Occasional Insanely Loud White Noise

[RichJordan]

Great news, glad you've got your issue fixed.

I don't think distance between PAW and the radio is causing the loud white noise - mine are about 6ft apart.

[exfirepro]

Great news Stu,

Glad you now have a fully working unit. Hopefully Lee will get to the bottom of what has been going on with your old unit, so we can learn more for the future. Pretty sure moving your unit and antennas will also have helped though.

Best Regards

Peter

[PaulSS]

I'm just glad it's not a problem with the Funke radio. I've got one of those on my shopping list and was beginning to suspect the interoperability between it and PAW but I'm now relieved those concerns are not valid 

[Ian Melville]

Has the issue been resolved for the original poster?

[RichJordan]

Hi.

I'm not sure what the next step is for me to resolve the issue on my PAW?

Thanks.

[Ian Melville]

The reason I asked was because there was a lot of whooping and high fives that Stu was up and running but the OP appeared not to be. Substitution would appear to be the next step, but only the PAW team can offer that. I wonder if there are any other PAW users near you?

[Admin]

Hi.
I'm not sure what the next step is for me to resolve the issue on my PAW?
Thanks.

Hi Rich

I will be taking a look at Stu's unit once returned to see if there is an issue.
I am still not totally convinced yet by one flight without interference
"one swallow does not a summer make... - Aristotle"

Rich, could you give us a full description of your installation, interconnect etc...

Thx
Lee

[sdkellner]

Rich - where are you?  If feasible I'd be happy to meet up and let you try my unit for a test flight.

Lee - my original unit was posted back to you yesterday; hopefully be with you soon, subject to the vagaries of Royal Mail.  I share your concerns about the risk of the problem returning; what gives me some hope is that the transponder link worked perfectly, for the first time in perhaps 20 flights, whereas everything else in the installation remained the same - this, for me, is a more convincing hint that there was a problem with my original unit.  And my interference-free flight was actually two flights  - perfect both there and back.

Best

Stu

[Admin]

Rich - where are you?  If feasible I'd be happy to meet up and let you try my unit for a test flight.

Lee - my original unit was posted back to you yesterday; hopefully be with you soon, subject to the vagaries of Royal Mail.  I share your concerns about the risk of the problem returning; what gives me some hope is that the transponder link worked perfectly, for the first time in perhaps 20 flights, whereas everything else in the installation remained the same - this, for me, is a more convincing hint that there was a problem with my original unit.  And my interference-free flight was actually two flights  - perfect both there and back.

Best

Stu

Hi Stu
2 flights is more encouraging 
I have also received your unit today
Many Thx
Lee

[RichJordan]

Hi Lee,

Any update on Stu's unit? Have you managed to reproduce the issue?

[Admin]

Hi Lee,

Any update on Stu's unit? Have you managed to reproduce the issue?

I ran it for 24 hours, and nothing!
Of course the differences are as follows :-

- Not connected to a transponder
although I did connect a USB/RS232 connector and configure as a transponder output, but nothing connected at the RS232 end

- Audio Connection difference
I had the audio out connected to a small amplifier - so impedences would be different

- Environmental
Clearly not in an aircraft, different power supply, not co-located to other RF sources (VHF, Transponder etc)


But no interference generated on any RF in the band from 108Mhz - 137Mhz

Thx
Lee

[JCurtis]

was he RF testing for radiated and/or conducted emissions?

These things are always awkward to diagnose, lots of interactions between items. More often than not it boils down to some kind of grounding issue somewhere.

[Admin]

was he RF testing for radiated and/or conducted emissions?

In Stu's installation he had PilotAware connected to a transponder (over USB/RS232) and connected to intercom ATR833 I think.
He was only experiencing noise on certain VHF frequencies and not at all times.

In my simple setup, I ran an SDR as a cheap spectrum analyzer.
I scanned the 108-137 Mhz range for 24 hours and picked up nothing, I did get some noise at 120mhz, but I had ran a 'control sample' without PilotAware powered up, which saw the same peak
you can see this earlier analysis here :-
http://forum.pilotaware.com/index.php/topic,873.msg10573.html#msg10573
The gain of the SDR was also pretty high at 38dB

This type of analysis is not one of my 'skillsets', and I know you have access to a pretty good spectrum analyzer Jeremy, maybe you could repeat the test ?

I think the point is that this was seen as happening infrequently at some point during the flight.
I am more inclined to believe this is a conducted issue rather than radiated.

Thx
Lee

[JCurtis]

I can do conduced testing, and now have a TEM cell for radiated testing.  The TEM cell is quite small though so may not get everything in, but it only needs to be the PAW connected to some serial devices and that would be easy enough to do.

If I get some time I'll hook up my PAW and give it a try to see what emerges.

I will be at an EMC test facility for a few days in the not too distant future, so will be comparing readings from my pre-compliance setup to theirs to give me a cross check.

[sdkellner]

Chaps

6 flights completed with my new PAW; almost 10 hours - and zero radio interference.

New PAW has performed almost faultlessly, with the only blip being an unprompted reboot on one flight.

I'm also getting reliable ADS-B out.

Best

Stu