9C Module Problems

[Chris Moon]

Jon:
    I saw this happen before at a contest, and asked my brother who is 
an RF engineer anout it.  He said it was either:
A) the transmitter overloading or "swamping" the front end of the 
receiver due to it being too close or the receiver out of tune.
B) spurious signals from the transmitter getting into the servo leads 
and causing garbage signals to the servos.

It is not a problem w/ the TX per se as it is PCM and if it was sending 
out  a bad data frame, it would be ignored by the RX.  The output of 
that particular TX module may be high enough to be causing the trouble.

Chris

JonLowe at aol.com wrote:

>All,
>I'm having a strange problem that I've traced to the frequency module in my 9C. While working on my pattern ship last nite, I noticed that when the elevator stick was moved rapidly, my two servos on elevator, using the ailevator function, did not always move together. This was most pronounced during rapid movement of the sticks, but occasionally happened during farily rapid, but more normal mvement rates of the stick. One servo or the other would significantly hesitate or jitter before moving. I then tried the rudder channel using a single servo, and at times that servo would hesitate or jitter prior to movement if the stick was moved rapidly, probably 50-60% of the time. Moving the sticks slowly essentially eliminated the problem, both on elevator and rudder. I also have a 9V transmitter on the same frequency (channel 16), so I set it up the same way, and the results were considerably better, both on elevator and rudder. Extreme rapid movement might cause something to happen, but probably less than 5% of the time. 
>
>I'm using TK modules in both transmitters (according to the Futaba site, TK are ok in both, but TP can only be used in the 9C, not the 9V). I swapped modules, and the problem followed the module. The 9C got better, and the 9V got worse. Swapping back repeated the previous problem. Extending or retracting the antenna or changing orientation or distance to the receiver antenna had no effect. 
>
>Both transmitters are in PCM mode, and everything else remained constant thruout the testing. The 9C is about a year old, and the TK module in question is only a couple of months old. 
>
>What is going on? I have not noticed glitching in flight, but I thought this might be contributing to problems I've been having with tracking during loops, as some correction might be fairly rapid. I acts like the module can't successfully transmit rapid changes in encoder output. Anyone else seen anything like this?
>
>Jon Lowe 
>  
>


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