R/C Signal booster

[sigve]

Hi

I have buildt a little r/c "robot" out of a toy rc car, but i have some problems with the range. it is a simple 2ch on/off radio system on 27 mhz. I was wondering how to make the range better, is it posible to make some sort of signal booster on the transmitter, and maby on the reciver as well. i guess you need someting more than a transistor ore an op-amp, but i dont now what?

Does anyone hav some schematics ore any ideas?

I only have a range of about 5 meters now so i realy need something.

Thanks for all replys

Sigve

[Acetronics]

Hi, Sigve

a CB linear amplifier ... will overfit.

Alain

[sigve]

oki....i am not sure wath that is...links?

thanks
sigve

[Terry S]

the easy way is to change to a longer tx aerial and tune the output coil for max range.

Terry

[Norman Adlam]

Hi

I have buildt a little r/c "robot" out of a toy rc car, but i have some problems with the range. it is a simple 2ch on/off radio system on 27 mhz. I was wondering how to make the range better, is it posible to make some sort of signal booster on the transmitter, and maby on the reciver as well. i guess you need someting more than a transistor ore an op-amp, but i dont now what?

Does anyone hav some schematics ore any ideas?

I only have a range of about 5 meters now so i realy need something.

Thanks for all replys

Sigve


Hi,

Depending on where you are you are likely to infringe all sorts of legislation if you attempt to up the power on a TX. You are allowed to increase the sensitivity etc of the RX, but chnages to a TX can potentially mess up other users, hence the regs! :)

Cheers,

[sigve]

thats a good idea, but the coil on the tx is not tunable :( ill try to replace it.

I dont think this wil be enough, i want a range of around 200 meters so i think i wil have to boost the outputsignal somehow.

why is it not possible to use a only HF transistor? (I know that it wont work but not why)

[slipstick]

What voltage does the transmitter run on ? If it's anything like the little Bitcar Txs just increasing the battery voltage and lengthening the antenna works wonders. These particular modifications have been discussed a lot in the Indoor and Micro forum.

Steve

[yctseng]

Why not just buy another normal TX/TR set to replace the old one. That would be
a more quicker and safer way to meet your requirements.

[vintage1]

In my YOOF I built a 27Mhz tranny. We wer limited to 0.5Watt ERP...mine went out with 18v on it and pulled a shade over 200mA..about 3.5watts input, and the power transistor - rated for 500mW, got hot, but stayed the course.

Legal it was not, with an estimated 3W ERP, but I could pull any superregen S/C tone model back from a mile downwind...irrespective of what frequency it was tuned to. And did so once, when the blokes silly 50mW transmitter failed to do the job...

Usually all you need to do is up the voltage, and maybe reduce an emitter resistor in the power stage and/or change to a more powerful output transitir.

Yeah, you should get it checked for sidebands etc etc etc.

You ought to keep to speed limits too..

[sigve]

Hi,

Depending on where you are you are likely to infringe all sorts of legislation if you attempt to up the power on a TX. You are allowed to increase the sensitivity etc of the RX, but chnages to a TX can potentially mess up other users, hence the regs! :)

Cheers,

there are rules yes,the max effekt is 10 mW e.r.p. (can this be right, i am not sure, i thing it is a little low) on 27mhz, how do i measure this?(what does e.r.p. mean?) how can i moddify the reciver?

sigve

[sigve]

Why not just buy another normal TX/TR set to replace the old one. That would be
a more quicker and safer way to meet your requirements.

This prodject is wery much about learning, learning about radio equipment and so on, and besides this system was easy to interface with the pc`s paralell port :D

sigve

[sigve]

What voltage does the transmitter run on ? If it's anything like the little Bitcar Txs just increasing the battery voltage and lengthening the antenna works wonders. These particular modifications have been discussed a lot in the Indoor and Micro forum.

Steve

it originaly ran on a 9V alkaline, but I now run it on 9.6V nimh (8S). oki i wil check out those forums.

sigve

[Mr.RC-CAM]

Some general info on MicroSizer Toy Car hacks, to increase range, are found here: http://members.aol.com/rchelicam/microszr/microszr.htm

Also, try searching the "Indoor and Micro Models" Forum for possible info to your model car. The toy car hack community is quite large there.

RC-CAM

[sigve]

Some general info on MicroSizer Toy Car hacks, to increase range, are found here: http://members.aol.com/rchelicam/microszr/microszr.htm

Also, try searching the "Indoor and Micro Models" Forum for possible info to your model car. The toy car hack community is quite large there.

RC-CAM

this is not an micro car, it is about 1:20, but i guess it is much of the same tecnology. I wil try replacing the output transistor and redusing the outp. resistans.

Graet info on that page :)

sigve

[Mr.RC-CAM]

...this is not an micro car, it is about 1:20, but i guess it is much of the same technology.Many of the low cost R/C model cars, tanks, and airplanes, are similar as far as the RF design is concerned. Most use the same IC set too. Once you review the microsizer page and the discussions in the Indoor forum, you will should find that simple tricks like increasing Tx and Rx antenna lengths will help out tremendously. The stock antennas are woefully inefficient due to their short lengths.

[ImaBiggles]

Legal it was not, with an estimated 3W ERP,
...irrespective of what frequency it was tuned to.

Too cool!