[ARC5] Single Transmitter Single Receiver 274-N in P-51-C

[Mike Morrow]

Of course you are right, Mike.  There are six frequencies shown in the column for MF homing that are outside the 200 to 400 kHz coverage of most beacon band receivers like the BC-1206-seriez.  (I didn't look at that column earlier.)  The simple common beacon band receiver that was found in many stateside aircraft of this type required Adcock A-N directional beacons and it's not too likely many of those were operating in Asia at the time.  So I was careless and wrong to cite the BC-1206...it had to be something like the MN-26 manual RDF that shows up in a photo from the article cited by Wayne and Gordon.

WRT VHF homing, that would have been done by the airfield on a signal from the aircraft.  It is likely that VHF channel D was 140.58 MHz, which became the common VHF-AM distress frequency until replaced by 121.5 in the late 1940s.  I'm not too familiar with military airfield VHF homing systems of that era... perhaps someone who is will describe the gear used for that.

Mike / KK5F

PS:  Were there any A-N ranges still operating when you began flying?  I was alive when they were still around, but I wasn't listening to much radio.  :-)


-----Original Message-----
>From: Michael Bittner <mmab at cox.net>
>Sent: May 3, 2018 5:36 PM
>To: Mike Morrow <kk5f at arrl.net>, arc5 at mailman.qth.net
>Subject: Re: [ARC5] Fw:  Single Transmitter Single Receiver 274-N in P-51-C
>
>Mike, There are 3 freqs above the range of the BC-1206 which does not 
>normally have a directional antenna, so I think the MN-26 is more likely. 
>And, you are probably correct on the SCR-522 and that this card was likely 
>for a different aircraft.  However, I don't understand how you do homing 
>with an SCR-522.  Is there a VHF direction antenna somewhere in this setup, 
>on ground or in the aircraft?
>
>Mike, W6MAB
>
>----- Original Message ----- 
>From: "Mike Morrow" <kk5f at earthlink.net>
>To: <arc5 at mailman.qth.net>
>Sent: Thursday, May 03, 2018 14:26
>Subject: Re: [ARC5] Fw: Single Transmitter Single Receiver 274-N in P-51-C
>
>> Mike W6MAB writes:
>>
>>> You can see the frequency card at:
>>> http://texasflyinglegends.org/index.php/2017/01/11/winter-update-on-the-p-51c/
>>> Looks like all low frequencies for reception and ADF,
>>> plus VHF for transmission and Homing.
>>>
>>> How to you do VHF homing with SCR-274N?
>>
>> The card is for an aircraft with the four-chznnel VHF SCR-522-A and a 
>> beacon band receiver like the BC-1206-series.  Up to four air-to-ground 
>> channels are shown for each field, and one or two homing channels from 
>> airfield to aircraft.  It seems unlikely that the card shown would have 
>> had much applicability to an aircraft with only a single-channel HF 
>> SCR-274-N set for communications.  Perhaps the restorers do not have the 
>> appropriate original card for the time period depicted by the restoration.
>>
>> Mike / KK5F