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Old February 7th 06, 01:55 AM posted to rec.radio.amateur.antenna
Bryan Martin
 
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Default Passive Repeater

The building location is maybe 500 feet away from where the repeater would
be. The parabolic grid is maybe 3000-3500 feet away from the repeater
location.

As for the output we will talk about the grid antenna first. It is
currently at 28mw which is adjustable up to 250mw but I would be way over
the limit with the 24db gain antenna (also the way I understand it which is
a learning in process I should not need to increase the xmit power due to
the focus of the directional type antenna). Plus since this will be out in
the open in a sealed weather proof box I don't want heating problems or bird
nuking etc.... Sadly I am unable to find out what the current MN-700 AP
which is located in the building transmits at or what the gain of the stock
antenna's is. I have purchased another AP similar to the one hooked to the
grid antenna which by default would be transmitting at 28mw with 7db gain
rubber duck antenna.

Passive antenna
"You simply take two antennas and join them with feeder". Help me out a bit
here if possible. So I take two antenna's such as
(http://sharperconcepts.zoovy.com/c=6...ct/YSC-HG2409Y)
and hook the pig tails together? Point one at the grid and one at the
building right? Does the gain really matter? Do they need to both be
directional?

"You may need to separate them some so they dont interfere with each others
capture pattern."
I dont think this would be an issue as one would have to be on 1 side of the
utility pole and one on the other. Do you think this would cause problems?




"Bob Bob" wrote in message
...
Hi again Bryan

A passive repeater is very simple.

You simply take two antennas and join them with feeder, then point one
antenna at one end of the link and the other at the other end of the link.
You may need to separate them some so they dont interfere with each others
capture pattern.

There will be a link budget that defines how much system gain (and thus
antenna gain) you need. You could conceivably get away with using the
standard AP antenna at that one end. As I said previously the software I
use for this is broken and I am not in a position to redo it by hand just
at the moment. There is a simple formula for determining path loss over a
line of sight path. You just do that twice with the received strength at
the repeater being the source power for the next link (minus about 3dB)

What are the distances from each site to the passive rptr location? If one
does the calclulation then outoput power and receiver sensitivity is also
needed.

Cheers Bob

Bryan Martin wrote:
Ok, my first test failed so far. Example of what I am doing is here
http://home.triad.rr.com/tempdir/images/layout.jpg. My next thing I am
thinking about trying is to place some kind of somewhat small (no
billboard) passive repeater at the end of the powerline attached to a
utility pole where it meets the field. No power this far out and
trenching is not an option. I can google and find hords of info about
people using passive repeaters to bend the signal but I cannot find an
actual passive repeater or how to build one. Also when dealing with this
type of repeater would it force me to have directional antenna's at both
ends where currently I have only the one directional parabolic grid at
the top of the powerline and just a standard AP inside the building.
Anyone think of anything else that may work. going over the forest is
also not an option. I own the land where the grid antenna is located but
I dont own the land where the building is located as I just have
permission to place a AP at that site. I am trying to make the impact as
minimal as possible at that site.

Bryan