Need RF Quiet USB Power Source

Solution is a choke on the cable.

I have a New Trent model IMP500 battery pack, and it's a huge generator of RF noise. It's so bad it makes noise without even having a cable connected to it! It's why I started looking for a quiet 12 vdc to 5 vdc USB power source...

-John, Q3

On Thursday, June 26, 2014 10:41:39 PM UTC-4, wrote:
On Thursday, June 26, 2014 7:48:50 AM UTC-7, John Carlyle wrote:
Can anyone recommend a 12 vdc to 5 vdc USB power source I can use to charge an iPhone in flight that won't break squelch on my glider's radio?

-John, Q3

Take a look at the New Trent Power pak http://www.amazon.com/gp/product/B003ZBZ64Q. Use it myself to charge my tablet and IPHONE but can't speak about RF noise though

I've used...

eBay item number: 251278536206

... in the past.

Seem to be much quieter (RF) than the usual USB adapters for cigar
lighters

KN

At 12:36 27 June 2014, John Carlyle wrote:
I have a New Trent model IMP500 battery pack, and it's a huge generator
of
RF noise. It's so bad it makes noise without even having a cable
connected
to it! It's why I started looking for a quiet 12 vdc to 5 vdc USB power
source...

-John, Q3

On Thursday, June 26, 2014 10:41:39 PM UTC-4, wrote:
On Thursday, June 26, 2014 7:48:50 AM UTC-7, John Carlyle wrote:
Can anyone recommend a 12 vdc to 5 vdc USB power source I can use to
charge an iPhone in flight that won't break squelch on my glider's radio?


-John, Q3

Take a look at the New Trent Power pak
http://www.amazon.com/gp/product/B003ZBZ64Q. Use it myself to charge my
tablet and IPHONE but can't speak about RF noise though

Thanks, Kevin! I'll add that to Jon's Blue Sea recommendation.

The only drawback is that it doesn't say if it works with iPhones. They require some resistors to work, see: http://www.epanorama.net/newepa/2010...arger-secrets/ There are resistors at the USB end, so maybe it does work with Apple products.

-John, Q3

On Friday, June 27, 2014 10:22:09 AM UTC-4, Kevin Neave wrote:
I've used...

eBay item number: 251278536206

.. in the past.

Seem to be much quieter (RF) than the usual USB adapters for cigar
lighters

KN

On Friday, June 27, 2014 9:32:57 AM UTC-7, John Carlyle wrote:
Thanks, Kevin! I'll add that to Jon's Blue Sea recommendation.



The only drawback is that it doesn't say if it works with iPhones. They require some resistors to work, see: http://www.epanorama.net/newepa/2010...arger-secrets/ There are resistors at the USB end, so maybe it does work with Apple products.



-John, Q3



On Friday, June 27, 2014 10:22:09 AM UTC-4, Kevin Neave wrote:

I've used...



eBay item number: 251278536206



.. in the past.



Seem to be much quieter (RF) than the usual USB adapters for cigar

lighters



KN

Do you have the traditional iPhone connector, or the new one (little thing named Lightning)? Resistors will work for most devices that use the old connector, but may not for the new one. There are some protocols run on the data lines to determine whether the power supply is suitable for the device, and how much power it can supply. The tiny little Lightning connector has electronics in it to do this among other things.

Early on Apple used resistors prior to there being any agreed standard on USB as to how to do this. These methods are sort of grandfathered in, but the newer devices are much more sophisticated. I found some that work work occasionally but not always,etc. The better name brand stuff works all the time.

The Blue Sea version has an aluminum can around the whole thing. They make both a cigarette socket one and a panel mount - it looks to me like the panel mount is just the cigarette one with a plastic housing over it to make it mountable. I have taken apart several of the cigarette lighter adapters, most of them are an ultrasonic welded plastic housing without much shielding. EMI engineering is still a bit of a black art, a copper foil covering (drained to a low impedance ground) and chokes is a good place to start - but don't be terribly surprised if it doesn't solve the whole problem.

Powerwerx.com also sell the Blue Sea panel mount USB and a lighter plug version.
Jim

Thank you, Jon, for the suggestion to go with brand name stuff.

Right now I'm using an iPhone 4, but I will upgrade to either the 4.7" or 5..5" model rumored for Fall release. That's why the Blue Sea adapter you suggested earlier in the thread was so interesting to me, since it claimed to meet Apple specifications. I do understand that I might have to shield whatever I buy, but I've done that before so no worries.

Thanks, Jim, for the Powerwerx.com reference for Blue Sea.

-John, Q3

On Friday, June 27, 2014 2:11:08 PM UTC-4, jfitch wrote:
Do you have the traditional iPhone connector, or the new one (little thing named Lightning)? Resistors will work for most devices that use the old connector, but may not for the new one. There are some protocols run on the data lines to determine whether the power supply is suitable for the device, and how much power it can supply. The tiny little Lightning connector has electronics in it to do this among other things.

