switching FM crystals
03-29-2016, 06:12 AM
#1
Thread Starter
switching FM crystals
I have a Futaba 72 FM band old school R127 narrow band receiver without a crystal. I want to remove a channel 14 crystal from another plane, put it in this (empty) receiver and put it into another plane I'm building. I have an original channel 14 FM Conquest transmitter that works just fine. All are narrow band 91 gold stickered, this should work ok, correct? I'll probably just put this airplane on my Tactic 2.4 XXT 650 computer radio eventually but I want to use this other plane for training. I got a very clean never flown Avistar 46 size high wing without Rx, servos and engine at a local Swap Meet for $15.00! I train newbies at my club and have flown Avistars before, they are excellent high wing planes, semi symmeterical wing too!
Thanks for any input.
Bill in Pa.
Thanks for any input.
Bill in Pa.
03-29-2016, 03:57 PM
#3
I seem to recall that Futaba Rx were split into High and Low groups or Frequencies. With the cutoff around the middle of available channels. Back then it was ok to switch crystals in your end of the range your Rx was originally in. Later Futaba did away with this and you could place whatever crystal you wanted in the Rx and be ok.
That being said I flew with fellas that would go to a fly in with a box of crystals. They would use the frequency lease occupied by other attendees. They never had a problem.
Your probably good but do a careful range check.
Pete
That being said I flew with fellas that would go to a fly in with a box of crystals. They would use the frequency lease occupied by other attendees. They never had a problem.
Your probably good but do a careful range check.
Pete
03-30-2016, 04:36 AM
#4
SOME Futaba receivers were tuned for the middle of the top half of the channels or lower half.
That high/low thing didn't apply to every receiver and many were center tuned. You'd have to ask Bax which ones were which if you were worried about it.
Having a receiver aligned by Futaba or Radio South is cheap peace of mine, first, you know it's tuned properly, and second the tuning process usually uncovers any other issues and they charge 15 bux or so.
That high/low thing didn't apply to every receiver and many were center tuned. You'd have to ask Bax which ones were which if you were worried about it.
Having a receiver aligned by Futaba or Radio South is cheap peace of mine, first, you know it's tuned properly, and second the tuning process usually uncovers any other issues and they charge 15 bux or so.
03-30-2016, 11:16 AM
#5
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When I was still flying Futaba 72 radios, I would have the Tx and Rx retuned every 4-5 years or so to ensure things were working as they were supposed to. I found that as the crystals aged, they would shift their tuning, still within limits, but at or near the opposite ends of my channel 24 frequency. Since going to 2.4 I have not looked back.
Hope this helps.
Karl
Hope this helps.
Karl
