ADF Homing

[Mistermann]

This video is from almost 4 years ago.  It shows two things regarding ADF that I am interested in understanding if they've been reported.

1)  When performing ADF using UHF the needles move to point the jet in the proper direction, BUT there is nothing audible played.  As you can see CAP sets up an audio file, but nothing plays in his first example.  I have setup a mission and it behaves the same.

2)  When performing ADF using FM, the needles don't work.  The audio file DOES play.

I have a SAR mission I am working on and I'd really like an SOS .ogg to play when tuned to the proper freq using ADF.  It doesn't appear I can get this to work.  I have no preference on UHF or FM.  Is there any way to accomplish this in the current A-10CII?

Might this get fixed with the upcoming ARC-210 radio additions?

I have the simplest of missions posted here for anyone interested.  2 Humvees at our favorite Caucasus airfield.  One broadcasting on 300 MHz UHF and the other on 31 MHz FM.  Make sure to select STRPT instead of TCN unselect ANY mode beneath the EGI button so the needles behave properly.

Thanks.

ADF testing.miz

Edited February 3, 2023 by Mistermann
Corrected STRPT mode statement

[Tholozor]

Cant watch the track at this moment, but did you check the knobs on the volume panel?

[Yurgon]

9 hours ago, Mistermann said:

1)  When performing ADF using UHF the needles move to point the jet in the proper direction, BUT there is nothing audible played.  As you can see CAP sets up an audio file, but nothing plays in his first example.  I have setup a mission and it behaves the same.

AFAIK the ARC-164 is an AM radio. In order to be able to listen to transmissions, they need to be amplitude modulated (AM).

Interestingly enough, UHF ADF works with both AM and FM signals.

9 hours ago, Mistermann said:

2)  When performing ADF using FM, the needles don't work.  The audio file DOES play.

Yeah, seeing the same, which is also exactly what was said in that 3 year old video.

9 hours ago, Mistermann said:

Might this get fixed with the upcoming ARC-210 radio additions?

Would be nice if they worked on the radios in general.

But AFAIK, the ARC-210 is going to replace the ARC-186 VHF AM (aka front) radio, and that's exactly the one that doesn't even have a homing indicator on the NMSP.

9 hours ago, Mistermann said:

Make sure to select STPT instead of TCN so the needles behave properly.

According to the manual, that should not be necessary, but in DCS it is. Fascinating.

Edit: It's mostly correct in DCS. When TCN is selected in the NMSP and the TACAN Mode Dial is set to REC or T/R, and when UHF Homing is active, UHF Homing does indeed take precedence for Bearing Pointer 1. In my test, it's only when the TACAN Mode Dial is set to OFF that Bearing Pointer 1 incorrectly rests in the 3 o'clock position when it should instead point to the UHF homing source.

9 hours ago, Mistermann said:

I have the simplest of missions posted here for anyone interested.

Awesome, thanks!

So, yeah, long story short: set the UHF transmission to AM instead of FM and then both listening to and homing in on it should work.

Edited February 3, 2023 by Yurgon

[Mistermann]

16 hours ago, Yurgon said:

So, yeah, long story short: set the UHF transmission to AM instead of FM and then both listening to and homing in on it should work.

Thank you @Yurgon!  One small correction.  In order for the needles to move NONE of the modes below the EGI switch can be enabled.  In my OP I incorrectly stated that STRPT needed selected.  

Changing to AM made all the difference and explains why CAPs sounds didn't work in his example either.  It might help if I learned what MHz equated to UHF vs. FM vs. VHF, but that's a different topic.  

Adding adjusted mission for anyone interested in testing this on their own in the future.

 

ADF testing.miz

Edited February 3, 2023 by Mistermann
added mission

[Pyrocumulous]

My testing, and what I'm understanding from above: ADF in ARC-186 radio (VHF FM) is non-functional still as of DCS 2.9.1.48335 Open Beta. Correct? Was trying to get it to work in Operation Persian Freedom Campaign mission 11.

[Yurgon]

46 minutes ago, Pyrocumulous said:

ADF in ARC-186 radio (VHF FM) is non-functional still as of DCS 2.9.1.48335 Open Beta. Correct?

I haven't tested it lately, but I'm not aware of any changelog entry regarding FM homing. That, together with your test, looks like a pretty strong indicator that this feature is indeed not currently implemented.

[vctpil]

 

On 2/2/2023 at 6:18 PM, Mistermann said:

Is there any way to accomplish this in the current A-10CII?

Create a trigger RADIO TRANSMISSION.

The range of a NDB is 300kHz to 1750kHz. Example, 410kHz must be entered as 0.41MHz. 

That was working well before the latest A-10CII, but maybe still working. 

Edited November 25, 2023 by vctpil

[jaylw314]

On 11/25/2023 at 11:50 AM, vctpil said:

 

Create a trigger RADIO TRANSMISSION.

The range of a NDB is 300kHz to 1750kHz. Example, 410kHz must be entered as 0.41MHz. 

That was working well before the latest A-10CII, but maybe still working. 

 

A-10CII can't receive NDB's, it only has (or should have) ADF for UHF and VHF-FM.

[InteR]

The AN/ARC 164 can perform ADF Homing in the AM band 'naturally' due to its design and capabilities. Additionally, thanks to its integration with other navigation and direction systems on board the A-10C, such as TACAN and other advanced avionics equipment, it can also perform ADF Homing in the FM band. This flexibility allows the A-10C to use multiple frequencies and systems to enhance its navigation and direction capabilities.

ED confirm in their A-10C manual that ADF homing on AN/ARC 168 FM is "not functional".

In real life, AN/ARC 168 FM radio may have CM-482 or CM-492 modules installed to offer ADF homing fuction.

"The CM-482 and CM-492 components mentioned in the AN/ARC-186 radio manual are control modules used to enable the ADF (Automatic Direction Finder) homing function. These modules allow the AN/ARC-186 radio to perform the homing function, which is essential for navigation and orienting the aircraft towards a specific radio signal".

These modules are necessary only if the homing capability is required in the aircraft equipped with the AN/ARC-186 radio".

So it would be very interesting to know if USA army did decide install that modules on their A-10C AN/ARC-186 radios.

[Yurgon]

25 minutes ago, InteR said:

So it would be very interesting to know if USA army did decide install that modules on their A-10C AN/ARC-186 radios.

If you're asking whether the A-10 (operated by the US Air Force and the Air National Guard, but never by the Army) can home in on VHF FM sources, yes, as far as I'm aware it could always do that. Just not in DCS, this feature is not implemented in DCS.