Early on Apple used resistors prior to there being any agreed standard on USB as to how to do this. These methods are sort of grandfathered in, but the newer devices are much more sophisticated. I found some that work work occasionally but not always,etc. The better name brand stuff works all the time.

The Blue Sea version has an aluminum can around the whole thing. They make both a cigarette socket one and a panel mount - it looks to me like the panel mount is just the cigarette one with a plastic housing over it to make it mountable. I have taken apart several of the cigarette lighter adapters, most of them are an ultrasonic welded plastic housing without much shielding. EMI engineering is still a bit of a black art, a copper foil covering (drained to a low impedance ground) and chokes is a good place to start - but don't be terribly surprised if it doesn't solve the whole problem.

John,

The basic problem is explained by several people above that these power converters* (converting 12vdc to 5vdc) use electronics that can emit high frequency noise which can be picked up by external devices like your ship's radio. The amount of noise is inversely proportional to the price you paid (less $$$ equals more noise).

Multiple people above mentioned adding a "choke" or "ferrite core" or "beads" (one and the same). Great idea. These keep the high frequency noise from getting onto the 12vdc bus and then into other devices.

But these will not help your problem as your external power pack is obviously not connected to the bus. The noise is getting into your radio through the air. This might indicate a poorly designed radio (Becker is one of the better brands) or your coax's shield isn't grounded correctly (check the BNC connector) or a cheap poorly designed external power pack.

Back to Ferrite Cores - You have probably seen some on your laptop's power supply as a thick oblong thingy molded onto the cord. The power wires are routed through these cores. They come in two varies; 1) a solid ring shape (torus) for new installations or 2) a snap on clamp style for retrofits. Route the power wires through at least twice. They are a good idea for all of your devices that connect to your ship's power bus. Here are some links.

http://www.k0bg.com/beads.html
http://en.wikipedia.org/wiki/Ferrite_bead
http://www.ebay.com/itm/5-Pcs-Black-...em418303 3af9

Good luck. Report back.

- John

* Old power supplies (converters) were "linear" and pretty dumb. Voltage regulation was difficult and they didn't easily handle varying voltage inputs. Any newer power supplies are "switching" and are a major step forward in technology. Pros: Much smaller, more efficient, able to handle multiple voltage inputs (like being able to use 110-220vac or 12-24vdc). Cons: the switching mechanism is high frequency and can be noisy. There is a switching power supply in the Oudie's power/data cable and seems to be very high quality and not very noisy.

http://en.wikipedia.org/wiki/Switched-mode_power_supply

Having a bit of searching for a battery pack, I found that several units
supply multiple DC voltages in addition to the 5v that everyone is
looking for. I believe it's that 9v or 12v up conversion that's causing
the RF noise. I'd suggest getting a 5v ONLY pack.

Dan Marotta

On 6/27/2014 5:59 PM, Six-Seven wrote:
John,

The basic problem is explained by several people above that these power converters* (converting 12vdc to 5vdc) use electronics that can emit high frequency noise which can be picked up by external devices like your ship's radio. The amount of noise is inversely proportional to the price you paid (less $$$ equals more noise).

Multiple people above mentioned adding a "choke" or "ferrite core" or "beads" (one and the same). Great idea. These keep the high frequency noise from getting onto the 12vdc bus and then into other devices.

But these will not help your problem as your external power pack is obviously not connected to the bus. The noise is getting into your radio through the air. This might indicate a poorly designed radio (Becker is one of the better brands) or your coax's shield isn't grounded correctly (check the BNC connector) or a cheap poorly designed external power pack.

Back to Ferrite Cores - You have probably seen some on your laptop's power supply as a thick oblong thingy molded onto the cord. The power wires are routed through these cores. They come in two varies; 1) a solid ring shape (torus) for new installations or 2) a snap on clamp style for retrofits. Route the power wires through at least twice. They are a good idea for all of your devices that connect to your ship's power bus. Here are some links.

http://www.k0bg.com/beads.html
http://en.wikipedia.org/wiki/Ferrite_bead
http://www.ebay.com/itm/5-Pcs-Black-...em418303 3af9

Good luck. Report back.

- John

* Old power supplies (converters) were "linear" and pretty dumb. Voltage regulation was difficult and they didn't easily handle varying voltage inputs. Any newer power supplies are "switching" and are a major step forward in technology. Pros: Much smaller, more efficient, able to handle multiple voltage inputs (like being able to use 110-220vac or 12-24vdc). Cons: the switching mechanism is high frequency and can be noisy. There is a switching power supply in the Oudie's power/data cable and seems to be very high quality and not very noisy.

http://en.wikipedia.org/wiki/Switched-mode_power_supply