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Are Futaba and Hitec dual conversion rx crystals interchangeable?

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Old 11-09-2005, 05:27 AM
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Capt Jim
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Default Are Futaba and Hitec dual conversion rx crystals interchangeable?

I fly with a Futaba 9C transmitter, using a synthesized Tx module. I have developed a nice selection of Futaba crystals that I use in all my Futaba receivers, and now I have aquired a Hitec RCD3200 Receiver. It is a dual conversion, ultra narrow band model # FM/HFD-08RD. My question is....can I safely use the Futaba crystals in the Hitec rx without any degradation of performance.
Thanks for the info.
Jim
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Old 11-09-2005, 06:14 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Let's see if I have this right. You spend hundreds of $ on a high end transmitter, probably thousands of $ on planes, engines, and flight packs, and you want to save something like $10 by interchanging crystals? Buy the proper Hitec crystal for your Hitec receiver.
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Old 11-09-2005, 07:05 AM
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JohnBuckner
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?


ORIGINAL: Capt Jim

can I safely use the Futaba crystals in the Hitec rx without any degradation of performance.
Thanks for the info.
Jim

Who knows? Certainly not Futaba or Hitec. Lots of people have tried various combinations but have no concept at all about the phrase you mentioned "degradation of performance". Not all crystals of the same channel are cut the same. They are cut to match the electronic characteristics of the product they are intended for.

John
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Old 11-09-2005, 07:32 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Nope...you sure don't have it quite right Chuck. The ten bucks for a Hitec crystal is indeed totally insignificant when you want just one; but if you want to develop wide ranging frequency availability, as I have done with my Futabas, it then becomes a significantly more costly investment. Do the math...50 channels...ten bucks per channel! It would obviously be much more cost efficient to simply scrap the Hitec and plug in another Futaba receiver.
Additionally, it seems to be an especially unecessary duplication of expense when many reports tend to indicate that each of these manufacturers crystals are in fact generating the very same frequency for use in their dual conversion receivers.
After all, there is no magic in the name label that they put on the device, and inside the can is merely a piece of quartz ground to resonate at a specific frequency when a current is passed through it. Therefore, in order for this thread to be meaningful, please...lets leave the responses to the individuals who are technically qualified to address the subject material.
Thanks for entertaining us with your need for irrelevant venting, however, your shortsighted non-technical response is considerably less than helpful.
Regards
Jim
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Old 11-09-2005, 08:03 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Jim, you've already got an answer from the people most qualified to respond, the manufacturers. They say don't do it. It seems you are hoping someone will validate your theory that it's ok. If you want to be able to fly any plane on any channel, go look at the Polk systems. Fully synthesized transmitters and receivers. Sorry if you didn't like my answer, but IMO investing in 50 channels worth of crystals is just as silly as your arrogant response.
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Old 11-09-2005, 08:25 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

As hobbiest, we should only support those activities that are compatable, safe and legal.
To use anything other than the manufacturers recommended accessories may not be in all of the three catagories.

While the Hitec and Futaba crystals may be compatable, the question comes are they safe and legal. From a manufacturers point of view, they are not safe because the units have not been tested using the competitors accessories. Is it legal, some of the FCC stuff I read basically says that accessories or attachements have to be qualified to the product they are installed in. So this activity may not be legal.
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Old 11-09-2005, 08:33 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

I will have to side with everyone else here on the crystal issue. I couldnt willingly put my potentially dangerous flying object into the air knowing I had an improper mix of radio gear. I dont see why even risking the investment in time and money into a model by putting it in the air with an mix of radio gear. Futaba has a synth module and rx setup already.

I just avoid crystals all together with my 9303 and synth module. There is a new "park flyer" radio from horizon which is more or less a JR 6102 on 2.4ghz. Hopefully the future of our hobby will allow more full synth setups where you just turn on and your radio will automatically find the next open frequency.

Still even with a nifty radio, I always always double check what my frequency was last set to so as not to shoot someone down when I go to turn on. Its an easy enough process to pick one channel to be on, take that frequency pin, then turn on my gear knowing I am not going to shoot someone down.
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Old 11-09-2005, 10:08 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Dual conversion crystals are cut to generate a signal from the local oscilator. Different recievers use different intermediate frequencies and have different charactaristics as far as impedence and the voltage they are set to operate at. Even though they may appear to work on the bench is no gaurantee they will work in flight and its fool hardy to take chances with your model and the lives of others to save 2 dollars.

As for legality, the fcc only cares about transmitters. From a liability stand point, if something happened and an investigation showed that you were going against accepted practice by mix and matching radio components your insurance and the AMA would probably (and rightly) leave you high and dry.
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Old 11-09-2005, 10:32 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

I am a graduate electrical engineer with 50 years of design, test, and systems engineering experience. I also served as the Kraft, Ek, and Royal representative in the Seattle area in the early seventies.
Its true that crystals are cut differently by different manufacturers, BUT, if you put in a crystal in the receiver and it works, then the cut, frequency, and offset must be correct. I would range check it, though, just to be safe.
I have a Futaba receiver that has had a Hitec crystal in it for several years. I also think I have a Hitec receiver that has a Futaba receiver but I am not sure. As long as they work I tend to forget about it.
To be safe, the manufacturer will not recommend another manufacturers part simply because they have no control over it
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Old 11-09-2005, 10:46 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

ORIGINAL: dirtybird

I am a graduate electrical engineer with 50 years of design, test, and systems engineering experience. I also served as the Kraft, Ek, and Royal representative in the Seattle area in the early seventies.
Its true that crystals are cut differently by different manufacturers, BUT, if you put in a crystal in the receiver and it works, then the cut, frequency, and offset must be correct. I would range check it, though, just to be safe.
Are you suggesting that a mere range check is adequate to confirm that the receiver is working well enough to be safe in this situation?
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Old 11-09-2005, 11:31 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

He is and its not IMO but hey whatever works for you.

