What Handi-Hams has is $30. They've put a tone in an swr meter and you tune it
for nul of the tone. Its designed for hf use. When I talked with them last
week they didn't know if you could use it for vhf or uhf. Guess you'd have to
have a sighted person see if you could get full scale deflection up there.
Tom
Tom Brennan KD5VIJ/AG, CCC-A/SLP R/D - AU
web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html