35MHz RC radio testing

I’ve noticed recently that my 35MHz RC range is down to about 300-400 meters. I thought this can’t be right as I’ve had this same kit out over 800 meters. At least with 35MHz it’s easy to tell when it’s going bad, you can hold the transmitter up and turn for home. This is not a long range plane so I wasn’t expecting a problem.

I looked at the old Dynam TX; about 4 years old with a lot of hours on the clock and a few good drops. Frequency was good and power output was down slightly but still OK.

I then thought about interference as I’ve had this problem in Lower Hutt. So I tested with another “test receiver” that I set up ages ago for fpv testing. With a TX running at home I went for a drive around the valley. At car roof height it worked out to about 4.5KM; as far as I could go. So range is not a problem. This is also why “long-wire” radios can interfere with each other over quite long distances.

Oh crap; that leaves the receiver and plane. Is it the receiver or the plane interfering with the receiver? Fitted into the plane is a camera video transmitter, FMA Co-Pilot, LED controller and too much wiring (which is why I left it for last).

About an hour of testing later, I decided that the receiver was at fault. Maybe a few too many hard landings. It’s a Corona synthesized 8-ch. I have spares so I’ll test one and swap it over; this time with a soft foam mount.


I removed the receiver from the plane and tested it along side another and the test receiver mentioned above. They all appear to be about equal. This means that the problem is likely related to layout in the plane, including metal push-rods, carbon-fiber reinforcing and wiring, affecting the receiver antenna. I have installed a modified receiver that will work better with a longer antenna. This should help.

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