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Please help with 27.195!

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Please help with 27.195!

Old 04-25-2009, 06:54 PM
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Default Please help with 27.195!

I ordered a scratch and dent aquacraft reef racer from tower hobbies. It discounted because it was missing it's transmitter. No problem, I have lots of transmitters, and even that the same crystal 27.195. Mine is the Traxxas green, but it is the same frequency. I cannot get it to work. I thought the speec control\reciever combo was bad, so I ordered another one and can't get it to work either. Does anyone have any idea's?

Thanks
Old 04-25-2009, 07:13 PM
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Default RE: Please help with 27.195!

In the 27MHz band there's AM and FM radio's ... they don't mingle .

There is also the difference in frequency by brand.
In Europe your (transmitter)27.195 is channel 24 .. the reciever is 26.725 (for Futaba) and 26.740(for MPX/JR/Acoms)
They will not mix either.

Solution : matched Xtals of the same brand .. did forget if it has to be the transmitter or the receiver brand.
Old 04-26-2009, 03:22 AM
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Default RE: Please help with 27.195!

I'm thinking that the reef racers are FM and the traxxas are definately AM. You want me to look for an old TX from a reef racer? Is it the RR 1 or RR2?
Old 04-26-2009, 08:59 PM
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Default RE: Please help with 27.195!

I actually have a number of transmitters around here. I have been a rc nut since getting my first truck when I was eleven. It was a Tamya Midnight Pumpkin. I spent all christmas putting it together. It was dark by the time I bolted the last tire on. Then my parents told me it was too late to even try it out! Yes, still scarred!

Anyway the point is I proably have a transmitter that will work, I just need to get the crystals. I had no idea different brands didn't interface with each other. I think the Reef Racer is AM, it does say right on it 27.195, which is what the green traxxas crystal says. The way they seal the receiver/esc you can't change the channel on the boat.

I'm pretty sure that Hitec and Futaba are interchangable, so I think I will stick some of these http://www3.towerhobbies.com/cgi-bin...I=LXH283**&P=7 in a transmitter and try them out.

I will be buying them at the LHS, I sort of ticked at Tower right now!

If you know anything else I would really apprciate it Thanks for the input so far, It is the purple, RR2.
Old 04-26-2009, 10:44 PM
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Default RE: Please help with 27.195!

I know that traxxas,hpi,futaba,duratrax,aquacraft,associated, ect. will all work with each others AM 27 mhz.
Old 04-26-2009, 10:57 PM
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Default RE: Please help with 27.195!

I don't want to even add this to the mix but there are some positive or negative shift variations in radios as well, just don't ask me how to explain it !
Old 04-27-2009, 12:06 PM
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Default RE: Please help with 27.195!

One thing we noticed messing around with cheap toys, tanks and micro boats, is that
manufacturers, like Nikko, mix up the "channels" they use for controlling the models.
So for example, if there are six channels on a frequency, the signals numbered 1,2,3,4,5,6,
Some toys will use channel 1 for throttle, but then use channel 4 for steering.
So any standard 2 channel radio may not match up.

We ended up transplanting the entire receiver to get additional range and use a standard transmitter.
Old 04-27-2009, 03:21 PM
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Default RE: Please help with 27.195!

The crystal in the TX shows the frequency transmitted to air. It doesn't matter whether its AM or FM. It also does not matter who made it. It is just the frequency that matters. That and the pin spacing.
The RX crystal has a figure offset by the IF of the RX.
Is the radio in the boat a standard type? It could be that a proprietary system uses something outside the normal signalling system, thus a different TX has no chance of working. Lots of designers have their own ideas aimed at cutting costs, and just don't worry about whether or not it will work with anything else.
You might well need a receiver transplant.
Old 04-27-2009, 10:30 PM
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Default RE: Please help with 27.195!

Well, that's just the thing. It has a ESC Reciever combo in it that I really like, it's well waterproofed and I'd like to use it. I know the transmitter that normally comes with the boat is a futaba. Thanks for the help so far!
Old 04-27-2009, 10:43 PM
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Default RE: Please help with 27.195!

If I know the 27.125 traxxas crystals don't work, should I buy futaba crystals to see if they work?
Old 04-28-2009, 09:55 AM
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Default RE: Please help with 27.195!

They will not work. IN fact since all the 27 AM (traxxas,futaba,tower,associated,hpi,duratrax,aqua craft, ect.) are the same none of them are going to work with the reef racer's FM RX. I think the only way to do it is to use the reef racers' FM transmitter.

The key difference and problem here is that you have AM tx and need FM.
Old 04-28-2009, 11:22 AM
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Default RE: Please help with 27.195!

The key difference and problem here is that you have AM tx and need FM.
Not only that, you need a TX that encodes in a way that the RX will understand. If the original was a "standard" TX, then another using the same modulation will work, but the easiest and most reliable way is an electronics transplant in the boat. That way, the entire thing works to 50 frames per second, with channel information presented in a form that the RX can understand.
Old 04-28-2009, 01:04 PM
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Default RE: Please help with 27.195!

MMM, thanks for that, my father in law has an aquacraft remote, perhaps I should try that before transplanting the elctronics.

It does list the freq as 27.195, doesn't that mean that it is AM?
Old 04-28-2009, 01:57 PM
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Default RE: Please help with 27.195!

No, it has to be the correct. The original reef racers were AM (like all the ones I've listed) the reef-racer2 with the RX/esc in one unit is FM.
Old 05-02-2009, 02:49 AM
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Default RE: Please help with 27.195!

I had the same problem of finding a receiver that can work with the RR2's transmitter which is a FM unit.
I tried the Duratrax's R303F receiver as someone had suggested, I think I used the proper X'tal for the RX that is Futaba's part.

Only receiver unit I can find that can work with the RR2's transmitter is the TacTic's RX/ESC combo unit, except that the throttle is reversed. But at least the TacTic can response to the RR2's FM TX with the same frequency. The frequency on supposed to be 27.145mHz as labelled on my RR2's box label. But the x'tal on the Tactac RX that work is actually 26.690mhz. I guess this may have something to do with the IF frequency on the Tactic.

I then openned the RR2 transmitter, and found that transmitter that labeled as channel 4 with FM 27.145mhz (as labelled on the box),
the x'tal inside the transmitter actually is 13.7525 mhz.

Can anyone figure out what is this mean and how can I find a FM RX that can work with my RR2 Transmitter ?
Old 05-02-2009, 07:30 AM
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Default RE: Please help with 27.195!

13.7525MHz, half 27.525. So the TX uses harmonics.
This means that a very proprietary system was used by the manufacturer, and they will likely be the only ones to supply a replacement that will work. If the method of transmitting is non-standard, it is an indicator that the signal encoding is also non-standard, so nobody elses receiver will make sense of the signal, and vice-versa.
The guess about the IF is spot on.
Old 05-02-2009, 06:54 PM
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Default RE: Please help with 27.195!

OK, my next question. WHY WOULD THEY DO THAT!
Old 05-02-2009, 07:31 PM
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Default RE: Please help with 27.195!


ORIGINAL: acejinx

OK, my next question. WHY WOULD THEY DO THAT!
So that you spend all your money only with that company.

[&:]

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