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I have a Icom HM-36 handheld microphone. Like all Icom mics it uses a condenser, and the bias coming out of the Icom rig is +8 volts. The microphone bias cominng out of the sBitx V2/V3 is, I believe, about +2.5 volts. Does anyone know how well the Icom HM-36 would work with the sBitx? I have the connectors to make an adaptor, so I suppose I could find out that way.
Jack, N6LN
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Well of course things could have changed, but based on the released V2 schematic I would guess the mic bias is more like?+12 See enclosed snippet of the schematic
In my experience, the sBitx needs considerably more mic output than an Icom.? ?I have had good success by using a -24dB output mic element.? ?
The enclosed article, while written relating to the ICOM series, also includes information on the element that I used in an identical?mic for the sBitx
if youtube?the ICOM mic, you may have trouble getting full output on SSB modes.
Good luck! Gordon
On Sat, Jan 13, 2024 at 7:46?PM John Terrell, N6LN < N6LN@...> wrote: I have a Icom HM-36 handheld microphone. Like all Icom mics it uses a condenser, and the bias coming out of the Icom rig is +8 volts. The microphone bias cominng out of the sBitx V2/V3 is, I believe, about +2.5 volts. Does anyone know how well the Icom HM-36 would work with the sBitx? I have the connectors to make an adaptor, so I suppose I could find out that way.
Jack, N6LN
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Thanks Gordon. Indeed the mic bias (tip) is +12V. I must have measured the PTT which is +2.5V. The mic pin on the Icom is +7.8V. The specs say it should be +8V. Based on the Icom HF-36 schematic I assume it would work with +12V.  I have 3 HFSignals microphones and I remember putting an upgraded element in one according to an post but it didn't seem to improve the gain. The problem is that the uBitx and sBitx rigs don't seem to have enough mic gain and beyond a mic gain level of about 50-60 the audio becomes too distorted. However, even below that point if I listen on my Icom receiver the voice audio sounds coarse and raspy. The same test using my Kenwood TS-850 to transmit and listening on my Icom shows smooth voice quality. I was hoping by using my Icom microphone I might get better sound out of my sBitx transmissions. With your amplifier relay mod I should be able to get audio reports with a strong signal. I'll find out one way or another. Jack, N6LN
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Yes, the sBitx needs quite a bit of audio. It¡¯s similar to the old heathkits in that regard!
The -24 DB Mike that I have created has created fantastic audio for me. And I don¡¯t have any problem fully modulating. ?
Notice that I came up with a digital filter solution for the lower power on upper side band on my particular radio?
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On Jan 14, 2024, at 17:36, John Terrell, N6LN <N6LN@...> wrote:
?Thanks Gordon. Indeed the mic bias (tip) is +12V. I must have measured the PTT which is +2.5V. The mic pin on the Icom is +7.8V. The specs say it should be +8V. Based on the Icom HF-36 schematic I assume it would work with +12V.  I have 3 HFSignals microphones and I remember putting an upgraded element in one according to an post but it didn't seem to improve the gain. The problem is that the uBitx and sBitx rigs don't seem to have enough mic gain and beyond a mic gain level of about 50-60 the audio becomes too distorted. However, even below that point if I listen on my Icom receiver the voice audio sounds coarse and raspy. The same test using my Kenwood TS-850 to transmit and listening on my Icom shows smooth voice quality. I was hoping by using my Icom microphone I might get better sound out of my sBitx transmissions. With your amplifier relay mod I should be able to get audio reports with a strong signal. I'll find out one way or another. Jack, N6LN
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The Icom HM-36 mike works, and the improvement is breathtaking! The highs come through much better--it doesn't sound so muffled. It still could use a little boost, although simply increasing the mic gain on the front panel still pushes the voice into distortion--so I'm not sure a preamp would do any more good. What exactly did you do?  Jack, N6LN
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Again, I don¡¯t quite understand this but simply using a mic with very high output works great.
The exact same thing is observed with external digital signals from a signallink for example; you have to change the jumper to get high enough output for this radio. ?
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On Jan 14, 2024, at 20:49, John Terrell, N6LN <N6LN@...> wrote:
?The Icom HM-36 mike works, and the improvement is breathtaking! The highs come through much better--it doesn't sound so muffled. It still could use a little boost, although simply increasing the mic gain on the front panel still pushes the voice into distortion--so I'm not sure a preamp would do any more good. What exactly did you do?  Jack, N6LN
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Gordon, I have a signalink that I use for FT8 with my FT-857D, and then I run WSJT-X on my laptop connected to the Signalink and the Yaesu, on nice days in the patio. Do you use the signalink with your sBitx? I run the WSJT-X program within the sBitx and with a larger monitor in the shack. So I don't need to use the Signalink. I use the 7-inch screen for convenience when I want to quickly change bands or modes and if I don't have the webUI window at the front. But I suppose if I go mobile with the sBitx I'll just use a laptop for the webUI.
