The pots to set the IRF510 bias on the uBitx and Bitx40 were backwards
from what most people would expect.
My best guess is that the sBitx follows this unfortunate tradition
since pin 3 of RV1 and RV3 is grounded, same as it was on RV2 and RV3 of the uBitx.
And it looks like the same Kicad symbol and blue physical part was used,
so fully clockwise for minimum bias voltage to the gates of the final is most likely.
I suggest you measure from the middle pin of RV1 to ground
with the power off using an ohmmeter, should show zero ohms
when gate bias is set to a minimum.
Jerry, KE7ER
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On Tue, Aug 2, 2022 at 08:55 AM, Niels Jalling wrote:
I have just burnet the PA IRFZ24's.
Where Is zero for the DRIVE_BIAS POT and PA_BIAS POT?
Is it where you expect it at anti clock wise end.
73 de oz9ny, niels
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On 8/2/2022 19:38, Rolan Rister wrote: <>
Looks like ring is PTT, tip is microphone audio. Thanks much. Planning on reworking a digital mode interface to use with it. -- Tom Sevart N2UHC St. Paul, KS
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Looks like ring is PTT, tip is microphone audio.
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Very nice schematic, easy to read! Thanks Charu.
- Your Logic input Vi pin 6 / U4 FST3157 is DC isolated from CLK2 and is DC biased by RV1.
I would have a direct Vi input from U3 SI5351 with 3.3V logic which satisfy ViHigh / ViLow, please share your reason.
- I would use 7862 to have 6.2V for pin 5 and use RV1 to bias the V+ from 2.5 to 3.5V for best IMD3 figure.
73 Pascal
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I can't remember, and I can't seem to find it anywhere, but with the uBitX v.6 microphone plug, is it tip audio/ring PTT, or tip PTT/ring audio?
--
Tom Sevart N2UHC
St. Paul, KS
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Re: Turn off WiFi on your sBitx
You can disable wifi completely by doing it in the /boot/config.tx file.
just edit and add "dtoverlay=pi3-disable-wifi" to the end and reboot.
You can do the command ifconfig before and after to see the wifi interface disappear.
Max
On Tuesday, August 2, 2022, 06:53:37 PM CDT, Bob Losee KO9V <loseeunc@...> wrote:
If this is caused by an audio device receiving from the wifi, is there a way to turn off the wifi to stop this? ?I tried to turn off the wifi in the menu that has our router listed but it doesn’t kill the sounds. ?That might be operator error…. There might be a way to shutdown the wifi at a low enough level that there is no interference with the audio system. ?It could be turned on when desired, such as updates or refreshing the time….prefer wifi to ethernet but the wifi noise is pretty bad Bob, KO9V?
On Aug 2, 2022, at 3:16 PM, Bob Losee KO9V via groups.io <Loseeunc@...> wrote:
? I’m having the same sounds… anywhere from 4 to 8 sounds then a several second pause, then starts again. ? Changing audio level makes no difference. I’ve never tried transmitting… just listened to WWV across town from me and it is a clean stable receiver. ?Tried logging in to my wifi but I still have two red X characters over the wifi symbol Bob, KO9V, Serial Number 20 On Aug 1, 2022, at 1:57 PM, Niels Jalling <niels@...> wrote:
?When I powered up my new sBitx I heard repeating noise from the loudspeaker. I knew I had seen the problem mentioned somewhere.
Found it on youtube:
Follow the description to turn off the WiFi and the noise goes away.
73 de oz9ny, niels
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Re: Turn off WiFi on your sBitx
If this is caused by an audio device receiving from the wifi, is there a way to turn off the wifi to stop this? ?I tried to turn off the wifi in the menu that has our router listed but it doesn’t kill the sounds. ?That might be operator error…. There might be a way to shutdown the wifi at a low enough level that there is no interference with the audio system. ?It could be turned on when desired, such as updates or refreshing the time….prefer wifi to ethernet but the wifi noise is pretty bad Bob, KO9V?
