I had one of those earlier tentech counters.  They actually were a 
frequency counter, but because it was reading the vfo frequency, they 
did some conversion inside so the reading came out right.  I tried using 
one on an atlas once, it sort of worked, but you had to add or subtract 
the if frequency--got kind of confusing.
73s
Butch Bussen
wa0vjr

On Tue, 10 Jul 2007, Ed Malmgren 
wrote:

> Colin, the Tentec 299 voice freq counter was made by T T probably back in
> the 70s for only their radios such as the Triton and I think they will work
> on the Omni A, D-C series.  This happened before my owning T T radios.so my
> knowledge in limited.  Ed K7UC  Ed K7UC
>