Topics

Noisy Pi4 - particularly on 2m


N5XMT
 

I picked up a pack of 4 adjustable 5A Buck converters off Amazon for 14 bucks  12v in, adjusted the output to 5.2V.  One I ran a USB-C cable from it to the Pi4 for power, the other 3 I ran the buck converter to the 5V GPIO pins for power.  All 4 are working great


On Wed, Jun 3, 2020 at 10:23 AM Tadd KA2DEW in NC via groups.io <tadd=mac.com@groups.io> wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  

Would it be worth $40 to have a 3 Amp linear supply through-hole KIT that does the above?  I have a schematic for a circuit to do this and handle charging, switchover, and relay protect for a GelCel UPS and early protection alert to Raspberry PI when the battery is getting close to damaging itself.  WN8P did the schematic.  We’re pondering making and selling PCBs (for cost via ETSY) and publishing a bill-of-materials for builder purchase from DigiKey.  

The design seems expensive.  I’m just wondering if it is worth it.  The cost includes the heat sync but no housing or Gel Cel.   Dunno.  It seemed a good idea at the time.  I can do really good kit building instructions. See this page: 


  KA2DEW

On Jun 2, 2020, at 8:33 PM, Chuck M via groups.io <cam51mail@...> wrote:

I've done that as well.  On pi3 tweaked the voltage until lightning icon stayed home.

Thingiverse has various case designs for them depending on model.  Also designs to make inline fuse holder.

Can also get something like this:

KD9DVB


On Tue, Jun 2, 2020 at 7:34 PM, nb7o
<khedgepe@...> wrote:

Another solution, that I use here, is to buy a dc-dc voltage converter.  I have a 12v to 5v dc-dc converter with a usb connector on the 5v side.  I have Anderson power poles on the 12v side and I plug it into my 50a 12v power supply.  The DC-DC converter I have provides 3a of power to the PI which also helps with low voltage conditions on the pi.

 

Seven three de kevin/NB7O



David Ranch
 


The one thing I haven't had much luck on is finding metal cases that support expansion to support one or two or three HATs, WITH a fan.  To me, something like this really needs a side-draft mounted fan to get the air movement to the CPU.  I've found these but not using ideally ferric metals (steel... not aluminum or plastic).

--David
KI6ZHD


On 06/02/2020 03:29 PM, John D Hays - K7VE wrote:
We have found that placing the board and any HATs in a faraday cage (metal case) solves on board problems.


 

Had one ham take his board and hat and wrap their plastic case in foil and it helped. 

On Wed, Jun 3, 2020 at 2:40 PM David Ranch <rpi4hamradio-groupsio@...> wrote:

The one thing I haven't had much luck on is finding metal cases that support expansion to support one or two or three HATs, WITH a fan.  To me, something like this really needs a side-draft mounted fan to get the air movement to the CPU.  I've found these but not using ideally ferric metals (steel... not aluminum or plastic).

--David
KI6ZHD


On 06/02/2020 03:29 PM, John D Hays - K7VE wrote:
We have found that placing the board and any HATs in a faraday cage (metal case) solves on board problems.



--
John D. Hays
Kingston, WA
K7VE

 


Ray Wells
 

$0.02 worth of comment.

I'd suggest that the output should be adjustable to near 5.2V (the USB spec allows for 5.25V) to compensate for USB power cable loss. My RPi4 is powered from a 12V battery source via a 5A SMPS with just a 6" lead to power the Pi. At 5.1V (measured at the SMPS output under load) the Pi was giving under-voltage messages but at 5.2V it hasn't complained once. Even my old RPi model Bs needed more than 5.1V into the USB power lead if they were to be reliable, and none of my units, model B or RPi4, work hard - all headless with very low cpu loads. If only the RPi Foundation had provided a barrel socket for power, sigh!

Ray vk2tv

On 4/6/20 3:23 am, Tadd KA2DEW in NC via groups.io wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  



 

I agree.  5.1 may be too low.  5.0 is very low for.a Raspberry pI 4B

On Jun 3, 2020, at 6:08 PM, Ray Wells <vk2tv@...> wrote:

$0.02 worth of comment.

