[ARC5] AN/ARR-69 inquiry

[zakariya.abu at yandex.com]

Francesco,

Thanks again for the follow up. I wonder actually what was the purpose 
of mass-installation of the ARA-25 and ARA-50 UHF DF sets if these were 
only to give bearing to another plane in flight or to an ELT on the 
ground? It's obviously nice that the equipment was available on many 
planes, but I wonder if the rather poor sensitivity eg. of the ARR-40 of 
some 6 microvolts limited the SAR/CSAR mission success? Do you happen to 
know the answer?

73,

Jan
SP5XZG


W dniu 24.03.2024 o 17:04, Francesco Ledda pisze:
> I stand corrected. In the F-4, the aux receiver could be used with the DF system.
> 
> Best, Francesco K5URG
> Sent from my iPad
> 
>> On Mar 24, 2024, at 10:39, zakariya.abu at yandex.com wrote:
>>
>> Thank you very much indeed, Francesco! Have a peaceful Sunday.
>>
>> W dniu 24.03.2024 o 12:58, Francesco Ledda pisze:
>>> See answers below!
>>> Best, Francesco K5URG
>>> Sent from my iPad
>>>>> On Mar 24, 2024, at 06:20, zakariya.abu at yandex.com wrote:
>>>>
>>>> I'd like to inquire about the AN/ARR-69 emergency UHF receiver (20 presets + 243 MHz guard) mostly used on naval jets as a go-between the AN/ARA-25 or AN/ARA-50 UHF DF "adapters" and an indicator (eg. the ID-250 RMI) that provided course to a UHF transmitter, whose signal was being picked up. I have a Collins brochure on the AN/ARR-40, but nothing on the AN/ARR-69. Hence, my questions are:
>>> USAF used ARR-69 as well
>>>>
>>>> (1) Was the AN/ARR-69 an updated (perhaps solid-state) version of the Collins AN/ARR-40 since both used the same C-1457/ARR-40 console control unit? If yes, in what dimension? Did both use crystal-controlled presets with the CR-23/U crystals? Were sensitivity and selectivity improved in the AN/ARR-69 compared to the AN/ARR-40?
>>> Yes! Yes! 1/3 the size. In F-4, ARR-69 was controlled by ASQ-19 control head. Need to check manual for crystal related Q. Download MIL-R-23767B(AS) for detailed specs.
>>>>
>>>> (2) Was the AN/ARR-69 indeed frequently used when TACAN or other navaids were available? Was it used in the air-to-ground mode only, or the air-to-air, as well, to home on other aircraft flying at altitude?
>>> No! No relationship with TACAN. A to A and A to G.
>>>>
>>>> (3) Could the AN/ARR-69 both in theory and practice pick up a signal from a low-power ELT, eg. an AN/PRC-90 or AN/URT-33, and effectively home on it via the AN/ARA-50 UHF DF?
>>>>
>>> Yes! In F-4, DF ARA-48 was only for main Comm.
>>>> (4) Considering the existence of the UHF DF equipment on military jets, did the military use a kind range beacons on UHF, which principle of operation resembled the old LF A-N range beacon system or the YE-ZB system, or the MF ADF?
>>> No!
>>>>
>>>> 73
>>>>
>>>> Jan
>>>> SP5XZG
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