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Re: Installing nextion 3.2P
Evan Hand
Gerard,
There is an issue with the Nextion screen backlight. It is common on most if not all of them. The issue is that the pulse width modulation used to dime the screen causes noise that gets back into the uBITX. I just run at full brightness. Others have done other things like install a 100ohm resistor and bypass capacitors in the power line to the Nextion or even using a separate 5volt regulator and capacitors for the Nextion. As I said at the beginning of this post, it is common and not viewed as a failure of the screen. Filtering of the supply voltage or a separate supply are the only two solutions That I know of at this time. 73 Evan AC9TU
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RF on mic when using amplifier
I was having some issues with RF getting on my mic cable and making the radio change frequency using the little Baofeng mic.
I put a .01u cap on the mic audio to ground in the radio. Still had problem. I put a .01u cap on the ptt to ground and BINGO! No more problems. I then removed the cap from mic audio and still had no issues. Just thought I would pass that along. It may help someone else. Chris
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Re: Installing nextion 3.2P
Evan,
You have to believe in fact that my screen Nextion work well there is a defect seen before look here With seach fonction, i find that:for the pb of brightness of the Nextion. see here: https://groups.io/g/BITX20/topic/29553962#64393 https://groups.io/g/BITX20/topic/71102272#75847 you answered in a post: On my v4 ubitx, setting the screen brightness to 100% reduced the 300 hz noise from the Nextion display. That setting was included in the CEC Nextion software, not sure in your implementation. The LCD brightness setting is a call in the Nextion screen editor software. Do need to put a control in the implementation to set it. You can reference the CEC HMI files to see how. Is there a solution? What to do?
cdt
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
Evan Hand
Aaron,
Yes, it looks like Q90 is not working properly. As Gordon said, most likely it was killed by a nearby transmitter. I would put 2 back to back diodes between the K1 relay contacts 12 and 16 after you replace Q90 and verify proper operation. it is always best to do things one at a time so that you know the results of each step. While waiting for the part, you can check the other transistors that are listed after Q90 on the chart. This is to verify that none of them were damaged. That is not likely but does not hurt to check. Good luck with the repair. 73 Evan AC9TU
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
does this mean that I need to replace Q90?
-- '72 Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
Gordon Gibby
Evan is helping you out a lot here. Your measurement showed that transistor is not turned on. And possibly worse. I haven’t looked at the schematic but he’s leading you down a good path
toggle quoted messageShow quoted text
Long long ago I explained how the capacitor system connected to the base of that transistor acted like a pump to blow that base emitter junction—With excessive reverse voltage— In the presence of a strong signal coming from the antenna. Which could be generated by nearby transmitter or nearby lightning. This can be prevented with a single diode from base to Emitter , the opposite direction to protect it from the reverse voltages. As you go further along this process of learning how to fix your rig, I hope you will add such a diode. I have to all of mine and have never had another one destroyed Gordon
On Sep 6, 2020, at 15:17, Aaron K5ATG via groups.io <k5atg@...> wrote:
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
I made the measurements. I hooked the uBITX V6 to a 50 ohm dummyload. I then plugged in the power cord and turned the transceiver on. I then plugged in the microphone and set the radio to USB on 20 Meters. I then wrapped a rubber band around the microphone to press in the PTT button to make the radio transmit. Then I measured the voltages on the Collector, Base and Emitter. For a ground I used the screw in the corner of the PCB board nearest to Q90. Here are the measurements that I recorded:
Collector: 13.13 Base:1.11 Emitter: 0.92 After taking the measurements I shut everything down for aprox 2 hours then I made the measurements again and this time they were all with 0.05 volts of the earlier measurements. -- '72 Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080
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Re: Installing nextion 3.2P
Hello,
Some pb's with my home made PCB µBitx. LOL 1) When I test the frequency encoder potientiometer, I have the impression that it does not follow correctly. If I am on the step of 50htz for example, by turning the encoder it can jump from 100Htz and more instead of 50. It does the same thing on your µBitx. I had other encoders, I change it, it’s the same. Everything is well wired and the signals are good at the oscillo. An idea? 2)another very strange phenomenon!! When I go into the LCD option for intensity. I have to always be 100%. If I touch the setting, a sound (low frequency ) is heard and it varies in frequency linearly if we go from 99 to 0%.!!!!!!! 3) When I use Spectrum analyser, there is always a 7.5 khz frequency that comes from the µBitx. It never changes any settings. 4) For your information, here the list of options that i have with the yellow menu: band select,Select VFO B,Select Mode, RIT on?,IF shift on?,ATT on?,CW: 12WPM change?,Split on?,VFO to channel?,Channel to VFO?,Memory Keyer,WSPR Beacon,SDR mode on?,Setup OFF?,Exit Menu, Set Calibration?,Set the BFO,Set CW RX BFO,Change CW Tone,CW TX->RX Delay,CW Start Delay,Change Key Type?,TX OFF,Exit menu. I think it’s complete, here the encoder seems to display all the options. Thank you for confirming me. Another thing, I saw that you align your µbitx with WWC radio. I don’t think I have a transmitter of this type in France. How to do it then. Last point, I checked everything on my PCB, welding, short circuit possible, value of components. Nothing abnormal. He saved a lot of work. Thank's for your help. Cdt
