I have a Bitx40 which was built from the kit and has been functioning rather well.
For no apparent reason the TX seems to have a problem (no TX)
I connected a RF meter to the radio and noted that when I key the mike the needle jumps and straight back down.
This indicated to me that some TX power has been supplied but not continuious.
Subsiquent keying of the ptt do not have any affect
I have changed the Mike , incase it was faulty. (and whistled in it too)
I also have a spare main board and I replaced it, with the problem persisting.
Any ideas on what further I can troubleshoot or test
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i spent 4 hours on ians site and github. downloaded a dozen or so files, could not get anything going from there. i will builds my project some more then try again.i may be looking too hard. didnt understand the whole CEC thing.
thanks again,
DAVE N4LKN
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Re: Power for continuous digimode
With standard gain settings I would not suggest it stock on FT8 which is a 50% run time.
With a small fan blowing over the stock heatsinks the output transistors get hot on FT8 after 8 cycles
I have two ubitx and it takes a minimum of about a 2x sized from normal heat sink and small fan The easiest test is to put your finger against the transistor after running it.
That said I have about 3-4x heat sinks and a ducted fan over the finals on my other ubitx and run 20 volts through the finals without any heating of the transistors. Well I am sure that there is heat but it is being dissipated It shows 20 watts power output on a mfj meter.
On FT8 the digital power level control works pretty good for controlling the final modulation.
Antenna matching is real important too. Even a 1.4:1 makes a difference in heating.
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Re: Totally Absurd -- Farhan being questioned in a police station about doctored sat picture
Happens in every country. However if you feel hurt and you are convinced they did not act properly you may have the possibility to report this to other departments so they may see to investigate internally. Keep calm and ... them politely!
Il 03/dic/2018 07:52, "Wayne Leake" < wayneleake@...> ha scritto: ?Sometimes the police can be a bunch of ignorant buttwipes. ?One sheriffs deputy tried to claim that we HAD to give a refund, when we had a sign that clearly stated no refunds. ?he did not really know the laws. ?Another time was the state police trying to question me on a murder that I had nothing to do with, other than living not too far from where it happened, and some twit claiming they saw me at a particular restaurant that had some bearing on the case. ?I was asked about a particular Saturday night, and I did not recall that particular night. ?Then a friend reminded me that I had spent the night at his place that particular date. ?That got them PO'd. Should not have, but they were defective detectives.
?On the other hand, some police are pretty decent people.
?the Sheriffs deputy we had here was a very good person. ?Sorry that they transferred him. Replaced with one person that was not bad, but then replaced that person with another that I was told was a real butthole.. ?Piss on the bad ones..
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Re: Spectrum purity of uBITX and BIT40
Warren discussed this in detail. TX IMD are quite bad, however it does not sound bad at all. Keep in mind it splatters if you shout into the mike. I will try the VOGAD add on, at least it should deliver an almost constant mic input.
Il 03/dic/2018 06:27, "Wayne Leake" < wayneleake@...> ha scritto: ?I notice that nobody mentions the best way to check an SSB outgoing signal. ?You need a good two tone audio signal generator. Along with a wide band scope, check that you see a good sine wave pattern. ?We had a setup for testing SSB CB Radios that did just this, so we could see how good the pattern was, ?The setup also checked an AM signal modulated with a single tone. ?You wanted a nice even sine wave. No flat topping, which meant over modulation, and modulation to a bit under where it would start to flat top ?this gave you the cleanest signal. ?Even on ham frequencies, you want the same results ?Make sure that the audio signals are a nice clean sine wave.
?Mixed with a nice clean signal on AM.
?I would say best to check the carrier on AM, as well as the audio sine waves for a nice clean sine wave.
?A square wave is not what you want to use for these tests.
