[TowerTalk] Lemme pick your brains
Jim White, K4OJ
k4oj at tampabay.rr.com
Thu Sep 4 12:52:17 EDT 2003
FCG es Towertalk de K4OJ
I am toying with the idea of building up 4 receive antennas for use on
10 - 40 meters...
I want make them verticals as I wish to isolate them as much as possible
from the transmitting antennas used on each of those bands which are
horizontally polarized yagis.
I am able to install them far away from the transmitting yagis )as well
as power lines) next to a pasture adjacent to the station. It has a
mote with fence posts around the outside of it... the fence posts would
be mounting points for the verticals.
They will be fed with 75 Ohm CATV hardline, and I have sufficient tubing
(I think) to make "full sized" verticals for each of these four bands.
Since they are not going to be used for transmitting and only for
receiving I am wondering about just how complex their design needs be.
If I understand correctly their length is not super critical and I hope
I can get away without having to "tune" them - just rivet up a bunch of
tubing and go so to speak... can I use "half of a yagi element" as close
enough size/model?
What is the easiest way for me to feed these taking into account it is
75 ohm CATV feedline (will a simple center to the vertical and shield to
the ground with a connector even be acceptable?)
- and -
how extensive a ground system should these need? Again - since I am
only using these for receive how much real improvement will I see if I
go hog wild with radials versus a small quantity under each....
ALSO - I am thinking that I will mount these at just above "ground
level" as opposed to raising them and using elevated radials - would the
elevated antenna hear any better with its base up say 8 or 10 feet or is
it not worth pursuing?
Lotsa questions I know, but here in FL the temperature is going to start
dropping fairly soon and I wanna hit the ground running as far as
installation of these antennas.
Thanks for your assistance - reply to me in private and I will digest
and summarize the collective towertalk knowledge base for the group...
Like K2KIR said about maxing ones signal on transmit I am angling to
maximize my receiving ability (already have the transmit side planned
out :-) )
73,
Jim, K4OJ
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