used the ARR-1 ( ZB-1,ZB-2,ZB-3 ) and ARR-2 starting in the 1930´s to guide 
> aircraft back to carriers after a mission. The ARR-1 types were used withe the RU type 
> receivers, the ARB Receivers, and the ARA and ARC-5 type navigational receivers until 
> replaced by the ARR-1 was replaced in the ARA-ARC-5 receivers by the ARR-2 starting 
> in 1943 The ARR-1 was fit to either the ARA/ARC-5 ( and SCR-274 ) by receivers using 
> several control boxes and a mount separate from the ARA/ARC-5/SCR-274 receiver. 
> The ARR-2 eliminated the need for the separate control boxes and separate mount in 
> the ARA/ARC-5/SRC-274 receivers. The ARB receiver also did not use the separate 
> control boxes for the ZB-1 homing device and the deceive itself clipped onto the top of 
> the ARB receiver, as it did with the RU type receivers. The Antenna on the YE 
> transmitter on the carrier rotated, and sent out a different Morse code letter every 30 
> degrees of rotation using a "U" shaped directional antenna ( the "Hay Rake" ). The 
> signal was modulated in such a way as to make the signal undetectable unless you had 
> the correct receiver set correctly. Declassified in 1947, the system stayed in use by the 
> USN until 1960 when it was replaced by VOR and TACAN.
> 
> Mark D.
> WW2RDO
> 
> "In matters of style, float with the current. In matters of Principle, stand like a rock. 
> ".  -  Thomas Jefferson 
> 
> Sent from my iPhone
> 
> On Feb 24, 2023, at 3:22 PM, Bart Lee <bart.lee.k6vk at gmail.com>wrote:
> 
> 
> "a switch that when pulled out set the radio to 276 Kc." 
> 
> What was that frequency at the time? A standard airfield A-N?
> 
> We have, at the CHRS Museum, a BC-1206 but not an R76-ARR-13.
> 
> Nice pix!
> 
> 73
> 
> ##
> -- --
> Bart Lee, K6VK, CHRS Archivist and Fellow, AWA Fellow, ARRL Liaison 
> 
> Texts only to: 415 902 7168
> 
> www.bartlee.com
> 
> {Bart(dot)Lee(dot)K6VK(at)gmail(dot)com}
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On Fri, Feb 24, 2023 at 9:54 AM Mark K3MSB <mark.k3msb at gmail.com> wrote:
> The P-51 Pilot Training Manual dated 15 Aug 1945 mentions only the SCR-522 (which makes 
> sense as by that date it would have replaced the SCR-274N).  The manual shows a Detrola LF 
> receiver mounted on the lower right side of the cockpit.   "The Detrola is a low-frequency 
> receiver. It operates between 200 and 400 Kc, which covers the transmission band for towers 
> and range stations through the United States."
> 
> I have no doubt that a BC-1206 could be used in place of the Detrola as visually they look to be 
> about the same size.
> 
> The BC-1206 was Setchell Carlson Model 524.  The Model 512 was the R-76/ARR-13.  It was 
> similar to the 1206 but had a switch that when pulled out set the radio to 276 Kc. See attachment.
> 
> Another important use of the BC-1206 and R-76 was they were used for ferry flights from the 
> factory to the facility that installed the radios. It was a temporary installation.
> 
> 73 Mark K3MSB
> 
> On Fri, Feb 24, 2023 at 11:07 AM <releazer at earthlink.net> wrote:
> Before WWII and even up until the 1970's to a limited degree, AN ranges were used on low 
> frequencies. These featured signals that gave a continuous tone if you were headed toward the 
> station and an A (Dit Dah) tone or an N (Dah Dit) tone if you were off to one side. Light aircraft 
> without even an electrical system could use the AN ranges for navigation, and also receive control 
> tower instructions by employing battery powered receivers. Fighter aircraft generally did not have 
> an ADF or even a loop antenna and so were equipped with LF receivers for the same 
> reasons. When SCR-522 replaced the SCR-274-N or SCR-283 equipment small LF receivers 
> were often installed in the cockpit to preserve the LF capability, such as the BC-1206 series made 
> by Detrola, Setchell Carlson and others. It is not clear to me how often the BC-1206 equipment 
> was retained for overseas use or how USAAF fighters in the UK homed in on their airfield 
> beacons.
> 
> Postwar the BC-1206 was replaced with BC-453 in many refurbished P-51's that had ARC-3 fitted 
> and can be seen perched high above the ARC-3 equipment under the bubble canopy.
> 
> Wayne
> WB5WSV   
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