hello,
Here you can see a sides of my printed circuit board. I modified for the Ardino power supply (10 ohm resistance + capacitors. For the power supply of the Nextion, it can be done directly on the 5v or by another regulator. I added a coil and capacitors too. On my alim block, I put an automatic regulation of the fan. it triggers when too hot.?
It takes time, but it¡¯s very informative. I think I would also modify some transistors according to the wiki. (Ex 2n2222) etc...
cdt
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The 1926 ?bitx of my great father
Hello,
Seriously, I found this old TSF, and the variable capacitors will serve me for an antenna loop.
I¡¯m still working on my own construction of ?Bitx where I can go from A to Z. The power supply is made, the box is pierced. There I made the printed circuits, it remains to be drill.
For the components, it comes from China, I received 95%.... over 2 months! But I have time.
But since I can only put a piece attached, I will open another post. You may see it.
Cdt
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Thank you Gentlemen!
I am now able to tune in strong local AM stations.? I went back to the BFO tuning tool and watched Ashhar YouTube.? I was not believing the tuning adjustment coming in around 150000, I just thought that was to far out of tolerance.? The video shows Ashhar adjusting to 130000 plus. So I think I am good.
Let me throw a broad question out there, what is the typical freg offset that others are coming up with???
Bruce Morrell KB8MW
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Re: Building a 12V Supply Board
I remember reading in an old spec sheet for a three-terminal regular that the operating voltage of the regulator was three volts. This no doubt depends largely on the design of the regulator but 3-4 volts should be considered operational. Keep in mind that if you use the maximum applied voltage, that means about 30 volts at the operating current needs to be dissipated unnecessarily because of the heat. Applying 12V is not excessive to me, though. Still, however, some kind of heat sink or fins on the three-terminal regulator is to me cheap insurance.
Bob ¡ª KK5R
On Thursday, July 9, 2020, 12:28:59 PM EDT, Evan Hand <elhandjr@...> wrote:
Peter,
Before you go through the trouble of building in the "noise" filter, I would first verify that the noise is coming from the 12 supply.? The best way to do that is to test the noise level on battery power.? You do not need to transmit, so any 12v battery capable of supplying 250 to 300 ma for a short time should do.? I have used a car jumper battery that I have and found little to no difference in the noise level on battery power vs mains supplied through either of my TexPower 13.8volt switching supplies. The noise is coming from the antenna in my neighborhood caused by QRM and high QRN noise levels on the air in general.
With the above understanding, I will make some suggestions for R2 to reduce the power dissipation of the 7805 regulator.? ?That does depend on the total current that you will need from the regulator, and THAT depends on what you have planned to add onto the rig that will need 5 volts.? If you add up the power requirements of all of the devices on the stock rigs, the total current is much less than 200ma, more like 120 ma (approximate, as I have not done all of the spec sheet validations? I did look up the stock version 6 2.8" display and that has a max of 80ma).? Then you have the minimum voltage that the 7805 needs to regulate to 5 volts.? I use 3 volts to get some safety margin.? That means you need to supply 5 + 3 = 8volts minimum at maximum current.? If the input voltage is truly 12 volts, and you want 8 volts to the regulator minimum at 200ma, and you need a 4volt drop at 200 ma, then 4/.2=20ohms.? That resistor will need to dissipate 4*0.2 = 0.8 watts.? All of these calculations are DC values, so the simple E=IR and P=EI and the transforms work.
For my rigs, I am adding second Nanos, larger displays with built-in GUI processors, and signal processors, so I have upped the max current to <1 amp (the maximum that the 7805 provided by HFSignals can regulate) and added other safety margins to get 4 ohms at 4 watts.? Were I to do it again, I would have added a second 7805 to supply the auxiliary equipment and not modified the Raduino board.
In general, the stock setup works well, and no changes are needed.? Adding a heatsink to the regulator can help if you are going to operate in high ambient temperatures.??
The other comment that I would make is that if you find you have RF noise from the power supply, then you will need to add capacitors to filter the higher frequency.? Something like a 0.1 to 0.01 uF ceramic disc.? The 470uF will not filter higher frequency stuff.? There is too high of internal resistance at RF in electrolytic capacitors.? You may also be better off to add an RF choke instead of the resistor.? I will let someone more knowledgable on that subject to make a true recommendation.
