Synth Radio & non Synth Receiver

[robriguez]

Ok, so I just won this kick ass JR XS3 radio from the last lottery. (thank you Woodie and all who bought tickets!! :bow: :bow: :bow: ) And I thought I would see if I can use it with the cars I already have. All but one run 27Mhz. My idea is that hopefully with the new radio I dont have to keep swapping out crystals. My current frequencies are 27.045, 27.095, and 27.195. As far as I can tell these are channels 2,3 and 5. Yes? no?

Well anyway, so I go through the manual of the JR XS3 and change the tx channel on the radio to channel 2. I flip on the juice to the buggy (27.045) and the servo starts twitching like crazy, I turn on the radio and they stop twitching but I get no response from the Steering servo or the ESC. So I do it the other way around, turn everything off, turn on the radio first then the buggy and same thing. No action what so ever. I turn on the original radio with crystals and all works fine.

I tried this with the other cars too and I get the same results. Can I not use a synth radio with a non synth receiver?

I dug through some of the old posts and it seems some people have said yes and some said no......Does anyone know the real deal? Is anyone running this type of setup??

Changing all the receivers out to synth wouldnt be the end of the world but if I can save the $60-70 x 4 rides = $240-$280 I would like to.

 

[robriguez]

Anyone??

 

[Mayhem]

It won't work. I think you need to buy sepreat recivers

 

[mcvickj]

Yes you will need to purchase synth receivers to use the XS3 with em.

 

[LarryA]

I don't know the radio in question but from what I've been told, if you use a new digital transmitter then the servos also must be digital. Basically a completely new set of electronics and at a premium price. This is what I was told. Correct this if I'm wrong.

 

[RobH]

I'd like to point out that the JR XS3 is a 75mhz FM tx those frequencies are not in the 75mhz band. Furthermore, I think they might be AM not FM.

I think you might be able to control another 75mhz FM reciever with out any trouble. I THINK! Don't nail that down as fact, I'm just guessing.

Also, I've heard a rumor that the "Novak" synth reciever works with the JR XS3. The novak (I hope I'm spelling that right) only costs $30 instead of the $60-$70 JR charges. I think it was MJ that said he runs the novak recievers with the JR XS3 (not 100% sure who it was).

Good Luck Mang!
Rob

 

[mcvickj]

I only asked if the Novak Rx units would work with the XS3. I will be placing an order for an XS3 shortly and I think I am just going to stick with the JR Rx unit that comes with the XS3. That way I know it will work for sure. I have asked around on different forums but I have't received a positive answer that would suite me. All I have heard is that it should work. Of course for the price I might I might see if the LHS will order me one so I can test it out.

 

[robriguez]

The JR XS3 that I won from Woodie is using the 27Mhz band. (Woodie...you trying to stiff me bro??? :stickup: )

All the rides I have run in the 27Mhz band as well accept for one. I too thought 27Mhz was for AM and 75Mhz was for FM. I'll look through the doc tonight but if the XS3 is FM 27Mhz then there is my problem.....the 3 27Mhz receivers I have are for AM. Duhhhhh

 

[Flash-R.C]

I would get the JR XS3 make sure you don't get the 27mhz (only 6 channels) get the 75mhz. 30 channels here I come wahoo.

Steve

 

[robriguez]

Too late Steve. I already have the XS3. I won it here on RCNT through the last lottery. I dont mind only the 6 channels, I doubt I will ever have more than 6 RCs. Well maybe... ...but I doubt it.

I was just hoping NOT to have to buy new receivers&servos. I'm gonna buy one of the Novaks to see how that works. If it does I'll just get new ones all the way around. Yeay!!! an excuse to upgrade!!!

 

[Flash-R.C]

WOW, your one lucky guy.

Steve

 

[SkyMaxx]

The twitching is caused by the tolerances of the receiver and the transmitter. The synthetic reciever has a better tuning capability and more exact tolerance than the crystals. You will find that the synth will react that way with most crystal driven receivers. Your best bet is to get a synth receiver for your other RCs or just deal with the "glitching".

If you must know the exact cause, I'll try and explain it. I'm betting Maxxmillion could give you the true electronics/electricians version, but I'll lay it out for you.

The crystals are kind of like shining a light through a beer bottle. The glass of the beer bottle focuses some of the light, but not all of it. The synth receiver is like shining that same light through a lens that is at just the right focal length. Not only does it focus the light, but it can cause it to burn (like a magnifying glass).

What does this mean...it means that the crystal gives a window tune centered on the assigned frequency. It does the job adequately, but does not have the accuracy or intensity of something that is finely tuned. The synth receiver, is a finely tuned "crystal" that is center tuned on whatever frequency you dial in. Therefore it gives better information or more focused information.

The glitching is caused by the fact that the crystal is not center tuned even though in the same channel in the same fashion that the synth is.

 

[HumboldtBlazer]

How can a 27mhz FM control a 27mhz AM?

Originally posted by Flash-R.C
WOW, your one lucky guy.

Steve

Yet another highly inteligent highly informative answer.