[ARC5] [cca] AN/APR-9B and AN/APA-70C question

[zakariya.abu at yandex.com]

Hello Mike,

Thank you very much indeed for the follow up.

Meanwhile I consulted with the book titled 'Grumman AF Guardian' (Naval 
Fighters Number Twenty) by Bob Kowalski, which, although contains 
numerous typos repeated by the AI, has a sketch of a AF-2W CM operator's 
office. The sketch mentioned, inter alia, the following items:

AN/APR-9B, with the C-654/APR-9 control, ID-226/APR-9 (panadapter?), 
CV-43/APR-9 mixer amplifier

AN/APA-70C, with the C-631/APA-70A control, SA-148A/APA-70 switching 
unit, J-268/APA-70 terminal box

To my surprise, the ID-304/APA-70C was not listed but the ID-24/ARN-9, 
which was an ILS indicator, more or less similar to the ID-304. No ILS 
was, however, present on the very aircraft. An image of an ID-24 can be 
viewed here: https://www.ebay.com/itm/336180252617. I believe the ID-24 
initially substituted the ID-304, and the latter could be fitted only a 
bit later on these birds.

Technically, the AF Guardians served only between 1950 and 1955.

73,

Jan SP5XZG


W dniu 10.04.2026 o 22:34, Mike Peace - VK6ADA via groups.io pisze:
> Hi Jan,
> 
> Refresh this link, I added the new content and answered your question:
> 
> https://vk6ada.com.au/the-an-apr-9b-and-an-apa-70c-on-the-af-2w- 
> guardian-passive-radar-homing-in-cold-war-asw/ <https://vk6ada.com.au/ 
> the-an-apr-9b-and-an-apa-70c-on-the-af-2w-guardian-passive-radar-homing- 
> in-cold-war-asw/>
> 
> Mike
> VK6ADA
> 
> On Fri, Apr 10, 2026 at 2:20 PM <zakariya.abu at yandex.com 
> <mailto:zakariya.abu at yandex.com>> wrote:
> 
>     Hello Mike,
> 
>     Thank you very much indeed for the rapid reply and the well-structured
>     AI article, which I find reliable.
> 
>     I also think that the data on the AN/APR-9B and AN/APA-70C combination
>     was correct as evidenced by the Grumman AF Guardian SAC documents,
>     which
>     can be downloaded from these websites:
> 
>     https://www.aahs-online.org/images/Navy_SAC/AF-2W.pdf <https://
>     www.aahs-online.org/images/Navy_SAC/AF-2W.pdf>
> 
>     or:
> 
>     https://www.generalstaff.org/CDA/Air/AF/
>     AF-2W_Guardian_SAC_1_OCT_1947.pdf <https://www.generalstaff.org/CDA/
>     Air/AF/AF-2W_Guardian_SAC_1_OCT_1947.pdf>
> 
>     The 'W' variant of the AF Guardian was used for adversary target/radar
>     detection using the radar of CM receiver with DF.
> 
>     My only question is what was the 'interface' between the AN/APR-9B and
>     AN/APA-70C as this matter remains unknown at the moment.
> 
>     73,
> 
>     Jan SP5XZG
> 
> 
>     W dniu 10.04.2026 o 20:31, Mike Peace - VK6ADA via groups.io
>     <http://groups.io> pisze:
>      > Hi Jan,
>      >
>      > Here's a post that contains some relevant answers to your questions:
>      >
>      > https://vk6ada.com.au/the-an-apr-9b-and-an-apa-70c-on-the-af-2w-
>     <https://vk6ada.com.au/the-an-apr-9b-and-an-apa-70c-on-the-af-2w->
>      > guardian-passive-radar-homing-in-cold-war-asw/ <https://
>     vk6ada.com.au/ <https://vk6ada.com.au/>
>      > the-an-apr-9b-and-an-apa-70c-on-the-af-2w-guardian-passive-radar-
>     homing-
>      > in-cold-war-asw/>
>      >
>      > 73s,
>      >
>      > Mike
>      >
>      > VK6ADA
>      >
>      > On Fri, Apr 10, 2026 at 11:51 AM zakariya.abu via groups.io
>     <http://groups.io> <http://
>      > groups.io <http://groups.io>> <zakariya.abu=yandex.com at groups.io
>     <mailto:yandex.com at groups.io>
>      > <mailto:yandex.com at groups.io <mailto:yandex.com at groups.io>>> wrote:
>      >
>      >     Colleagues,
>      >     I am writing with a technical question, since I don't know
>     any other
>      >     more knowledgeable people on such matters than you.
>      >     My question is related to the A.R.C./Collins/AIL AN/APR-9B
>      >     countermeasure receiver, which was apparently used with the
>     AN/APA-70C
>      >     indicator. An image of a C-654/APR-9B Dzus tuning control can be
>      >     found here:
>      > https://militaryantiquestoronto.com/product/ww2-us-early-warning-
>     <https://militaryantiquestoronto.com/product/ww2-us-early-warning->
>      >     radar-receiver-control-model-c-654-apr-9b/ <https://
>      > militaryantiquestoronto.com/product/ww2-us-early-warning-radar-
>     <http://militaryantiquestoronto.com/product/ww2-us-early-warning-radar->
>      >     receiver-control-model-c-654-apr-9b/>
>      >     Plenty of ID-304/APA-70C indicators can be found these days
>     on the
>      >     web auction portals, eg. here:
>      > https://www.ebay.com/itm/127342018932 <https://www.ebay.com/
>     itm/127342018932> <https://www.ebay.com/ <https://www.ebay.com/>
>      >     itm/127342018932>
>      > https://www.ebay.com/itm/175229218743 <https://www.ebay.com/
>     itm/175229218743> <https://www.ebay.com/ <https://www.ebay.com/>
>      >     itm/175229218743>
>      >     These look almost like typical VOR/ILS navigation indicators
>     of that
>      >     vintage. However, their nomenclature suggests that they saw more
>      >     specialized service.
>      >     The available online documentation listed the AN/APR-9B and
>      >     AN/APA-70C as used on the Grumman AF-2W Guardian ASW
>     aircraft. Link
>      >     here
>      >     (see p. 457):
>      > https://www.history.navy.mil/content/dam/nhhc/research/histories/
>     <https://www.history.navy.mil/content/dam/nhhc/research/histories/>
>      >     naval-aviation/dictionary-of-american-naval-aviation-squadrons-
>      >     volume-1/pdfs/app1-1.pdf <https://www.history.navy.mil/
>     content/dam/ <https://www.history.navy.mil/content/dam/>
>      >     nhhc/research/histories/naval-aviation/dictionary-of-
>     american-naval-
>      >     aviation-squadrons-volume-1/pdfs/app1-1.pdf>
>      >
>      >     My question is: was the ID-304/APA-70C indeed used with he
>      >     AN/APR-9B, and if yes was it used as an aid to the crew to DF
>     and home
>      >     on an adversary radar transmitter (eg. installed on a vessel) to
>      >     facilitate an attack?
>      >     73,
>      >     Jan SP5XZG
>