All,
I must say, I'm impressed by this little radio. The receive side is perfectly competent and clean-sounding on SSB. I did make a few calls but nobody responded. 10W just isn't much. I haven't actually verified yet that it makes RF though.
Somewhere in the junk I have a nice Narda 30db 20W attenuator. With that, I can plug the rig - through the attenuator - directly into an oscilloscope.
I found a 12V 3.5A wall wart for a Netgear wifi router - works *perfectly*. It even has the right
connector! I know the docs say to use a linear supply - but I couldn't hear any PS hash.
- Jerry KF6VB
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Yes that automatic fast tune is annoying it skips a whole Mhz if one isn't careful. My pot was fine but the distance between board and front panel was messed up I could barely get the mike connector to make the right contact. I had to hold it and push it in. Not a problem anymore I migrated to a bigger case and a different connector for mike key and antenna.
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Allard¡¯s latest. The same software that was in it when I had it running before.
--
72 and God bless
KD4EPG
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Ashhar Farhan,
The issue is a mechanical one.? My v6 volume control knob is also "bearly on the shaft."? Another 1/4 inch length of the shaft would make it much easier to attach the knob so that it does not rub against the case or mounting screw that is partly under the knob.? It takes some practice and trial and error to get it right.? The extra torque that is required to turn on and off the power switch makes it more sensitive to a bad setting.
What?Jerry KF6VB is saying is he will replace the supplied pot with one that has the shaft adjusted to better fit the enclosure. I suspect that he will need to purchase a long shaft pott and cut it down to fit.
73
Evan
AC9TU
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Re: radio will transmit CW but not voice
On Sun, Apr 18, 2021, at 09:06 PM, <theaddies@...> wrote:
I also checked the microphones on the oscilloscope.? I didn¡¯t realize the voltage from them was so low.? I could see my voice when I screamed but not well for sure.? I don¡¯t think the problem is the mic¡¯s.? I took a picture of my board thinking that perhaps something is missing.? There are 2 components that are not filled in but perhaps they aren¡¯t supposed to be there.
Andrew, The electret cartridge in the mic needs a positive voltage bias to work properly.? That bias is around 3 to 5 volts DC.? Then the signal is fed into the mic preamp through a capacitor.? Here is the mic preamp from the v6 schematic:  R60 is dropping the 12volts down to around 3volts through the LED and resistors in the mic.? For some mics, this is not enough and there have been reports of removing some of the resistors and led that have improved the audio output of the mic.? I do not have links for those threads.? You could do a search of the messages to see if you can find the mod. To test with an oscilloscope you would need to have a 12volt source, a 1uF capacitor, and a 4.7kOhm resistor.? An easier way is to connect to a mic input on a PC and use the PC to test the mic.? I use this free audio spectrum analyzer program on my Windows PC: There are other free audio test programs like Audacity.? The key is the mic input on the sound device.??You need an audio input card that has a mic input.? Most of the USB low-cost dongles do.? That is also the case for most laptop mic inputs. I did a quick measurement on my v6 and found that I need at least 0.12volts peak to peak to get 7 watts out.? That is with a two-tone signal generator, 5watts with a single 1900Hz tone at 0.1volts.? When I ran the tone generator into a powered speaker and held the mic close to the speaker I got similar results. Have you done the BFO calibration?? If the BFO is off it can put the audio signal on the edge of the SSB filter that would reduce the signal to the following stages.? Here is the video from Ashhar Farhan (the lead designer of the ?BITX for HFSignals) that goes through the calibration process.? I would suggest that you skip the first BFO adjustment and the frequency calibration and just go to the last BFO tuning.? You want to put the "noise plateau" towards the 3000Hz bar to get the most effective signal output.? There is a compromise with the sound quality of the received signal.? It may take a couple of settings to get it where you like it.? Also, note that the current BFO value is not saved.? When you go into the BFO adjustment it starts from a default value every time.? You need to record the values that you set so that you can track the effects of the changes on the signal. Above are just suggestions. 73 Evan AC9TU
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What software are you running on the BitX40? I have Allard Munter's and highly recommend it as a big improvement. I have found myself inadvertently trying to listen on USB, could that have been the issue?
=Vic=
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you can parallely connect a volume control from AUDIO connector on the right side of the main board. - f
On Mon, Apr 19, 2021 at 10:49 AM Dennis Yancey < Kd4epg@...> wrote: Replace the volume pot with one of more suitable sizes.
--
72 and God bless
KD4EPG
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Replace the volume pot with one of more suitable sizes.
--
72 and God bless
KD4EPG
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I have a bitx40 that I built a couple of years ago. I had it working well, it got shelved and not used for a while. I got it out, got it going but the receive is totally garbled and not understandable. I have tried the calibration as defined with the red wire. The original ppm offset I had used was 68. I have tried values from -180 to +180 and none seem to make much difference. I so save the value the restart the radio.?
--?
