USB Power warning

[GrahamB]

My Classic arrived this morning and unusually for me I spent some time reading all the documents first. I noticed that on page 2 of the very useful "Start Here" document there is a picture showing "the Kit" which includes a 2-port usb cig-lighter plug in. Can I offer a bit of a health warning on these, I used one in my PA28 and (although I didn't connect it at the time) we started to get a load of problems with our radio. Almost at the point of giving it to the avionics engineers to fix when someone suggested that it may have been the usb power plug, it was. On test this turned out to be a fairly effective short range radio jammer under load.

The solution I implemented was to put a Charge2 power supply on both sides of the aircraft giving me 4 radio undetectable (as far as I am concerned), load protected ports.

Others may be lucky with the smaller usb plug-in units but if you do get interference start your investigations there, there is a good solution on the market.

[Admin]

Hi Graham

Thanks for the heads up, we have seen similar effects with the cheaper Adapters.
I think you get what you pay for is the important note here, a £1.99 adapter from China, will not be useful.

A good quality adapter is very important, I think reports of the Anker devices are favorable.
Other solutions are available

Thx
Lee

[gvpsj]

A common problem. Wire the gubbins up in a tiny metal box (Maplin etc.) and earth the case sorts it out and a lot cheaper that the certified stuff

[JCurtis]

A common problem. Wire the gubbins up in a tiny metal box (Maplin etc.) and earth the case sorts it out and a lot cheaper that the certified stuff

That can help with the radiated emissions, at the expense of potential overheating of the cheap chargers, they often run quite hot when anywhere near their rated capacity.  Some try and use the cigarette socket as a shield and a heat sink, which isn't much use.  The majority of them have horrendous conducted emissions too (that turn your wiring into an antenna for the interference, both supply and USB sides) as you don't have to test for that on battery powered chargers they just ignore it for the likes of CE compliance. 

Anything designed for use in aviation has very strict radiated and conducted emissions requirements, for obvious reasons.