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Electronics => Electronics => Topic started by: airman00 on January 21, 2008, 11:20:08 AM

Title: Amplifying R/C signal
Post by: airman00 on January 21, 2008, 11:20:08 AM: How can I amplify an R/C signal to a helicopter to the maximum distance possible ?

I will post specs for the heli in about half an hour , once I find the manual for the heli.

Thanks,
Eric
Title: Re: Amplifying R/C signal
Post by: cooldog on January 21, 2008, 11:22:09 AM: extend the antenna
Title: Re: Amplifying R/C signal
Post by: paulstreats on January 21, 2008, 11:27:12 AM: Give more power to the transmitter if you can. This is a sure fire way of increasing range
Title: Re: Amplifying R/C signal
Post by: HDL_CinC_Dragon on January 21, 2008, 11:29:33 AM: Perhaps making a directional transmission antenna (such as a Cantenna. Google it :)) would help signal strength when your facing it.
Title: Re: Amplifying R/C signal
Post by: airman00 on January 21, 2008, 11:33:02 AM: Quote from: paulstreats on January 21, 2008, 11:27:12 AM
Give more power to the transmitter if you can. This is a sure fire way of increasing range

Yes but wouldn't I also have to change some of the components in the transmitter. Like if It is powered by 6V I cant just connect 12V, can I?

also, by more power you mean more voltage or more current, or a combination of both?
Title: Re: Amplifying R/C signal
Post by: cooldog on January 21, 2008, 11:34:26 AM: don't jump from 6v to 12v

start slowly like add another battery to make it 7.5v
Title: Re: Amplifying R/C signal
Post by: ed1380 on January 21, 2008, 12:13:57 PM: would an op amp work?

I'm sure you can get sample chips for amplifying radio signals.
I've seen them for audio signals
Title: Re: Amplifying R/C signal
Post by: airman00 on January 21, 2008, 12:18:39 PM: no like how would I actually go about amplifying it .

connect an op amp to the wire connecting to the antenna or perhaps connect an op amp to the reciever end?

would powering it with a larger voltage do anything?

what's also weird is that I cannot find any retailer of r/c amplifiers out there.
Title: Re: Amplifying R/C signal
Post by: Kagi on January 21, 2008, 12:27:43 PM: You might check these boards. There is a massive amount of knowledge on them about RC. http://www.rcgroups.com/forums/index.php (http://www.rcgroups.com/forums/index.php) . Hope it helps.
Title: Re: Amplifying R/C signal
Post by: airman00 on January 21, 2008, 12:36:44 PM: thanks I will post a question over there
Title: Re: Amplifying R/C signal
Post by: Admin on January 25, 2008, 09:23:02 PM: yeap an op-amp will work . . . make sure its a high frequency amplifier . . . like 72MHz+ ;)

also, make your antennas parallel for maximum range
Title: Re: Amplifying R/C signal
Post by: ed1380 on January 25, 2008, 10:38:40 PM: i got a Q admin. would the op amp be put on the receiving or transmitting side?
Title: Re: Amplifying R/C signal
Post by: Admin on January 25, 2008, 10:42:50 PM: at least the transmitting end, but you can do it on both for double the amp fun ;D
Title: Re: Amplifying R/C signal
Post by: paulstreats on January 26, 2008, 08:17:41 AM: I would personally just use one at the transmitting end since its the tranmitted signal that you need to amplify. If you use one at the receiving end then you will be amplifying any noise and interference as well the signal.

Remember admins suggestion for a high speed op amp. The faster the better
Title: Re: Amplifying R/C signal
Post by: Steel_monkey on January 26, 2008, 10:07:14 AM: If you need more distance-> you need more power-> you need power amplifier, not voltage amplifier. I am not sure opamp will help- its output power is low, it is not designed for power amplification ( taking in account 80 MHz bandwidth). As I saw in my tiny Dragonfly 5#5 transmitter, output amplifier is simple 1-transistor A-class power amp (I can see closer if anybody is interested).
About basic electronics I personnaly reccomend "The art of Electronics", Horowitz and Hill (called Electronics Byble).
Title: Re: Amplifying R/C signal
Post by: Admin on January 26, 2008, 10:25:32 AM: there are power amps you can get, but yea, not sure on frequency.

a MOSFET *might* be capable of doing this . . . not sure on frequency though . . .
Title: Re: Amplifying R/C signal
Post by: Steel_monkey on January 26, 2008, 01:29:38 PM: I just made little search- here is nearly standard schematic for power amplifier. This is D class, mine is A class ( they just don`t care about my batteries). Output inductors and caps match amplifier output with antenna.
Personally, I would not even try to do something with 80-MHz until I had access to the fast scope (at least).
(http://rcmaster.ru/club/glider/tx_stady/output.gif)
Title: Re: Amplifying R/C signal
Post by: airman00 on March 16, 2009, 07:27:12 PM: *Reviving topic*
I'm looking to amplify the Sparkfun RF modules - the ones I used here http://narobo.com/articles/rfmodules.html (http://narobo.com/articles/rfmodules.html)

So what would I do to amplify the transmitter range , I'm clueless here. Connect the op amp to what?
Thanks in advance
Title: Re: Amplifying R/C signal
Post by: Admin on March 25, 2009, 12:57:48 AM: Hook up an oscilloscope between ground and antenna output and see what signals it emits.

You can probably use a MOSFET and a larger voltage source to amplify the output (I'll leave it up to you to figure that one out).
Title: Re: Amplifying R/C signal
Post by: dunk on March 25, 2009, 03:36:41 AM: if you poke around on Digikey you will find lots of dedicated RF amplifiers.
digikey.com -> RF and RFID -> RF Amplifier ICs and Modules
takes you here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=3539647 (http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=3539647)
there are 1,575 items though so picking the one you want might take a little time...

the datasheets for these components should tell you how to use them but in general they are connected to the between the transmitter and the outgoing antenna.

dunk.