I got bored staying home due to Covid-19 so I used Tinkercad to draw up these accessories.? The carrying handle doubles as a stand.? The knob inserts bulge up.? I attached the .stl files if you would like to print your own in your favorite color.  -- Lee - N9LO? "I Void Warranties"
?
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Analog signal processing questions
I've got some questions on my ever-evolving uBITX, specifically associated with some additional elements I've added to both the TX and RX audio lines.? (No schematics available at the moment, but will post later/if needed.)
RX audio:
I homebrewed a narrow CW audio filter using a TL974 op amp, powered with +5V from my regulator.? The CW filter is centered at ~700 Hz, with ~200 Hz bandwidth, and uses 3 sections of the TL974.? The 4th section of the TL974 is used as a line-out buffer for a separate line-out that goes to a rear-panel mounted RCA jack.? The input to the filter is connected to the VOL-H tap on the schematic, i.e. prior to the volume control.? The output of the filter is connected to a toggle switch to allow bypassing the filter; the output of the switch is tied both to (a) the top of the volume pot, as well as (b) the input to the line-out buffer.? So the line-out is NOT controlled by the volume control.
Issues/Questions:
(1) The filter passband appears to be about right.? I do notice, however, that as I tune a signal into the center of the passband, as it gets stronger I get some additional audible artifacts, almost a buzzing sound.? It appears to correlate to loudness... if I turn down the volume, it will go away, but then the overall volume of the signal is greatly reduced.? I will note that this is using the headphone output, which IS controlled by the volume pot.? Any thoughts on what could be causing this?? I will also note that signals will tend to move in and out of this artifact region, and when they do so, their volume changes (which is annoying).
(2) I use the ND6T RF AGC from kit-projects.? Where should I be taking the audio signal from to control the (RF) AGC?? Normally, it's from the top of the volume pot.? I actually soldered a wire from the volume side of R70 to the AGC.? But that means that my AGC can potentially be controlled by audio signals that are inside the IF passband of the crystal filter, but are outside the AF passband of the CW filter when it's in use.? Should I have the AGC input come from after the audio filter?
TX audio:
I also have a line-in signal on the back panel.? I've built a circuit with a TL972 op amp that I uses for two purposes:? (1) one section is used as a mic preamp (see ref A below), and (2) the second section is used as a simple active mixer to mix the mic input and the line input.? The output of the mixer is connected (via capacitor) to the MIC input on the uBITX V5 schematic.? These new circuits are all powered off full-time +5V from the regulator (not the TX DC line that powers the Q6 mic preamp).
Issues/Questions:
(3) I noticed that, even without pressing the PTT, if I speak into the mic, I hear the mic audio in my headphones.? I'm assuming this is because they are "always on".? However, I also assumed that, since the TX power to Q6 is disabled if the PTT is not depressed, that transmit audio would not get through.? Is this a bad assumption? Is this a normal effect of this circuit, or is it possible that I have too much mic gain now, that manages to push itself through Q6 even when TX is off?
Thanks for any input you can provide!
Rob KC4UPR
Ref A: http://rason.org/Projects/hbmic/hbmic.htm
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A Swedish homebrew uBITX made in Dubai
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Re: The 1926 ?bitx of my great father
Please don't destroy that receiver.? It's part of radio history?? Restore it.
I would bet it was a kit.? And almost all of those radios used 01A tubes or the equivalent. ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Peter LB0K
Sent: Saturday, July 11, 2020 7:08 AM
To: [email protected]
Subject: Re: [BITX20] The 1926 ?bitx of my great father ? Hi Gerard
I would like to echo Michael's comment about pulling apart an ANTIQUE receiver that looks to be relatively whole. Your Grandfather's old wireless receiver would go well in the collection at the Bergen Broadcasting station () There we have two transmitters (one delivered from Germany and one from England in 1936-7), and a fairly wide selection of receiver sets, mostly from after 1945.?
