[Amps] Solid State HF amps and kits

[Peter Chadwick]

Jim said:

>I've seen some plans for relay-switched low-pass filters

When you do the sums on the kVAR involved at 1500 watts, it's pretty awesome.
Then when you consider the effects of SWR too - I normally figure on being able
to 
operate into a 2:1SWR.

One trick that seems to have disappeared, but was popular just over 50 years ago
when TVI first raised its ugly head, was the 'half wave' filter, which has the
advantage 
of reproducing at its input the load impedance at its output.

I've looked at motor tuning, but that's no easy task, either. A half wave filter
using 
RG213 for the capacitors does simulate OK, but 12 foot lengths of 1/2inch
diameter 
coax don't really fit with miniaturisation! OTOH, a good 35MHz cut off LPF will
do for 
18MHz and above.

73

Peter G3RZP