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On Aug 2, 2022, at 3:16 PM, Bob Losee KO9V via groups.io <Loseeunc@...> wrote:
? I’m having the same sounds… anywhere from 4 to 8 sounds then a several second pause, then starts again. ? Changing audio level makes no difference. I’ve never tried transmitting… just listened to WWV across town from me and it is a clean stable receiver. ?Tried logging in to my wifi but I still have two red X characters over the wifi symbol Bob, KO9V, Serial Number 20 On Aug 1, 2022, at 1:57 PM, Niels Jalling <niels@...> wrote:
?When I powered up my new sBitx I heard repeating noise from the loudspeaker. I knew I had seen the problem mentioned somewhere.
Found it on youtube:
Follow the description to turn off the WiFi and the noise goes away.
73 de oz9ny, niels
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Re: A short video of sBitx working
Don't see any reason it would not receive ok down there.
though you may need to hack the RPi software some.
The stock sBitx is not appropriate for transmitting on 630 meters.
There is no transmit low pass filter appropriate for 630 meters, you would have to add one
or you would generate some very strong harmonics.
Jerry, KE7ER
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On Tue, Aug 2, 2022 at 02:32 PM, Alan Cooper wrote:
I am trying to figure out if it will operate down below the AM Broadcast band,? there is a lot of Ft8
used on our 630Meter band on 474 khz.
?
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Re: Postman came with a box from hfsignals
Still waiting for my shipping notification. I've got one coming without the display and Pi.
?got #26!!!!? ?You beat me!!! but i still feel HONORED.? ?Gotta find a power connector and wire it all up.? Should have a logitech mouse/keyboard wireless in the car.? ?Tons of MEETING this week, but nice to have gotten this.? ?It came VERY NICELY PACKED.? ? My neighbor has theXiegu.....each has its points but this is a LARGE milestone in ham radio history, another one due to Ashhar!? (on the left is one of my primitive homebrew "go-boxes" for portable emergency deployments.
Gordon KX4Z
 
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I use an emtech zm-2 tuner and also a ldg z100 tuner. both seem to work 100%.
Im an odd ball,. I like just a little bit of swr on my antennas. 1:5 seems to get out better where i live.I also use rg6u quad shielded cable also.My ubitx loves it. doesnt have a problem.
73
David
ac9xh
good thru hamcall.net,qrzcq.com and FCC
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Niels,
A quick reminder to readjust the bias whenever you replace the finals.
73
Evan
AC9TU
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THIS IS FOR HUMOR AND SMILES!!!!! Enjoy, 73 David ac9xh I came across this on another website .it was originally published in QST magazine 1967: ![[picture of G5BD in his shack , click for larger version]](http://www.wb9kzy.com/g5bd2.jpg)
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Re: A short video of sBitx working
Ashhar and group,
is there a manual or something resembling a spec sheet on the sBitx available anywhere?
I am trying to figure out if it will operate down below the AM Broadcast band,? there is a lot of Ft8 used on our 630Meter band on 474 khz.
Thanks for any info or input
Alan w7aln
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niels, If you have a dummy load, try loading into that first to see if anything else is wrong before hooking up your antenna? after re-installing finals and checking surrounding components.
Also, if you have another transceiver, try to preload the tuner to 20 meters first so the antenna will be pretty close to being matched, then hook up your sbitx and see how it works then.
good luck on your sbitx 73 David ac9xh
On Tuesday, August 2, 2022 at 11:40:51 AM EDT, Niels Jalling <niels@...> wrote:
I can't tell the SWR numbers for my antenna but I have just burned one of the IRFZ24's in the PA.
It was on 20m. Power settings was set to 5 and my antenna tuner didn't even finish the tuning process before the sBitx broke down.
I used to have SWR of 1.4 - 1.6 on the antenna when tuning is done.
