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hitec receiver not compatible with 9C?

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Old 07-16-2004, 02:48 PM
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MiloDeOjai
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Default hitec receiver not compatible with 9C?

Something strange is going on...

In the process of switching over my planes to my new Futaba 9C transmitter, one of the receivers does not seem to work with the 9C... The RX in question is a hitec super slim narrow band on ch. 23, which still works fine with my old radio. My other hitec receiver is working fine with the 9C. Anyone know why??

Thanks, Milo
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Old 07-16-2004, 03:34 PM
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JohnBuckner
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Default RE: hitec receiver not compatible with 9C?

Hitec Rx's are made in positive and negative as well as selectable shift versions. A positive shift Rx will only work with a positive shift Tx and vice versa. Unless either the Tx or the Rx has the selectable shift feature.

Hitec Tx's
Futaba Tx's

Are negative shift.


JR Tx's
Airtronics Tx's

Are positive shift.

John
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Old 07-16-2004, 03:41 PM
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MHawker
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Default RE: hitec receiver not compatible with 9C?

Was your other radio Futaba? Are the RX's all on the same channel as your 9C? Any of them PCM?
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Old 07-16-2004, 07:57 PM
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Default RE: hitec receiver not compatible with 9C?

Is the other TX or radio a Futaba unit?

What type of TX module is in play a standard fixed crystal module or a synth unit?
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Old 07-18-2004, 11:17 AM
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MiloDeOjai
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Default RE: hitec receiver not compatible with 9C?

Based on what John said, I think this is what's going on: the RX is a hitec, but I took another look at it and it says "JR" on it, so it must be + shift. My other TX is an airtronics RD6000 with a shift-select feature, which explains why the RX works with that TX but not my 9C. My 9C is a fixed crystal module on ch. 23.

So, that brings up another question: can I change the shift by changing out the crystal?
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Old 07-18-2004, 12:46 PM
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Default RE: hitec receiver not compatible with 9C?

Unfortunately a crystal frequency change will not change the the Tx/Rx's modulation shift. I don,t believe the 9c has a selectable shift but could be wrong. Probably the best best is to just start building up you flight packs (Rx's, servos etc.) as everyone will eventually do. Then just reserve the your positive shift Hitec Rx for use with the Airtronics Tx.

I have a rather large variety of Rx's and if I used a Tx without both modulation shift select and synthesized modules then a huge portion of my fleet would be instantly grounded.

John
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Old 07-19-2004, 09:59 AM
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Default RE: hitec receiver not compatible with 9C?

The 9C is not shift-selectable. Your 'JR' Hitec RX is not compatible and there is nothing you can do to make it so. Sell it to someone who has either a JR or a TX that has shift-selection. You mentioned the Airtronics. The Hite Eclipse 7 is also shift-selectable.
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Old 07-25-2004, 04:08 PM
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Default RE: hitec receiver not compatible with 9C?

It won't work as it is.But contrary to what has been stated,it requires only changing a crystal within the receiver to change the shift.It may not be cost effective to have it done,But I'd check with Hitec or kraft midwest to see if they will change it for you.Tha simple solution IS to reserve it for use with the Airtronics equipment,But I wanted to clarify that the only difference is the crystal.
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Old 07-25-2004, 06:52 PM
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Default RE: hitec receiver not compatible with 9C?

The original poster thought that changing the Rx's Frequency crystal can change the modulation shift and the point is changing a freq. crystal will not and cannot change the Rx's modulation shift. What you are referring to is an internal changeover and not within pratical application of the ordinary user.
Your statement will cause no end of consfusion to that user. Changing a RX crystal Will not alter a Rx's modulation shift.

John
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Old 07-25-2004, 09:51 PM
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Default RE: hitec receiver not compatible with 9C?

I believe KB9STD was refering to a filter crystal that is internaly hard mounted on the receiver, not the frequency crystal.
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Old 07-26-2004, 06:39 AM
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Default RE: hitec receiver not compatible with 9C?

Precisely, and certain to cause confusion because he choose imply that my original post is wrong. Changing a Frequency crystal in a RX will not alter the modulation shift, a plain and simple answer to a simple question in post #5.

John
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Old 07-26-2004, 01:48 PM
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Default RE: hitec receiver not compatible with 9C?

Agreed. In "our" world, changing crystals means the frequency crystal.... which will not change the shift... Let's not confuse anyone with internal modifications.
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Old 07-28-2004, 10:58 PM
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Default RE: hitec receiver not compatible with 9C?

Sorry Guys! I don't want,and didn't mean to confuse anyone. However I am going to defend my statemant,and clarify some of Your cofusion.

Yes,I was refering to changing a crystal "Within" the receiver. And I stated "WITHIN" the receiver,and suggested having Hitec or Kraft Midwest make the change.

NO, I am NOT talking about a "crystal Filter".I said a crystal,and if you want to call that a "frequency Crystal" OK.I don't know what other type of crystal it could be.We are talking about a "Dual Conversion" receiver. There are two crystals,and Two interfrequency sections.
That's how "Dual Conversion" works, Dual crystals,and I'm talking about "HAVING" the "Other" crystal changed.

If the rule of this forum is " simple answers for simple minds",Just put that into the rules.But you can't answer questions about reversing servos then.

See this excerpt from George Steiner explaining the concept.

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