Hi Guys,
> The simple fact is that some amplifiers are built with almost the same
> components that were used in the 100 watt transceivers. Bandswitches,
> parasitic suppressors, and even tank coils in some amplifiers are not
> significantly larger than in the old tube drivers.
My DX-100's tuning capacitor is smaller than the tuning cap in a
my SB-220, and every other amp I have.
I can still make it arc (like I can the SB-220 cap) if I mistune the
amplifier, over-drive it, operate it without a load.
If you designed a PA that would never arc or fail under any of the
many variable conditions of the real world, very few people would
buy it. Most amateurs couldn't even afford it.
> There is a practical problem in the design of amplifiers, however, since
> the components of the amplifier (in a properly designed amplifier) are
> larger. This means that the spacing between components increases - which
> leads to greater stray inductance and capacitance. This may be a
> significant cause of problems for high powered amplifier design and
> construction.
No. The most significant cause of problems are limitations in what
you can afford to do and still have a marketable product. The
market, not the engineering, dictates how much money there is to
spend.
Putting in $500 dollars worth of cost to everyone, just so it corrects
$1.00 worth of average cost per customer, is rarely done with any
product. Amateur radio products, with their low profit margin, are no
exception.
The only bad part about this "parasitic stuff" is the bad information
circulated doesn't even help people understand what to do to solve
problems, or why failures actually occur.
None of this stuff is magic, or hard to understand. But it is more
complex than "oh, it must have been a parasitic. Send me $19 and
I'll make it go away if you also change the bad part".
73, Tom W8JI
w8ji@contesting.com
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