What I did was remove C102 and put a little higher value trimmer into C103 (which is not fitter)
then adjust the carrier frequency and see if you make it sound better. Worked for me!
Raj
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At 20/10/2018, you wrote: The BITX40 I am building receives somewhat OK but the transmitters audio is terrible with distortion and/ narrow bandwidth.
I think I may have 1 or 2 bad 12.0 MHz crystals when I inject a signal thru the filter and look at the various nodes. I see
the strongest peak at around 11.997830 MHz.
The bandpass is only around 1,700 Hz at best (11.998800 to 11.997100)!
The crystals are from MEC and the letters / numbers on them are: 12.000 G
MEC AH6L1
Does anyone know of a suitable replacement in the USA for them?? Any special characteristics?
Thank you,
Michael
n2zdb
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Maybe no help, but here's a filter mod I've been playing with on the ubitx
Jim
On Friday, October 19, 2018, 6:49:31 PM PDT, Michael Trager <mtrager1@...> wrote:
The BITX40 I am building receives somewhat OK but the transmitters audio is terrible with distortion and/ narrow bandwidth.
I think I may have 1 or 2 bad 12.0 MHz crystals when I inject a signal thru the filter and look at the various nodes. I see
the strongest peak at around 11.997830 MHz.
The bandpass is only around? 1,700 Hz at best (11.998800 to 11.997100)!
The crystals are from MEC and the letters / numbers on them are:?? 12.000 G
?????????????????????????????????????????????????????????????????????????????????????????????????????????? MEC? AH6L1
Does anyone know of a suitable replacement in the USA for them?? Any special characteristics?
Thank you,
Michael
n2zdb
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Re: Harmonics and Relay Replacement
Sascha,
The problem with yet another board is that there is no good way to couple the grounds between them.
As to clean solutions, just what is that?? You have a dirty board and the only clean solution is fix the board
as everything else is simply trying to make it work...maybe.
Allison
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On Fri, Oct 19, 2018 at 06:49 PM, Michael Trager wrote:
Any special characteristics?
yes, they have to be matched within 100Hz of the others.? ? 12mhz crystals are easy to find
and buy but matching is up the you.? To get say 4 matched I often buy ten and test.
However if the filter is narrower than expected you might try different value loading capacitors.
for example if 100pf are used try 91 pf for all of them.??
If you look at nodes you may get bad results as the act of probing the test point loads the
filter with some amount of capacitance and alters its behavior.? Even a 10x probe varied from
about 9-13PF depending on who made it and what length cable.? That is more than enough
to disturb the filter behavior.
Allison
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The BITX40 I am building receives somewhat OK but the transmitters audio is terrible with distortion and/ narrow bandwidth.
I think I may have 1 or 2 bad 12.0 MHz crystals when I inject a signal thru the filter and look at the various nodes. I see
the strongest peak at around 11.997830 MHz.
The bandpass is only around? 1,700 Hz at best (11.998800 to 11.997100)!
The crystals are from MEC and the letters / numbers on them are:?? 12.000 G
?????????????????????????????????????????????????????????????????????????????????????????????????????????? MEC? AH6L1
Does anyone know of a suitable replacement in the USA for them?? Any special characteristics?
Thank you,
Michael
n2zdb
|
Re: Harmonics and Relay Replacement
I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Ah Sascha, Looks aren't everything eh?? You would be happier with the supermodel that has an awful personality? The work need not look bad at all -- it's all up to how you do it and it gives one the chance to show their construction skills beyond the paint-by-numbers stage.? In the end it can be an accomplishment to be proud of! And I'm not sure if the off-board solution works the same as Allison's plan?? Hers also reduces the number of relays engaged and that need switching so CW and PTT operation would be smoother. 73, Mark. PS:? Only read Crime and Punishment from Dostoevsky -- really dramatic and emotional.? Always thought the TV detective Colombo was modeled after the police detective in that book.? And Quiet Flows the Don was a very good read also.?
