When on 6M, the distorted Mic audio comes through the passive speaker. It also happens when doing the 2-Tone test, and I have a dummy load on antenna output and using power as low as 20W. So it appears something is getting to somewhere it shouldn't be getting to within the G2. I also notice that when PS is enabled, the sound through the speaker is greatly reduced! The greater the power output, the more it is noticeable.
Has anyone else noticed this?
73
John
N2KBE
Mic and 2-Tone heard thru speaker on 6M
Re: Mic and 2-Tone heard thru speaker on 6M
I also notice that in Thetis, it is the same volume regardless of whether PS is enabled or not. In pihpsdr, turning PS on greatly reduces it, where it may no longer be an issue. Interesting? BTW, I am using a G2 with 7 inch display, and also a hand Mic connected to front panel.
Re: Mic and 2-Tone heard thru speaker on 6M
When you are listening to mic audio (not two tone), does it sound slightly delayed?
Re: Mic and 2-Tone heard thru speaker on 6M
WU2O,
No, there doesn't seem like there is any delay to me. I would have to use test instruments to measure it.
I have noticed that when I remove the 10 wire ribbon cable connector that goes to the small board at the back of G2, the sound is no longer heard while transmitting. I tried re-locating the cable to keep it away from the PA/LPF area, but it didn't do any good. Of course I had to make a longer cable.
No, there doesn't seem like there is any delay to me. I would have to use test instruments to measure it.
I have noticed that when I remove the 10 wire ribbon cable connector that goes to the small board at the back of G2, the sound is no longer heard while transmitting. I tried re-locating the cable to keep it away from the PA/LPF area, but it didn't do any good. Of course I had to make a longer cable.
Re: Mic and 2-Tone heard thru speaker on 6M
Take a look at this topic: viewtopic.php?t=5307
The first, and easiest, thing to do might be to put a terminator on the 10MHz input.
Note that the ribbon cable you removed attaches to the balanced mic input preamp board. If you are not using that board you could leave it disconnected.
The first, and easiest, thing to do might be to put a terminator on the 10MHz input.
Note that the ribbon cable you removed attaches to the balanced mic input preamp board. If you are not using that board you could leave it disconnected.
Re: Mic and 2-Tone heard thru speaker on 6M
I already have a 50 ohm SMA termination on the 10Mhz input.
One end of the 10 wire ribbon cable I removed attaches to the PA board, the other to the small board on the rear of the G2. I believe the larger ribbon cable on the small rear board attaches to the Saturn board.
Christoph modified pihpsdr, so that the G2 can select to disable the Audio Amp during Tx (in the Radio menu) when using the Mic. There is a "pop" noise when one releases the Mic PTT, but it is not that bad. Only really need it for the 6M band. I also notice the unwanted noise doesn't appear at the headphone jack.
One end of the 10 wire ribbon cable I removed attaches to the PA board, the other to the small board on the rear of the G2. I believe the larger ribbon cable on the small rear board attaches to the Saturn board.
Christoph modified pihpsdr, so that the G2 can select to disable the Audio Amp during Tx (in the Radio menu) when using the Mic. There is a "pop" noise when one releases the Mic PTT, but it is not that bad. Only really need it for the 6M band. I also notice the unwanted noise doesn't appear at the headphone jack.
-
laurencebarker
- Posts: 313
- Joined: Mon Nov 11, 2019 7:39 pm
Re: Mic and 2-Tone heard thru speaker on 6M
The 10 wire ribbon cable from the PA board to the rear panel I/O board has 3 signals on it:
1. pin 7: an unused bias control signal, that could be used to disable PA bias. That signal is always 0v and has no effect.
2. pin 5: an analogue signal from the 13.8V sensing circuit on the PA board, so the input voltage can be measured and reported
3. pin 1: an analogue signal from the PA current measuring circuit on the PA board, so the PA current can be reported.
All those signals are routed to the 26 way cable that runs to the Saturn board itself.
If you were transmitting a digital mode (eg FT8) the current monitor would be constant level. If you are transmitting SSB, then it has the envelope of your speech peaks on it; it is a single ended signal and can couple noise into something else. The external speaker connections go through the same board, and it could somehow be coupling noise onto the speaker output. Those are supposed to be balanced (ie no connection to ground) so how coupling happens isn't clear.
The microphone signals aren't present on the I/O board, but the balanced mic input connector is next to it. (That is a separate connector with screened cable connection to the preamp board, rather than being on the PCB). My balanced mic cable is bundled to that ribbon cable, but doesn't need to be.
1. pin 7: an unused bias control signal, that could be used to disable PA bias. That signal is always 0v and has no effect.
2. pin 5: an analogue signal from the 13.8V sensing circuit on the PA board, so the input voltage can be measured and reported
3. pin 1: an analogue signal from the PA current measuring circuit on the PA board, so the PA current can be reported.
All those signals are routed to the 26 way cable that runs to the Saturn board itself.
If you were transmitting a digital mode (eg FT8) the current monitor would be constant level. If you are transmitting SSB, then it has the envelope of your speech peaks on it; it is a single ended signal and can couple noise into something else. The external speaker connections go through the same board, and it could somehow be coupling noise onto the speaker output. Those are supposed to be balanced (ie no connection to ground) so how coupling happens isn't clear.
The microphone signals aren't present on the I/O board, but the balanced mic input connector is next to it. (That is a separate connector with screened cable connection to the preamp board, rather than being on the PCB). My balanced mic cable is bundled to that ribbon cable, but doesn't need to be.
Laurence Barker G8NJJ