On 02/24/2023 3:38 PM Mark K3MSB <[email protected]> wrote:
______________________________________________________________Without checking my notes... 276 Kc was not related to AN ranges.
It was a standard ground to air frequency for use by aircraft that didnt have a transmitter or didn't have 2 way comms on the several other standard airport frequencies in the 3 to 5 Mc range.
73 Mark K3MSB
On Fri, Feb 24, 2023, 3:21 PM Bart Lee <[email protected]> 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 LiaisonTexts only to: 415 902 7168
{Bart(dot)Lee(dot)K6VK(at)gmail(dot)com}
On Fri, Feb 24, 2023 at 9:54 AM Mark K3MSB <[email protected]> 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 <[email protected]> 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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