Re: How to set bias on sBitx?
#sBitx
Peter, The bias setting procedure is in the assembly manual at the very end.
- f
I just replaced the finals Q18 and Q19 and discovered a cracked leg on driver Q16 so replaced it.
What is the procedure (or where is it documented) for adjusting the bias?
Pete WK8S
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How to set bias on sBitx?
#sBitx
I just replaced the finals Q18 and Q19 and discovered a cracked leg on driver Q16 so replaced it.
What is the procedure (or where is it documented) for adjusting the bias?
Pete WK8S
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Goddy
I'm not seeing the /tree directory in github. Is there a trick to finding it?
Joe
W3JDR
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Thanks Goody
What version # should display on the screen?
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Re: File /uBITX_6_N8ME_2_VU3GAO_Mods.zip uploaded
#file-notice
Jack, The option was on the version of Arduino IDE that I downloaded.? Here is a link to the Arduino web that explains how to add boards: The Board is an Arduino Nano.? The processor is ATmega328P (Old Bootloader). 73 Evan AC9TU
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Re: File /uBITX_6_N8ME_2_VU3GAO_Mods.zip uploaded
#file-notice
Evan, ? Thanks¡ I was away from home all day. I am not offered the old bootloader option. I can set all the other options. Where/how do I fix that and obtain the missing bootloader? ? Jack KD4IZ ?
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From: [email protected] < [email protected]> On Behalf Of Evan Hand Sent: Friday, September 9, 2022 23:13 To: [email protected]Subject: Re: [BITX20] File /uBITX_6_N8ME_2_VU3GAO_Mods.zip uploaded #file-notice ? Jack,
I am at home and downloaded the newest file in the groups.io file section, extracted it, and compiled it.? I did not get any errors.? Here is the tools dropdown in the Arduino IDE:
73
Evan
AC9TU
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Re: Daylight again schematic questions
Hi Paul,
As you your question #4, just use your imagination.? Take a look at the manual for the old MMR-40 QRP rig.? They use a PTO made of brass nuts soldered to a PCB just as you describe.
Cheers,?? Mark
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Re: sBitx Update Kit Received!
#sBitx
Got mine in 9 land.
--
Ken KC9BSD
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Re: Some calculations on the IF filter and USB filter
Gerald,
This is probably more than you wanted to know, but...
There is one central encoder reading function in the KD8CEC software "enc_read()". It also uses a polling approach as opposed to interrupt. The approach is a little unusual in that the encoder is connected to two Analog lines not the usual digitals. (I think this might have been borrowed from the original OEM uBITX software) So state changes are discovered by changes in voltage thru the ADC converter. There is also a time constant that is used to ensure that the voltage read is "stable".??
OT follows:
Although clever , it is a real pain in regards to porting KD8CEC code to a different processor. You need to special case each processor based on their voltage reference. Right now, Nano, NanoEvery, and Nano-BLE are happy with the original 500 (out of 1024 number) for "on". but Nano IOT and the Nano? RP Connect the number needs to be set at 200. We see what happens when I get around to trying the Teensy 4...
73
Mark
AJ6CU
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Re: Some calculations on the IF filter and USB filter
Jerry,
The KD8CEC software uses the Nextion graphics card that has its own graphics processor for graphics update. Only data is being processed by the Nano.
Still, there is more data processing going on for the other features, so the point of the Nano being pushed to its limit could be true. ?I have not found a tuning problem with the CEC software.?
73
Evan
AC9TU
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Re: Some calculations on the IF filter and USB filter
I have the old 16x2 display.? If that little Nano processor is too busy updating
graphics on the bigger displays, that could also cause trouble when tuning.
Jerry
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On Sat, Sep 10, 2022 at 09:23 AM, Jerry Gaffke wrote:
It could be that interrupts are active when tuning the VFO,
causing it to misbehave even if it uses the same code.
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Re: Some calculations on the IF filter and USB filter
Jerry,
Thank you for all your precisions.
My Ubitx is homemade.
It uses the MOTHY schematic that I modified a bit.
It is in double sided smd with an integrated CAG + TDA2030 amp.
The advantage of my mounting is that it can use a directly welded USB filter, or one can use removable filters.
I made two for 11MHZ and one for 12MHZ.
But this is not perfect in terms of response, it would be necessary to change some quartz.
The 12mhz is a little better.
The 45MHZ part is a bit different too, and I always feel like I¡¯m on the slope of the filter because the reception is very hard to align.
We¡¯re getting close to winter, il will have more time to look at that.
cdt
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Re: File /uBITX_6_N8ME_2_VU3GAO_Mods.zip uploaded
#file-notice
Jack,
I reread your post and noted that you have the wrong board selected.? See the Tools dropdown in my prior post.