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Re: Harmonics and Relay Replacement
Ahh so Kees has made a board. Is there a link to it? Are they for sale?
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On Oct 19, 2018, at 5:45 PM, Arv Evans < arvid.evans@...> wrote: Problem, and solutions are not that simple.? Allison has added comments to the Wiki that describe both problems and solutions.? Kees has made a daughter board available for the
relays and LPF components.?
Overdriving the audio apparently is a big contributer to some problems.? Stage gain
arrangement is another potential issue.? Board layout and component placement has
been identified as problematic.? There are ways to operate the uBITX that mostly keep
it within reasonable limits, but some apparently want to exceed those parameters.
Unfortunately those who have recently joined the group may not have followed the process
that has led up to present state of things.?
Arv _._
On Fri, Oct 19, 2018 at 3:12 PM Sascha Bohnet | DL5SMB via Groups.Io <saschabohnet= [email protected]> wrote: I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Is maybe anyone good at pcb designing?
Then we could make a daughterboard, desolder the whole filter part on the main board and put everything on the daughterboard on top.
Maybe the placing of all the parts could remain the same on the additional board and only the traces would need some rearranging.
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Re: Harmonics and Relay Replacement
I¡¯m surprised someone hasn¡¯t fabricated a board that the relays and coils can be moved to and the board can be mounted on top of the ubitx with standoff¡¯s and then wired up to Ubitx.?
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On Oct 19, 2018, at 5:17 PM, Gordon Gibby < ggibby@...> wrote:
?Well.......you can do all that, and I'm sure that Allison's solutions would work quite well!? ??
however, that is an AWFUL LOT of work, which is why I came up with a pcb daughterboard to just add right hand side relays and move just a FEW traces to wires heading outbound.? ?This had a very salutory effect, in almost every case dramatically reducing
the harmonics.? ?
It is possible that there are other intermediate steps that might also solve the problem.? ?But Allison has already put a HUGE amount of effort into this and I doubt she is going to do any more ---- her suggestions for the current board would solve many
of its probems;, and her contirubtions to a different company's power amplifier have provided a road map to a better power amplifier solution.? ??
So there are likely now several solutions that work and you can just take your pick of how much work you wish to do in order to improve things.? ?
Cheers,
gordon
I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Is maybe anyone good at pcb designing?
Then we could make a daughterboard, desolder the whole filter part on the main board and put everything on the daughterboard on top.
Maybe the placing of all the parts could remain the same on the additional board and only the traces would need some rearranging.
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Re: Harmonics and Relay Replacement
...and having read it, have you watched it (Frank Herbert's)? and follow-on Children Of (also a trilogy)? Well worthwhile!? Lord Of The Rings did that to me, too: sit down, read it, get up. 40 hours or more straight: Total immersion!
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Solved - I had PTT and ground reversed on my microphone, and then I had wrong pins when I tried to PTT with a piece of wire.? all seems okay now, yes I did align the PA bias as instructed after my effort.
73 Curt
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Re: Harmonics and Relay Replacement
Problem, and solutions are not that simple.? Allison has added comments to the Wiki that describe both problems and solutions.? Kees has made a daughter board available for the
relays and LPF components.?
Overdriving the audio apparently is a big contributer to some problems.? Stage gain
arrangement is another potential issue.? Board layout and component placement has
been identified as problematic.? There are ways to operate the uBITX that mostly keep
it within reasonable limits, but some apparently want to exceed those parameters.
Unfortunately those who have recently joined the group may not have followed the process
that has led up to present state of things.?
Arv _._
On Fri, Oct 19, 2018 at 3:12 PM Sascha Bohnet | DL5SMB via Groups.Io <saschabohnet= [email protected]> wrote:
I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Is maybe anyone good at pcb designing?
Then we could make a daughterboard, desolder the whole filter part on the main board and put everything on the daughterboard on top.
Maybe the placing of all the parts could remain the same on the additional board and only the traces would need some rearranging.
