Re: sBitx Mic input - assist request
Thanks everyone for the discussion, much appreciated.
I did find a typo in my measurements documentation. The base is 2.9 v not 3.9. That resolves the concern with QD1.
Using a fluke 8062 to measure. It has been reliable for years and I checked it against my Simpson 260.?
?
I have removed from circuit.?
CD28
LD6
CD29
CD27
RD15
QD1
There should be 11.9 volts at? open end of RD21, and I'm still only getting 2.1 v.?
I have removed RD 21 and verified 10K Ohms and reinstalled. I'm now looking for a solder bridge, lifted pad or some other PCB issue.
?
May just bypass this mic preamp and use an external one that I know works. Spent too much time on this.... especially since I will probably use the sBitx for FT8/POTA most of the time.
?
Will update you with next findings.....
?
73,
?
WF4RC-Rob
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Farhan might I ask whi the pico and not just add a pc8575 or pc8574 i2c gpio expander into the mix if you need more gpio.
I think the z2w over pico w is alot better and mre power performance.
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Re: zbitx update, shipping, pico, et al
sbitx is being praised while zbitx is being talked about.
Those who have little knowledge of the knowledge of certain components believe that one day it will be able to do what the sbitx can do with the many developments.
Don't believe it, it won't be able to do that. This is a small radio that you can take up to the mountain with you and make a few digital and cw QSOs with it.
If you choose the right microphone, you can also use it in voice mode.
This is what it was designed for. If you are interested, you can compare the knowledge of the individual parts on the Internet using the search engines.
--
Gyula HA3HZ
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Re: sBitx Mic input - assist request
QD1 is toast, the base to emitter voltage is too high!
Recheck and if you find Voltage between base-emitter is much more
that say 0.7 volts then replace the transistor and you audio will
be back.
Raj, vu2zap
On 09/03/2025 9:32 PM, WF4RC Carroll
via groups.io wrote:
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Show quoted text
I have a new sBitxV3 board only. Everything is working except
the Mic input. I started experimenting with some microphone I
had and the recorded transmission has lots of noise and very low
audio. I measure 2.1v on mic input tip. I think it should be 5v.
Can anyone guide me as to what the issue may be and where I
should look. Here are my measurements/ calculations.?
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Re: zbitx update, shipping, pico, et al
Aaron,
The radio works out of the box, have no doubts. However, you can tinker with it if you want to, but no one insists on it.
The sbitx wouldnt be what it is without the contributions of so many folks who have tinkered with it. The aim of making it programmable is just that.
You can use this like a traditional radio that works all the modes like SSB, CW. What makes the sbitx and the zbitx different is that it keeps getting better with age as folks keep adding features and modes to it. Just look at JJ's team's mind blowing port of QSSTV and FreeDV as an examplr
On Mon, Mar 10, 2025, 6:46 AM David T-- VE3TOS via <digiital= [email protected]> wrote: From what I understood the email from Farhan was explaining that in the future should there be any need to update the firmware to the raspberry pico that to avoid issues with end users needed to install the software to update the pico on their PC that he was working on a work around where you will connect a cable from the raspberry zero W2 to the pico and update the firmware that way.?? No radio is perfect out of the box and especially sdr like radios where software/firmware is always changing .
I would assume that the radio would be radio to go out of the box . What he explained was to make things easier to upgrade the firmware in the future when they need to fix bugs.??
Also the bitx radios are to be expected some hacking around will be required at some point.? I'm confused with all this. When I open the package, install the batteries I want it to work. I'm not interested in jumping through a bunch of hoops like the DX FT-8. Please don't ship until it works.
?
Aaron
W4AAN?
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On Mar 9, 2025, at 21:55, Ted via groups.io <k3rta@...> wrote:
?Solution found.
It was chiefly the BFO - and for all I know, I might have set it wrong in the first place 2-3 years ago when I swapped out the board, and never knew.??