Tomorrow I'll get new IRFZ24's
73 de oz9ny, niels
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Re: Turn off WiFi on your sBitx
I’m having the same sounds… anywhere from 4 to 8 sounds then a several second pause, then starts again. ? Changing audio level makes no difference. I’ve never tried transmitting… just listened to WWV across town from me and it is a clean stable receiver. ?Tried logging in to my wifi but I still have two red X characters over the wifi symbol Bob, KO9V, Serial Number 20
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On Aug 1, 2022, at 1:57 PM, Niels Jalling <niels@...> wrote:
?When I powered up my new sBitx I heard repeating noise from the loudspeaker. I knew I had seen the problem mentioned somewhere.
Found it on youtube:
Follow the description to turn off the WiFi and the noise goes away.
73 de oz9ny, niels
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Actually , Farhan had forgotten to update the Schematic on his GithHub page, as a result of which I was searching for a route from the Antenna Connector to the RF port he used. ? But some pledger privileges came to the rescue and I found the right schematic. ? I hope the schematic on the Github is updated. ? I am building a very limited portion of the design. The Exciter and the RPi HAT. ? I attach herewith my version of the schematic for all reference. This is going to be a TH version of the project, with 1/8W resistors ? regards charudatt – VU2UPX ?
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From: [email protected] <[email protected]> On Behalf Of Pascal Nguyen
Sent: 03 August 2022 01:09
To: [email protected]
Subject: Re: [BITX20] sBitx doubt ? Hi Charu
Looking forward to see your design, must be very interesting by rolling your own. - What’s ?the catch between the schematic from GitHub (1rst mixer to antenna via LPF) and the updated from Raj (1rst mixer to antenna bypassing LPF)?
- Do we need a band pass filter for the 1st RX mixer or a single 30MHz LPF is good enough?
- Has any one successfully booted an RPI 400 (identical to RPI4 without EEPROM) or it’s not compatible?
73 Pascal
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Re: Postman came with a box from hfsignals
?got #26!!!!? ?You beat me!!! but i still feel HONORED.? ?Gotta find a power connector and wire it all up.? Should have a logitech mouse/keyboard wireless in the car.? ?Tons of MEETING this week, but nice to have gotten this.? ?It came VERY NICELY PACKED.? ? My neighbor has theXiegu.....each has its points but this is a LARGE milestone in ham radio history, another one due to Ashhar!? (on the left is one of my primitive homebrew "go-boxes" for portable emergency deployments. Gordon KX4Z  
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Just got the LRS-150-12 to run it with.? Now all I need is the sBit so I can run.? Waiting for it to ship "sans Pi" as I already have the Pi.
Gerry Sherman
Sent by the Thunderbird
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Niels - that sound like a full wave.? I understand that if an
antenna is a multiple of a half wave it can be hard to tune.? My
suggestion: switch to a manual tuner & use an analyzer
(Antuino) to get it to an acceptable SWR.
Gerry Sherman
Sent by the Thunderbird
On 2022-08-02 17:59, Niels Jalling
wrote:
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I don't know the initial vswr. My antenna is a wire around 20
meters long with an automatic tuner at the end.? Then 5 meters
coax between tuner and the rig.
Normally it matches the PA in less than 20 seconds but that may be
too long mismatch time for the sBitx.
Band was 20m and transmit level was set to 5,
73 de oz9ny, niels
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Hi Charu Looking forward to see your design, must be very interesting by rolling your own.
- What’s ?the catch between the schematic from GitHub (1rst mixer to antenna via LPF) and the updated from Raj (1rst mixer to antenna bypassing LPF)?
- Do we need a band pass filter for the 1st RX mixer or a single 30MHz LPF is good enough?
- Has any one successfully booted an RPI 400 (identical to RPI4 without EEPROM) or it’s not compatible?
73 Pascal
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Shirley Dulcey KE1L