This receiver does have some intriguing details that I'd like to find out more of. ? Could you find it possible to take more pictures of the receiver, of the top and inside from several angles; of the two handles on the front,? from the back, if that has any details.?
Also interesting would be info about the valves or tubes if any are still fitted, a manufacturers label or mark, size etc. etc.? and if you could send these to me off the list I will be grateful. I beg understanding for using this list for a reply, it is after all very seldom one sees any untouched examples of these antique wireless receivers.
Having apologised I can now go back to modifying my uBITX,
LB0K -? Peter ?
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This email has been checked for viruses by AVG antivirus software.
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--
¡_. _._
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Re: Building a 12V Supply Board
The best way to prevent noise is to use a linear regulator as you only have to flatten out the 60 hz line noise and prevent rf from the radio getting back into it.
As far as the raduino goes, it uses the 7805, a linear regulator and is by nature quiet.? If you are concerned about heat add a heat sink.? You might consider a couple diodes in series rather than a resistor.?
Other regulators in the radio include the arduino, as well there is another 7805 to control the bias of the drive MOSFETs.
all the best
Dave
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Re: Building a 12V Supply Board
You can use a 7808 or 7809 between the 12/13.8V and the 7805 to split the dissipation
The AMSRO1-7805 does 36V, the VXO7805 does 36V as well unless you set it up for -5V output (not what we want here.) These are a PC board with parts attached to make a switching module, they're not quite identical to a usual TO-220 plastic blob with metal tab but pretty close; Just insulate it from the heat sink, which isn't a bad idea with any regulator, to prevent shorting it out. Datasheets are always easy to get (though for new folks, understanding them may require some hairpulling, screams of dismay, etc., just ask on the list though and someone will help interpret.)
For an example of what they look like, see and though that one doesn't appear to need a heat sink - Still I'd put 0.1 uF caps on input and output and (overdoing caps is a thing for me, cheap and prevents some problems) probably 10 uF caps both places as well. They changed things since my last order, it happens!
Mark
On Saturday, July 11, 2020, 06:11:41 PM PDT, Bob Lunsford via <nocrud222= [email protected]> wrote:
Mark, do the new replacement 7805's also have a max input voltage of 35V or is it capable of higher voltage? Also, are they in the same package?
Bob ¡ª KK5R
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mark ----- Forwarded Message ----- Sent: Saturday, July 11, 2020, 04:39:53 PM PDT Subject: Re: [BITX20] Building a 12V Supply Board
To get an efficient 12V to 5V regulator, you can look at the 7805 equivalent modules like the AMSRO1-7805 or the VXO7805, these are switching regulators so they are efficient but noisy so you might want to put them in a metal enclosure (a heat sink as part of the enclosure is a good idea) and put say a 10 uF and 0.1 uF capacitor right next to them, to reduce radiated noise. They are pretty much a drop-in replacement (double check that you have the pinout right though as otherwise you can let the magic silver-grey smoke out.)
You can search for such things on - They cost me $2 or so each, not lots more than a regular 7805, and I tend to install those in anything battery-powered as you get ~90% efficiency, which beats the heck out of the ~42% efficiency you get out of a stock 7805 run on 12V! Reminds me to buy a few more. I'm putting some into a couple always-on AC powered devices just to reduce power costs on AC.
Mark
On Thursday, July 9, 2020, 06:36:15 PM PDT, Bob Lunsford via <nocrud222= [email protected]> wrote:
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
|
Re: Building a 12V Supply Board
The AMSRO1-7805 does 36V, the VXO7805 does 36V as well unless you set it up for -5V output (not what we want here.) These are a PC board with parts attached to make a switching module, they're not quite identical to a usual TO-220 plastic blob with metal tab but pretty close; Just insulate it from the heat sink, which isn't a bad idea with any regulator, to prevent shorting it out. Datasheets are always easy to get (though for new folks, understanding them may require some hairpulling, screams of dismay, etc., just ask on the list though and someone will help interpret.)
