RC toy car signal repeater

[christodoulos]

So I bought a small rc car with a small antenna, and its range, in which it operates, is to small (aprox. 3-4 meters). At first I thought I should extend the antenna of the car however the car couldn't support a larger antenna.

Then I thought that I could make some kind of a signal repeater using one more pair transmitter-receiver. So I bought another rc car (with an operating range of about 100m) and tear it apart. I tried to connect the transmitter to the receiver, using mosfets. The basic idea is when the recever receves a signal it activates the transmitter in order to re-transmit it. By putting this device close to the mini rc car I could expand the range.

However the mosfet circuit I design didn't work at all. I used as reference this diagram for the rx/tx : https://www.instructables.com/file/FMRBHT0GV0KKOQK and also I read this project :https://www.instructables.com/id/Arduino-controls-cheap-RC-car-transmitter/#step1. So I connected the pin 6 of the receiver to the gate of an irfz44, the ground of the receiver to the ground of the transmitter, the pin 1 of the receiver to the drain of the mosfet and the ground of the transmitter to the gate. The transmitter oparates with 3V source and the receiver with 6 V.

So, what am I doing wrong?

Thanks in advance

 

[kam1787]

I am fairly sure you have to have 2 different frequencies.

 

[chuckey]

By far the easiest way is to boost the power of your existing transmitter. I have been trying to fix a RC car working on 50 MHZ. If I connected a simple diode probe to the base of the aerial , I got about 7V of RF, what are you getting?
Frank

 

[christodoulos]

I am fairly sure you have to have 2 different frequencies.

Well I actually use the forward and backward for receiving and left and right for retransmitting.

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By far the easiest way is to boost the power of your existing transmitter. I have been trying to fix a RC car working on 50 MHZ. If I connected a simple diode probe to the base of the aerial , I got about 7V of RF, what are you getting?
Frank

How can I measure the Voltage of RF? Can a simple multimeter do the job?

 

[jpanhalt]

What is the carrier frequency? Have you considered a directional antenna for the transmitter? If it is 2.4 GHz, that might be quite easy. I agree, the receiver and transmitter for the repeater cannot be on the same frequency without some form of blanking/gating. Different channels, which are on the same same frequency, won't accomplish that.

John

 

[chuckey]

A diode detector is three components, a low value capacitor, 1 NF, that connects the signal to the diode. The diode is also connected to your meter earth. The junction of the diode/cap then goes via a 10 K resistor to the meter live. Depending on which way the diode is connected the meter "live" could be + or -. If you want it +, then connect the diodes cathode (banded end) to live. The best sort of diode is a germanium point contact (lowest voltage drop), then a hot carrier diode then a silicon switching diode (highest voltage drop). Power rectifier diode will not work.
Frank