Author Topic: Use of Mobile Phones in aircraft - CHIRP edition 92e  (Read 589 times)

neilld

Use of Mobile Phones in aircraft - CHIRP edition 92e
« on: June 08, 2022, 12:11:55 pm »
The latest CHIRP GA newsletter ( https://www.chirp.co.uk/ ) contains an item relating to use of mobile phones in aircraft and potential interference with other onboard electronic equipment (e.g. radio interference)
Have any issues been identified with iGRID during the test and validation process that we should be aware of?

DFN
« Last Edit: June 08, 2022, 12:22:02 pm by neilld »

Admin

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #1 on: June 08, 2022, 01:41:59 pm »
Hi Neil

We have been extensively testing this over the last 6 months, and have found no issues.
Can you post a link to the article ?

thx
Lee

steveu

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #2 on: June 08, 2022, 03:08:54 pm »
The latest newsletter is here, and the references start on page 4:

https://www.chirp.co.uk/upload/docs/General%20Aviation/Edition%2092%20eVersion%20May%202022.pdf

It's a response to an article on page 9 here:

https://www.chirp.co.uk/upload/docs/General%20Aviation/CHIRP%20GA_Feb%2022.pdf

Thing is, a lot of older certified stuff predates the newer rules on EMC, and wasn't ready for busts of RF energy at mobile frequencies.

At the risk of being dismissive, most people are flying with mobile phones on and not in airplane mode, so would see the problem even without iGrid.

AIUI, iGrid is just piggy backing off a mobile phone with data services running that's usually there anyway...

The only interference I've heard is when my headset lead runs over my mobile phone in a pocket separated only by a layer of cloth.
I now route the cable differently...

neilld

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #3 on: June 08, 2022, 04:09:37 pm »
Lee,
@steveu has beaten me to it with the full link.  My only comment would be that in the past, when I have forgotten to set my phone in flight mode, I have had interference on the radio when the phone is not in use (presumably some kind of "keep alive" signal.  With iGRID, when the phone is active all the time (or at least in "heartbeat" mode) will the situation get worse?  There may also be issues relating to age of avionic equipment, wiring layout, proximity of phone etc.
When our aeroplane gets back from its annual I will give it a try.

thanks
DFN

neilld

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #4 on: June 25, 2022, 04:16:31 pm »
Finally got a chance to try out the latest iGrid setup this week.  On first contact with ATC, on pressing the PTT buton I had a loud high pitched tone in my headset. After repeated attempts checking connections etc (and a ticking off from ATC) I switched the PAW off and the problem appeared to go away. I flew without the PAW but on returning to the airfield I reconnected everything as before and there was no issue so I assumed that the problem was elsewhere in our radio installation.
I have just tried to replicate the problem (at home on the ground) using the same setup (PAW,Tablet, Phone etc) but with a hand held radio (Yaesu FT-450) and have found that it is possible to replcate the high pitched tone as found in the aircraft.  I have not carried out any extensive testing yet but moving the phone around at varying distances from the rest of the equipment can produce or eliminate the noise.  Unfortunately there does not appear to be a relative (phone) position that guarantees no interference i.e holding the phone in a given position may or may not cause the interference.
Am I the only one who has experienced this & if not any guidance to resolve gratefully received?
Note:- I have used this PAW for a number of years without issue, the only difference now being the latest iGrid software and the WiFi dongle.
It is a PAW classic upgraded to Rosetta spec. by the fitting of a RPi Model 3.
I am using a Bluetooth receiver to connect to PAW for audio alerts.

neilld

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #5 on: June 27, 2022, 09:02:50 pm »
The only interference I've heard is when my headset lead runs over my mobile phone in a pocket separated only by a layer of cloth.
I now route the cable differently...
What was the interference you experienced? - continuous tone, intermittent, always present or only when transmitting?
I am getting a continuous tone when transmitting.

thanks

DFN

exfirepro

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #6 on: June 27, 2022, 11:00:06 pm »
Hi Neil,

I have now been testing / using iGRID since early November last year (7 months) without any issues whatever. Whilst I have noticed ‘white noise’ on a couple of very recent flights which has made radio reception difficult on certain frequencies, I’m pretty sure it wasn’t in any way related to my mobile phone or iGRID. In my case the interference only affected reception and stopped completely when I powered down my audio mixer, which feeds audio warnings from both PilotAware and SkyDemon on my iPad into my intercom. I suspect the problem may have been due to the unit’s batteries going flat, but haven’t had a chance to go back down to the airfield since to check this. When I manage to do so I will report my findings.

Best Regards

Peter

steveu

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #7 on: June 28, 2022, 11:40:31 am »
The only interference I've heard is when my headset lead runs over my mobile phone in a pocket separated only by a layer of cloth.
I now route the cable differently...
What was the interference you experienced? - continuous tone, intermittent, always present or only when transmitting?
I am getting a continuous tone when transmitting.

A low level set of digital pulses, as the RF from the phone interfered with the audio in the lead.