I'd suggest that the output should be adjustable to near 5.2V (the USB spec allows for 5.25V) to compensate for USB power cable loss. My RPi4 is powered from a 12V battery source via a 5A SMPS with just a 6" lead to power the Pi. At 5.1V (measured at the SMPS output under load) the Pi was giving under-voltage messages but at 5.2V it hasn't complained once. Even my old RPi model Bs needed more than 5.1V into the USB power lead if they were to be reliable, and none of my units, model B or RPi4, work hard - all headless with very low cpu loads. If only the RPi Foundation had provided a barrel socket for power, sigh!

Ray vk2tv

On 4/6/20 3:23 am, Tadd KA2DEW in NC via groups.io wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  




w2ttt
 

Tadd et al,

Try this

They come in 10A and 15A versions.

Also this

3A two USB A females.

73,

Gordon Beattie, W2TTT

201.314.6964

Get Outlook for Android





On Wed, Jun 3, 2020 at 7:59 PM -0400, "James Gordon Beattie Jr" <w2ttt@...> wrote:

Tadd et al,
Try this
They come in 10A and 15A versions.

Also this

3A two USB A females.

73,
Gordon Beattie, W2TTT
201.314.6964




On Wed, Jun 3, 2020 at 6:35 PM -0400, "Tadd KA2DEW in NC via groups.io" <tadd@...> wrote:

I agree.  5.1 may be too low.  5.0 is very low for.a Raspberry pI 4B

On Jun 3, 2020, at 6:08 PM, Ray Wells <vk2tv@...> wrote:

$0.02 worth of comment.

I'd suggest that the output should be adjustable to near 5.2V (the USB spec allows for 5.25V) to compensate for USB power cable loss. My RPi4 is powered from a 12V battery source via a 5A SMPS with just a 6" lead to power the Pi. At 5.1V (measured at the SMPS output under load) the Pi was giving under-voltage messages but at 5.2V it hasn't complained once. Even my old RPi model Bs needed more than 5.1V into the USB power lead if they were to be reliable, and none of my units, model B or RPi4, work hard - all headless with very low cpu loads. If only the RPi Foundation had provided a barrel socket for power, sigh!

Ray vk2tv

On 4/6/20 3:23 am, Tadd KA2DEW in NC via groups.io wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  




Chuck K4RGN
 

A reviewer reported 5.11 V at 1.0 A output and 5.02 V at 1.9 A with 60 mV ripple. He said that based on efficiency measurements, this device can’t sustain 10A continuous load because of internal heat buildup.

Another reviewer noted that the screw terminals aren’t large enough to accommodate the gauge wire for high currents. 

Other reviews reported 5.16 V at 5 A output... 5.2 V... four units at 4.6 V...

Chuck Till, K4RGN


 

Thanks Gordon.  We need at least 5.1V at the Raspberry Pi and prefer 5.2V regulated and reliable at the power supply.  
The best solution we have right now is a variable output DC supply with solder tabs to attach a USB socket.   I don’t like that solution, but it’s the best we have. 

On Jun 3, 2020, at 8:52 PM, w2ttt <w2ttt@...> wrote:

Tadd et al,

Try this

They come in 10A and 15A versions.

Also this

3A two USB A females.

73,

Gordon Beattie, W2TTT

201.314.6964

Get Outlook for Android





On Wed, Jun 3, 2020 at 7:59 PM -0400, "James Gordon Beattie Jr" <w2ttt@...> wrote:

Tadd et al,
Try this
They come in 10A and 15A versions.

Also this

3A two USB A females.

73,
Gordon Beattie, W2TTT
201.314.6964




On Wed, Jun 3, 2020 at 6:35 PM -0400, "Tadd KA2DEW in NC via groups.io" <tadd@...> wrote:

I agree.  5.1 may be too low.  5.0 is very low for.a Raspberry pI 4B

On Jun 3, 2020, at 6:08 PM, Ray Wells <vk2tv@...> wrote:

$0.02 worth of comment.

I'd suggest that the output should be adjustable to near 5.2V (the USB spec allows for 5.25V) to compensate for USB power cable loss. My RPi4 is powered from a 12V battery source via a 5A SMPS with just a 6" lead to power the Pi. At 5.1V (measured at the SMPS output under load) the Pi was giving under-voltage messages but at 5.2V it hasn't complained once. Even my old RPi model Bs needed more than 5.1V into the USB power lead if they were to be reliable, and none of my units, model B or RPi4, work hard - all headless with very low cpu loads. If only the RPi Foundation had provided a barrel socket for power, sigh!