72 and God bless
KD4EPG
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Re: radio will transmit CW but not voice
Don't give up.? ?You will gradually learn more and more and solve the problem.? ?My first radio didn't work for about 6 months -- got shipped back to Benton Harbor for more work maybe TWICE.? ? I learned a ton of radio in that frustrating effort.? ?Served me well for years.? ?Dumb me sold that HW-16...finally bought on on Ebay to restore recently.??
Gordon
I had another go at the whole thing tonight.? I resoldered most of the joints.? The issue is still the same.? When I scream into the microphone I get nothing.? If I switch to cw and key the mic I get tones.? I connected a 3.5 mm jack up to my frequency generator.? The head pin was positive and the top ring was ground.? If I shorted the middle ring with ground the radio would try to transmit.? I fed a 1kHz signal at a voltage level of 0.01V.? I wasn¡¯t sure what level I should set, but I could just barely hear that signal with headphones. ? I also checked the microphones on the oscilloscope.? I didn¡¯t realize the voltage from them was so low.? I could see my voice when I screamed but not well for sure.? I don¡¯t think the problem is the mic¡¯s.? I took a picture of my board thinking that perhaps something is missing.? There are 2 components that are not filled in but perhaps they aren¡¯t supposed to be there. ? I am bummed about this thing.? I am relatively new to ham and I just wanted to get this working to get me more comfortable with the whole thing. ? Thanks for the help and suggestions.  ? ? This may be an obvious statement but you say you key the mic.? Do you speak into the mic Evan, I should have also said that I am using an SDR as a receiver.? On the waveform when I key the microphone I see nothing.? Whilst, when I key the microphone with CW selected I can see the signal loud and clear. ? Andrew ? ? theaddies,
The first thing to do is always verify that the measurement is correct.? In this case that both rigs are set up to receive the other rig.? Same frequency and sideband.
Assuming that is correct, and still no audio, then I would suspect the microphone.? What test equipment do you have to help in diagnosing the issue?? At this point an oscilloscope would be nice, however, an RFProbe with a DMM can help in tracking the signal from the mic to the product detector/modulator if you do not have an oscilloscope.
Here is how to build one if you do not have an RF probe or oscilloscope:
Another test is to connect an audio tone source (your PC with an audio tone program as an example) and then key the PTT ring.? I made an adapter that connects the tip of a 3.5mm plug with the tip of the plug to the computer, shield to shield, and a switch between the shield and the ring of the plug that goes to the rig mic input.? If you get rf out of this setup then the mic is most likely the issue.
Let us know what test equipment that you have so we can give you suggestions based on your equipment.
73
Evan
AC9TU
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Re: radio will transmit CW but not voice
I had another go at the whole thing tonight.? I resoldered most of the joints.? The issue is still the same.? When I scream into the microphone I get nothing.? If I switch to cw and key the mic I get tones.? I connected a 3.5 mm jack up to my frequency generator.? The head pin was positive and the top ring was ground.? If I shorted the middle ring with ground the radio would try to transmit.? I fed a 1kHz signal at a voltage level of 0.01V.? I wasn¡¯t sure what level I should set, but I could just barely hear that signal with headphones. ? I also checked the microphones on the oscilloscope.? I didn¡¯t realize the voltage from them was so low.? I could see my voice when I screamed but not well for sure.? I don¡¯t think the problem is the mic¡¯s.? I took a picture of my board thinking that perhaps something is missing.? There are 2 components that are not filled in but perhaps they aren¡¯t supposed to be there. ? I am bummed about this thing.? I am relatively new to ham and I just wanted to get this working to get me more comfortable with the whole thing. ? Thanks for the help and suggestions.  ?
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From: [email protected] < [email protected]> On Behalf Of W2CTX via groups.io Sent: Sunday, April 18, 2021 11:33 AM To: [email protected]Subject: Re: [BITX20] radio will transmit CW but not voice ? This may be an obvious statement but you say you key the mic.? Do you speak into the mic Evan, I should have also said that I am using an SDR as a receiver.? On the waveform when I key the microphone I see nothing.? Whilst, when I key the microphone with CW selected I can see the signal loud and clear. ? Andrew ? ? theaddies,
The first thing to do is always verify that the measurement is correct.? In this case that both rigs are set up to receive the other rig.? Same frequency and sideband.
Assuming that is correct, and still no audio, then I would suspect the microphone.? What test equipment do you have to help in diagnosing the issue?? At this point an oscilloscope would be nice, however, an RFProbe with a DMM can help in tracking the signal from the mic to the product detector/modulator if you do not have an oscilloscope.
Here is how to build one if you do not have an RF probe or oscilloscope:
Another test is to connect an audio tone source (your PC with an audio tone program as an example) and then key the PTT ring.? I made an adapter that connects the tip of a 3.5mm plug with the tip of the plug to the computer, shield to shield, and a switch between the shield and the ring of the plug that goes to the rig mic input.? If you get rf out of this setup then the mic is most likely the issue.
