[BC] Diplexing an AM antenna.

[Dana Puopolo]

Usually a consulting engineer designs the diplexer and it comes rough-tuned
from the builder. At your power levels, there would likely be two cabinets
that would either both be connected to the tower, or one would be connected
through the other. The ATU's would probably be in the same cabinets.
Higher power diplexes usually need shunt filters on each transmitters'
output.

The FCC will require sum and difference frequency measurements for spurious
before program teats are authorized.

Many consultants can design these units. I would agree that Kintronics would
be my choice to build it.

-D


</div>------ Original Message ------
Received: Mon, 30 Apr 2007 10:52:39 PM EDT
From: "Ronald J. Dot'o Sr." <ron.doto at comcast.net>
To: "The Brain Trust" <tech-assist at radiolists.net>,	"Broadcasters' Mailing
List" <broadcast at radiolists.net>Cc: 
Subject: [BC] Diplexing an AM antenna.

Hi Gang,

I'm about to take on a job I've never done before and would be grateful for 
any advice.

I'm under the impression that a diplexer is like a double ATU with filter 
traps to couple each station to the tower while rejecting the other station 
from the respective transmitter's output.

Is it very different from tuning a single ATU for each respective station?

Any suggestions on who to get the diplexer from?  Do they usually provide 
detailed tuning instructions?

The frequencies are 1220 and 1490, both 1 Kw. class C's.  I don't know what 
the tower resistance is yet.

Thanks for any help,

Ron D. 

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