[BC] Diplexing an AM antenna.

[Milton R Holladay Jr.]

LBA, PhaseTek, and Kintronics design and build them. IIRC, each input will
go into a matching network (ATU) followed by pass-one/reject-the-other
filters prior to the combining point, possibly followed by common matching
component(s).
They will want to know the actual tower impedance at each frequency, though
it may be possible for them to predict close enough from  the tower
dimensions.
There is or was a wonderful paper on Kintronics' website about them for all
to read..........
M
----- Original Message -----
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>
Sent: Monday, April 30, 2007 10:51 PM
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.