For an example of what they look like, see https://www.digikey.com/product-detail/en/dcomponents/AMSRO1-7805-NZ/2721-AMSRO1-7805-NZ-ND and https://www.digikey.com/product-detail/en/cui-inc/VXO7805-1000/102-4258-ND/ though that one doesn't appear to need a heat sink - Still I'd put 0.1 uF caps on input and output and (overdoing caps is a thing for me, cheap and prevents some problems) probably 10 uF caps both places as well. They changed things since my last order, it happens!
Mark
On Saturday, July 11, 2020, 06:11:41 PM PDT, Bob Lunsford via groups.io <nocrud222@...> wrote:
Mark, do the new replacement 7805's also have a max input voltage of 35V or is it capable of higher voltage? Also, are they in the same package?
Bob ¡ª KK5R
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mark ----- Forwarded Message -----
From: M W <rd232d@...> Sent: Saturday, July 11, 2020, 04:39:53 PM PDT Subject: Re: [BITX20] Building a 12V Supply Board
To get an efficient 12V to 5V regulator, you can look at the 7805 equivalent modules like the AMSRO1-7805 or the VXO7805, these are switching regulators so they are efficient but noisy so you might want to put them in a metal enclosure (a heat sink as part of the enclosure is a good idea) and put say a 10 uF and 0.1 uF capacitor right next to them, to reduce radiated noise. They are pretty much a drop-in replacement (double check that you have the pinout right though as otherwise you can let the magic silver-grey smoke out.)
You can search for such things on https://www.findchips.com/ - They cost me $2 or so each, not lots more than a regular 7805, and I tend to install those in anything battery-powered as you get ~90% efficiency, which beats the heck out of the ~42% efficiency you get out of a stock 7805 run on 12V! Reminds me to buy a few more. I'm putting some into a couple always-on AC powered devices just to reduce power costs on AC.
Mark
On Thursday, July 9, 2020, 06:36:15 PM PDT, Bob Lunsford via groups.io <nocrud222@...> wrote:
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
|
Re: Building a 12V Supply Board
Mark, do the new replacement 7805's also have a max input voltage of 35V or is it capable of higher voltage? Also, are they in the same package?
Bob ¡ª KK5R
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mark ----- Forwarded Message -----
From: M W <rd232d@...> Sent: Saturday, July 11, 2020, 04:39:53 PM PDT Subject: Re: [BITX20] Building a 12V Supply Board
To get an efficient 12V to 5V regulator, you can look at the 7805 equivalent modules like the AMSRO1-7805 or the VXO7805, these are switching regulators so they are efficient but noisy so you might want to put them in a metal enclosure (a heat sink as part of the enclosure is a good idea) and put say a 10 uF and 0.1 uF capacitor right next to them, to reduce radiated noise. They are pretty much a drop-in replacement (double check that you have the pinout right though as otherwise you can let the magic silver-grey smoke out.)
You can search for such things on https://www.findchips.com/ - They cost me $2 or so each, not lots more than a regular 7805, and I tend to install those in anything battery-powered as you get ~90% efficiency, which beats the heck out of the ~42% efficiency you get out of a stock 7805 run on 12V! Reminds me to buy a few more. I'm putting some into a couple always-on AC powered devices just to reduce power costs on AC.
Mark
On Thursday, July 9, 2020, 06:36:15 PM PDT, Bob Lunsford via groups.io <nocrud222@...> wrote:
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
|
Re: Hello dear I am Dr. Aisha Gaddafi
This is SPAM that needs to be blocked...
