If you use 7/8" hardline for the feedline you will need to use 2 jumpers at either end for your connections. This will add a minimum of 4 more connectors to the overall feedline, introducing more loss. More importantly, this will add more points of possible failures. I would use 1/2" hardline for the entire run. Less connectors, less to go wrong.
73, Joe, K1ike -------------- Original message ---------------------- From: "Willis M. Hagler" <[EMAIL PROTECTED]> > Hello All, > > I am putting up a UHF repeater in Seattle and have a question > regarding feedline losses. The repeater site is on top of a > building and the distance from where the repeater/duplexer will be > located is less than 25 feet of coax distance away from the antenna > mount.
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Hello All,
I am putting up a UHF repeater in Seattle and have a question
regarding feedline losses. The repeater site is on top of a
building and the distance from where the repeater/duplexer will be
located is less than 25 feet of coax distance away from the antenna
mount.
Of course I would like to reduce the system losses as much as possible
so I'm willing to pay for ~25 feet of 7/8" Heliax. However my
question is more about the loss experienced with inter-series
connectors in the feedline.
The 7/8" Heliax is not very friendly to bend and route into the
cabinet for direct connection to the duplexer, so every repeater I've
seen has a short chunk of something more friendly like RG-214 going
from the duplexer, through the cabinet, and then joins to the Heliax
with some kind of N-male/N-male adapter.
What kind of signal loss occurs through such an adapter at 442mhz? On
such a short run am I losing more signal through a Male/Male adapter,
such that I just may be better off running a single segment of RG-214
the entire 25 feet?
As far as I can tell, 25 feet of RG-214 would be about 1.28 dB of
loss, while 25 feet of LDF5-50a Heliax would be as low as 0.2 dB, but
if a single Male/Male adapter causes anything close to 1 dB of loss
than it seems like a wash to me...
Thanks for any advice.
73 and Merry Christmas to everyone.
Mark Hagler
W7WMH Seattle
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