swr

If there are two radios on the same channel but one is a neg shift transmitter (Futaba) and the other is post shift (JR) turned on. Would that cause interferences to the Futaba receiver in that r/c plane if we are using PPM modulation in both transmitters?

dirtybird

My Feedback: (5)

Yes

swr

Why would that happen if the shifts are different?

s3nfo

My Feedback: (14)

Because shift only affects encoding, which side of the center freq the system looks at for reference. Freq is still freq.

If a country and western radio station and a hard rock radio station were transmitting on the same freq would they interfere with each other? Why, the format is different............(not a great analogy, but best I could do before coffee)

CP140

I'm a little fuzzy on the theory, but my understanding is that the carrier frequency is "shifted" away from the centre of the band in pulses to encode the information being sent to the receiver. Just because one shifts one way and one shifts the other way doesn't mean that there is no frequency overlap.

I'm sure somewhere a radio guru is cringing as he/she reads this and can give a better (more accurate?)explanation.....

smokingcrater

i've flown at a field with another guy who had opposite shifts... (not at the same time) anyway, the effect is much different the same shift interference. in fact, the the servos would NEVER twitch or do anything else that looked like interference, they would just stop working when the other tx was too close. (basically the same as you turning of your tx, most dual conversion rx's won't do anything)