I recently finished assembling my GB Ultimate ARF. Took it out for a test fly on a really rotten day (mid 40's, 25 mph wind, clouds). Did a range check with the engine (ST 90) off. Couldn't do one running as there was nobody else at the field. Everything checked out ok. Took off, and within 5 secs got a strong radio hit. Throttled back flew around for about 20 secs more and got another, so I landed.

Here's the question, I used the very convenient pre-installed antenna tube, even though it runs parallel to the metal pull-pull cables for the rudder. Yes, I knew that was a bad idea, but figured maybe they were smarter than me. Long story short, has anybody else experienced these kind of problems???? I did move the antenna but haven't had a chance to try it again yet.

I understand your concern, but my first instinct is that the problem lies elsewhere. I've used that scenario without problems. Start at the beginning and answer some of these questions. Is the Radio spank brand new, or not. Has it been aligned/tuned lately? Has it had a rough life? Are there any loose connections. I had a brand new NiMh pack with a loose wire on the positive terminal that acted like a hit, but was actually making intermittent contact during the flight. I was escared but made it back OK. Check some of these things and let me know_Bob

I have this same plane and although I changed a few things with the servo mounting I don't think the antennae issue your concerned about would be the problem with the exception of a couple of items.

If your antennae is flying out the back end and can possibly make contact with a control rod or make contact with metal clevises or control horns.

I have seen one flier in our club install his pull/pull cables in an x fashion. Never could convince him that's not the way it's done. Although I'm not any kind of electronic/radio expert the thought of two wires rubbing back and forth against each other isn't good for anything and the cable on that fliers' airplane were bare metal. Oh, he did crash it. Went out of control right after takeoff and on previous flights he always had radio glitches.

And lastly, as bob_nj stated loose connections will getcha. I have a Giant Aeromaster and before I flew it for the first time my radio was acting whacky. Everything was new when I installed the radio system and after going through it I found 3 servo leads had loose wires. When I replaced the bad leads my problems went away.

Hope you get it whipped.

I've had two of these ARFs (plus a kit version) and no radio problems. If not a direct radio hit maybe consider power line resonation or the like. I doubt the rudder cables were a factor unless you used a metal clevis on each end and a metal horn. Maybe invest in some rope for a tethered radio check. Vibration can show intermetent contact problems which otherwise go un-noticed until srash. What was the take off voltage of the flight pack? I did lose my first Ultimate to a battery failure. I do feel your pain, but simply put... There is a reason they call it the ULTIMATE. Get another if you believe you can.