Thread
:
Ham radio backstay antenna feed line
View Single Post
#
5
posted to rec.boats.cruising
Larry
external usenet poster
First recorded activity by BoatBanter: Jul 2006
Posts: 5,275
Ham radio backstay antenna feed line
wrote in news:1174870222.221326.262340
@n59g2000hsh.googlegroups.com:
I'll be curious to see how this effects my HAM radio performance since
the original installation had coax as the feedline!
It won't help. Boats running low power (150W) and end-fed, untuned short
wire antennas have SUCKY signals, no matter what you do....especially on
the lower HF bands. A 55' backstay, between the insulators, is an
antenna at 8.5 Mhz, if you have a good ground on the tuner (1/4
wavelength) and a great 1/2 wavelength antenna at 17 Mhz, where it
doesn't even need a ground system to work against. At any other
frequency band, especially below 8 Mhz, the antenna is way too short to
fit the RF wave onto and the lower you go the worse it gets. Between 8.5
and 17 Mhz, the antenna is a complex impedance with a lot of inductive
reactance. The wave doesn't fit well the further away from 8.5 and 17
Mhz you get, killing its radiating potential.
Use 468/ft length = Mhz to determine what resonance is for your backstay.
It'll work fair there on 150W. Far away from there in frequency, it'll
suck, just like everyone else's. Hams use resonant antennas for a
reason...(c;
Larry
--
Message for Comcrap Internet Customers:
http://tinyurl.com/3ayl9c
Unlimited Service my ass.....(d^
Reply With Quote
Larry
View Public Profile
Find all posts by Larry