Re: Spectrum purity of uBITX and BIT40
Hi Simon,
I don't think this is true.? What is true with homebrew, is that the device doesn't not have to be tested by the FCC; the spectral requirements are still the same, but it is up the the user to figure out how to meet them.? That is where the "test, training, education, etc." comes into play!
73,
Mark.
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Re: Spectrum purity of uBITX and BIT40
Seem to hear that self build, home brew is more relax under fcc laws than mass production factroy machine, to allow progress in test, training, education, etc., in principle. ??
Still want to emit a as clean as possible signal, for common good
73 Simon
On Monday, December 3, 2018, Simon via Groups.Io <simonhk7= [email protected]> wrote: If i buy a new one, is the good relay come with present version??
Or it is consider a user mod, that i need to buy my own good relay
73 Simon On Monday, December 3, 2018, ajparent1/KB1GMX < kb1gmx@...> wrote: Clark,
Its not solely the relays.? Its also the interaction of the pcb routing of the interconnects.
lower the C of the contacts or better routing and the problem disappears.
Since the bitx40 is monoband it has none of those issues and is much cleaner.
Allison
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Re: Spectrum purity of uBITX and BIT40
If i buy a new one, is the good relay come with present version??
Or it is consider a user mod, that i need to buy my own good relay
73 Simon
On Monday, December 3, 2018, ajparent1/KB1GMX < kb1gmx@...> wrote: Clark,
Its not solely the relays.? Its also the interaction of the pcb routing of the interconnects.
lower the C of the contacts or better routing and the problem disappears.
Since the bitx40 is monoband it has none of those issues and is much cleaner.
Allison
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Re: uBitx Function Button ERROR
Rf pickup on adc can be observe by loading an adc read arduino program, on serial monitor. Use handheld 2m tx with ant near the push button and wiring
73 Simon
On Monday, December 3, 2018, Simon via Groups.Io <simonhk7= [email protected]> wrote: Connect multiple thick ground wire from pcb , said rf plug, to multiple point of case, for each piece of casing metal plates. Contact between metal plate is not fully reliable, in strict sense.?
73 Simon On Monday, December 3, 2018, Evan Hand < elhandjr@...> wrote: I had the same issue with a metal case.? The interesting thing for me was that on a single band 20m dipole I did not have the issue.? When I connected to a tri band (40/20/10) I started having the problem, only on 20m.? Solved it with grounding of the coax shield and ferrite clip ons.
What type of antenna are?you using?
Evan AC9TU???
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Re: Is push pull hf amp has higher spectral purity
Garbage in, garbage out.?
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Show quoted text
On Dec 2, 2018, at 3:40 PM, iz oos < and2oosiz2@...> wrote: The push pull has the advantage to deeply attenuate the even harmonics, all versions of the ubitx were good in that, the issue was on odd harmonics, 3rd, 5th.... With push pull a less steeper low pass filter can be used. Especially the 'corner'? frequency can be chosen higher than it would be otherwise. A single low pass filter can also be used for a couple bands. So you save a lot in filtering and relays, it's more a matter of cost and convenience I believe. Monoband qrps are much easier, the ones I had assembled don't have a push pull final, just a normal amplifier and a low pass filter to remove any harmonics. Maybe even I could design a monoband transceiver...
--
¡_. _._
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Power for continuous digimode
As is kit without mod, How much power output is ubtx and btx40, for 100 percent continuous digimode?
Should i use a larger heat sink?
Can output higher with higher voltage and bigger heatsink, for 100 percent on duty cycle?
73 Simon
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Re: uBitx Function Button ERROR
Connect multiple thick ground wire from pcb , said rf plug, to multiple point of case, for each piece of casing metal plates. Contact between metal plate is not fully reliable, in strict sense.?
73 Simon
On Monday, December 3, 2018, Evan Hand < elhandjr@...> wrote: I had the same issue with a metal case.? The interesting thing for me was that on a single band 20m dipole I did not have the issue.? When I connected to a tri band (40/20/10) I started having the problem, only on 20m.? Solved it with grounding of the coax shield and ferrite clip ons.
What type of antenna are?you using?
Evan AC9TU???
