Best on the move GSM,CDMA

Just that your original question struck me at first a bit unclear. Differences between driving, boating and in a plane?

I first imagined driving a car around small racetrack (all within range of the same tower)at the fastest speed possible. Or the same with a boat. I assumed that your question was about cell to cell tower handoffs and not how fast one is moving, less you are travelling really fast

 

For General Aviation there's a few things to consider:
A GSM phone will give you that GSM type sound/interference with your radio and also play games with your GPS(it has happened to me), but CDMA does NOT. CDMA's problem, flying high above a city, would be the phone seeing too many PN offsets and not knowing which one to use when you try to initiate a call so call connect times might be long.

 

No, moving high and fast on CDMA doesn't mean you will get dropped. I've held calls flying over urban areas on CDMA without a problem, but like I said, connecting might sometimes create a problem if you're seeing too many PN offsets. My Moto does much better in those situations than my old LG
GSM never affected my VOR from what I remember, the only thing it affected was my radio with that GSM type sound even once in a while when the phone was not in use, and it sometimes messed with my GPS. CDMA never did any of that. The only CDMA problem I sometimes have is connecting the call.

 

YOur experience with GSM dropping more calls than CDMA in your area when driving has nothing to do with the technology, but rather with how the networks are set up. That specific GSM network in your area has some things it seeds to straighten out- whether the dropping of calls happens because of capacity issues or because of coverage.

And your background noise observations are correct, that's the CDMA vs. GSM difference.

 

Personally I've had really good luck with CDMA -- as long as I'm in a well covered area -- I drove to the airport the other day (in Phoenix - about a 30 mile drive for me...) while talking to a friend of mine -- No breakups or distortion at all.

Yeah, the whole GSM speaker/radio thing really sucks -- One reason CDMA is better lol...

I would imagine that the GSM radio bug would interfere most with VOR/COM radios... it may also interfere with 121.5/406mhz ... Which would really suck if your ELT couldn't transmit because of interference (or if the FSS couldn't do a DF steer - though those aren't really done too much anymore thanks to GPS.)

 

It sounds like you have discovered what my avionics textbook calls "propeller modulation". It was something to watch out for on NAV radios, and could be altered (and confirmed) by varying the RPM of metal props. It's a mechanical interence, rather than electronic or electrical.

Think about how old fighter aircraft have body mounted machine guns, firing through the propeller, without shooting off the prop tips. The trigger has to be inhibbited as a prop blade passes in front of the muzzle. At 1500 RPM with a two bladed prop, a tip goes by over the engine cover 50 times a second.

The GSM handset is transmitting 217 times per second, and it's not synced to the prop at all. Sometimes all's clear, sometimes a pulse is blocked, and sometimes pulses are reflected through divergent multiple paths (partially cancelling at the cell site antenna for a weaker signal). lt's not surprising you had a call drop; and the further the handset's antenna is from the prop, the smaller this effect will be. (A rear seat passenger would have a better chance of completing a call in progress.) Loss of pulses degrades the connection.

Makes sense?

COtech

 

Yes, could have been anything. Next time have a call going, turn on XPONDER first before engines, and see. Transponders receive on 1030 and reply on 1090 MHz, so that doesn't seem close to either cellular or PCS bands.

The prop modulation would still put holes in CDMA's continuous bitstream, by blocking and reflecting. More than could be error corrected, so the call drops.

I started flying myself then too, in 1975 through about early 1980. Made PP-SEL, about 150 hours, started instrument instruction. I WANT a Grummen American Tiger AA-5B (will accept Cheetah AA-5A)--fastest, cleanest non-complex aircraft made, IMO (have 15 hours in it). In 1980 I married and started buying a house. Still married and nearly paid for! Youngest child is a college senior, likely going on to phamacy school. I will resume flight, at least at the ultralight level, soon. No telling what it will take to get a duplicate Airman's certificate in this age from our FAA.

I did get my first computer in 1978, rationalizing that electricity was cheaper than AVgas. 1974, we were looking at the prices and datasheets of the Intel 8080A chipset, or the Motorola 6800 set, or the MOS Technology 6502 family, and saying "this is neat stuff!".

COtech