---------------------- Forwarded by Tyler G Stewart/BENN/CEC on 10/30/97
09:00 AM ---------------------------
Tyler G Stewart
10/30/97 09:03 AM
To: n4zr@contesting.com
cc:
Subject: Re: [TowerTalk] CATV Hardline (Document link not converted)
Remeasure it using a wattmeter and 75:50 ohm matching transformers and let
me know what you get.
I wouldnt trust loss measurements from one of those antenna sweepers, and
most are not set up for 75 ohms. However, it's
always possible that you have some other problem with that particular
feedline.
73, Ty K3MM
To: towertalk@contesting.com
cc: (bcc: Tyler G Stewart/BENN/CEC)
Subject: Re: [TowerTalk] CATV Hardline
At 12:48 AM 10/24/97 +0100, Tyler Stewart wrote:
>I've never heard that and have seen no evidence to support it. It's all
>good stuff and all is a copper clad aluminum center with an aluminum
jacket.
>At HF there is almost no difference in loss...it's probably slightly
higher
>due to the smaller center conductor of 75 ohm cable. It's not worth
>worrying about.
>
For whatever it's worth, my run of approximately 250 feet of 3/4" CATV
hardline measures (with an Autek RF-1) to have 1.6 dB of loss at 28 MHz -
not nearly so good as the Handbook table says it should be (about .36
dB/100 fit). Of course, this includes 2 home-brew UHF connectors. I've
checked for moisture infiltration, etc., but this is about what the
installation measured right off the reel. I wonder if others have
compared measurements of their actual installation with the Handbook table
-- I'd sure like to recoup that elusive "'nother dB."
73, Pete Smith N4ZR
n4zr@contesting.com
"That's WEST Virginia. Thanks and 73"
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