The above are my thoughts and should be verified before you take action on them.? I do make mistakes at times.
73
Evan
AC9TU
|
Back in the days of the Commodore 64, there was a recurring problem with the main power connection pin on the board having a hairline crack in the solder joint. All that needed to be done was reheat it. It was a simple repair that caused many techs to have some crazy moments on the repair bench.
Bob ¡ª KK5R
On Thursday, July 9, 2020, 11:37:23 AM EDT, Evan Hand <elhandjr@...> wrote:
I believe that Sarma has hit on the most probable cause.? I have had issues with the antenna pins coming loose, so the red power lead to the mainboard is a good candidate.? If you add the leakage current of the finals to the 87 ma that I measured you get the 90ma.? Could also be just a bad connection to the pin in the connector.? If you have a pin you could measure the red wire connection to see if there is 12 volts on it.
73
Evan
AC9TU
|
Re: Building a 12V Supply Board
Keep all leads short or be prepared to add large and small caps at each end of the long leads because voltages can build up across stray inductance caused to long leads. Like a 10 MFD and a 0.1 disc ceramic (also with short leads) in parallel. A disc ceramic cap can be a problem at 20M and above if the leads are too long.
IBM axiom: "Anything can be done if it is logical. The only problem is implementation." An extension of this is a lot of small problems can jump out at the builder if too little thought is put into the process.
If something works satisfactorily, theory is no longer a factor.
Bob¡ª KK5R
On Thursday, July 9, 2020, 11:23:00 AM EDT, peter.mccracken@... <peter.mccracken@...> wrote:
Hi all, I want to build a dedicated power supply board mounted to the back of the case and remove the regulator that is currently on the raduino, I also want to try to "clean" as much noise as possible from the supply whilst doing this. I only have rudimentary knowledge of this stuff but the below is my attempt at designing something for this. The idea is to clean up the 12V supply before connecting it to the ubitx mainboard and also use a resistor to drop the voltage into the regulator somewhat before feeding that into the Raduino. I am not sure what value would be good for R2. I would be grateful for any suggestion as to how I could do this better.  Best regards, Peter.
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Bruce,
As Curt said in his response, the BFO has a HUGE impact on the sensitivity of the rig.? You need to have the audio response centered in the passband of the SSB filter.? The way that I have done that is to use either an audio spectrum analyzer or the BFO Tuinig aid web page here:
The full alignment process is outlined in this video from Ashhar Farhan:
Note that the first BFO adjustment is to provide the low audio frequency response for zero beating, then use it to calibrate, then set the BFO for the full audio spectrum.? It is important to adjust the BFO for the low range response so you can hear the zero beat signal better.? Then for best sensitivity and audio response to center the plateau properly. between 300 and 3,000 Hz.
Try the BFO adjustments to see if that helps get you on the frequency and with a good response.??
BTW, For me in Illinois WWV on 10MHz at night has been the best source for calibration.? There other frequencies at 2.5, 5, 15, and 20MHz as well.? Low frequencies during the night, and higher frequencies during the day.
73
Evan
AC9TU
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Bruce
have you performed an alignment of the BFO?? if it were decently off sensitivity would be reduced.? of course listen to the lower ham bands as their should be strong signals there.?
Curt wb8yyy
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Bruce,
Q74 is used to mute the audio in when in transmit mode.? This reduces the input, yet still allows the sidetone to feed the audio amp to be herd.? If you check the rest of the schematic, you would see that there is no voltage source until T/R goes high, turning on the gate and then shorting the audio feed line that has been opened by the relay from the product detector.?
You can use any AM broadcast station for calibration, as long as you know the exact frequency of the station.? Even USA AM could be used, however the higher the frequency the easier it is to be accurate.
FWIW
73
Evan
AC9TU
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Re: Building a 12V Supply Board
Peter
All this seems to point to a uBITX or BITX that is being run at near maximum? audio volume level.? I would probably look at RF and IF circuitry to see why it? is necessary to have the volume turned up so high.??
