carl24bpool

I understand that you obviously don't agree with me trying to learn the hobby without club membership but is there any need to comment if you can't even contribute? It's as if you make an attempt to persuade others to not offer assistance. Why don't you just leave my threads alone and save yourself some time?

I asked the original question in order to get help. I then ask follow up questions and challenge answers. Not because I think I know what I'm talking about, it's to delve deeper into my fellow members knowledge and experiences. I know nothing about the radio gear and after all the brilliant replies here I realise now how little I know.

i did know that crystal swapping was legal here because I did it a lot with cars when there would be half a dozen of us out at same time. I never knew about the retuning though and a lot of the car stuff was all Acoms so matched I guess.

i think I'll try and get a hitec specific crystal to match the one in the receiver but I'm not sure about the module in my tx. It's got a box in the back that comes out but it has a frequency specific crystal in it. Channel 63 from memory.

like jester said though ill invest in 2.4 soon as I would like the peace of mind of a better connection to my aircraft.

thanks again for all the replies guys. Ill probably read each one another ten times before I absorb it all. Lol.

on_your_six

My Feedback: (11)

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rgburrill

HighPlains, not only incomplete but some of it downright wrong. Oh well.
Carl24bpool, you'd probably be better off changing the receiver crystal than the transmitter. They are usually cheaper and don't require any "retuning" But you still have the potential problem if negative/positive shift. If you aren't sure your transmitter can change it's shift then it might be best to go to HobbyKing (yes, I said that) and buy a cheap receiver made for the Hitic. Or spend a little more money and buy a Hitec receiver.

HighPlains

My Feedback: (1)

Haven't you heard? 3x4=11 now. I decided to edit out that some of this thread was wrong, just don't need to bring the IRS (psst, or the NSA) into this. Everybody gets a ribbon..............

carl24bpool

This makes sense since I can then leave the same crystal in the transmitter.

My transmitter is a Hitec Optic 6 and my receiver I use is this one:

http://www.ebay.co.uk/itm/Hitec-HFD-08RO-35Mhz-Dual-Conversion-Receiver-/321027757861?pt=UK_ToysGames_RadioControlled_JN&hash=item4abebed725

My transmitter has a module on the back which reads:

RF Module
HPF-Mi
CH63 35.030

The receiver says dual conversion on it.

Does this mean the Futaba receiver I want to use needs to be dual conversion?

I know the new receiver is cheap but I hate wasting things and the Futaba one I have is brand new.4

opjose

As others have already told you, if you do this your TX is very likely to cause interference on OTHER channels.

I've had it happen to me when a particular (idiot) non-club member showed up with a TX, that he had changed crystals on.

I was flying 72mhz ( yes this applies to 35 as well ) and I noticed that whenever my plane passed anywhere within 50 feet of his pilot's station I was getting interference, though we were on separate frequencies.

I went over and talked to him and discovered he had changed out the crystals himself, and worst still he had not used crystals from the same manufacturer. He would not accept that this was a bad idea, against club rules and FCC regulations.

I proceeded to explain that if I lost my plane as a result of his negligence, he would be paying for it.

We never saw the guy again, but the lesson learned helped other 72mHz flyers.

carl24bpool

Opjose, I totally understand this now and will adhere to all the advice.

as mentioned earlier though am I okay changing the crystal in the receiver? Surely lots of you guys do this so they all fly from the same transmitter. Or am I wrong?

JohnBuckner

My Feedback: (1)

Yes, yes and no you are correct!

Now please understand since we finally found out which of the FM versions of the Optic 6 you own, You only need to seek out a systhesized module for your Optic 6 on the 35Mhz band. You can change frequencys on the two little bitty dials on the side to you hearts content and remove the old single frequency module and plug in the snth module. Its that simple.

There will be no loss of performance with the synth module simply because in includes the entire RF section within that module. I have I think nine synth modules on 72 thrown in a drawer because I have replaced all with 2.4 modules in all my hitec radios which include the Prism 7x's, Eclipse, Eclipse Pro, and Aurura 's . The Optic 6 is the only one in the hitec line I have not used.

The Reason and point I told you this is there are bound to be folks who have replaced their Hitec Synth modules with 2.4 modules and would only be to happy to pass their old synth modules on for a pittance.


John

carl24bpool

That's great thanks John.

does this also mean I can convert my transmitter to 2.4 with a module and receiver? If so then that's likely the way ill go eventually.

i guess I'd have to change antennae too though?

j.duncker

My Feedback: (2)

First you need to pull the module on the Hitec Tx and double check that you have a Hitec Tx crystal in the side and that it is indeed channel 63.

I have safety checked quite a number of used Txs with a marked frequency on the back which had a different crystal and hence a different frequency in the side of the module.

Then you would need a Futaba rx crystal for your Futaba receiver The receiver will say on it whether it is dual conversion or single conversion. Just get the sc or dc crystal.

There is another potential gotcha Futaba have a system called PCM if you have a Futaba PCM receiver it will not work with your Hitc Tx even if the crystals are correctly matched. The receiver will say PCM on the front.

If you tell us which futaba Rx you have we can confirm that it will work and which type of crystal you need.

JohnBuckner

My Feedback: (1)

Yes it does of course then you must use a hitec 2.4 receiver also. No you do not have to replace the antenna. The new 2.4 antenna comes with the module and a short wire and a new base. The old antenna is unscrewed and the new base inserted and the new antenna is popped on. Oh and the modulation type is set for that model in programing in other words you must set that model for FM(PPM) modulation.

By the way Your Tx will handle PCM receivers also as long as they are Hitec PCMS receivers.

Actually if you had a Synth module you could handle the futaba receiver (of course as above if not a PCM receiver, look on the label) and use many (I forgot how many airplanes the Optic holds) 2.4 receivers with just one module that changes out.

John







Carl these include when this photo was made some time back, there are three old Prism 7X's Three old Ecliipse 7 (not the Pro) and one A9 as well as a single JR10

All have been converted to 2.4 and all could still fly 72 (in our case) simply by switching out the modules and screwing the original antennas back in.

NJRCFLYER2

My Feedback: (42)

Shouldn't matter.

johnwmuir

It isn't complicated at all. In the UK it is perfectly legal and straightforward to change crystals. All 35MHz radio gear here was supplied with externally mounted crystals to make this easy. It causes no problems whatsoever with interference on adjacent channels.
All that Carl needs is a Hitec transmitter crystal in the Hitec transmitter (transmitter crystals are just the one kind, there's no choice between single or dual conversion) and a Futaba receiver crystal on the same channel in the Futaba receiver (either single or dual conversion, depending on what it says on the receiver). And that's it.
All this illegal to change crystals, retuning transmitters and positive or negative shift stuff is valid in the USA but not here in the UK/Europe.
HTH.

JohnBuckner

My Feedback: (1)

John thank you for confirming what I noted in post #22 and that is that Futaba FM product sold through the Europeon market are positive shift Futaba FM product sold through the North American is Negative shift.

John

carrellh

Your transmitter is not single or dual conversion. Single/Dual conversion are terms applied to receivers and the crystals are different.

It might be easiest to find out exactly what receiver is in the trainer and get a correct crystal for it on the same channel as your Optic 6.