Hi Tim,
Yes it is a linear PA for 1-30MHz.
I did disconnect all filters etc. and just connected input and output
directly with 2 short pieces of coax. That worked fine. 180W clean output.
I'll try out your suggestion and recheck every path and see if I find the
"bug".
Thanks!
73
Michael
"Tim Wescott" wrote in message
...
Michael wrote:
Hi,
I built the AN762 amp along with 6 low pass filters with parts bought
from Communication Concepts.
The amp itself (180W version) works fine and can easily produce 180W with
5W input.
Now to the problem and question:
I wanted to put it in a good solid case with the filters, a RX/TX relay
(8A 240V Omron relay also bought at CCI) a manual switch for the filters
and the filters.
I also found a good heat sink for the PA.
I connected all parts with short runs of RG-58, but a lot of the power
seems to get lost in this system. If I'm lucky I can get 100W out. Even
if I bypass the filters. Is RG58 a bad choice for the internal wirering?
Is the manual switch a bad choice?
What special things should I address for optimum perfomance?
In my case the PA is placed on the back panel direcly mounted on the heat
sink. I made a rectangular hole in the back for the PA board.
The input and output connectors are also on the back panel. The filters
are mounted at the bottom of the box and connected to a band switch
mounted on the front panel. Behind the filters and in front of the PA is
the RX/TX relay cirucuit.
73
de
Michael
OZ8AGB
Is this HF? RG-58 should be fine. RG-174 should be fine for that matter,
if this is HF or even VHF. I would suspect that you either have one
defective component, a poorly attached connector, or a damaged cable.
Assuming that it's linear you could just put 5W in, let it run into a
solid dummy load for a while, then feel around the input path for the hot
thing. If you're losing 2 watts to one component you'll be able to feel
it.
If you can you may want to feed the amp it's 5W directly and see if it
still gives 180W. If it were me and I was desperate I'd yank the amp out
of the case, make sure it was doing 180W on the bench, then put it back in
the case checking at every step. So I'd verify 180W with it just bolted
in, then verify power through the filters (accepting a bit of loss), then
verify power with the case's connectors, etc., until I either found the
problem or had my completed amp.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com