On Saturday, July 11, 2020, 7:22:14 PM EDT, Dr aisha gaddafi <draishagaddafi92@...> wrote:
Hello dear I am Dr. Aisha Gaddafi
I am Dr. Aisha Gaddafi, the daughter of late Libyan president, am contacting you because I need a Partner or an investor that will help me in investing the sum of $27.500.000.00 USD in his or her country, the funds is deposited here in Burkina Faso where I am staying for the moment with my children as my husband is late, I would like to know your mind and interest towards the investment of the total sum mentioned Above, as my partner and beneficiary of the funds I want to inform you that you will receive 40% share of the total sum after the transfer of the said funds {$27.5 Million USD} is completed into your account, while the balance as my own share will be used for the investment in your country.
Please after reading this mail try and make sure you reply and contact me with this my private email address: { draishagaddafi92@...}
so that I will see your mail and reply you without delaying, please note once again that it is necessary that you reply me through this my private email address: { draishagaddafi92@...} if you really want me to see your respond and interest concerning the transaction Yours friend
Dr. Aisha Gaddafi.
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Re: Building a 12V Supply Board
FYI I used an LM2596 dc to dc converter to drop the 13.8 vdc from P1 to 5vdc It¡¯s rated to 3a. I use it to feed my TDA 2030a audio amp, my SSM 2167 mic preamp/compressor and theRaduino ?board.I bent the raduino1 pin 4 up so it doesn¡¯t set into the socket thus isolating the 13.8 supply from the raduino board.seems to work well. I did put a choke on the 5vdc output wire and I don¡¯t have a problem with RF noise.-- ?
73
Mick VA3EPM?
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Re: Building a 12V Supply Board
To get an efficient 12V to 5V regulator, you can look at the 7805 equivalent modules like the AMSRO1-7805 or the VXO7805, these are switching regulators so they are efficient but noisy so you might want to put them in a metal enclosure (a heat sink as part of the enclosure is a good idea) and put say a 10 uF and 0.1 uF capacitor right next to them, to reduce radiated noise. They are pretty much a drop-in replacement (double check that you have the pinout right though as otherwise you can let the magic silver-grey smoke out.)
You can search for such things on https://www.findchips.com/ - They cost me $2 or so each, not lots more than a regular 7805, and I tend to install those in anything battery-powered as you get ~90% efficiency, which beats the heck out of the ~42% efficiency you get out of a stock 7805 run on 12V! Reminds me to buy a few more. I'm putting some into a couple always-on AC powered devices just to reduce power costs on AC.
Mark
On Thursday, July 9, 2020, 06:36:15 PM PDT, Bob Lunsford via groups.io <nocrud222@...> wrote:
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
|
Building a 12V Supply Board
(Resending because when I reported that obvious SPAM about the 27 mil or whatever funds, I was auto-kicked from the group?! Weirdness. Very sorry if this is a repeat but guessing that my post was lost due to being booted. Weird.)
Mark ----- Forwarded Message -----
From: M W <rd232d@...> Sent: Saturday, July 11, 2020, 04:39:53 PM PDT Subject: Re: [BITX20] Building a 12V Supply Board
To get an efficient 12V to 5V regulator, you can look at the 7805 equivalent modules like the AMSRO1-7805 or the VXO7805, these are switching regulators so they are efficient but noisy so you might want to put them in a metal enclosure (a heat sink as part of the enclosure is a good idea) and put say a 10 uF and 0.1 uF capacitor right next to them, to reduce radiated noise. They are pretty much a drop-in replacement (double check that you have the pinout right though as otherwise you can let the magic silver-grey smoke out.)
You can search for such things on https://www.findchips.com/ - They cost me $2 or so each, not lots more than a regular 7805, and I tend to install those in anything battery-powered as you get ~90% efficiency, which beats the heck out of the ~42% efficiency you get out of a stock 7805 run on 12V! Reminds me to buy a few more. I'm putting some into a couple always-on AC powered devices just to reduce power costs on AC.
