"Phil Clements" <philk5pc@tyler.net> says --
>One of the dead give-aways on a S.S. amp
>is the band switch and the low-pass filters
>for each band. You need at least 6 filters
>in the output to cover all nine bands.
>Even a "single-bander" needs an L/C filter
>in the output to even come close to meeting
>type-acceptance standards.
"True t'ing."
To their credit, the ARRL has assiduously included suitable low-pass
filters in all their HF SS final designs I've seen published for some 15
years.
I've seen some plans for relay-switched low-pass filters, and I guess by
now somebody's got them working right. I still haven't seen any practical
high-power auto-tune filters for HF -- these have been successfully
implemented for microwave frequencies and milliwatt power levels, but even
PIN diodes aren't quite fast enough at amateur price levels to "catch" a
harmonic on keydown.
I'd like to think it's possible to develop an affordable desktop kilowatt
transceiver with output bandpass filtering that tracks the VFO and tunes
after keydown and before transmission -- but come on, how many of us have
"pounced" on a DX station when the band magically quieted for 150 ms?
If the new high-end SS amps do have this kind of capability built in, I'd
like to know. Until then, I'll have to settle for an autotune Alpha with a
pi network to keep my emissions (mostly) legal.
Jim N6OTQ
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