Ray vk2tv

On 4/6/20 3:23 am, Tadd KA2DEW in NC via groups.io wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  





David Ranch
 


Hello Everyone,

I've had good luck with these units keeping up at 5.1volts @ 5amps and so far, they seem reliable and reasonably RF quiet but I put them in metal enclosures to help with any possible issues:

https://www.ebay.com/itm/XL4015-5A-DC-Buck-Step-down-Adjustable-Voltage-Power-Converter-w-LED-Voltmeter/142968844998?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D142968844998%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

It's a little bigger and while the display is nice, you don't need it once it's set.  It doesn't measure/display DC current


On the other hand, these similar units FAIL to keep 5.1v after only 500mA of current:

https://www.ebay.com/itm/2pcs-XL4015-5A-DC-Buck-Step-Down-Voltage-Converter-Constant-Current-Power-Module/152837387238?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D3%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D152837387238%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

This cheaper, simpler, smaller device says it uses the same buck components on it but it clearly doesn't perform.  Two units drop to 5.00v @ 2.47A according to a quality volt meter.  A Raspberry Pi might be tolerant of this t I agree with Mark, it's best to measure 5.1v at the GPIO pins of the Raspberry Pi.

--David
KI6ZHD




On 06/03/2020 11:26 AM, Mark Griffith via groups.io wrote:
There are lots of these modules around, some are better than others.  I have used some that output 5.15 volts consistently, and some just 5.0 volts.  Some have two micro USB connectors, some do not.  I have a few of these I use now that are very reliable.  eBay is a good place to find them.

I guess for $13 you get some and see what happens.  You can also afford to get a few as backups in case of failure.

In my shack, I use a West Mountain Radio PG40S power gate which takes 15 volts from an old Radio Shack analog power supply, and outputs about 14.8 volts to a Anderson Power Pole power block, and keeps a Type 27 deep cycle battery charged.  From the power block I use a few of these DC-DC step down modules to convert to 5.1 volts.  I have the same setup at my home (shack is in a different location) with a smaller battery to power the PiGate development devices and a radio.  If the power fails, the battery is switched in instantly and give me enough power to supply my PiGate RMS station for a day or so, or my home development site for about 12 hours.

There are lots of solutions.  Experiment!

Mark
KD0QYN



 



On Wednesday, June 3, 2020, 12:29:02 PM CDT, Tadd KA2DEW in NC via groups.io <tadd@...> wrote:


What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  

Would it be worth $40 to have a 3 Amp linear supply through-hole KIT that does the above?  I have a schematic for a circuit to do this and handle charging, switchover, and relay protect for a GelCel UPS and early protection alert to Raspberry PI when the battery is getting close to damaging itself.  WN8P did the schematic.  We’re pondering making and selling PCBs (for cost via ETSY) and publishing a bill-of-materials for builder purchase from DigiKey.  

The design seems expensive.  I’m just wondering if it is worth it.  The cost includes the heat sync but no housing or Gel Cel.   Dunno.  It seemed a good idea at the time.  I can do really good kit building instructions. See this page: 


  KA2DEW

On Jun 2, 2020, at 8:33 PM, Chuck M via groups.io <cam51mail@...> wrote:

I've done that as well.  On pi3 tweaked the voltage until lightning icon stayed home.

Thingiverse has various case designs for them depending on model.  Also designs to make inline fuse holder.

Can also get something like this:

KD9DVB


On Tue, Jun 2, 2020 at 7:34 PM, nb7o
<khedgepe@...> wrote:

Another solution, that I use here, is to buy a dc-dc voltage converter.  I have a 12v to 5v dc-dc converter with a usb connector on the 5v side.  I have Anderson power poles on the 12v side and I plug it into my 50a 12v power supply.  The DC-DC converter I have provides 3a of power to the PI which also helps with low voltage conditions on the pi.

