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Old September 24th 06, 03:20 PM posted to rec.radio.cb
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First recorded activity by RadioBanter: Jul 2006
Posts: 985
Default Amp Design Concept -- Preliminary

Jimmie D wrote:
Point to point wiring does not have to mean the birds nest constuction you
describe. RF wiring could well be stamped out metal pieces mounted on Teflon
or ceramic. very repeatable, very stable. It could also mean the isolted pad
constuction where smalll sqares of PC board are glued to a substrate. This
has proven reliable, obviously an improvement over PC board material could
be found.and better mounting methods than glue.


Yes, I agree with you. The problem is that these amp builders are not
using the point-to-point methods you describe. From what I can see...
they are gluing pieces of copper clad board (via double sticky tape) to
a non-etched copper-clad board. They have no regard for characteristic
impedance of trace widths
(http://www.pcb123.com/help/calculators/microstrip.html). I also am not
really crazy about the longevity of double-sticky tape... LOL


There are two big problems I see with most amp designs. One is biasing, even
the cheapest Boomer would be much improved if it had an adequae bias
circuit. The other is proper setup. I doubt if someone mostly interested in
how well they can make the power meter swing will pay much attention to
setup instuctions. Attenuators on the front end would be a joke. How would
establish proper drive for a given setup with only a cheap power/VSWR meter.



Agreed, my new amplifier design
(http://www.telstar-electronics.com/S...202879ABTC.pdf) now has
thermal tracking class AB biasing. I also don't use any front-end
attenuators. Like you say, proper setup is critical to any good
station. The operator needs to pay attention to the drive requirements
of the amplifier... and should adjust the driver accordingly.

www.telstar-electronics.com



 
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