Jack, N6LN
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Thanks, john, I actually haven¡¯t used the built-in software very much yet. I do a great deal of Winlink and so I have to have an external sound interface in order to do that because there is very limited support for Linux in WINLINK.?
?It works just great once a bunch of things are figured out, and part of it was the fact that it really needs a high audio input, which I sure has confirmed incidentally and gave us a number for which I forgot. Additionally I had to adjust the digital filtering to handle the discrepancy between lower side band and upper side band which I think Ashhar has also confirmed. ? ? I simply multiplied the coefficient on the side that needed more power by about the ?square root of two and all was much better. ? ?At some point I¡¯m going to map it better and make a better inverse filter but for the moment that got me working, with full or close to full power on upper side band?
Getting ready to use this radio for a really neat science project with my pre-calculus students and I¡¯ll be writing more about it here soon, I¡¯m really amazed at what we have access to?
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On Jan 15, 2024, at 19:55, John Terrell, N6LN <N6LN@...> wrote:
?Gordon, I have a signalink that I use for FT8 with my FT-857D, and then I run WSJT-X on my laptop connected to the Signalink and the Yaesu, on nice days in the patio. Do you use the signalink with your sBitx? I run the WSJT-X program within the sBitx and with a larger monitor in the shack. So I don't need to use the Signalink. I use the 7-inch screen for convenience when I want to quickly change bands or modes and if I don't have the webUI window at the front. But I suppose if I go mobile with the sBitx I'll just use a laptop for the webUI.
Jack, N6LN
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HUGE difference! Check it out for yourself with my audio files.So here's what both sound like. I transmitted my voice through each microphone and recorded the audio received on my Icom-7600 directly through the USB connection to the Voice Recorder accessory on my connected Windows 10 PC. So this is exactly what it sounds like on the receiving end.
Amazing.
73,
Jack, N6LN
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Yup.? ?Big difference.? ?Congrats!? Remember we can adjust ANY microphone through simple math now in this radio.? ?I'm getting ready to do a science fair experiment with my precalculus students where we emphasize the highs and de-emphasize 200 Hz and below to see if it increases intelligibiliity.? ?Will putt out some code snippets soon on this presuming it works.? ?It worked perfectly to fix the power differences?between lower and upper sideband....
Gordon
On Mon, Jan 15, 2024 at 9:55?PM John Terrell, N6LN < N6LN@...> wrote: HUGE difference! Check it out for yourself with my audio files.So here's what both sound like. I transmitted my voice through each microphone and recorded the audio received on my Icom-7600 directly through the USB connection to the Voice Recorder accessory on my connected Windows 10 PC. So this is exactly what it sounds like on the receiving end.
Amazing.
73,
Jack, N6LN
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Here is the code snippet where I changed the USB filtering:? ?The coefficient may well be different for every different radio.? ?I twiddled this on the real radio after starting on my computer.? ?I think I ended up with between 1.4 and 1.7 for the coefficient.? ?Here, for safety, I have put in 1.4? ?You will need to measure your own radio.? Remember these are VOLTAGES, power differences will be squared.
// TBD: Something strange is going on, this should have been the otherway
if (r->mode == MODE_LSB || r->mode == MODE_CWR)
// zero out the LSB
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
else
{ // zero out the USB
for (i = MAX_BINS/2; i < MAX_BINS; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
// GLG: double the eventual USB signal to make up for unknown losses
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = __real__ fft_out[i] * 1.4;
__imag__ fft_out[i] = __imag__ fft_out[i] * 1.4;
}
}
//now rotate to the tx_bin
for (i = 0; i < MAX_BINS; i++){
int b = i + tx_shift;
if (b >= MAX_BINS)
b = b - MAX_BINS;
if (b < 0)
b = b + MAX_BINS;
r->fft_freq[b] = fft_out[i];
On Mon, Jan 15, 2024 at 10:00?PM Gordon Gibby via <docvacuumtubes= [email protected]> wrote: Yup.? ?Big difference.? ?Congrats!? Remember we can adjust ANY microphone through simple math now in this radio.? ?I'm getting ready to do a science fair experiment with my precalculus students where we emphasize the highs and de-emphasize 200 Hz and below to see if it increases intelligibiliity.? ?Will putt out some code snippets soon on this presuming it works.? ?It worked perfectly to fix the power differences?between lower and upper sideband....
