Model Forum / Radio Controlled / Helicopters / July 2003

I've seen reports of mobile phones near transmitters causing this to happen.
But I've never believed them.

The most common reason for a radio to reset itself during flight is
old, well used, worn switches that will do a "make before break".
Because of the way the switches are wired in the Futaba TXs this will
instantaneously create a short circuit between the internal 5V and
ground power supply rails. Perhaps you should ask your friend if the
incident happened while he was toggling a switch.

Normally the TX will not read of write to the CAMPac unless changes
are made to the model program. However it is possible that the short
circuit corrupted the communication between the radio and the CAMPac.
The first four bytes in the memory (header) indicate if the CAMPac is
initialised and with what TX. If any of them is changed by a false
write then the TX will want to initialise the CAMPac again. However I
am sure that the TX asked for confirmation before resetting the model
programs in the CAMPac to MDL-9..etc and this takes quite some time to
complete as the write cycles to the CAMPac are fairly slow. So I am
sure your friend saw that the TX was re-initialising the CAMPac.

I would say that the whole event was a bad coincidence. If the CAMPac
header data were not corrupted the radio would have been functional
again within a couple of seconds.

Please don't blame mobile phones for everything bad that happens at
the field and you can't explain. Where do you think your phonebook
entries are stored in your mobile phone? Yes, both your phone, SIM
card and the new VISA smart cards have EEPROM memory identical to the
one used for CAMPac. So is your VISA card going to be useless if you
carry it with you together with a mobile phone?

Regards,
Angelos
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