Becker AR4201 transmit volume low

[John Foster]

I just installed a Becker AR4201 that I picked up used from the UK (frequency spacing change from 25 to 8.33). I have it paired with a Peiker TM 170 I got from W&W based on their compatibility statements on the website. It will transmit voice, but it is extremely soft/quite and the receiver needs to have the volume all the way up to hear it. Does anyone know what the problem is and how to fix it? I did a search but didn't come up with any answers. Thanks.

[markde...@gmail.com]

Is there a match between mic type and how it’s wires? Dynamic vs Electret?

[John Foster]

On Thursday, July 18, 2019 at 10:38:56 AM UTC-6, markde...@gmail.com wrote:
> Is there a match between mic type and how it’s wires? Dynamic vs Electret?

From W&W website:

"This microphone WILL WORK with:

• Becker
• Walter Dittel

This microphone WILL NOT WORK with (use TM168):

• Flightline
• Microair
• Trig
• XCOM

- See more at: https://wingsandwheels.com/avionics-instruments/radios-transceiver/microphones/peiker-microphone/tm170.html#sthash.Vw92UtR5.dpuf"

[Bob Kuykendall]

On Thursday, July 18, 2019 at 9:03:59 AM UTC-7, John Foster wrote:
> I just installed a Becker AR4201 that I picked up used from the UK (frequency spacing change from 25 to 8.33). I have it paired with a Peiker TM 170 I got from W&W based on their compatibility statements on the website. It will transmit voice, but it is extremely soft/quite and the receiver needs to have the volume all the way up to hear it. Does anyone know what the problem is and how to fix it? I did a search but didn't come up with any answers. Thanks.

Try adjusting the mic sensitivity setting SF16 using service mode. See pages 3-11 and 3-16 of this manual (Thanks, Cumulus Soaring!)

https://www.cumulus-soaring.com/becker/AR4201-Manual.pdf

--Bob K.

[markde...@gmail.com]

On page 2-6 you will notice that pin 5 and pin 18 are for different types of mics....

[Dan Daly]

On Thursday, July 18, 2019 at 12:57:40 PM UTC-4, markde...@gmail.com wrote:
> On page 2-6 you will notice that pin 5 and pin 18 are for different types of mics....

I replaced a microair 760 with a Euro AR4201 this spring. I used the same boom mic, and pin 18 works for it (electret). I expect hooking a TM170 to pin 5 (dynamic mic) might fix your problem.

[John Foster]

I used the wiring harness that W&W makes for this radio, so whichever pin that goes to is what I used. I'll look at the diagram again, but I can't say for sure what pin the actual mic wire comes from. Thanks.

[John Foster]

Thanks Bob. This looks really promising. I'll give it a try this evening.

[John Foster]

I tried adjusting the mic sensitivity in service mode all the way up to 63, but it didn’t seem to make any difference. I have the wiring harness from Wings and Wheels. How would I go about switching pin 5 with pin 18?

[Dan Daly]

On Friday, July 19, 2019 at 11:45:19 AM UTC-4, John Foster wrote:
> I tried adjusting the mic sensitivity in service mode all the way up to 63, but it didn’t seem to make any difference. I have the wiring harness from Wings and Wheels. How would I go about switching pin 5 with pin 18?

The mic wire on my W&W AR4201 harness was on pin 18. If you want to move it to pin 5, unsolder it from 18, move it to 5, and solder it.

Pin-outs are in the manual.

[John Foster]

Thanks. That seems simple enough.

It raises a related question though: the mic is a dynamic un-amplified mic (Peiker TM170). If I understand things correctly, the way the harness is currently wired (pin 18) would be for a standard, not a dynamic mic. Why would they do that? The Becker mic is a dynamic mic, as is the Peiker.

[moshe....@gmail.com]

The diagram in the manual also shows different ground pins for the two types of mics, that may or may not matter, but best to follow what it says. A dynamic mic (as you have) sends a much weaker signal than a condenser mic, and also should not have a DC voltage applied to it. That's why they have separate connections.

Depending on the type of connector, the pins may be removable (need a special tool), swapping them that way would be faster than re-soldering. Find a friend who has the relevant skills and tools.

And return the mic sensitivity setting to normal before you try transmitting again...

Enjoy the radio. My glider came with this type radio and it's been solid.

[John Foster]

I was able to get a hold of a pin tool for the wiring harness and was able to swap pin 18 for pin 5. This fixed the problem. Apparently, I ordered the wiring harness as a "standard" wiring harness and did not read the options carefully enough to select the "dynamic" wiring harness for this radio. Less than learned.

[John Foster]

Another thing I wondered about was whether I would need to change the ground pin as well from 14 to 6, but it appears all is working as intended with just the change of pin 18 to pin 5. Thanks for all the help everyone.

[John DeRosa OHM Ω http://aviation.derosaweb.net]

On Saturday, July 20, 2019 at 1:57:53 AM UTC-5, John Foster wrote:
> Another thing I wondered about was whether I would need to change the ground pin as well from 14 to 6, but it appears all is working as intended with just the change of pin 18 to pin 5. Thanks for all the help everyone.

John,

Glad you worked things out.

Not having the schematic for the Becker 4201 (anyone have one?) I honestly don't know if the different ground pins for standard or dynamic microphone are actually directly connected together within the radio or are kept separate. But I suspect they might be separate and go to different amplification circuits. Why? To reduce noise being transmitted along with your voice. That being said you won't harm the radio by using the "wrong" ground pin.

Bottom line - If your receive audio is clean then you could leave things alone. Test your audio quality by having a friend transmit while you are listening a considerable distance away on a handheld. The distance is important because nearly any radio will sound great (little or no background noise) when in close proximity. Better yet take a test flight and ask someone "far away" how you sound.

PS - You might want to reset the dynamic mic gain setting (SF16) back to the original value.

My $0.02.

- John (OHM)