This is a question about a Marconi Canada commercial HF
amp, -NOT- a CB-type amplfier. It is a model BL-100 (not
a Courier BL-100 tube CB amp).
This amp uses four modules to generate 1KW of RF. All
the amp modules are in a bottom enclosure, then a large
rack of cooling fans is in the middle, then the top rack
enclosure contains massive brute-force bandpass filters.
There is a single coax input, but multiple coax outputs
which are switched in and out by relays on the filter board,
depending on which band you switch to (I guess the
assumption must have been that if you had enough money
to buy this amp, you have enough real estate for separate
antennas for each band). This behemoth takes a 48VDC
supply, which I was lucky enough to locate with battery
backup! (Thanks TELCO!). (Yes, I realize it's positive
ground, but I can make it work, I'm fairly certain.)
I'm not going to use the original exciter, so this amp is
not going to have the capability to switch between the
different outputs (unless I can design some manual
switching arrangement).
My question is this- in the group's opinion, would the RF
follow the path of least resistance if I just tie all the filter
inputs and outputs together (sort of like installing multiple
Hustler loading coils on a mobile antenna), or must the
various filter combinations be switched in and out as band
changes occur? I guess I -could- run it without the filter
board, but it probably would no longer meet spectral purity
requirements, which is why the engineer put the filter
board there to start with. I want to use it if I can.
Any ideas? Is anyone on the list using one of these, or
have any experience with them?
Thanks, -Web Williams in Myrtle Beach, SC
Kind regards, -Web Williams in Myrtle Beach, SC
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