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Author Topic: Macgregor 27Mhtz crystals  (Read 119 times)

roycv

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Macgregor 27Mhtz crystals
« on: October 07, 2017, 10:42:35 PM »

Hi all does anyone know if the crystals as above are compatible with Futaba ones.  I have a boat fitted out with old not JR Macgregor  2 ch RC and a green crystal, which I would be happy to leave as it is and use a Hitec or Futaba 27Mhtz transmitter.  Will they be compatible?

regards Roy
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malcolmfrary

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Re: Macgregor 27Mhtz crystals
« Reply #1 on: October 08, 2017, 09:56:43 AM »

They should be.  The transmitter crystals should show the actual frequency to air.  Depending on the convention chosen by the manufacturer, the receiver will either show the "from air" frequency (same as the TX crystal) of the offset value, usually air frequency -455KHz (or 0.455MHz).  Or just the colour code and a marking for TX or RX.  Back then, there was a lot of commonality with components of the radios, so mixing and matching could happen. 
Futaba had to be a bit different, using the same signals as everybody else, but with different logic and pulse lengths meaning you had to operate the servo reverse and use the slider trim if swapping between one transmitter and another, but that was nothing to do with crystals.
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roycv

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Re: Macgregor 27Mhtz crystals
« Reply #2 on: October 08, 2017, 10:19:29 AM »

Hi Malcolm thanks, there is a band 5 green crystal in the (BEC) receiver and all is fitted into a nicely made Billings Mary Ann and as I like restoring model boats it would be nice to keep this in its' contemporary fitting out.  The speed controller is a moving arm on a resistance wire potentiometer (not Bobs board) and if it works I shall retain it.
I have 27 Mhtz Tx's so no problem there and I have lots of crystals.
My first concern was the servo wires but they are conventional in layout order.
I shall check it all out later this afternoon.
regards Roy
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