73
Evan
AC9TU
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Re: Some calculations on the IF filter and USB filter
Note that my old posts were in reference to the old v3 uBitx from 2017.
The v5 and v6 uBitx hardware has an IF filter using 11.059 mhz crystals, not 12.000 mhz.
The passband is a couple khz lower than the nominal crystal frequency since we are using the
series resonant mode of the crystal in the filter, not the parallel resonant mode
which is more commonly used in oscillators.
The code in post 44278 assumes we want the BFO frequency always below the 12mhz IF passband
to avoid hetrodynes (and resultant audio tones) between the BFO and an oscillator on the Arduino Nano.
This was solved on v5 and v6 by moving to the 11.059 mhz crystals.
So now that code could be expanded to have four possible cases, where the VFO at clk2 is always high side,
clk1 into the second mixer can be either high or low side as per 44278, and the bfo can now be high or low side also.
Moving the BFO between high and low side will swap the sidebands, just like moving clk1 does.
Moving both the BFO and clk1 to the other side simultaneously will cause no change in the sideband selected.
Jerry, KE7ER
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On Sat, Sep 10, 2022 at 09:23 AM, Jerry Gaffke wrote:
I use my own uBitx code, no idea what the other distributions are doing.
Yes, if the BFO tunes smoothly and the VFO jumps around, that does suggest a problem with the code.
I would expect the BFO and VFO would use the same code when reading the encoder,
first thing to do is see if that is not the case.
It could be that interrupts are active when tuning the VFO,
causing it to misbehave even if it uses the same code.
Jerry, KE7ER
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Re: Some calculations on the IF filter and USB filter
I use my own uBitx code, no idea what the other distributions are doing.
Yes, if the BFO tunes smoothly and the VFO jumps around, that does suggest a problem with the code.
I would expect the BFO and VFO would use the same code when reading the encoder,
first thing to do is see if that is not the case.
It could be that interrupts are active when tuning the VFO,
causing it to misbehave even if it uses the same code.
Jerry, KE7ER
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On Sat, Sep 10, 2022 at 09:16 AM, Gerard wrote:
Jerry,
?
Yes, thank you. As I said, I¡¯m going to dig into the question and I found various posts explaining all this.
I would like to take this opportunity to ask you a question.
I always test with the KD8CEC version.
I noticed when turning the encoder at variable speeds that the frequency display could jump in "leaps".
I thought it was due to interference on the encoder because there are bounces.
What intrigues me, is when doing the BFO setting, I can turn the encoder at different speeds, the frequency display is always done in a linear way, that is to say in 5khz increments.
I therefore" wonder, if the program does not manage the encoder differently between BFO calibration and frequency change.
only an Arduino expert can see this in the CEC software
cdt
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Re: Some calculations on the IF filter and USB filter
Jerry,
?
Yes, thank you. As I said, I¡¯m going to dig into the question and I found various posts explaining all this.
I would like to take this opportunity to ask you a question.
I always test with the KD8CEC version.
I noticed when turning the encoder at variable speeds that the frequency display could jump in "leaps".
I thought it was due to interference on the encoder because there are bounces.
What intrigues me, is when doing the BFO setting, I can turn the encoder at different speeds, the frequency display is always done in a linear way, that is to say in 5khz increments.
I therefore" wonder, if the program does not manage the encoder differently between BFO calibration and frequency change.
only an Arduino expert can see this in the CEC software
cdt
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Re: Some calculations on the IF filter and USB filter
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sBitx Update Kit Received!
#sBitx
Received my kit here in W3 land. Yeahhhhh
73
Goody
K3NG
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Re: Receiving SBITX this week
#sBitx
Makes sense!.? Thanks for the feedback.?
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Re: Daylight again schematic questions
Right now I've built the SMD1206 pcb Daylight allanalog circuit ( less the power RF) 80x70mm, but I can do better, of course, this is just a test.
Some more? questions:
1) What the exact frequency of BFO?
2) BFO output is not sinusoidal: is this a problem? It seem heavely polarized, without Xtal, collector is at 1.5Vcc, it goes at 5Vcc with a resistor in the range of MegaHoms.
3) The 100 ohm R18 resistor on balanced modulator seems too low, it destroys my zener , I used a 1Kohm as the other circuit with SA602 ( I use SA612)
3) Again on Q11, Q12 an Q13: is Q12 base really connected with the emitter of Q11?
Can we save some transistor ( they are seven on TX section!) using a large band little? transformer on Q11 and delete Q12 & Q13?
4) On PTO again: without a 3d printer, and no one selling it, is someone interested in an alternative PTO, built with part of PCB with nuts solderet on it, something
as output RF transformers for high power push-pull power fet RF amplifiers?
That's all for now, soon I will add a pic of my PCB
Paolo
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Jack Spitznagel (KD4IZ)
Gerard
Paul Allison