R/C toy car transmitter

[Admin]

Hi All: I posted my technial question in another FORUM.i M Thinking that wwasn t the right place for this question.Becuase i have not gotten any response. (1/10 Scale cars)… I just dought a R/C car kit to build, and to learn about how they funtion.I been trying to find out in the output power stage of the amplifier Q2 in the circuit schematic.What is the output power ,that its set at. In milliwatts. To determine the maximum distance or range forthe output power.Can i do this using OHMS-LAW to fine this out.Or can anybody explain this to me in the most simplest form that i could understand. Sorry at this time I cannotpost this SCHEMATIC. The CIRCUIT can be seen at http://www.elenco.com/manuals/rcc-7k.pdf. Can anybody who knows R/C electronic help me. THANK YOU. PS Any help would be very apprecited… newbie JJ. :smiley16:

[betty.k]

keep your hat on, sometimes it takes a while for a response. just need to wait for the right person to come along:8ball:

[micro_Amps]

That link doesnt work for a start.

[Admin]

HI Again: That website does work. I guset it might be where you are. Or something when down on that site.Can you review my first question again and try that website a few more times.I come from the states.Thats why the website-page i inclued works for me.Try these. http://www.elenco.com.usa or http://www.elenco.com.us OR http://www.elenco.com the last one should work.When you get to there website go to there home page and look for there project kit remote radio control car kit. OR look for there user manuals. THE ONE TO LOOK FOR IS (rcc-7k.)belive me its there. THANK YOU… PS Let me know if you in to the site. I HOPE YOU OR SOMEONE OUT THERE COULD HELP ME.
😯

[Admin]

The internet is world-wide.

I’m in the USA and it doesn’t work for me, either. I tried looking at their Manuals page, and looking in their catalog but perhaps it’s too new or it’s discontinued?

Google found the manual on someone else’s website:

TechEdu.com

Those ICs used appear to be pin for pin compatible with the TX2 and RX2 chips.

Ohms law won’t help you figure out the output power. The circuit must be designed to be no more than the maximum allowed for this type of unlicensed transmitter. The easiest way to boost range is to increase voltage to the transmitter’s output transistor (while keeping it the same at the IC) but then you are likely to be over the legal power limit.

Another easy way is, if it is a 27MHz as this one is, put a CB Radio antenna on the transmitter. And check receiver antenna length It isn’t as critical but should be as long as you can make it up to 9 feet. ;’)

You may also find your range is being shortened by interference. The receiver is using a simple design that is very sensitive with few parts, but is by nature wideband and very much subject to interference. That’s why you can’t run two cars on 27MHz even if they are on different frequencies. So you could replace the front end with a superheterodyne receiver. It’ll take more parts.

Maybe a tuned front end, with mixer followed by 455KHz ceramic filter IF and an MK484 as a 455KHz IF amp/detector. Yes, I’ve thought about this and have some of those ICs already. You must get a crystal for the receiver then, one that is 455KHz off from the transmitter crystal.

Hmmm…. just did a search, here’s a circuit tailor made! Leave off the LM386, use the output from the ZN415 pin 7, run into Pin 14 of your receiver IC AF2311.

Superheterodyne Receiver

Now- why do you need more range? You are likely to be interfering with other RC cars if you are racing others, and how far do you think you’ll be from your car?

[Admin]

I meant to say, the receiver design in all these little cars is called a Super Regenerative.

Super-Regen info

[Author]

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