Chris,
There aren't many ways around the laws of physics. If you can't get adequate
physical separation, and can't afford a duplexer...perhaps you just can't
afford to operate a repeater.
Can you gather enough interested users, and get everyone to chip in for a
duplexer? If not, maybe your local user community isn't large enough to need a
220 MHz repeater!
You might be able to gather a group adequate to fund and support a 220 repeater
if you got closer to the Charleston area, linked into a hub in Charleston, etc.
Your elevation might have some definite linking possibilities if folks in
Charleston wanted a 220 MHz hub that could get them coverage farther west on US
26, for example.
Generally, if you need to raise money to get a project done, you need to be
able to cover a population center large enough to include a bunch of potential
users. Given your area's population growth, if you have the connections,
getting the town or county to help fund a sanctioned emergency repeater system
might be an avenue, but you'd better have enough users on 220 to make it work
if it's ever called up. The economy will be against you in this pursuit; your
population growth will be an advantage.
Remember, finding the money to get it built and installed is only the start of
the financial fun. You'll need an ongoing budget for maintenance and repair, or
the machine will spend too much time down, and the users will wander off to
other pursuits.
Good luck!
73,
Paul, AE4KR
----- Original Message -----
From: cmcclel...@aol.com
To: Repeater-Builder@yahoogroups.com
Sent: Monday, August 30, 2010 6:44 PM
Subject: Re: [Repeater-Builder] Duplexers
Thank you for your response.
The problem is that the repeater is located on top of a building and the
tower on that building is only about 20 feet tall. We can move the two antennas
apart horizontally, but only 20 feet vertically. Duplexers are way too
expensive and hard to find for the 200 Mhz band. We are running about 20 watts
and the frequency separation is 1.6 mhz. Sometimes a week signal comes in and
sometimes the transceiver is desensitizing the receiver and covers it up. Any
suggestions?
Thanks
Chris
In a message dated 8/30/2010 8:36:53 P.M. Eastern Daylight Time,
wb6...@verizon.net writes:
Chris,
You do not have to use a duplexer, but it makes building a repeater SO much
easier! Keep in mind that "antenna separation" usually means vertical
separation, not horizontal separation. Moreover, the same isolation
provided by 1000 feet of horizontal separation might be provided by 10 feet
of vertical separation. The amount of isolation you need is based generally
on the transmit power, frequency separation between TX and RX, and the
sensitivity of the receiver. The receiver bandwidth and antenna types also
play a factor.
73, Eric Lemmon WB6FLY
-----Original Message-----
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mackey
Sent: Monday, August 30, 2010 4:44 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Duplexers
Our club was recently given a 220 repeater. We have two seperate antennas.
We do not have a duplexer. My question is do we have to have a duplexer? How
can we keep the transmitter from desensitizing the receiver? The antennas
are apart but can be moved farther.
Thanks
Chris
Kg4bek
