[Milsurplus] R-28/ARC-5 frequency multiplier scheme?

[C.Whitaker]

de WB2CPN
Back when I had a real job with USAF:
 From the AN/ARC-5 list:
A   116.1     Control Tower Primary (Ch A)
B   126.18   Control Tower Secondary (Ch B)
C   140.58   Emergency and Direction Finders. (Ch D)

 From his Set 2:
A   121.5     Guard and Emergency (Half of 243.0, the UHF Guard)
C   126.18   Control Tower Secondary

Crystals on BC-640 and 522 were 18th Harmonic.

Nice memories of those days.
73  Clete
++++++++++++++++++++++++++++++++++++


On 2/19/2012 5:54 PM, Mike Morrow wrote:
> Jay wrote:
>
>> I have two R-28's with the following crystals:
>>
>> #1 has:
>>            A = 4550 kc
>>            B = 4970 kc
>>            C = 5570 kc
>>            D = 5660 kc
>>
>> #2 has:
>>            A = 4775 kc
>>            B = 5660 kc
>>            C = 4970 kc
>>            D = 5375 kc
>>
>> I'm guessing the total multiplication value is 26 as this puts
>> these channels in the aeronautical band. Where there standard
>> channel frequencies and  frequencies specific to NAS's?
> In November I posted on the ARC5 list the crystal information for
> ALL common WWII-era VHF-AM command sets (AN/ARC-1, -3, -4, -5, and
> SCR-522).  That posting is found at:
>
>    http://mailman.qth.net/pipermail/arc5/2011-November/009252.html
>
> The info excerpt for the AN/ARC-5, showing the frequencies supplied
> with new sets, is:
>
>> AN/ARC-5                         R-28/ARC-5  T-23/ARC-5
>>               A       116.10       4550.00     6450.00
>>               B       126.18       4970.00     7010.00
>>               C       140.58       5570.00     7810.00
>>               D       142.74       5660.00     7930.00
>> Equipment Operating Frequency Range:  100 to 156 MHz
>> Crystal Type:  Receiver - DC-31   Transmitter - CR-1A/AR (DC-30)
>> Receiver Frequency MHz = Crystal Frequency kHz x 24 / 1000 + 6.9
>> Transmitter Frequency MHz = Crystal Frequency kHz x 18 / 1000
>>     Transmitter Channel Allowable Frequency Ranges
>>        Channel    T-23/ARC-5       T-126/ARC-5
>>           A       100 to 124       100 to 124
>>           B       122 to 146       100 to 124
>>           C       122 to 146       100 to 124
>>           D       132 to 156       122 to 146
> Your set 1 has the four frequencies that were supplied in all new
> sets, as listed above.  Your set 2 is on:
>
>     A   121.50 MHz
>     B   142.74 MHz
>     C   126.18 MHz
>     D   135.90 MHz
>
>> It would be interesting to know where these were used based on
>> the crystals installed or is this a futile question?
> The frequencies in both of these sets were very commonly used
> in all US VHF-AM command sets during WWII (set 1, when 140.58 MHz
> was a common calling/distress frequency) and in the years afterwards
> (set 2, when 121.50 MHz became standard for that use).
>
> You can "google" "140.58 MC" and "142.74 MC" (and the other frequencies
> as well) to find out more.
>
> Mike / KK5F
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