Author Topic: PAW noise on radio (SOLVED)  (Read 266 times)

rogellis

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PAW noise on radio (SOLVED)
« on: May 15, 2019, 05:15:59 pm »
The new Rosetta is up and running, and providing a lot of RF noise on the radio, so that I need full squelch to stop it.

I did suspect it was coming down the charging lead into the radio, so I disconnected the charger and the noise remained.  So the interference is definitely airborne RF.  (I can hear the standard PAW ‘signature buzz’ on the radio speaker.). 

In fact, the radio will pick up the buzz if I put the antenna anywhere near the power cabling to the PAW.  So the RF is being transmitted by the power leads to the PAW.

I covered the PAW unit with bacofoil, to no effect.    I took off the PAW antenna, to no effect.   I also tried a ferrous core on the PAW power leads, to no effect.  But turning off the PAW does stop it.


It seems I need some kind of suppressor on the power leads.  Would something like the following be effective?  And which lead should it go on, the +ve, the -ve, or both....?

https://www.ebay.co.uk/itm/12V-CAR-AUDIO-NOISE-FILTER-HUM-KILLER-ENGINE-REMOVAL-SUPRESSOR-POWER-WIRE-SOUND/202630119474?hash=item2f2db24032:g:GaIAAOSw7D1cSJm4


Thanks,
RE






« Last Edit: May 15, 2019, 11:22:43 pm by Admin »

Paul_Sengupta

Re: PAW noise on radio
« Reply #1 on: May 15, 2019, 05:20:39 pm »
What are you using to power the PAW?

Admin

Re: PAW noise on radio
« Reply #2 on: May 15, 2019, 05:21:07 pm »
Hi Roger

Can you please post information on the Following
1. Power lead used
2. Power supply used
3. Screenshot  of the Home Page (after noise has been observed)

Thx
Lee
« Last Edit: May 15, 2019, 06:25:56 pm by Admin »

Ian Melville

Re: PAW noise on radio
« Reply #3 on: May 15, 2019, 05:55:58 pm »
I think this says it all. Buck converts can be as noisy as f... er, as noisy things can be.  ;)

Regards power supply, I bought the following from Ebay......

12V to 5V 3A 15W USB DC-DC Buck Converter Charger Step Down Module Power Supply

This is a very lightweight in-line unit, and seems to give the 3 Amp it claims. Just chop off the USB connector, and go. 

RE

Paul_Sengupta

Re: PAW noise on radio
« Reply #4 on: May 15, 2019, 07:41:13 pm »
Ah, if it's the CPT one, they're terrible for noise!

I made a comment here. I haven't tried these personally but there's a different one that someone on the forum recommended.

http://forum.pilotaware.com/index.php/topic,873.msg11320.html#msg11320

Paul_Sengupta


rogellis

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Re: PAW noise on radio
« Reply #6 on: May 15, 2019, 08:06:13 pm »
.
The problem is the DC converter.    With the buck converter the interference goes out to 1.0m, but with the Anker it only goes out to 0.15m.  (Number 6 on the squelch).

The problem is that I cannot have a car cigarette lighter holder and an Anker converter in a lightweight glider, as it will weigh more than the aircraft. 

Is there a lighter option?

R

exfirepro

Re: PAW noise on radio
« Reply #7 on: May 15, 2019, 09:44:39 pm »
Rob,

If you are interested in something lightweight and ‘clean’ (RF wise), take a look at the various versions of ‘Charge 2’ - The spec quotes 96g for one version - see  https://charge4.harkwood.co.uk/ OK they are a bit more expensive, but totally reliable in my experience. I have been using the 4-port version in my flexwing for 3 years now and know of loads of others using both the 2 and 4-Port versions.

Regards

Peter

Paul_Sengupta

Re: PAW noise on radio (SOLVED)
« Reply #8 on: May 16, 2019, 10:05:41 am »
There's a different DC-DC converter recommended in the links above.