Mark
On Thursday, July 9, 2020, 06:36:15 PM PDT, Bob Lunsford via groups.io <nocrud222@...> wrote:
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
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Bora,
You have an incorrect file loaded for the v6 board.? The correct version is in the attached zip file on GitHub:
The uBITXV5 folder has the correct files for the v6 board as well.? You can use Xloader to load the hex file into the uBITX without going through the Arduino IDE.? I have not used the source code for the CEC software, so not sure which define statements you need to set in order to compile for a v6 board.? Just use Xloader and the?UBITXV5_CEC_V1.200_NX.hex file.? I am assuming that you have the Nextion display configured with the correct tft files.
73
Evan
AC9TU
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Hi all,
I use UBITX_CEC_V1.1_NX. hex for V6. But I can't found open code. My BFO fabrication setting 11.996.850Mhz. But I need an 11.050.00Mhz fabrication setting because of my SSB ladder filter 11.059MHz.
Please help
--
TB3EN From Turkey. Electronic Communication Technician, Member YM3KM.
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Re: The 1926 ?bitx of my great father
I would bet it was a kit. ?And almost all of those radios used 01A tubes or the equivalent. ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Peter LB0K
Sent: Saturday, July 11, 2020 7:08 AM
To: [email protected]
Subject: Re: [BITX20] The 1926 ?bitx of my great father ? Hi Gerard
I would like to echo Michael's comment about pulling apart an ANTIQUE receiver that looks to be relatively whole. Your Grandfather's old wireless receiver would go well in the collection at the Bergen Broadcasting station () There we have two transmitters (one delivered from Germany and one from England in 1936-7), and a fairly wide selection of receiver sets, mostly from after 1945.?
This receiver does have some intriguing details that I'd like to find out more of. ? Could you find it possible to take more pictures of the receiver, of the top and inside from several angles; of the two handles on the front,? from the back, if that has any details.?
Also interesting would be info about the valves or tubes if any are still fitted, a manufacturers label or mark, size etc. etc.? and if you could send these to me off the list I will be grateful. I beg understanding for using this list for a reply, it is after all very seldom one sees any untouched examples of these antique wireless receivers.
Having apologised I can now go back to modifying my uBITX,
LB0K -? Peter ?
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-- ¡_. _._
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Re: The 1926 ?bitx of my great father
Hi Gerard
I would like to echo Michael's comment about pulling apart an ANTIQUE receiver that looks to be relatively whole. Your Grandfather's old wireless receiver would go well in the collection at the Bergen Broadcasting station () There we have two transmitters (one delivered from Germany and one from England in 1936-7), and a fairly wide selection of receiver sets, mostly from after 1945.?
This receiver does have some intriguing details that I'd like to find out more of. ? Could you find it possible to take more pictures of the receiver, of the top and inside from several angles; of the two handles on the front,? from the back, if that has any details.?
Also interesting would be info about the valves or tubes if any are still fitted, a manufacturers label or mark, size etc. etc.? and if you could send these to me off the list I will be grateful.
I beg understanding for using this list for a reply, it is after all very seldom one sees any untouched examples of these antique wireless receivers.
Having apologised I can now go back to modifying my uBITX,
LB0K -? Peter ?
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Re: The 1926 ?bitx of my great father
Restore that fantastic piece of history. It would be a shame not to restore it and make it work. Just my 2 cents.
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Re: The 1926 ?bitx of my great father
Hate to see you destroy that piece of history for just the capacitors¡ ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of ³Ò¨¦°ù²¹°ù»å
Sent: Friday, July 10, 2020 1:27 PM
To: [email protected]
Subject: [BITX20] 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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I only have access to one of my calibrations for a v4.? It was 175000.
73
Evan
AC9TU
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Re: The 1926 ?bitx of my great father
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On Fri, Jul 10, 2020 at 11:57 PM ³Ò¨¦°ù²¹°ù»å < kabupos@...> wrote: 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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Lee
_Dave_ AD0B
Bob Lunsford
Mick
Bora G¨¹rb¨¹z
MadRadioModder