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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7277 Bitx >Bitx Today 12/2/18
I have my radio on that frequency.
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Re: uBITX - Limiting power output
Don't know for sure. ?Christmas party this afternoon so be tomorrow before much else gets done.
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On Dec 2, 2018, at 12:12 PM, AndyH < ahecker@...> wrote: The stock ?BITX has a drive adjustment at RV1 - the pot that follows the first stage in the RF chain (Q90).? I've used mine to drive a WA2EBY amp on 40 meters and adjusting RV1 was all it took to drop the peaks to 5 W.??
Andy, KG5RKP?
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Re: Missing link bitx40 circuit diagram
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On Sun, Dec 2, 2018 at 09:26 AM, Simon wrote:
Would hfsignals please restore the missing link in?
?
?
At top 10 percent, "download the circuit diagrams"
?
73 Simon
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Re: uBITX - Limiting power output
Two watts will deliver 5-7 watts. The 2 meter transverter by TenTec I think has a bandpass filter at the input which might filter out the spurs on SSB (CW should be fine in any case).
Il 02/dic/2018 18:47, "Curt via Groups.Io" <wb8yyy= [email protected]> ha scritto: Yes I know the 1208 as it was hard to adjust my then hf rig to not overdrive the transverter on ssb, when it could be fine on cw. My 1208 did best with only 2 watts drive on ssb. The stock ubitx has no transmit drive adjustment. I would add a transmit drive pot before the PA. You may need someone to listen to your signal to get the level correct, unless you have a peak power meter.
The 2m transverter from tentec has a leveling loop, it is much better at managing drive level. But sure having a qrp rig with a known 20m output level is useful here.
For now, assemble your ubitx and enjoy it. I suggest avoiding bands above 20m until you have added mods to improve spurious.
Curt
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UbitX audio hiss but no rx
Sent from my Huawei tablet
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Hiya,
I have finished building my UbitX. It is hissing in the earphones (no speaker connected yet) I can hear static, but no rx signal. I tried tuning through some bands with a known good antenna attached, but just hiss. At certain points I did hear a break in audio,
I'm thinking it may be flicking to a different crystal.
No mic connected yet. I have tried touching the two antenna terminals with a damp finger, but there was no change.
Please remember I am a Muppet, and give instructions as simply as possible.
73
Sean "the Muppet" 2E0SFQ
Sent from my Huawei tablet
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Re: uBITX - Limiting power output
The stock ?BITX has a drive adjustment at RV1 - the pot that follows the first stage in the RF chain (Q90).? I've used mine to drive a WA2EBY amp on 40 meters and adjusting RV1 was all it took to drop the peaks to 5 W.??
Andy, KG5RKP?
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Re: RF power chain mods and improvements..
I only had a flat tip for my weller iron. I got a pointy tip recently and found that the tip didn¡¯t stay tinned for very long and it didn¡¯t heat the solder as quick as my flat tip. I¡¯ve soldered some small components with success with the flat tip, even as large as it was. A good magnifying glass and a steady hand helps.?
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On Nov 25, 2018, at 3:54 PM, ajparent1/KB1GMX < kb1gmx@...> wrote: Andyh,
The most common problem is a very hot iron and a pointy sharp tip. The very small tip
often means running higher heat so it can heat larger joints but one hot they maybe
too hot.? Also the excess?heat often causes the materialization at the end of the devices
to disintegrate if not outright cracking the part.
If people saw what I use they would likely faint.? My PES51 I usually have a .90"
tip in it, sometime the .125 wide and the second iron a older Wtcp-60 a larger .250 tip,
and its a 60W temp controlled iron!? Its handy as it makes heating both ends of a
1206 easy.?
Doesn't hurt I have a massive number of years experience with PACE, HAKKO,
and Weller servicing and building.? One thing is not ripping everything up that
can be left alone.
Allison
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Re: uBITX - Limiting power output
Yes I know the 1208 as it was hard to adjust my then hf rig to not overdrive the transverter on ssb, when it could be fine on cw. My 1208 did best with only 2 watts drive on ssb. The stock ubitx has no transmit drive adjustment. I would add a transmit drive pot before the PA. You may need someone to listen to your signal to get the level correct, unless you have a peak power meter.
The 2m transverter from tentec has a leveling loop, it is much better at managing drive level. But sure having a qrp rig with a known 20m output level is useful here.
For now, assemble your ubitx and enjoy it. I suggest avoiding bands above 20m until you have added mods to improve spurious.
Curt
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Re: uBITX - Limiting power output
Depends on how much power you have on 14Mhz, a 10w non inductive fixed attenuator is best, to be on the safe side - 3db.
Il 02/dic/2018 17:39, "Charles French" < crayp0st@...> ha scritto: I want to use my v4 uBITX (under construction), with a Ten-Tec 1208 6m Transverter (SSB) that requires input of MAX 5W. What¡¯s the best way to limit the uBITX output power? Ideas appreciated, Thanks.
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uBITX - Limiting power output
I want to use my v4 uBITX (under construction), with a Ten-Tec 1208 6m Transverter (SSB) that requires input of MAX 5W. What¡¯s the best way to limit the uBITX output power? Ideas appreciated, Thanks.
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Have you looked at the Hamskey.com (Ian Lee KD8CEC) web site?? The files for his firmware versions include options for bath parallel and serial LCD interface.? I also believe that there was a modification that could be made to the source to change the Si5351 to the I2C link, and change the address for the Si5351 chip.
The files are on Git Hub:
Sorry, but I do not remember where on Ian's site that I read about the source modification.? There may be comments in the source files from Github.
Hope this helps
Evan
AC9TU
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Missing link bitx40 circuit diagram
Would hfsignals please restore the missing link in?
At top 10 percent, "download the circuit diagrams"
73 Simon
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thank you but there is still 3 pages of entries and most do not the si5351 dds. with i2c
anyone?
d
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Signal level at TP1 for current batch of ubitx and also bitx40
We want to buy either a uBitx, multiple band or bitx40, single band, for "experimental use", apart from normal use.?
We have a Arduino DDS AD9850 board programmed to generate psk31 RF at hf freq. It transmits about 1 mili watt, 0 dBm, to a dummy load ok.
We plan to cut pin 1 of T2, top left corner of circuit diagram of ubitx, at below link, to isolate the rest of the circuit. The dds signal will go into TP1. Appropiate relay will be energized. Singal from dds has been cheched and was clean enough, as it has its own filter also added, the ubitx has filter L1 to L4.?
Before we buy it, would appreciate advises from the forum.? Will the same mod work on the single band bitx40? I was told the diode mixer "generally" work at -16dBm. Will that be the case for these 2 radios?? It will be simple to use resistor attenuator, if dds output is too strong. If it is too weak, we are not too confident to add an amplifier ourself. Any advises on this will be appreciated
Singal into the 2 stages PA will be clean enough. Likely cleaner than the ubix as the diode mixer generate some unwanted signal. Any idea on the output spectrum purity (pa and post pa lpf)
73 Simon
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YO8UFO
_Dave_ AD0B
Jim Sheldon