If you want to use an Anker cigarette lighter adaptor, you can take it apart and hard wire it in. Someone on here has done that:
http://forum.pilotaware.com/index.php/topic,1428.0.html

Ancien

Re: PAW noise on radio (SOLVED)
« Reply #9 on: May 16, 2019, 01:47:53 pm »
Roger
For a lightweight option there's this:

https://www.amazon.co.uk/HitCar-Converter-Charger-Inverter-Recorder-Micro-USB-Left-Angle-3Meters/dp/B071KPF75F?psc=1&SubscriptionId=AKIAILSHYY

All I can say is that I have used this [hardwired to a CB] for nearly two years without any problems or interference. You can choose the angle of the micro USB to suit your setup.
I ran it for several days in my workshop before installing it and had no dropouts.

Good luck.
Bob

exfirepro

Re: PAW noise on radio (SOLVED)
« Reply #10 on: May 16, 2019, 04:38:59 pm »
Roger
For a lightweight option there's this:

https://www.amazon.co.uk/HitCar-Converter-Charger-Inverter-Recorder-Micro-USB-Left-Angle-3Meters/dp/B071KPF75F?psc=1&SubscriptionId=AKIAILSHYY

All I can say is that I have used this [hardwired to a CB] for nearly two years without any problems or interference. You can choose the angle of the micro USB to suit your setup.
I ran it for several days in my workshop before installing it and had no dropouts.

Good luck.
Bob

Glad to hear your converter is working Bob, but in my experience these things can be a bit ‘hit or miss’. OK if you get a good one but others can be noise machines. Also for anyone else tempted to try this route, - I just checked the ad link and two of the options are listed as ‘Mini-USB’ which won’t fit the PAW, so be careful what you order.

Best Regards

Peter

rogellis

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Re: PAW noise on radio (SOLVED)
« Reply #11 on: May 17, 2019, 01:49:38 pm »
.
Anyone else had experience of the converter Bob highlighted.?   It looks like a good option, if it works.

Couple of other points:

I complained to Anker, and they are now contemplating making an in-line version of their quality (cigarette lighter) converter.  I hope they do.    Perhaps others could complain to them, to show there is a market.

If not, I was thinking of wiring the back of the cigarette lighter, and covering it with a shrink-tube end-glove.  It would look semi-professional.   I did try breaking open the last one, but they are too well made for that - it took a lot of drilling to break it open.


One last observation.   Every other instrument I have bought for the glider can tolerate a voltage of between 6v and 20v, so you do not have to worry about power supplies.  The only fussy eater out of all those units, is the PAW.

Roger

Admin

Re: PAW noise on radio (SOLVED)
« Reply #12 on: May 17, 2019, 03:51:19 pm »
...
If not, I was thinking of wiring the back of the cigarette lighter, and covering it with a shrink-tube end-glove.  It would look semi-professional.   I did try breaking open the last one, but they are too well made for that - it took a lot of drilling to break it open.

Did you see this ?
http://forum.pilotaware.com/index.php/topic,1428.msg16227.html#msg16227
thx
Lee

rogellis

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Re: PAW noise on radio (SOLVED)
« Reply #13 on: May 17, 2019, 08:46:53 pm »
Ok, thank Lee, a slightly better way of doing it.   If my soldering skills are up to it (without dropping solder into the unit...!)

R



rogellis

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Re: PAW noise on radio (SOLVED)
« Reply #14 on: May 17, 2019, 08:55:41 pm »
Talking of radio RF interference...

Another source of radio interference is the 12-9v DC converter that runs the radio.   Again a cheap Chinese job.   

I tried a strip-down of the (much better) original DC converter that came with the radio, but you have to be so careful about anything touching the coil inside it, as that immediately gives radio hiss.

Going back to the cheapo unit, if I hold the outgoing wires from the DC converter, all hiss stops (repeatable 100%).  But I don’t think me holding the wires is a long term solution. 

I tried a ferrous ring, but no difference.  So I spanned the two wires with a 1,500 ohm capacitor, and that stopped most of the hiss.  Not as good as me, as a suppressor, but nearly there....

Is there anything better I can use, to stop the hiss by the electrical feed?   A decent DC converter would be nice, but cannot find one in that 12-9v range.

Cheers,
R