Let us know what test equipment that you have so we can give you suggestions based on your equipment.
73
Evan
AC9TU
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Heh,
That's what a DX-100 is for ;)
73,
Bill KU8H
bark less - wag more
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On 4/18/21 2:35 PM, Arv Evans wrote: Curt
I wonder how many on this group are running their uBITX on 11 meters?
Arv
_._
On Sun, Apr 18, 2021 at 11:53 AM Curt via groups.io <> <wb8yyy@... <mailto:[email protected]>> wrote:
okay let's do some simple math -- 25 kW, maybe 50% efficient, 220
volts feeding it -- who has a 227 amp outlet in their home?
now for only 1 kW it brings it down to what an existing household
circuit might support.
I recall hearing about someone's visit to a DX contest station,
noting their 5 kW amplifier.? the reply was 'well we only use that
much power to break a pileup on a rare multiplier ....'
nothing against more power - but everyone keep in mind a 4X change
is about 1 S-unit.? enjoy your radiations.
Curt
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Re: Unresponsive ubitx V6
Hi Evan and Jerry
I've ordered a new display TFT screen from Amazon via prime, hopefully it will be delivered tomorrow? (Monday)
Regards
Dave G4HUM
On Sat, 17 Apr 2021, 22:06 Dave Hazzard via , <davidroyhazzard= [email protected]> wrote: Cheers Evan
I've got that now thank you :0)
Regards
Dave
Dave,
I should have sent the picture to show the ILI9341 header.? Pin 14 is at the top of the picture decreasing down.
73
Evan
AC9TU
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Curt
I wonder how many on this group are running their uBITX on 11 meters?
Arv _._
okay let's do some simple math -- 25 kW, maybe 50% efficient, 220 volts feeding it -- who has a 227 amp outlet in their home??
now for only 1 kW it brings it down to what an existing household circuit might support.?
I recall hearing about someone's visit to a DX contest station, noting their 5 kW amplifier.? the reply was 'well we only use that much power to break a pileup on a rare multiplier ....'?
nothing against more power - but everyone keep in mind a 4X change is about 1 S-unit.? enjoy your radiations.
Curt
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On 2021-04-18 09:20, Arv Evans wrote: you can use a spectrum analyzer to monitor your modulation level. If lacking even that test
equipment *** What an age we live in! When I was a young ham, a spectrum analyzer was an extremely expensive piece of test equipment. In later years, I would drool at HP-141T units at the flea market - they were still unaffordable, and just too big and heavy. Fast forward to the present - I just scored a "tinySA" aka "Tiny Spectrum Analyzer" for a princely sum just north of fifty bucks. It covers .1MHz to 350MHz at "high quality", and should be perfectly adequate for monitoring the spectrum output of a ham radio HF transmitter. I'm thinking of making a voltage probe antenna for mine so it can monitor the ham bands for activity. It did come with a little extending whip antenna, but sensitivity is too low for anything but commercial broadcast. - Jerry KF6VB
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okay let's do some simple math -- 25 kW, maybe 50% efficient, 220 volts feeding it -- who has a 227 amp outlet in their home??
now for only 1 kW it brings it down to what an existing household circuit might support.?
I recall hearing about someone's visit to a DX contest station, noting their 5 kW amplifier.? the reply was 'well we only use that much power to break a pileup on a rare multiplier ....'?
nothing against more power - but everyone keep in mind a 4X change is about 1 S-unit.? enjoy your radiations.
Curt
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Why? I found it informative and interesting as I had no idea that people were running CB radios with that much power. It also makes me wonder how the guy can sell something like that on the internet. I, for one, am glad it was posted.
Jack, W8TEE
On Sunday, April 18, 2021, 12:06:57 PM EDT, R. M. Baker <w8yn@...> wrote:
-- Jack, W8TEE
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Aaron
If you are going to use an "amplified microphone" on your uBITX then
you will need to have a microphone level control to avoid overdriving
the balanced modulator and causing spurious signal generation.
If you do not have an SSB type station monitor you can use a spectrum
analyzer to monitor your modulation level.? If lacking even that test
equipment it is possible to use a power output meter and adjust audio
level for the point just below where modulated RF starts to compress
on voice peaks.
Arv _._
Howdy friends,
I read somewhere in this fine group about using this microphone for the uBITX v.6?
I also believe that I?found a topic here on changing the 4 pin connector to the 3.5 mm connector that the uBITX v.6 uses. Could someone please point me in the correct direction?
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080
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Re: Raduino32 v5. Full duplex Audio remote
Hola Ashhar,
I have tested through the internet and it works quite well. In this case I have only tried sending to the server, because you have to open the ports and through the mobile it is not possible.
?
I don't know RTP well, but I'm going to study it and give it a try.
¸é²¹³¾¨®²Ô
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Vic WA4THR