On someone else's aircraft, I've come across a continuous tone when transmitting because the aircraft battery has not recovered to a level where it powers the radio properly after starting. Fitting the radio with a battery charging from the aircraft overcame this short term issue, by guaranteeing a voltage level to the radio.

When the fault existed as described above, it was only on start up; on returning to the airfield after half an hour the squeal would be gone.

However, this is grasping at straws, but worth eliminating.

Is the PAW on the same switch as the radio?



exfirepro

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #8 on: June 28, 2022, 03:09:03 pm »
Hi All,

That obviously varies by aircraft (even between individual aircraft within any specific type or model). I changed to a Lithium Battery in my flex quite a while back - which considerably improves starting (it fired up immediately after lying dormant right through the first lockdown). Nonetheless, the initial voltage drop when engaging the starter can still cause PilotAware to drop out briefly and restart.

As I say, the effects will vary by aircraft, but I now only power up secondary systems after engine start. Obviously when operating from controlled airfields, you need radio to request engine start, but I suggest minimising all other secondary systems until your generator has come fully on line.

Regards

Peter

neilld

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #9 on: June 28, 2022, 04:02:55 pm »
On someone else's aircraft, I've come across a continuous tone when transmitting because the aircraft battery has not recovered to a level where it powers the radio properly after starting. Fitting the radio with a battery charging from the aircraft overcame this short term issue, by guaranteeing a voltage level to the radio.

When the fault existed as described above, it was only on start up; on returning to the airfield after half an hour the squeal would be gone.

However, this is grasping at straws, but worth eliminating.

Is the PAW on the same switch as the radio?

[/quote]
That sounds possible and would explain why the noise had gone away when I got back, however the aircraft has just come back from annual with a new battery.
I have limited (for limited read zero) knowlege of telecommunications, if low battery voltage was the issue, what causes the squeal?
My PAW is separately powered from a battery pack.

thanks

DFN

steveu

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #10 on: June 28, 2022, 04:42:12 pm »
On someone else's aircraft, I've come across a continuous tone when transmitting because the aircraft battery has not recovered to a level where it powers the radio properly after starting. Fitting the radio with a battery charging from the aircraft overcame this short term issue, by guaranteeing a voltage level to the radio.

When the fault existed as described above, it was only on start up; on returning to the airfield after half an hour the squeal would be gone.

However, this is grasping at straws, but worth eliminating.

Is the PAW on the same switch as the radio?


That sounds possible and would explain why the noise had gone away when I got back, however the aircraft has just come back from annual with a new battery.
I have limited (for limited read zero) knowlege of telecommunications, if low battery voltage was the issue, what causes the squeal?
My PAW is separately powered from a battery pack.


Sorry, my explanation left a lot to be desired.

Starting the engine takes a lot out of the battery, and it takes a little while for the charging to get aircraft electrics back to something like 13.8V to 14.4V, even when the battery is new. The low voltage doesn't supply enough juice to the radio, and it howls on TX where there's a large current drain. This is because a circuit in the radio is being run under the wrong conditions to modulate audio on the radio wave. One way to prevent this is to fit the radio, if a hand held, with a rechargeable battery that provides a cushion against drops in aircraft voltage. The radio runs off its own battery, charged from the aircraft but has a cushion/buffer in case aircraft voltage drops.

The easiest way to disprove this theory is to run the radio off its dry cell case with ordinary batteries in it, if the radio does not have a rechargeable battery supplied with it. At this point, the radio is decoupled from the aircraft power, so the fact that after starting, aircraft voltage is not full welly is taken out of the equation. If it still howls, then this is not the reason why.

If the radio is panel mount, disregard all the above.

One other thing to check is that there is no sidetone set on the radio, but this is usually an Icom problem and I think you said you had a Yaesu.

Admin

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #11 on: June 28, 2022, 05:32:48 pm »
Are there any voltage regulators involved here taking battery input and using switch mode regulators ?

neilld

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #12 on: June 28, 2022, 08:25:24 pm »
Thanks all for input
With hindsight, I think my issue is radio related and not PAW as noone else appears to have the problem.
Also there are a number of factors at play:-
Aircraft just back from annual
New battery (in aircraft)
New software and hardware in PAW
First use of mobile phone in aircraft
Curved ball from Chirp edition 92e
I think the last item may have generated some confirmation bias on my part.
I will be more methodical in troubleshooting next time I go flying.

thanks

DFN

exfirepro

Re: Use of Mobile Phones in aircraft - CHIRP edition 92e
« Reply #13 on: June 28, 2022, 09:38:30 pm »
Hi Again Neil,

Don’t beat yourself up with this. You were perfectly correct to report your concerns.

Yes we tested iGRID extensively over many months before release, so we could fully understand how it operates in the real world and find out if there were any significant issues. Thankfully, we didn’t find any, but with a relatively small range of aircraft / pilots / GSM devices / and networks, it isn’t outwith the bounds of possibility now that iGRID is out in the much wider community that we may still come across the odd issue.

The important thing is that we all keep an open mind and assess each report objectively to try to establish exactly what is going on, and if and how it relates to PilotAware.

Please keep us informed.

Best Regards
Peter