[Amps] MOSFET amp filtering - was: auto-tune

[Steve Wright]

On 12/12/16 17:17, many people wrote:
>
>>> Not if the SS amplifier had an out impedance of one or five thousand
>>> Ohms.
>> But they don't. Typically a few ohms. You could step it up to a few
>> thousand with a transformer and then run it through a pi network I
>> suppose, but then you lose the advantage of SS amps: they are
>> naturally broadbanded and don't require tuning  [...]

Broadband - That's just not true.  90% of the topic has been about 
filtering and diplexing - that's not broadband if have to have per-band 
filtering, even if we DON'T have to have per-band matching.

If we are going to be hams, then we find new ways to do things, 
especially if it's cheap and repeatable.

If the topic is filtering and maintaining a good match - then why can we 
not transform up to the input impedance of an inexpensive multiband 
matching system?

What would be the input impedance of a multiband matching and filtering 
system that was half the price and complexity of the currently used 
per-band filter?  Would the loss of that transformer be a magnitude 
worse than a 50ohm output transformer?



Steve  ZL1BHD