You may get away with it but its been my experiance that the people that do this are the same people that stand on the flight line staring at their transmitters with a stupid look on their face wondering why their pride and joy needs a ride home in a dust buster.
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Old 11-09-2005, 12:51 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Wow, I'm glad I didn't reply to this thread! Everyone having family trouble or something?

'scuse me while I tiptoe away... remember, new people read these threads.

Have a nice day,
Dave Olson
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Old 11-09-2005, 04:47 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?


ORIGINAL: piper_chuck

ORIGINAL: dirtybird

I am a graduate electrical engineer with 50 years of design, test, and systems engineering experience. I also served as the Kraft, Ek, and Royal representative in the Seattle area in the early seventies.
Its true that crystals are cut differently by different manufacturers, BUT, if you put in a crystal in the receiver and it works, then the cut, frequency, and offset must be correct. I would range check it, though, just to be safe.
Are you suggesting that a mere range check is adequate to confirm that the receiver is working well enough to be safe in this situation?
Yes.
As someone explained, a crystal simply produces a frequency when a current is passed thru it. If that frequency is correct and the amplitude is sufficient thats all you need. You can tell if the amplitude is correct if you range check it. If the amplitude is not adaquate you won't have any range. If the frequency is not correct it won't work at all
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Old 11-10-2005, 07:10 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

yes you can, So long as the hitec receiver is set up for futaba then you can use a futabe crystal or a hitec crstal made for Futaba. There are no differences other then the system they are designed for. I fly a P-40 at Top Gun with a Futaba 129pcm and a Hitec crystal in the receiver. Never a glitch.
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Old 11-10-2005, 09:11 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Well I'm not saying it wont work. Infact its completely possible that they are the exact same crystal, manufactured by the exact same company and one has Futaba labels on it and one says Hitech. It wouldn't even surprise me. But.........unless you know for sure, swapping internal components, and rf modules and so forth between manufacturers is like drinking that 3rd straight beer and driving home, you may have gotten away with it 50 times but ...............................
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Old 11-10-2005, 09:20 AM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

In order to resolve this issue to my satisfaction, I have resorted to developing my own empirical data. Specifically, I have removed the Hitec crystal, installed a Futaba crystal, and performed a range check. All functions are normal, and the range check was identical with either crystal.
Thank you one and all for your comments.
Jim
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Old 11-10-2005, 03:30 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Good for you Capt. Jim. The next step is to put that setup in one of your "disposable" planes & try it for a while. I too am an electronic engineer with 31 years experience & I have to concurr with Dirtybird. The crystal will either work & work well, hardly work at all, or not work & this can be confirmed by a normal range check.

Someone insinuated that a proper range check would not give an indication as to wether or not your combination would work, so I have to wonder, how do they verify that new reciever & crystal combo they just put in their new plane is in fact working, if a range check isn't good enough?

I try to use like manufacturers recievers and crystals, but I have found that Hitec, Futaba & also FMA crystals and recievers all seem to be interchangable, as long as the frequency shift is compatable.

I wonder if Futaba, or JR for that matter, would condone the use of their transmitter with a Hitec reciever, yet it is done every day by many many RC'ers.

Just my .02, probably not worth much in the grand scheme of things.
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Old 11-10-2005, 05:03 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

On the FMA site they tell you that their RX will work with a DAD, Hitec, or their own crystals. They claim the Futaba crystal won't work!
IF everything was interchangeable they wouldn't have to say this.
Just food for thought.
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Old 11-10-2005, 05:19 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?


ORIGINAL: cassidy

On the FMA site they tell you that their RX will work with a DAD, Hitec, or their own crystals. They claim the Futaba crystal won't work!
IF everything was interchangeable they wouldn't have to say this.
Just food for thought.

I dunno, but I have two older FMA 8 channel recievers that I use all the time, don't own any FMA crystals, truthfully, didn't even know they marketed crystals.
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Old 11-10-2005, 09:01 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

I just Bought an ultra stick a few months ago, but would like to fly more than once a week. i was thinking of getting an aerobatic electric plane, but the plane i'm thinking of getting has 4 channels, and i have a 6 channel radio. will the current standard receiver work with an electric, or do i need to buy a new receiver? As i mentioned earlier, i am new to this hobby and i'm sorry if it's a stupid question, but could a 4 channel receiver work with a 6 channel transmitter if i only need 4 channels?
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Old 11-10-2005, 09:05 PM
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Default RE: Are Futaba and Hitec dual conversion rx crystals interchangeable?

Yes, it will work fine.
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