Receiver sensitivity should be in the 0.1 to 0.3 microvolt level for MDS (Minimum? Discernable Signal).? Have you set your BFO way outside the IF passband??? That might be something to look?at.? If the BFO is way outside the IF filter it? will appear that the receiver is insensitive and thus require turning the volume? (audio gain) to high levels.
If you have an audio amplifier that has a sensitive input you can use a 0.1 mfd? capacitor to couple that amplifier to the DC power lead.? It should show any? audio range noise.? If you use a diode detector ahead of this audio amplifier? you should be able to hear any RF noise that might be present on the DC? power leads.
You should be able to decrease AF noise on DC power lines by adding a 470 mfd to 2700 mfd capacitor between DC positive and DC negative (observe? polarity of the capacitors).??
RF on the power leads can usually be decreased by adding 0.1 mfd capacitors? across the DC supply lines, both at the power supply and at the power input to? the transceiver.
Arv
_._
It's definitely coming from the mains, if I switch off the soldering iron I get a <clack> on the audio of the radio, if I switch off the main light switch in the room I get an extremely loud <CLACK>. I have a PS30SWII switching power supply, I was considering doing this on its mains lead..
... which looks encouraging, but I also want to "filter" more on the incoming 12v. I also have the problem of "clicks" when using the encoder and you can hear "noise" when pressing the touch screen.
More info is that I will install a Nextion 5" screen at the weekend along with a second nano. I have some info on how to reduce the noise from the Nextion.
Evan, thanks for the info on calculating the required resistor size, that all makes sense as does the comment about the disc capacitor.
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Bruce,
The MFJ is handy but its far from calibrated in frequency.??
Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO
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Fellow Utix v6 users.? I have a new v6 radio I am trying to determine if it is properly working.? I am unable to pick up wwv signals so I am calibrating using a mfj 259b as a signal source.? I have gone through the calibration process to the best of my knowledge.
Next I started checking voltage in the recv circuit . q20,21,22,40,41,42 and 70 check out.? Q74 has o dc volts on all leads.? Is this correct???
Thanks for your responses. Bruce
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Re: Building a 12V Supply Board
The ¡®clacks¡¯ are most likely radiated noise and not conducted. This is normal. ? Dale W4OP ?
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of peter.mccracken@...
Sent: Thursday, July 9, 2020 1:09 PM
To: [email protected]
Subject: Re: [BITX20] Building a 12V Supply Board ? It's definitely coming from the mains, if I switch off the soldering iron I get a <clack> on the audio of the radio, if I switch off the main light switch in the room I get an extremely loud <CLACK>. I have a PS30SWII switching power supply, I was considering doing this on its mains lead.
... which looks encouraging, but I also want to "filter" more on the incoming 12v. I also have the problem of "clicks" when using the encoder and you can hear "noise" when pressing the touch screen.
More info is that I will install a Nextion 5" screen at the weekend along with a second nano. I have some info on how to reduce the noise from the Nextion.
Evan, thanks for the info on calculating the required resistor size, that all makes sense as does the comment about the disc capacitor.
|
Re: Building a 12V Supply Board
It's definitely coming from the mains, if I switch off the soldering iron I get a <clack> on the audio of the radio, if I switch off the main light switch in the room I get an extremely loud <CLACK>. I have a PS30SWII switching power supply, I was considering doing this on its mains lead..
... which looks encouraging, but I also want to "filter" more on the incoming 12v. I also have the problem of "clicks" when using the encoder and you can hear "noise" when pressing the touch screen.
More info is that I will install a Nextion 5" screen at the weekend along with a second nano. I have some info on how to reduce the noise from the Nextion.
Evan, thanks for the info on calculating the required resistor size, that all makes sense as does the comment about the disc capacitor.
|
Re: Building a 12V Supply Board
Hi,
I would agree that a noisy power supply should be tamed at the power supply. I will suggest looking at the schematics of PC switching power supplies and focus on the filtering circuits that introduce the AC supply current from your electric energy company - aka your power mains. There are capacitors and chokes in that filter. I had a problem with one a number of years ago and could not have that computer turned on while using the radio. That is really inconvenient when we want to run digital modes:)
I found those filter parts had been omitted to save a few pennies. The circuit board had the traces and the mounting points and the silk screen for the parts. It had jumpers to carry AC power past those places and no filter parts. I installed the needed parts and the computer was then usable with the radio.
