How do you know this? Is the range check (with the antenna down) not doing well? (How far are you getting?) Something else?
| > thought it was a battery problem...
Low batteries don't usually cause poor range. Battery problems usually manifest themselves as the batteries not lasting very long -- but they usually work fine for at least a little while after being freshly charged. Long enough to do a range check, anyways.
| > Thought it might be the RX antenna, so I replaced it...no | > difference.
The RX antenna is just a wire -- of a specific length. If you replace it with something longer or shorter, you'll reduce your range. Unless it's been broken internally, it's not something you want to replace.
| > I'm convince now that it must have "slipped" out of tune. I will | > not trust it anymore.
It's prudent to not trust it. But if you really want to know what happened to it, you'll really need to send it to Airtronics and have it fixed. Even if they just replace it because they can't repair it, the prices are usually at most half the price of new equipment. (At least with other vendors -- I've never dealt with Airtronics personally.)
You could also bring your equipment down to the local club and ask them about it. I could probably help you narrow down what the problem was (receiver, transmitter, batteries, etc.) in a few minutes, and so I imagine somebody near you could do so as well.
| > Well, here are my choices: I have a new Futaba Skysport with my NexStar. | > I'm wondering if I should just buy a Futaba Rx and crystal to match my Tx | > and use connector adapters for the Airtronic servos...
Are these the *really* old connectors that have wires sticking out of the servo plugs? If not, you don't need any adapters, though you might need to pop out the wires from the current plugs and change the order they're in. (I seem to remember that airtronics servos were wired differently.) If you do have the old servo plugs, I'd suggest cutting the old ones off and replacing them that way, but that's harder to do properly and it might be safer for you (I assume you're pretty new to all this) to just replace the servos -- they're obviously pretty old anyways. In any event, don't buy those adapters
-- they're just another thing to fail and they're expensive.
| > this will cost me about $100 or should I take a chance and buy a | > used Futaba RX and TX for $100? Any help is appreciated.
As long as you either 1) know what to look for, or 2) trust the person selling you the equipment, used equipment is usually a very good deal. If somebody in your club or a friend wants to sell you an old radio, and he knows what he's doing and the price is right, do it. You might need to replace the batteries, but old equipment (as long as it's post-1991) usually works just as good as new stuff. But if you don't know/trust the guy selling it, and can't tell if it's good yourself, it's a bit dangerous.
If you do decide to go the `new receiver' route, keep in mind that you can use Hitec receivers, and they're a good deal cheaper for the same quality. For example, if you go here --
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you can use the M-5 (not Hitec, but still a
*great* receiver -- I have about 6 of them now) for $55, or the Hitec Supreme 3200 for $60. And that includes the crystal. Or any other receiver on this page will work, as long as it says it works with Futaba. (Except for the GWS R4P or Plantraco park flier receivers. And you probably don't want the Ham band receivers.)
| Get a spread spectrum setup. The best...
Bad, bad advice. From what I can tell, the commercial spread spectrum R/C setups aren't even available yet -- all we've seen are prototypes. Is *anybody* actually selling these things yet? (as in now, today?)
In any event, there's considerable concern about interference and range problems with any R/C controller that uses the 900 mHz or 2.4 gHz bands. Alas, we don't really have any real world success or failure stories to relate - we just don't know how well it'll work in the real world. Not having to worry about channel conflicts would indeed be very nice, but I wouldn't suggest that a relative newbie (I'm assuming that the original poster fits this category) should run out and get these new things the moment they're available. Let other people work out the kinks first :)