Echo on audio when using "Radio Mic Boost"

Anthony_G7LRQ
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Joined: Wed Aug 11, 2021 8:05 pm

Echo on audio when using "Radio Mic Boost"

Postby Anthony_G7LRQ » Sun Jun 12, 2022 4:21 pm

I have Anan 100D running protocol 1 V6.0 and PiHPSDR V2 controller.

Recently been getting comments that my TX audio is poor and has a echo making it un readable.

I haven't changed anything and have been using a KOSS SB45 headset with the setup for months.

I initially thought is was RF getting into the headset etc, but this been discounted and I finally found this if I turn the "Radio Mic Boost" off it stops the problem, but I then have quiet audio, just turning the "Mic Gain" up and the problem returns.

Does anyone have any thoughts why this is happening and how to correct it?

Anthony G7LRQ/G7L
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w-u-2-o
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Re: Echo on audio when using "Radio Mic Boost"

Postby w-u-2-o » Sun Jun 12, 2022 6:41 pm

Why have you discounted RFI into the microphone input? An echo on transmit is the absolute number one symptom of RFI getting into the microphone input of our radios. The latency from mic to antenna makes for a perfect echo generator (some people might call it reverb). This is almost certainly your problem. I'd be willing to bet a beer on it!

The reason it gets worse when mic gain is higher, either because you turned up mic gain or because you activated mic boost, is because the RFI is not noticeable at lower gain levels. But of course neither is your desired audio, either ;)

My understanding is that the SB45 uses an electret microphone element and is wired for compatibility with PC mic inputs. Stock PC microphone wiring will not work properly (see this topic). Have you created an adapter for your SB45 mic connector? Have you turned on the mic bias in piHPSDR? If not, then that might explain some of the RFI problem, as without proper wiring and without bias turned on you have to run the mic gain way too high.

This is not a piHPSDR question and after you reply this topic will be moved to the Microphones sub-forum.
Anthony_G7LRQ
Posts: 14
Joined: Wed Aug 11, 2021 8:05 pm

Re: Echo on audio when using "Radio Mic Boost"

Postby Anthony_G7LRQ » Wed Nov 16, 2022 11:27 pm

Sorry for the delay in replying, been busy.

So maybe my comment about being RF was incorrect. So how do I stop it, I can reduce the output power to less than a watt and the problem is the same, into either a dummy load or antenna.

I have an adapter box that the SB45 plugs into and is combined with a footswitch so audio in/out and ptt all work through the front of my 100D , The JP4, 5 and 6 are set correctly on the Angelia board to provide Mic Bias and PTT. No option in piHPSDR that I am aware of for bias.

The other thing that confuses me with this issue, is I mainly uses the Anan as a transverter driver, using the low power Tvtr O/P and TVtr RX and when using the system this way and running full 400w on any frequency from 144 to microwaves, I don't get any echo issues at all. I assume in this configuration it bi-passes most of main PA board and only uses the Angelia O/P power.
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w-u-2-o
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Re: Echo on audio when using "Radio Mic Boost"

Postby w-u-2-o » Thu Nov 17, 2022 2:07 am

Anthony_G7LRQ wrote:Sorry for the delay in replying, been busy.

5 months later is very busy, ha ha :D

So maybe my comment about being RF was incorrect. So how do I stop it, I can reduce the output power to less than a watt and the problem is the same, into either a dummy load or antenna.

That's very odd, especially since you say it doesn't happen when using the ANAN with the transverter.

I have an adapter box that the SB45 plugs into and is combined with a footswitch so audio in/out and ptt all work through the front of my 100D , The JP4, 5 and 6 are set correctly on the Angelia board to provide Mic Bias and PTT.

With the mic bias properly applied to the electret microphone of the SB45 the mic boost option should not be required. Are you no longer using mic boost?

No option in piHPSDR that I am aware of for bias.

Nor should there be. With the 100D and prior models all PTT, bias and mic wiring is handled by the jumpers. You will only see those controls appear in piHPSDR (or linHPSDR, or Thetis) when the hardware type is 200D or newer (Orion card or newer).

The other thing that confuses me with this issue, is I mainly uses the Anan as a transverter driver, using the low power Tvtr O/P and TVtr RX and when using the system this way and running full 400w on any frequency from 144 to microwaves, I don't get any echo issues at all. I assume in this configuration it bi-passes most of main PA board and only uses the Angelia O/P power.

Yes, that is very strange.

If you use USB audio with piHPSDR does the problem go away?

You may have a strange grounding or bonding problem in your setup since you say operation into a dummy load does not correct the issue.
Anthony_G7LRQ
Posts: 14
Joined: Wed Aug 11, 2021 8:05 pm

Re: Echo on audio when using "Radio Mic Boost"

Postby Anthony_G7LRQ » Sat Nov 19, 2022 2:59 pm

5 months later is very busy, ha ha :D

Quicker reply this time :)

With the mic bias properly applied to the electret microphone of the SB45 the mic boost option should not be required. Are you no longer using mic boost?

I am still using the mic boost, without this I have to increase the mic gain from 10 to 45 to get a reasonable audio level and then the echo is still present. I do have the mic bias set correctly as it doesn't work at all if I change the jumper.

If you use USB audio with piHPSDR does the problem go away?
I don't have any a way to connect audio via USB to test.
What I did try was I wired an old handheld fist mic with a jack plug and plug that straight in the front and connected headphones to the socket as the issue is exactly the same, so clearly nothing to do with my adaptor box or SB45 headset.

I can only think the echo must be happening in the amplifier part of the Anan :(

I have no idea how to cure this, I also plugged in an extension speaker into the rear socket and that has the same echo present.

If this can't be solved the ANAN will have to be changed to another radio for HF use :(
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w-u-2-o
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Re: Echo on audio when using "Radio Mic Boost"

Postby w-u-2-o » Sat Nov 19, 2022 9:07 pm

Anthony_G7LRQ wrote: I am still using the mic boost, without this I have to increase the mic gain from 10 to 45 to get a reasonable audio level and then the echo is still present. I do have the mic bias set correctly as it doesn't work at all if I change the jumper.

While it probably has nothing at all to do with this problem, it doesn't say much for the output level of that microphone. You might start thinking about something else.

I don't have any a way to connect audio via USB to test.

It may be important that you find a way to do this. USB sound adapters are cheap.

I also plugged in an extension speaker into the rear socket and that has the same echo present.

I don't understand. When you do this what are you listening to? Receiver audio?

If this can't be solved the ANAN will have to be changed to another radio for HF use :(

It seems very unlikely the problem is the ANAN.

Have you tried running the ANAN with Thetis on a Windows machine?

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