I took the advice on the KD8CEC site to use an audio spectrum analyzer program [for Android, i use "Spectroid"] to listen to the rig on a clear frequency. I? tuned the white noise for as even a blanket between 300hz and 3khz as I can judge.? I then hooked up Memory Manager and re-tuned to WWV by making changes to the master clock value rather than dealing with all of that other carrier cal trouble.??
At this point, I hollered into a dummy load and discovered I could hear only the desired sideband on a redundant radio, upper or lower, corresponding with the intended one.?
CW followed, moving the CW BFO around until I got the tightest curve I could manage between letting in as much 600hz as it can while rejecting as much treble as it can. There's a CW filter add-on here, but its nice to be able to trim it a little beforehand.?
I sure appreciate the encouragement.? Sometimes we just have to go back to the beginning and see if following the instructions on a new day (or new year) improves the outcome.
Tnx & 72
Ted K3RTA? On Sun, Mar 9, 2025 at 11:40, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote: He could offset the carrier a bit one way or the other, (maybe by 1500 Hz ?) and then plot the response of the filter by looking at the noise pattern on any waterfall display
It would be a great learning exercise also!!
Gordon kx4z?
On Mar 9, 2025, at 10:37, Evan Hand via groups.io <elhandjr@...> wrote:
? Hi Ted,
?
Since you have the Memory Manager software, I suggest you save the values to a file and do the BFO adjustment again.??
?
I thought about the symptoms again and do not believe the modulator failure is the most likely cause.? The carrier is significantly reduced in the video.? If the modulator failed, I would expect a much higher value for the carrier (BF0).? Also, the SSB crystal filter would limit the output to a 3KHz span.? It could be that the SSB filter is damaged somehow.
?
Hopefully, others can chime in here, as I cannot explain the data.
?
73
Evan
AC9TU
|
Solution found.
It was chiefly the BFO - and for all I know, I might have set it wrong in the first place 2-3 years ago when I swapped out the board, and never knew.??
I took the advice on the KD8CEC site to use an audio spectrum analyzer program [for Android, i use "Spectroid"] to listen to the rig on a clear frequency. I? tuned the white noise for as even a blanket between 300hz and 3khz as I can judge.? I then hooked up Memory Manager and re-tuned to WWV by making changes to the master clock value rather than dealing with all of that other carrier cal trouble.??
At this point, I hollered into a dummy load and discovered I could hear only the desired sideband on a redundant radio, upper or lower, corresponding with the intended one.?
CW followed, moving the CW BFO around until I got the tightest curve I could manage between letting in as much 600hz as it can while rejecting as much treble as it can. There's a CW filter add-on here, but its nice to be able to trim it a little beforehand.?
I sure appreciate the encouragement.? Sometimes we just have to go back to the beginning and see if following the instructions on a new day (or new year) improves the outcome.
Tnx & 72
Ted K3RTA?
On Sun, Mar 9, 2025 at 11:40, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote: He could offset the carrier a bit one way or the other, (maybe by 1500 Hz ?) and then plot the response of the filter by looking at the noise pattern on any waterfall display
It would be a great learning exercise also!!
Gordon kx4z?
On Mar 9, 2025, at 10:37, Evan Hand via groups.io <elhandjr@...> wrote:
? Hi Ted,
?
Since you have the Memory Manager software, I suggest you save the values to a file and do the BFO adjustment again.??
?
I thought about the symptoms again and do not believe the modulator failure is the most likely cause.? The carrier is significantly reduced in the video.? If the modulator failed, I would expect a much higher value for the carrier (BF0).? Also, the SSB crystal filter would limit the output to a 3KHz span.? It could be that the SSB filter is damaged somehow.
?
Hopefully, others can chime in here, as I cannot explain the data.
?
73
Evan
AC9TU
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Re: zbitx update, shipping, pico, et al
From what I understood the email from Farhan was explaining that in the future should there be any need to update the firmware to the raspberry pico that to avoid issues with end users needed to install the software to update the pico on their PC that he was working on a work around where you will connect a cable from the raspberry zero W2 to the pico and update the firmware that way.?? No radio is perfect out of the box and especially sdr like radios where software/firmware is always changing .
