On 31 Aug 2011 12:41:25 GMT, dave wrote:

Geoffrey S. Mendelson wrote:

Allodoxaphobia wrote:

We still don't have a clear description of what the OP is trying to
accomplish.

Take two radios, two j-poles and a lot of coax and make a repeater.
Obviously I will need some sort of controller in between but that's
irrelevant.

I want to place one J-pole (or similar antenna) at one corner of my garden,
and another at the other one (10 meters apart).

One will be used to receive a signal, the other to relay it. They both
will be somewhere on the 144-146mHz band, with the output being a few watts
with a max of 20.

Besides the distance, I was looking for a cheap way of not having
the transmitted signal block the receiver. The duplexer in question
is rated at 75dB isolation with a 3.5mHz split, I can only have .6 mHz.

What I was wondering is that since at a .6mHz split, the isolation will
be a lot less, can I somehow combine the two sides to make a better
filter?

Thanks,

Geoff.


If you have two antennas you don't need a duplexer. Just notch the
transmit from the receive antenna.
I think that is what he is asking. Can he takes his duplexer and use
it as an extra sharp notch filter for his receiver. One "side" is
already set up for that purpose. He is asking if the "side"
originally intended for the transmitter can be used to further filter
the receiver.