On Thu, 08 Jul 2004 22:25:31 GMT, Gary S. Idontwantspam@net wrote:

The problem is that what he had asked for, continuous tx coverage for
"approximately 60 MHZ thru 500 MHZ", would be technically difficult,
and thoroughly illegal for amateurs.

One reason that we have broad band power amplifiers for the 1-30 MHz
range is that we have transistors with sufficient ( 10) _current_
gains at the highest operating frequency (i.e. the transistor fT is at
least 300 MHz).

To reach 500 MHz operating frequency, the fT would have to be
somewhere close to 5 GHz, which is available at low power levels ( 1
W), but not with significant power levels.

It should be noted that even if there is no _current_ gain above the
fT frequency, there might still be some _voltage_ gain (and hence
_power_ gain) above transistor fT, especially when tuned loads are
used. This is why you can build VHF/UHF amplifiers for a limited
frequency range with considerable power output.

Paul OH3LWR