Yes function generators are very inexpensive, especially
on ebay. There are many good ones for under 100.00.
I have one, but my problem is there does not seem to be
a tutorial I can find about how to actually set them.
There are a bunch of different variables including
positive offset, duty cycle, voltage output etc.
If you know of any info on using an off the shelf frequency
generator please let me know.
I have seen the Heathkit photos of the ones they used in
Rifes lab in San Diego.
I am using mine as a zapper set on 35KHZ.
T