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Re: uBITX - Limiting power output
Charles French,
just back down RV1 on the bitx.? or better yet start at 0 (FYI its counter-clockwise to max not min
as its backward) and run it up till the 1208 gives full power using CW.? Since the bitx does not?
have alc it has no issues with spiking power.
FYI I have the 1208 and depending on what values were installed the internal attenuator could
be 5W or lower. Too much power and you fry the mixer diodes.
Mine was optimum with about 2W and I'd get about 11W SSB out with a 13.8V supply.
The driving radio was HB 20M and used it for years that way.? Now it serves standby
in case the main radio (TT 6n2) gets ill.
Allison
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Re: Is push pull hf amp has higher spectral purity
So, for current version that if i buy today, is it basically true that the overall story is?
1. btx40 is just meeting fcc spec, i believe is 50dBc for lower freq,
2. Ubtx is just a bit short, but not too far
73 Simon
On Monday, December 3, 2018, ajparent1/KB1GMX < kb1gmx@...> wrote: Simon,?
The structure of the amp is not the sole element of the question.? I have a single ended that beats the push-pull
of the ubitx by miles.? I also have a QSX amp that is push pull and is very clean.? In the end its not if A or B
but how well the design was executed.
Right now the V4 ubitx solves no issues over the V3 save for now it does not use the TDA2822 audio amplifier chip.
Allison
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Re: uBitx Function Button ERROR
I had the same issue with a metal case.? The interesting thing for me was that on a single band 20m dipole I did not have the issue.? When I connected to a tri band (40/20/10) I started having the problem, only on 20m.? Solved it with grounding of the coax shield and ferrite clip ons.
What type of antenna are?you using?
Evan AC9TU???
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Re: uBitx Function Button ERROR
Is there a publicly published circuit diagram for the push button and tuning knobs, connect to p1 of radioduno, that marked as a0 to a?, analogue input.
Some switch use adc, switch resistor, so each push button produce different voltage. Hence, one line for many switch. As in dfrobot arduino lcd and switch plug in,widely used.
Chip input line can pick up rf and rectify it as analogue voltage. Put 0.1uF on the adc line normally work, if it use the adc design as above. Tie the switch wiring away from rf final pa area. In extreme case, use screen cable and copper fold wrapping, as in one of my work case.? Since the kit use normal cable, likely tie it away ftom rf pa is enough
73 Simon
On Monday, December 3, 2018, iz oos < and2oosiz2@...> wrote: Ground loop somewhere? Is it connected with other stuff except the antenna?
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Re: Is push pull hf amp has higher spectral purity
Simon,?
The structure of the amp is not the sole element of the question.? I have a single ended that beats the push-pull
of the ubitx by miles.? I also have a QSX amp that is push pull and is very clean.? In the end its not if A or B
but how well the design was executed.
Right now the V4 ubitx solves no issues over the V3 save for now it does not use the TDA2822 audio amplifier chip.
Allison
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Re: Spectrum purity of uBITX and BIT40
Clark,
Its not solely the relays.? Its also the interaction of the pcb routing of the interconnects.
lower the C of the contacts or better routing and the problem disappears.
Since the bitx40 is monoband it has none of those issues and is much cleaner.
Allison
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Re: Spectrum purity of uBITX and BIT40
The output filter relays in the uBitX are double pole double throw, one pole switches the input of the filter, the other switches the output of the filter. ?The original relays have too much capacitive coupling between the input and output of the filter, thus making the filter less effective. ?The replacement relays not only have lower capacitive coupling they are spaced for it. ?The latter is important as i means you can count on future relays to work as expected. ?The problem with using non-spec¡¯ed characteristics is they may change over time.
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Show quoted text
New to here. Just wondering what is the relay and harmonic story. My "general impression" for relay is that it is mechanical metal contact and "length" is not too long. Why it affects lpf filter effectiveness?
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Re: uBitx Function Button ERROR
Ground loop somewhere? Is it connected with other stuff except the antenna?