I would assume that the radio would be radio to go out of the box . What he explained was to make things easier to upgrade the firmware in the future when they need to fix bugs.??
Also the bitx radios are to be expected some hacking around will be required at some point.?
I'm confused with all this. When I open the package, install the batteries I want it to work. I'm not interested in jumping through a bunch of hoops like the DX FT-8. Please don't ship until it works.
?
Aaron
W4AAN?
|
Re: zbitx update, shipping, pico, et al
I'm confused with all this. When I open the package, install the batteries I want it to work. I'm not interested in jumping through a bunch of hoops like the DX FT-8. Please don't ship until it works.
?
Aaron
W4AAN?
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Re: zbitx update, shipping, pico, et al
Pierre,
?
As Farhan said:
First, we are shipping the micro USB cables with the radios that will allow the raspberry pi zero to move the latest firmware from zbitx's sbitx folder to the Pico.
?
The Pico is updated by the RPi Zero 2W, the user doesn't get involved beyond attaching a USB cable from one device to the other (that's how I understand it)
?
Ken, N2VIP
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Re: sBitx Mic input - assist request
There appear to be one or more measurement errors here. ? The bulk of the measurement suggest that the transistor is indeed within its linear range despite the unexplained base emitter voltage. ?So I strongly suspect some measurement errors or a faulty measurement device.
If there still is DC voltage present on the other side of the one micro F capacitor ?then the capacitor is defective. But again, I suspect measurement error is what’s really going on and if this were me, I would just very very carefully reconfirm every device and every measurement before I try to figure much more out.
It’s very strange to have a base emitter voltage anything greater than 0.6. ?And the collector measure measurements demonstrate the device is not saturated. ?
So I suspect the reason this makes ?no sense is that something isn’t correct. ? Voltmeter lugging circuits down or reading incorrectly, some form of RF input to the voltmeter who knows.
Waiting to hear more clues.
Gordon kx4z?
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On Mar 9, 2025, at 17:33, WF4RC Carroll via groups.io <WF4RC@...> wrote:
? the mystery continues.?
removed :
CD28
LD6
CD29
CD27
QD1
?
Still have 2.1v at junction of LD6 / CD29 [both removed].? With power off measuring about 2K to ground at that point. Going to tke a break and start over tomorrow... Welcome any thoughts.
?
?
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Re: zbitx update, shipping, pico, et al
The zbitx main board has a Pi Zero 2W and the front panel has the pico W. The pico2W didnt work with the display, nor did we need it to work the front panel.
Which raspberry pi zero does it have?
the Pi zero W (Broadcom BCM2835 ARMv6 1GHz 1 core + WiFi)
or the pi zero 2W? (Broadcom BCM2711A1 Cortex-A72 1GHz Quad-Core 64bits +WiFi)
or the 1.3 (Broadcom BCM2835 ARMv6 1GHz 1 core no WiFi)?
?
Thanks for the clarification.
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Re: sBitx Mic input - assist request
the mystery continues.?
removed :
CD28
LD6
CD29
CD27
QD1
?
Still have 2.1v at junction of LD6 / CD29 [both removed].? With power off measuring about 2K to ground at that point. Going to tke a break and start over tomorrow... Welcome any thoughts.
?
?
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Re: zbitx update, shipping, pico, et al
<<
THEN:
The Raspberry Zero 2, that powers the zbitx (zero bitx because of? the RPI zero in it), can't handle this display as the GPIO pins on it are all used up. Hence, the zbitx sports a new microcontroller, the Raspberry Pico W (with Wifi and Bluetooth on it!) that handles the front panel. This offloads the user interface to this microcontroller that handles the 3.5 inch TFT display. The two talk to each other over the I2C bus (Pi is the master, Pico is the slave).
>>
I understand you had to modify the main board, which has now two microcontroller: the original Zero 2 to which is added a Pico W?
