On Fri, 05 Nov 2004 10:11:08 +0800, Steve Underwood <email@example.com>
>Allan Herriman wrote:
>>All "solid state" finals for broadcast FM have been around since the
>>'80s. At the time, they were better in terms of reliability, but not
>>initial purchase price.
>>I don't know how the comparison stands today.
>I said big FM transmitters. 100kW ERP from a silicon final stage? I
>haven't seem that used
>Up to a couple of kW things are OK, but you need to stack too many well
>matched transistors to keep scaling things. Minor mismatches cause a lot
>of stress, and reliability tends to be rather poor.
Interesting. Usually solid state transmitters are used because they
are *more* reliable (= more cost effective in the long term) that the
valve units they replace.
That was certainly the case for the microwave SSPAs produced by a
company I used to work for.