 

Seven three de kevin/NB7O




N5XMT
 

don't trust the voltmeter on those!
Had a guy that was building a reef controller (leviathan) and using 2 of those.  one for the Pi, and another for 10v for PWM lighting control.  he set them both to the "proper" voltage according to the display on the converter.  with it all together, he powered it up and literally smoked his Pi.  display said 5V, he checked it after the smoke and it was actually putting out 11.5.
I purchased the ones of that same family without the voltmeter on them.  5A adjustable, and they work perfectly.  I set them with my DMM

On Thu, Jun 4, 2020 at 3:52 PM David Ranch <rpi4hamradio-groupsio@...> wrote:

Hello Everyone,

I've had good luck with these units keeping up at 5.1volts @ 5amps and so far, they seem reliable and reasonably RF quiet but I put them in metal enclosures to help with any possible issues:

https://www.ebay.com/itm/XL4015-5A-DC-Buck-Step-down-Adjustable-Voltage-Power-Converter-w-LED-Voltmeter/142968844998?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D142968844998%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

It's a little bigger and while the display is nice, you don't need it once it's set.  It doesn't measure/display DC current


On the other hand, these similar units FAIL to keep 5.1v after only 500mA of current:

https://www.ebay.com/itm/2pcs-XL4015-5A-DC-Buck-Step-Down-Voltage-Converter-Constant-Current-Power-Module/152837387238?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D3%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D152837387238%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

This cheaper, simpler, smaller device says it uses the same buck components on it but it clearly doesn't perform.  Two units drop to 5.00v @ 2.47A according to a quality volt meter.  A Raspberry Pi might be tolerant of this t I agree with Mark, it's best to measure 5.1v at the GPIO pins of the Raspberry Pi.

--David
KI6ZHD




On 06/03/2020 11:26 AM, Mark Griffith via groups.io wrote:
There are lots of these modules around, some are better than others.  I have used some that output 5.15 volts consistently, and some just 5.0 volts.  Some have two micro USB connectors, some do not.  I have a few of these I use now that are very reliable.  eBay is a good place to find them.

I guess for $13 you get some and see what happens.  You can also afford to get a few as backups in case of failure.

In my shack, I use a West Mountain Radio PG40S power gate which takes 15 volts from an old Radio Shack analog power supply, and outputs about 14.8 volts to a Anderson Power Pole power block, and keeps a Type 27 deep cycle battery charged.  From the power block I use a few of these DC-DC step down modules to convert to 5.1 volts.  I have the same setup at my home (shack is in a different location) with a smaller battery to power the PiGate development devices and a radio.  If the power fails, the battery is switched in instantly and give me enough power to supply my PiGate RMS station for a day or so, or my home development site for about 12 hours.

There are lots of solutions.  Experiment!

Mark
KD0QYN



 



On Wednesday, June 3, 2020, 12:29:02 PM CDT, Tadd KA2DEW in NC via groups.io <tadd@...> wrote:


What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  

Would it be worth $40 to have a 3 Amp linear supply through-hole KIT that does the above?  I have a schematic for a circuit to do this and handle charging, switchover, and relay protect for a GelCel UPS and early protection alert to Raspberry PI when the battery is getting close to damaging itself.  WN8P did the schematic.  We’re pondering making and selling PCBs (for cost via ETSY) and publishing a bill-of-materials for builder purchase from DigiKey.  

The design seems expensive.  I’m just wondering if it is worth it.  The cost includes the heat sync but no housing or Gel Cel.   Dunno.  It seemed a good idea at the time.  I can do really good kit building instructions. See this page: 


  KA2DEW

On Jun 2, 2020, at 8:33 PM, Chuck M via groups.io <cam51mail@...> wrote:

I've done that as well.  On pi3 tweaked the voltage until lightning icon stayed home.

Thingiverse has various case designs for them depending on model.  Also designs to make inline fuse holder.

Can also get something like this:

KD9DVB


On Tue, Jun 2, 2020 at 7:34 PM, nb7o
<khedgepe@...> wrote:

Another solution, that I use here, is to buy a dc-dc voltage converter.  I have a 12v to 5v dc-dc converter with a usb connector on the 5v side.  I have Anderson power poles on the 12v side and I plug it into my 50a 12v power supply.  The DC-DC converter I have provides 3a of power to the PI which also helps with low voltage conditions on the pi.