<<
NOW:
Future updates to the front panel (like moving the comms between the zbitx and the front-panel to bluetooth or even wifi to make it a remote head) will need a way to update the firmware to the Pico. It is usually done with an Arduino IDE running on a computer with micro USB cable from the PC to the Pico. That is the easy part. The hard part was that getting the Arduino going on a PC, installing the Pico package and then the TFT display libraries is like pulling teeth. There has to be a better way. We realized this last week when I shipped out the Pico firmware to our folks at HF Signals. If they(HF Signals) couldn't get the Arduino IDE setup on their PC within minutes, I?was very skeptical and most users of zbitx would.
>>
Did you manage to find an easy and better way for plain OMs to setup the Arduino IDE?
73 - Pierre - FK8IH
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Re: sBitx Mic input - assist request
the base-emittter voltage of QD1 schould be about 0,7 V but is
3,9 V -2.3 V = 1.6 V, my guess: defect transistor or wrong
measurement.
Am 09.03.2025 um 17:02 schrieb WF4RC
Carroll:
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I have a new sBitxV3 board only. Everything is working except
the Mic input. I started experimenting with some microphone I
had and the recorded transmission has lots of noise and very low
audio. I measure 2.1v on mic input tip. I think it should be 5v.
Can anyone guide me as to what the issue may be and where I
should look. Here are my measurements/ calculations.?
|
Hi Michael,
?
AFAIK The schematic is correct. Double-check your tracing. Solder bridges on the board could also confuse the measurements. I use a magnified headset to verify traces. Since it is a two-sided board, no hidden traces exist between layers.
?
73
Evan
AC9TU
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Evan,?
?Is it possible that R5 and R6 are mislabeled on the schematic? After I removed Q9,Q10,Q101,R5 and R6, to check continuity of pads and traces, I found that bottom of R6 connects to the gate-pin1 of Q10, not the source-pin3, and connects to the source-pin3 of
Q101 and not the gate-pin1, as indicated in the schematic. The schematic is from Farhans github, titled sbitx v3 production. Let me know, thanks!
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Yes, I was somewhat relieved that I am getting the proper Tx signal. I feel that I may need to remove Q9, Q10, Q101 and check the continuity, rule out damaged pads/traces, and swap in new components. Also when I mentioned using
through hole for Q10,Q101, I was thinking about using regular 2n7000 in place of the sot23 2n7002. Would those work?
-------- Original message --------
From: "Evan Hand via groups.io" <elhandjr@...>
Date: 3/6/25 2:07 AM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael,
?
The TX signal works (recieve at 0.15 volts, transmit at 3 volts).
?
?
The pins on Q9 are marked in this photo:
?
The gate (pin 1) of Q9 should be higher, and the tab (Pin 2 or drain) should be 0 volts when receiving and close to 12 volts on transmission.? It could be a failed Q9, Q10, Q101, or combination.? I would start with Q10, as it should pull down the gate
of Q9 to turn it on and supply the 12 volts to the driver stages.??
?
?
Q101 is a 2n7002 MOSFET.? This can not be replaced with a 2n2219.??
?
?
The above is based on not getting 12 volts on the tab of Q9.
?
73
Evan
AC9TU
?
-- Mike - K8MCB?
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Re: sBitx Mic input - assist request
CD29 could be leaking.? Without a mic connected, the voltage on the tip should be approximately 9.9/10th of the voltage supplied to the sBitx.? That assumes a 10meg input resistance on your meter.? There should be no current draw through RD21, though I suspect you derive the current reading from the voltage drop across it.? The voltage drops when the mic is connected.
?
Try disconnecting CD29 and measuring the voltage again.
?
Reducing RD21 can increase the bias voltage to the mic.
?
73
Evan
AC9TU
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Re: sBitx Mic input - assist request
Thanks for the input and replies,
There was no mic connected when I made the measurements. Can anyone verify/ confirm that the Tip of the TRS MIC plug should be at 5v? I suspect QD1 as well .? The mic I was using was electret and needed a 3.3-5v Vin. That was how I found out the Tip was only at 2.1.
Any ideas are wlecome. Thanks everyone.?
?
73.
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Re: zbitx update, shipping, pico, et al
Thank you for the update, very much appreciated.? ?Doug
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HA3HZ
Raj vu2zap
Ted