Il 02/dic/2018 20:31, "Daniel" < gonewiththeego@...> ha scritto: Hello everyone! I have a case from an old 2m transceiver and I decided to use it for my uBitx. Everything is fitting well, I am proud of what I accomplished. I have a big, BIG problem. Whenever I push to talk and I start talking into the microphone, the function menu is appearing for I don't know what reason. Only when I speak!? I have checked the wiring for a hundred of times, still no mistake. It's actually the same wiring I used in the old plastic case which worked flawless. This one is a metal case. I also soldered the antenna coax to the output of the uBitx because I suspected it has something to do with some RF leaking or so, I don't know. For the record, I would like to point that when I keep my hand on the output plug, the menu function is not appearing. I twisted all the wires, in separate pairs, audio and digital, still the same. I would strongly appreciate ANY kind of information because right now I'm out of solutions for this. Maybe only erasing the menu function from the firmware, but this is Kalashnikov. Thanks!
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Re: Is push pull hf amp has higher spectral purity
The push pull has the advantage to deeply attenuate the even harmonics, all versions of the ubitx were good in that, the issue was on odd harmonics, 3rd, 5th.... With push pull a less steeper low pass filter can be used. Especially the 'corner'? frequency can be chosen higher than it would be otherwise. A single low pass filter can also be used for a couple bands. So you save a lot in filtering and relays, it's more a matter of cost and convenience I believe. Monoband qrps are much easier, the ones I had assembled don't have a push pull final, just a normal amplifier and a low pass filter to remove any harmonics. Maybe even I could design a monoband transceiver...
Il 02/dic/2018 20:18, "Simon" < simonhk7@...> ha scritto: Is push pull generally has higher spectral purity than single end transister ? ? Ubitx is push pull, bitx40 is single end.
I read comments stating that bitx40 has better spectural than ubitx, because it is single band, simpler circuit. Is it true for present batch, revision?? I meant, the comments could refer to many revisions over time. ?
How "bad" is the situation? It is not too far from fcc spec., right? There were quite a number of posting on spectural purity? Is the latest batch solved the issue now.?
73 Simon
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uBitx Function Button ERROR
Hello everyone! I have a case from an old 2m transceiver and I decided to use it for my uBitx. Everything is fitting well, I am proud of what I accomplished. I have a big, BIG problem. Whenever I push to talk and I start talking into the microphone, the function menu is appearing for I don't know what reason. Only when I speak!? I have checked the wiring for a hundred of times, still no mistake. It's actually the same wiring I used in the old plastic case which worked flawless. This one is a metal case. I also soldered the antenna coax to the output of the uBitx because I suspected it has something to do with some RF leaking or so, I don't know. For the record, I would like to point that when I keep my hand on the output plug, the menu function is not appearing. I twisted all the wires, in separate pairs, audio and digital, still the same. I would strongly appreciate ANY kind of information because right now I'm out of solutions for this. Maybe only erasing the menu function from the firmware, but this is Kalashnikov. Thanks!
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Re: Spectrum purity of uBITX and BIT40
New to here. Just wondering what is the relay and harmonic story. My "general impression" for relay is that it is mechanical metal contact and "length" is not too long. Why it affects lpf filter effectiveness?
73 Simon
On Sunday, December 2, 2018, iz oos < and2oosiz2@...> wrote: Hard to tell, for what I know, there have been different production batches, each board was checked but may slightly behave differently from others. Current production should have solved relays issues that were mainly responsible for insufficient odd harmonics suppression. For older versions like mine, ver 3 a simple change with better relays (Axicom) resulted in a better harmonics suppression. As for TX purity it is not an IC7300. Speaking loud and very close to the mike results in splatters, TX imd was found being not too good. There is no ALC. My impression is that modulation is effective (the filter is narrow and if BFO is set far enough it sounds pretty dx) and I had received good modulation reports. In a nutshell if one can only listen to classical music will probably dislike it, and this is why I love it!
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Is push pull hf amp has higher spectral purity
Is push pull generally has higher spectral purity than single end transister ? ? Ubitx is push pull, bitx40 is single end.
I read comments stating that bitx40 has better spectural than ubitx, because it is single band, simpler circuit. Is it true for present batch, revision?? I meant, the comments could refer to many revisions over time. ?
How "bad" is the situation? It is not too far from fcc spec., right? There were quite a number of posting on spectural purity? Is the latest batch solved the issue now.?
73 Simon
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Re: 7277 Bitx >Bitx Today 12/2/18
Forgot to add : Call sign is k0mbt
73?
Dave
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MadRadioModder
YO8UFO
_Dave_ AD0B