 

Seven three de kevin/NB7O




David Ranch
 


Hello N5XMT,

Agreed.. and when I said "volt meter", I meant "Fluke 75 DMM".  :-)  I would never trust those built-in volt meters but this one is pretty close being just 0.1v off.  On the unit with the display, it has a mode to adjust /correct the volt meter's measurement by 0.1v increments.  Nice but still not trustworthy in my book.  I also feel it's important to measure the final 5.1v at the +5v pin on the Raspberry Pi's 40pin header.  I don't recommend to measure it at the output of the power supply or it's "plug" cable as sometimes that entire chain can have a LOT of losses.   Once you measure 5.1 at the GPIO header, measure the voltage again at the power supply.  If it's much higher than say 5.3volts, you'll know you have a poor power connection!


Btw.. for those who care, was using the following device to create the various loads:

    https://elekitsorparts.com/product/digital-battery-capacity-tester-electronic-load-with-lcd-display-battery-meter

It's barebones but it's a nice way to load test batteries, power supplies, etc. and maxes out at 150 watts.


ps.  This is the same site that sells the new F5HDK NPR-70 modems ( https://hackaday.io/project/164092-npr-new-packet-radio ).  These units can sustain 50Kbps (and much faster) of TCP/IP traffic over 70cm amateur radio.  We now have a setup running in the Bay Area, CA and it's working well.  This fills in a gap where packet is too slow and Wifi mesh networks won't reach.  Check out the documentation to see what it is (and isn't) but none the less, a new toy for data nerds.

--David
KI6ZHD



On 06/05/2020 03:56 AM, N5XMT wrote:
don't trust the voltmeter on those!
Had a guy that was building a reef controller (leviathan) and using 2 of those.  one for the Pi, and another for 10v for PWM lighting control.  he set them both to the "proper" voltage according to the display on the converter.  with it all together, he powered it up and literally smoked his Pi.  display said 5V, he checked it after the smoke and it was actually putting out 11.5.
I purchased the ones of that same family without the voltmeter on them.  5A adjustable, and they work perfectly.  I set them with my DMM

On Thu, Jun 4, 2020 at 3:52 PM David Ranch <rpi4hamradio-groupsio@...> wrote:

Hello Everyone,

I've had good luck with these units keeping up at 5.1volts @ 5amps and so far, they seem reliable and reasonably RF quiet but I put them in metal enclosures to help with any possible issues:

https://www.ebay.com/itm/XL4015-5A-DC-Buck-Step-down-Adjustable-Voltage-Power-Converter-w-LED-Voltmeter/142968844998?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D142968844998%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

It's a little bigger and while the display is nice, you don't need it once it's set.  It doesn't measure/display DC current


On the other hand, these similar units FAIL to keep 5.1v after only 500mA of current:

https://www.ebay.com/itm/2pcs-XL4015-5A-DC-Buck-Step-Down-Voltage-Converter-Constant-Current-Power-Module/152837387238?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3764b6405b884841bf7d82ec84c3e719%26pid%3D100675%26rk%3D3%26rkt%3D15%26mehot%3Dpp%26sd%3D152947310464%26itm%3D152837387238%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A36341bc4-a6b4-11ea-bb45-74dbd1804293|parentrq%3A817cfefe1720aa6529494dcdfff17a5a|iid%3A1

This cheaper, simpler, smaller device says it uses the same buck components on it but it clearly doesn't perform.  Two units drop to 5.00v @ 2.47A according to a quality volt meter.  A Raspberry Pi might be tolerant of this t I agree with Mark, it's best to measure 5.1v at the GPIO pins of the Raspberry Pi.

--David
KI6ZHD




On 06/03/2020 11:26 AM, Mark Griffith via groups.io wrote:
There are lots of these modules around, some are better than others.  I have used some that output 5.15 volts consistently, and some just 5.0 volts.  Some have two micro USB connectors, some do not.  I have a few of these I use now that are very reliable.  eBay is a good place to find them.

I guess for $13 you get some and see what happens.  You can also afford to get a few as backups in case of failure.

In my shack, I use a West Mountain Radio PG40S power gate which takes 15 volts from an old Radio Shack analog power supply, and outputs about 14.8 volts to a Anderson Power Pole power block, and keeps a Type 27 deep cycle battery charged.  From the power block I use a few of these DC-DC step down modules to convert to 5.1 volts.  I have the same setup at my home (shack is in a different location) with a smaller battery to power the PiGate development devices and a radio.  If the power fails, the battery is switched in instantly and give me enough power to supply my PiGate RMS station for a day or so, or my home development site for about 12 hours.

