Nur,
first of all, I assume that those frequencies are legally
licensed in whatever country you're in. You didn't mention
anything about a duplexer or mechanical cavity filters, so
can I assume you aren't using any? A 1 MHz Tx/Rx separation
is very close at VHF to use for a repeater, unless you have
a good duplexer with 80 dB or so of Tx-RX isolation, or have
the Tx and Rx antennas vertically isolated by about 80 feet
or more. Horizontal separation is not very helpful, as it
would require a separation of nearly 10 times that
horizontally to obtain the same isolation as the 80' of
vertical isolation. Of course, this requires a tower, or
tall building (maybe a water tank?). If you don't have one,
you will need a duplexer, or run the transmitter power down
to a couple of watts and get as much vertical isolation as
you can. Summary: You're probably desensitizing your own
receiver with your transmitter, which creates both wideband
noise, and direct receiver desens from overload.

Good Luck,
Rick T.


Newbie wrote:
Hello All,

We bought a kenwood repeater TKR-750 and 2 diamond F23 antennas plus
the programming software.

Unfortunately we can't hear anything beyond one kilometer. Here are the
frequencies we are using:

TX 15900
RX 16000
TONE1413

The equipment are being used in africa in a remote location for an NGO
helping refugees I am back here in the states now.

I would appreciate any pointers from the group.

Thanks.

- Nur