Ok I'm a relative newbie so I'll ask also. I ran 1/2" Heliax up my tower
for HF. But 75 ohm CATV line can be used also? Being a cheapskate I'd much
rather spend nothing so explain. My radio/amp wants 50 ohm but the feed
line is 75 ohm and the antenna is some range also based upon freq. Are you
supposed to do a complex analysis of this or is it safe to take a simplistic
view of it (in terms of station performance)?
[mailto:firstname.lastname@example.org]On Behalf Of Pete Smith
Sent: Thursday, July 18, 2002 11:01 AM
Cc: 'Troy Thoele'; TOWERTALK@contesting.com
Subject: Re: [Towertalk] Newbie Question
At 12:44 PM 7/18/02 -0500, Red wrote:
>Normally I'd agree that heliax is overkill on HF, but suggest you check
>the attenuation of any coax, expecially on 10 and 15 meter. Ordinary RG-8
>loses about 1.2-1.3 dB per 100 feet at 30 MHz. That amounts to 3 - 3.25
>dB for 350 feet; half the power!
But 75-ohm 3/4" CATV hardline is just a hair lossier than 7/8" Heliax at 30
MHz (.3-.35 dB/100 ft), can often be bought for free, and lends itself to
inexpensive connector fabrication.
73, Pete N4ZR
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