There are lots of solutions.  Experiment!

Mark
KD0QYN



 



On Wednesday, June 3, 2020, 12:29:02 PM CDT, Tadd KA2DEW in NC via groups.io <tadd@...> wrote:


What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output).  Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B.  Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer.  Sockets are good.  
We’d further like this device to be $20 or less.  I’ve seen things which are really close to what we want for as little as a couple of dollars.  But close doesn’t count here.  It has to be 5.1 VDC and it has to be always on, and it has to take DC input.  

Would it be worth $40 to have a 3 Amp linear supply through-hole KIT that does the above?  I have a schematic for a circuit to do this and handle charging, switchover, and relay protect for a GelCel UPS and early protection alert to Raspberry PI when the battery is getting close to damaging itself.  WN8P did the schematic.  We’re pondering making and selling PCBs (for cost via ETSY) and publishing a bill-of-materials for builder purchase from DigiKey.  

The design seems expensive.  I’m just wondering if it is worth it.  The cost includes the heat sync but no housing or Gel Cel.   Dunno.  It seemed a good idea at the time.  I can do really good kit building instructions. See this page: 


  KA2DEW

On Jun 2, 2020, at 8:33 PM, Chuck M via groups.io <cam51mail@...> wrote:

I've done that as well.  On pi3 tweaked the voltage until lightning icon stayed home.

Thingiverse has various case designs for them depending on model.  Also designs to make inline fuse holder.

Can also get something like this:

KD9DVB


On Tue, Jun 2, 2020 at 7:34 PM, nb7o
<khedgepe@...> wrote:

Another solution, that I use here, is to buy a dc-dc voltage converter.  I have a 12v to 5v dc-dc converter with a usb connector on the 5v side.  I have Anderson power poles on the 12v side and I plug it into my 50a 12v power supply.  The DC-DC converter I have provides 3a of power to the PI which also helps with low voltage conditions on the pi.

 

Seven three de kevin/NB7O





Steve
 

As suggested by Brian N2KGC I have tried unplugging the HDMI cable, which made no change in the noise. My 5.1v power supply is one of these
https://ebay.us/a6eMV9
with 13.8v in from my shack 12v power supply
When swapped for a Belkin (reasonable quality?) wall wart also makes no difference.
What did make a difference was unplugging the trackball I use where it plugs into the keyboard.
Now I am looking for some ferrites but here again lies uncertainty. First port of call was RSOnline, here in the UK, where I am confronted by a selection of 1145 products which - ok - I can filter down to 155. but still, not wanting to choose almost at random on RS I found
https://ferrite-shop.com/ferrite-material/
which would appear to tell me I need #43 material but then, do I need to use rings instead of cable clamps. It looks like ferrite shop do not stock a #43 clamp - does anybody
I would really like to read around this subject a bit more; links to good sources of info would be appreciated.
73's and thanks

Steve
G4SDM

 


Randon Loeb
 

Is this a known issue with pi 4? I have a 3b+ in a 3d printed case that sits literally next to my radio and have no problems. That pi is connected with cat cable and audio to the radio.

Another 3b+ that runs the 3d printer sits a couple feet from the radio (i.e. no common grounding) and still no rf problems.


On Tue, Jun 2, 2020 at 1:59 PM Steve <steve@...> wrote:

Setting up for this evenings 2m UKAC I noticed the noise floor was around S8. The obvious suspect being the recentle added Pi. It was!
Not helped by the fact I have it in a perspex case. It's also very close to the rig
The plan is to put it in a metal case and do the same with the power supply - although I might also change that for a
https://uk.farnell.com/tracopower/txm-015-105/power-supply-ac-dc-15w-5v-3a/dp/2363846
Which are made to a slightly higher standard than the wall worts (or is it wart?) that are everywhere.
Thoughts on the above - please - alternative suggestions.
73's
Steve

G4SDM


Steve
 

As much as any noise in a modern shack goes. yes I'd say its a common issue, the noise source is always there. Whether it affects you is another matter, this depends on how your kit is laid out and what that kit is.
I have only just heard it on 2m - so now the challenge is to find out one which piece of wire is its transmitting antenna and apply my chokes thereto. My first line of attack will be the USB cables
I don't intend to start putting everything in metal boxes just yet.

Steve

G4SDM