Elenco Radio Controlled Car Soldering - Manual (Page 21)

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If you have an oscilloscope then you may test the remote control
transmitter for basic operation. Set the scope for 1V/div vertical
scale and 1ms/div horizontal scale.
Install a 9V battery in the
transmitter if you haven’t already done so. Connect your scope
probe to the transmitter antenna (leave the probe ground
unconnected), turn on the transmitter, and push the left transmitter
lever. You should see a stream of high-frequency bursts at least
1Vpp in amplitude, of either 0.6ms or 1.8ms duration, and
separated by 0.6ms. (This waveform is described in more detail in
the Theory of Operation section). You will not be able to get a clear
picture due to your lack of a good trigger for your scope - do not be
concerned.
Most transmitter problems are due to connections
within the unit breaking loose during shipping, so this test is
primarily testing for the presence of a transmitted signal. Test the 6
transmitter functions: forward, forward-left, forward-right, backward,
backward-left, and backward-right (the 7th function is stop). Note
that on some models the steering lever only works if you are also
pressing the forward/backward lever. The burst patterns are slightly
different for each function, this is not of interest now but is described
in the theory of operation section. If your transmitter does not work
properly then refer to the troubleshooting section.
If you do not have an oscilloscope but do have a frequency counter, you can run the above test the same way
except instead of seeing a waveform on your scope your counter should measure a signal of 10 MHz to 50 MHz
(the actual frequency is 27.9 MHz but your counter may read differently due to the burst form of the signal).
15 TRANSMITTER TESTING
typical transmitted waveform (not to scale)