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
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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
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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
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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
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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
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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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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 ?
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From: [email protected] <[email protected]> On Behalf Of Evan Hand
Sent: Thursday, 9 July 2020 4:01 PM
To: [email protected]
Subject: Re: [BITX20] construction? 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
|
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
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That's what it should read when the finals have had their bias adjusted iirc
On Thu, 9 Jul. 2020, 10:28 am , < vk3jh@...> wrote: Hi I purchased a V5 last year and am only now starting to put it together. I have wired up the DC power plug as per the instructions and the instructions tell me if I apply 12v it should draw between 90 and 110 ma.? Mine draws 3.5ma. Can anyone give me some clues.? Many thanks.
Ray? VK3JH
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Yeah, I don't know what bloat was added, but there's a reason I called out the specific IDE version in the Readme file :)
Reed
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Hi, Ray.
Is the Raduino connected?
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Hi I purchased a V5 last year and am only now starting to put it together. I have wired up the DC power plug as per the instructions and the instructions tell me if I apply 12v it should draw between 90 and 110 ma.? Mine draws 3.5ma. Can anyone give me some clues.? Many thanks.
Ray? VK3JH
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All compiles fine under 1.8.9... the updated libs in 1.8.13 seem to cause bloating...
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What version of Arduino are people using to compile this ?
Thanks!
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Re: D hole plate to fit SO-239 bulkhead hole - SO-239 to BNC conversion
Dale,
Correct save for NOS abounds and also poor quality copies.
Its more be wary and careful.
?
Allison
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No direct email, it goes to bit bucket due address harvesting in groups.IO
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Bob,
Mounting from the back side was only part of a complete mod.? Do only partial
and you get poor result.? Basically for that iteration a half fast fix was not a fix at all.
See the wiki for the fix and wiring plus the code patch to take advantage of it.
Also if you burnt the tracks off that give you head start.
If you still burning off tracks investigate a better tool and or soldering skills.
The Mod I wrote up for V3.?
By V4,? V5, and 6 it was incorporated into the board layout.? We have a Wiki
here for history and knowledge.
Allison
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No direct email, it goes to bit bucket due address harvesting in groups.IO
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Found it,? installed it, and it works great.? Thanks again. -- Lee - N9LO? "I Void Warranties"
?
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Tried to compile this on 1.8.13 and....
"C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr/bin/avr-size" -A "d:\\tmp\\arduino_build_194091/ubitxv6.ino.elf"
Sketch uses 30754 bytes (100%) of program storage space. Maximum is 30720 bytes.text section exceeds available space in board
?
Global variables use 819 bytes (39%) of dynamic memory, leaving 1229 bytes for local variables. Maximum is 2048 bytes.
.... so close and yet so far. Any ideas for shaving off a few bytes ?
Thx!
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I suggested mounting the relays on the opposite of the board's ground plane as you say back in the days of the V4 and I remember someone trying it. The results from him was it provided no great improvement as far as meeting FCC requirements, at that time.
Please let us know if this does provide an improvement since the board for the V3 and the V4 may not be exactly the same.
This would also mean making sure the four corners of the board are mounted to a metal box, for example, to make sure the ground plane is indeed at an effective ground for the RF signals and possibly ensure a better overall ground.
Bob ¡ª KK5R
On Wednesday, July 8, 2020, 2:50:31 PM EDT, Mark - N7EKU <n7eku@...> wrote:
Hi Ken,
I did Alison's changes for the relays on my v3.? It might work well for you, as with the relays mounted on the bottom side, their pins all end up on the top side where most of the traces are.? I can upload pictures of my board if you want.? The work will require changes to the raduino code afterwards.
73,
Mark
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Ted
Lee
Bob Lunsford