Hi you all, here PU1BZZ Alexandre, from Brazil
Ok, The repeater builder is a great site (and a BIG thanks for all
involved, I donated and encourage all to donate at least a dollar. If all of
us donate 10 dollars/month to the sites who help us, what a great net this
would be, what is 10 dollars in your monthly income?). But I have some
"special needs" I haven't seen in repeater builder, so I came to ask you:
"How to build a small group repeater in a very tight budget?"
I'll try to explain Brazil to the ones who doesn't know it: We cannot
afford to import duplexers. The raw material to build it is expensive and
hard to come by. Also, hardlines are a no-no-buy here. Forget connectors to
be used in hardlines. So, how does we build a repeater?
We have a small repeater of our local amateur group. This is a radio
(yes, ONE radio) with TX and RX stages separated, two antenna outputs, one
mast, one antenna on top (RX) and one antenna on the middle of the mast
(TX). No grounding, no duplexer, no special measures. Of course, this is way
beyond what I can do, but I need to know better what to do. So I have some
questions, and these questions could become a tutorial on repeater builder:
"How to build a thigh-budget-repeater"
- What is the vertical (or / and horizontal) separations of the
antennas? How can I determine the separations, with the sensibility of my
reciver and the power output of my transmitter?
- In a tower (we got a 6-meters tower to be installed on repeater site
soon), how is the RIGHT way to ground it? I have a franklin lightining
arrestor. Should I put it on top or on the side of the tower? If it goes on
top, where do I put my antenna(s)?
- Having a tx and a rx one near another, I'll have enough RF leakage to
have desense on RX?
- How can I determine the coverage of the repeater? Is there a SAFE
computacional way to do that, or will I need to take my car and taking
measurements around the 'peater perimeter?
- Any homebrew methods to make a repeater SAFE from lightning? A pair of
gilettes, one connected to the coaxial hot wire and another to the ground is
said to work, but what are the collateral effects? Will it cause arcing from
the TX to ground?
- Any tips I should follow?
Of course, you don't need to say "a duplexer would be better", "use
poly*", "have a better budget", "buy better radios" and like. I do know all
of that, but we DON'T have a way to buy a duplexer, poly* and better radios
:o)
Thanks a lot,
Alexandre
PU1BZZ
(and yes, I take lemonnade from a rock, that is the way things works in
Brazil :o))