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Re: Raduino 4 Line Single Sided PCB boards
Evan Hand
Adrian,
I would recommend sending a private message to Rahul. I would also recommend that you direct your post to an individual, or at least be more specific as to what you are asking. Gordon's reply was for the original HF Signals boards that are not open source. I believe that you are asking about the board designed by Rahul VU3WJM. Just suggestions on my part. Welcome to the group! 73 Evan AC9TU
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Evan Hand
Nikhil B,
Did you try CW? That would isolate it to the power amp if no power in that mode. Here is a PDF with static dc voltages for the uBITX. NOTE: You do need to press the PTT to go into TX mode to take the TX voltages. Be sure to have a dummy load or tuned antenna when doing those tests. 73 Evan AC9TU
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Re: Raduino 4 Line Single Sided PCB boards
Gordon Gibby
I don't think the company prefers to give away its intellectual property however several folks (including me) have created pcb's that control the si5351 chip and include the raduino and could do that job easily. for example consider the files at: https://www.qsl.net/nf4rc/Tech/BeginningSWRBoardFinalV11.dip That board was intended to be usable as either a raduino or as an SWR system (the latter never really worked very well) Gordon
On Sun, Sep 6, 2020 at 6:21 AM Adrian Stokes via groups.io <kerravon=blueyonder.co.uk@groups.io> wrote: new to this group where can i find the gerbers for this board.
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Re: Raduino 4 Line Single Sided PCB boards
Adrian Stokes
new to this group where can i find the gerbers for this board.
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Re: Yaesu MH-31 mic works great!
Erwin - PE3ES - F4VTQ
Could you post a connection diagram please Chris.
-- PE3ES - F4VTQ - Erwin 73
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Does the RX work ?
toggle quoted messageShow quoted text
If that is Ok then start with D1/2/5 Q20/21/22 and Q40/41/42. Check transistor voltages and diodes for dry solder. It could also be the interstage toroids if RX is poor. Raj
At 06/09/2020, you wrote:
When i keep my other SSB reciver in the room and talk, i can hear my voice on that receiver. But watt meter show no power. What is the problem? Which part do i need to check?
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BTW when i say no power i mean zero power (no means to measure miliwatts).
With my limited knowledge i think, SSB signal is generated, converted to RF signal but that RF signal is not getting amplified to give more power. As CW is giving 5watts, final IRF must be ok. Problem lies somwhere in between.
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Thanks Evan for prompt reply, but i dont think mic drive is an issue here because with the same setup earlier it was pushing 5 to 7 watts on ssb.
Then it was sitting idle for 5-6 months away from any RF source. Now when i power it on with same setup, no SSB. Wattmeter i am using is sensitive for low 1watt. I tried long Helooooowwww, no power.
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
Evan Hand
Measure DC voltage from each of the three leads of the SMD transistor (collector, base, emitter) to Ground or common on the uBITX. Here is the pinout of the transistor.
The wiring is per the SOT-23 pinout. This must be done while the uBITX is transmitting. That can be CW or SSB. SSB is better, as with no audio on the mic there is very little RF to interfere with the DC measurements. The expected voltages are in the PDF document in this message: https://groups.io/g/BITX20/message/81762 73 Evan AC9TU
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Re: UBITX Ver6 Salvaging the Baofeng microphone for more SSB RF output power!
Jeff Debes
There has been at least two issues with the Baofeng mics:
toggle quoted messageShow quoted text
1) Weaker than nominal modulation 2) A high failure rate See other posts on this .
On Sep 5, 2020, at 11:21 PM, ohwenzelph via groups.io <Ohwenzelph@...> wrote:
--
jeff.debes@...
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Re: UBITX Ver6 Salvaging the Baofeng microphone for more SSB RF output power!
ohwenzelph
Hi Rob,
I am not clear on what is going on here, is this the mike that comes with the uBitxV6? or some other Baofeng mic that you picked up to use? And you are just removing whatever surface mount resistor that you find inside so that the electret element inside gets fed with a higher voltage? Seems a little ill defined and vague, but seems you are having success. Are the internal workings of the supplied mics somewhat variable? thanks jer aa1of
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Re: uBitX V6 no transmit power
#ubitxv6
#ubitx-help
#tx
Evan you asked;
Did you get a chance to measure the 3 leads of Q90? What measurements do you want me to make to Q90 -- '72 Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080
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