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Hi all,
My newest design......
73' PD0LEW, Johan Holstein
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Re: Harmonics and Relay Replacement
?Well.......you can do all that, and I'm sure that Allison's solutions would work quite well!? ??
however, that is an AWFUL LOT of work, which is why I came up with a pcb daughterboard to just add right hand side relays and move just a FEW traces to wires heading outbound.? ?This had a very salutory effect, in almost every case dramatically reducing
the harmonics.? ?
It is possible that there are other intermediate steps that might also solve the problem.? ?But Allison has already put a HUGE amount of effort into this and I doubt she is going to do any more ---- her suggestions for the current board would solve many
of its probems;, and her contirubtions to a different company's power amplifier have provided a road map to a better power amplifier solution.? ??
So there are likely now several solutions that work and you can just take your pick of how much work you wish to do in order to improve things.? ?
Cheers,
gordon
toggle quoted message
Show quoted text
I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Is maybe anyone good at pcb designing?
Then we could make a daughterboard, desolder the whole filter part on the main board and put everything on the daughterboard on top.
Maybe the placing of all the parts could remain the same on the additional board and only the traces would need some rearranging.
|
Re: Harmonics and Relay Replacement
I would really like to try out Allisons solution with the complete rearrangement of the filters. However I am a big fan of "clean" solutions,
and all this wiring, cutting etc. looks really sloppy to me.
And I would really hate it, if it did not work out as it should and then i would have completly ruined my board.
Is maybe anyone good at pcb designing?
Then we could make a daughterboard, desolder the whole filter part on the main board and put everything on the daughterboard on top.
Maybe the placing of all the parts could remain the same on the additional board and only the traces would need some rearranging.
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display problem with KD8CEC firmware
Good evening
i have a problem with update KD8CEC. After installing this update the original display 1602P doesn't turn on. I used the instructions of? guide but I can't understand where is the problem.
I tried with the original arduino nano and with a compatible version but the results are the same.
can anyone help me ?
Thank You? ? ? IZ0TKC
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Doug
thanks for reply.? i checked -- i have 4.7k between pins 2 and 3 when measured at the raduino (that connector that's mounted near top of display.?
I am using the uBITX box from Sunil, so it has a preassembled digital bundle cable from raduino to the uBITX -- i have display etc so its not backwards I think.? I will continue to look for an error in my work, but it takes PTT being grounded for rig to go bananas.?
Curt
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Re: Harmonics and Relay Replacement
I still havent finished Brothers Karamazov. Yes, I have read it cover to cover several times. Not yet finished.
On Fri, Oct 19, 2018 at 10:33 PM ajparent1/KB1GMX < kb1gmx@...> wrote: On Thu, Oct 18, 2018 at 02:08 PM, RCBoatGuy wrote:
has anyone tried shielding the relays from the PCB using copper tape between the board and relays
Carl,
Yes back in early july.? Didn't help much at all maybe 2db at the high end of the band.
Look at the wiki pictures two of the longer lines have RF power on them and they all loop
back to KT1 and past all the others.? Not good.
Allison
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Re: uBITX microphone suggestions
Hey! You can use an old smartphone which you don't need anymore. You just install any kind of "mic to speaker" app on the phone and wire the input of uBitx to the stereo jack of the phone. It's just running perfect for me. From the volume up-volume down buttons you can adjust the "gain" to say so.? My electret microphone doesn't work at all and I don't have an another one. It just came like this.?
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Re: Harmonics and Relay Replacement
On Thu, Oct 18, 2018 at 02:08 PM, RCBoatGuy wrote:
has anyone tried shielding the relays from the PCB using copper tape between the board and relays
Carl,
Yes back in early july.? Didn't help much at all maybe 2db at the high end of the band.
Look at the wiki pictures two of the longer lines have RF power on them and they all loop
back to KT1 and past all the others.? Not good.
Allison
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Raj vu2zap
David Posthuma
YO8UFO