Gordon
On Mon, Jan 15, 2024 at 9:55?PM John Terrell, N6LN < N6LN@...> wrote: HUGE difference! Check it out for yourself with my audio files.So here's what both sound like. I transmitted my voice through each microphone and recorded the audio received on my Icom-7600 directly through the USB connection to the Voice Recorder accessory on my connected Windows 10 PC. So this is exactly what it sounds like on the receiving end.
Amazing.
73,
Jack, N6LN
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// TBD: Something strange is going on, this should have been the otherway
if (r->mode == MODE_LSB || r->mode == MODE_CWR)
// zero out the LSB
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
else
{ // zero out the USB
for (i = MAX_BINS/2; i < MAX_BINS; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
// GLG: double the eventual USB signal to make up for unknown losses
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = __real__ fft_out[i] * 1.4;
__imag__ fft_out[i] = __imag__ fft_out[i] * 1.4;
}
}
//now rotate to the tx_bin
for (i = 0; i < MAX_BINS; i++){
int b = i + tx_shift;
if (b >= MAX_BINS)
b = b - MAX_BINS;
if (b < 0)
b = b + MAX_BINS;
r->fft_freq[b] = fft_out[i];
/////////////////
But which file is this?
Jack, N6LN
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Gordon,
Thanks again for your wonderful relay mod for keying an external amplifier. By using the sBitx V2/V3 to drive my amplifier to almost a kilowatt I was finally able to get reliable signal reports on SSB tonight with the Icom handheld microphone. I am happy to report that the setup has excellent audio quality. Now when I operate remotely by QRP I¡¯ll know that the SSB doesn¡¯t need any further modification.
73,
Jack, N6LN
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that's great!? ?I was doing experiments with the digital signal processing tonight and strangely, I got poor results from a homebrew mic that I think I had working very well with my DE -- when tried on the V2.....? mysteries never cease.
That is fantastic?that you have the icom mic working! I have the parts to try the same thing, will need to do that. THANKS! Gordon
On Tue, Jan 16, 2024 at 12:26?AM John Terrell, N6LN < N6LN@...> wrote: Gordon,
Thanks again for your wonderful relay mod for keying an external amplifier. By using the sBitx V2/V3 to drive my amplifier to almost a kilowatt I was finally able to get reliable signal reports on SSB tonight with the Icom handheld microphone. I am happy to report that the setup has excellent audio quality. Now when I operate remotely by QRP I¡¯ll know that the SSB doesn¡¯t need any further modification.
73,
Jack, N6LN
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John, the code snippet comes from the tx_process in sbitx.c
I'm not reaching success there yet, but in a couple hours ofwork, I got a lot better at handling the arrays of sounds and frequencies...... Gordon
On Mon, Jan 15, 2024 at 11:16?PM John Terrell, N6LN < N6LN@...> wrote: // TBD: Something strange is going on, this should have been the otherway
if (r->mode == MODE_LSB || r->mode == MODE_CWR)
// zero out the LSB
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
else
{ // zero out the USB
for (i = MAX_BINS/2; i < MAX_BINS; i++){
__real__ fft_out[i] = 0;
__imag__ fft_out[i] = 0;
}
// GLG: double the eventual USB signal to make up for unknown losses
for (i = 0; i < MAX_BINS/2; i++){
__real__ fft_out[i] = __real__ fft_out[i] * 1.4;
__imag__ fft_out[i] = __imag__ fft_out[i] * 1.4;
}
}
//now rotate to the tx_bin
for (i = 0; i < MAX_BINS; i++){
int b = i + tx_shift;
if (b >= MAX_BINS)
b = b - MAX_BINS;
if (b < 0)
b = b + MAX_BINS;
r->fft_freq[b] = fft_out[i];
/////////////////
But which file is this?
Jack, N6LN
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"Gordon,
Thanks again for your wonderful relay mod for keying an external amplifier. By using the sBitx V2/V3 to drive my amplifier to almost a kilowatt I was finally able to get reliable signal reports on SSB tonight with the Icom handheld microphone. I am happy to report that the setup has excellent audio quality. Now when I operate remotely by QRP I¡¯ll know that the SSB doesn¡¯t need any further modification.
73,
Jack, N6LN"
Huge success!? And just goes to show that with a sufficiently?cleaned output, we can even use this as a nice exciter for a linear.? ?I need to try one of those mics.... Gordon
On Tue, Jan 16, 2024 at 12:26?AM John Terrell, N6LN < N6LN@...> wrote: Gordon,
Thanks again for your wonderful relay mod for keying an external amplifier. By using the sBitx V2/V3 to drive my amplifier to almost a kilowatt I was finally able to get reliable signal reports on SSB tonight with the Icom handheld microphone. I am happy to report that the setup has excellent audio quality. Now when I operate remotely by QRP I¡¯ll know that the SSB doesn¡¯t need any further modification.
73,
Jack, N6LN
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John Terrell, N6LN