I hope this helps somebody.
73,
Bill KU8H
bark less - wag more
toggle quoted message
Show quoted text
On 7/9/20 12:28 PM, Evan Hand wrote: Peter,
Before you go through the trouble of building in the "noise" filter, I would first verify that the noise is coming from the 12 supply.? The best way to do that is to test the noise level on battery power.? You do not need to transmit, so any 12v battery capable of supplying 250 to 300 ma for a short time should do.? I have used a car jumper battery that I have and found little to no difference in the noise level on battery power vs mains supplied through either of my TexPower 13.8volt switching supplies. The noise is coming from the antenna in my neighborhood caused by QRM and high QRN noise levels on the air in general.
With the above understanding, I will make some suggestions for R2 to reduce the power dissipation of the 7805 regulator.? ?That does depend on the total current that you will need from the regulator, and THAT depends on what you have planned to add onto the rig that will need 5 volts.? If you add up the power requirements of all of the devices on the stock rigs, the total current is much less than 200ma, more like 120 ma (approximate, as I have not done all of the spec sheet validations? I did look up the stock version 6 2.8" display and that has a max of 80ma).? Then you have the minimum voltage that the 7805 needs to regulate to 5 volts.? I use 3 volts to get some safety margin.? That means you need to supply 5 + 3 = 8volts minimum at maximum current.? If the input voltage is truly 12 volts, and you want 8 volts to the regulator minimum at 200ma, and you need a 4volt drop at 200 ma, then 4/.2=20ohms.? That resistor will need to dissipate 4*0.2 = 0.8 watts. All of these calculations are DC values, so the simple E=IR and P=EI and the transforms work.
For my rigs, I am adding second Nanos, larger displays with built-in GUI processors, and signal processors, so I have upped the max current to <1 amp (the maximum that the 7805 provided by HFSignals can regulate) and added other safety margins to get 4 ohms at 4 watts.? Were I to do it again, I would have added a second 7805 to supply the auxiliary equipment and not modified the Raduino board.
In general, the stock setup works well, and no changes are needed. Adding a heatsink to the regulator can help if you are going to operate in high ambient temperatures.
The other comment that I would make is that if you find you have RF noise from the power supply, then you will need to add capacitors to filter the higher frequency.? Something like a 0.1 to 0.01 uF ceramic disc.? The 470uF will not filter higher frequency stuff.? There is too high of internal resistance at RF in electrolytic capacitors.? You may also be better off to add an RF choke instead of the resistor.? I will let someone more knowledgable on that subject to make a true recommendation.
The above are my thoughts and should be verified before you take action on them.? I do make mistakes at times.
73
Evan
AC9TU
|
Re: Building a 12V Supply Board
Peter,
Before you go through the trouble of building in the "noise" filter, I would first verify that the noise is coming from the 12 supply.? The best way to do that is to test the noise level on battery power.? You do not need to transmit, so any 12v battery capable of supplying 250 to 300 ma for a short time should do.? I have used a car jumper battery that I have and found little to no difference in the noise level on battery power vs mains supplied through either of my TexPower 13.8volt switching supplies. The noise is coming from the antenna in my neighborhood caused by QRM and high QRN noise levels on the air in general.
With the above understanding, I will make some suggestions for R2 to reduce the power dissipation of the 7805 regulator.? ?That does depend on the total current that you will need from the regulator, and THAT depends on what you have planned to add onto the rig that will need 5 volts.? If you add up the power requirements of all of the devices on the stock rigs, the total current is much less than 200ma, more like 120 ma (approximate, as I have not done all of the spec sheet validations? I did look up the stock version 6 2.8" display and that has a max of 80ma).? Then you have the minimum voltage that the 7805 needs to regulate to 5 volts.? I use 3 volts to get some safety margin.? That means you need to supply 5 + 3 = 8volts minimum at maximum current.? If the input voltage is truly 12 volts, and you want 8 volts to the regulator minimum at 200ma, and you need a 4volt drop at 200 ma, then 4/.2=20ohms.? That resistor will need to dissipate 4*0.2 = 0.8 watts.? All of these calculations are DC values, so the simple E=IR and P=EI and the transforms work.