?Wayne WA2YNE
On Sun, Dec 2, 2018 at 5:29 PM Mark McNabb < n7eku@...> wrote: 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: Totally Absurd -- Farhan being questioned in a police station about doctored sat picture
?Sometimes the police can be a bunch of ignorant buttwipes. ?One sheriffs deputy tried to claim that we HAD to give a refund, when we had a sign that clearly stated no refunds. ?he did not really know the laws. ?Another time was the state police trying to question me on a murder that I had nothing to do with, other than living not too far from where it happened, and some twit claiming they saw me at a particular restaurant that had some bearing on the case. ?I was asked about a particular Saturday night, and I did not recall that particular night. ?Then a friend reminded me that I had spent the night at his place that particular date. ?That got them PO'd. Should not have, but they were defective detectives.
?On the other hand, some police are pretty decent people.
?the Sheriffs deputy we had here was a very good person. ?Sorry that they transferred him. Replaced with one person that was not bad, but then replaced that person with another that I was told was a real butthole.. ?Piss on the bad ones..
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Re: Spectrum purity of uBITX and BIT40
?I notice that nobody mentions the best way to check an SSB outgoing signal. ?You need a good two tone audio signal generator. Along with a wide band scope, check that you see a good sine wave pattern. ?We had a setup for testing SSB CB Radios that did just this, so we could see how good the pattern was, ?The setup also checked an AM signal modulated with a single tone. ?You wanted a nice even sine wave. No flat topping, which meant over modulation, and modulation to a bit under where it would start to flat top ?this gave you the cleanest signal. ?Even on ham frequencies, you want the same results ?Make sure that the audio signals are a nice clean sine wave.
?Mixed with a nice clean signal on AM.
?I would say best to check the carrier on AM, as well as the audio sine waves for a nice clean sine wave.
?A square wave is not what you want to use for these tests.
?Wayne WA2YNE
On Sun, Dec 2, 2018 at 5:29 PM Mark McNabb < n7eku@...> wrote: 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: uBITX - Limiting power output
Nice to point out that existing pot. I suggest leaving it there, lift one leg and try a second pot in series on front or rear panel to trim the output power. Just he careful to route coax around the board so it does not compromise the filters or provide other unwanted leakage, I think this is the greater challenge.
I used the 1208 until I zapped the preamp. Also mine was an early one with a poor quality circuit board, but it could be restored if I ever have use for it. yes I had also thought 2 watts to be optimal drive.
Curt
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Re: 7277 Bitx >Bitx Today 12/2/18
I have had that same issue and would recommend 7180.
Evan AC9TU
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Re: uBITX - Limiting power output
You could add relays and pots to adjust power across bands.? I'm thinking about using the current system for 'max out' and a second layer for 'max 5W out' when feeding my WA2EBY.
Andy, KG5RKP
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On Sun, Dec 2, 2018 at 06:50 PM, Charles French wrote:
Thanks for the feedback from all of you.
?
Allison, I wonder if that pot could be brought out to the front panel using some silver/teflon coax for the round trip without creating too many isues? Or is that just asking for trouble?
?
Thanks again!
On Dec 2, 2018, at 1:30 PM, Jim Sheldon < w0eb@...> wrote:
?
Don't know for sure. ?Christmas party this afternoon so be tomorrow before much else gets done.
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: uBITX - Limiting power output
Thanks for the feedback from all of you.
Allison, I wonder if that pot could be brought out to the front panel using some silver/teflon coax for the round trip without creating too many isues? Or is that just asking for trouble?
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Show quoted text
On Dec 2, 2018, at 1:30 PM, Jim Sheldon < w0eb@...> wrote:
Don't know for sure. ?Christmas party this afternoon so be tomorrow before much else gets done. 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: 7277 Bitx >Bitx Today 12/2/18
There is a strong broadcast signal on 7275 which is putting a fairly strong carrier on 7277.? Not good for weak signal work.?? Seems to me the calling frequency should be moved to someplace below 7200 and above 7175 to get away from the broadcast signals.? General class licensees can operate SSB starting on 7175.
Jim
W6yxy
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Re: UbitX audio hiss but no rx
I had the same problem.
(Well, at least I thought I did, turns out it was a PICNIC error).
Put the radio in CW mode, and find an AM station.
Hope that helps.
Dave - AI6K
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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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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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_Dave_ AD0B
MadRadioModder