For my rigs, I am adding second Nanos, larger displays with built-in GUI processors, and signal processors, so I have upped the max current to <1 amp (the maximum that the 7805 provided by HFSignals can regulate) and added other safety margins to get 4 ohms at 4 watts.? Were I to do it again, I would have added a second 7805 to supply the auxiliary equipment and not modified the Raduino board.
In general, the stock setup works well, and no changes are needed.? Adding a heatsink to the regulator can help if you are going to operate in high ambient temperatures.??
The other comment that I would make is that if you find you have RF noise from the power supply, then you will need to add capacitors to filter the higher frequency.? Something like a 0.1 to 0.01 uF ceramic disc.? The 470uF will not filter higher frequency stuff.? There is too high of internal resistance at RF in electrolytic capacitors.? You may also be better off to add an RF choke instead of the resistor.? I will let someone more knowledgable on that subject to make a true recommendation.
The above are my thoughts and should be verified before you take action on them.? I do make mistakes at times.
73
Evan
AC9TU
|
I believe that Sarma has hit on the most probable cause.? I have had issues with the antenna pins coming loose, so the red power lead to the mainboard is a good candidate.? If you add the leakage current of the finals to the 87 ma that I measured you get the 90ma.? Could also be just a bad connection to the pin in the connector.? If you have a pin you could measure the red wire connection to see if there is 12 volts on it.
73
Evan
AC9TU
|
Building a 12V Supply Board
Hi all, I want to build a dedicated power supply board mounted to the back of the case and remove the regulator that is currently on the raduino, I also want to try to "clean" as much noise as possible from the supply whilst doing this. I only have rudimentary knowledge of this stuff but the below is my attempt at designing something for this. The idea is to clean up the 12V supply before connecting it to the ubitx mainboard and also use a resistor to drop the voltage into the regulator somewhat before feeding that into the Raduino. I am not sure what value would be good for R2. I would be grateful for any suggestion as to how I could do this better.  Best regards, Peter.
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Appears loose pins on the 3 wire power plug.? Especially if? Red wire is loose? and? some leakage current on the brown Tx wire somewhere could be an answer for 3.5mA
Sarma vu3zmv
On Thu, 9 Jul 2020, 5:16 pm Ray Lenthall VK3JH, < vk3jh@...> wrote: Hi Evan ? Thanks for your reply.? I have checked the voltage form the power supply and it is 12.3 v.? I bypassed the diode in case there was a problem there but still came up with the same result of 3.5ma rather than the 90ma. ? 73 ? Ray ? ? Ray,
There are 7 2n3904 transistors that should be on in a linear bias plus the LM386 audio amp when in receive.? If you have wired the power correctly (the RED wire is the +12volts to everything EXCEPT the PA)? it should read 90+ma.? I would check your power wiring as a start.? I would also check the power supply to verify that it is providing 12volts.
The readings are without the Raduino connected, per the original wireup instructions.? The PA bias adjustments come later and will add another 200ma + the Raduino current requirements?to the readings.?
My v5 is buried in a case with a 3.5" Nextion screen, AGC, and an outboard audio amp, so it is not easy for me to get to the readings from that board for comparison. As stated in the first paragraph above, you most likely have a power supply/wiring issue.
73
Evan
AC9TU
73
Evan
AC9TU
|
Not sure I understand bypassing the diode.? Per the wire up instructions, the supplied diode is to be used for reverse voltage protection, and if you wired it per the instructions then bypassing the diode would short out the supply.
I would verify that you are getting the 12volts to R18, R38, R52, and R71.? These are the active stages with power when the Raduino is disconnected.? The voltage drops that I got across them are:
R18 = .4 volts? so that is drawing 40ma
R38 = .4 volts so that is drawing 40 ma
R52 = .52 volts so that is drawing 2.4 ma
R71 = .46 volts so that is drawing 4.6 ma
Total = 87 ma close to the 90 ma specified.? There could be other sections that make up the last 3 ma or it could be the meter or resistor value differences.
Also, check that the power connector is plugged in correctly and not offset by a pin or in reversed.?
I really do not know what could cause these symptoms, other than an open on the board or wiring.? I have not seen, nor read of this type of behavior.??
Happy hunting!
73
Evan
AC9TU
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Bob Lunsford