Bigger is most times Better. Especially when Big is the correct value.
For my 160 Meter, 1/4 WL vertical, which is more than 400 feet from my
operating position, I use 1/2" CATV hardline X 2.
Since the feed point impedance of the vertical measures ~ 39 Ohms, I
parallel two of the 75 Ohm cables for a near perfect match to the antenna.
The 420 foot long run of paralleled cables dampens the slight mismatch
between the presented impedance of 37.5 Ohms and the desired 50 Ohms for the
amplifier such that the Alpha does not light a single reflected power
segment from 1.800 to 1.880.
The calculated loss is a mere 0.2%. The proof is in the pudding. It works
stupendously well.
73 de Milt, N5IA
-----Original Message-----
From: k1fz
Sent: Tuesday, April 29, 2014 6:59 AM
To: Carl ; Mike Waters ; topband
Subject: Re: Topband: 1000 feet 5/8" hardline or 600ohm True Ladder line.
Heating is not a good guide for long coax runs. One watt of heating, in one
foot of length, would hardly be detectable. Multiply times 1000 feet and a
kilowatt of power is lost.
The same logic not to use small diameter house wiring applies, The amount
of current through the wire needs to be considered.
73
Bruce-K1FZ
www.qsl.net/k1fz/beveragenotes.html
----- Original Message -----
From: "Mike Waters" <mikewate@gmail.com>
To: "topband" <topband@contesting.com>
Sent: Saturday, April 26, 2014 9:17 PM
Subject: Re: Topband: 1000 feet 5/8" hardline or 600ohm True Ladder line.
Hardline for 160 meters?
I've mostly used hardline where I really needed it, like back when I was
doing weak signal work on the low end of 144 MHz.
Is 75 ohm CATV-type RG-6 (F-6) coax available where you live? That's what
I use on 160m to feed my inverted-L that is quite a distance from the
operating position. I buy Commscope quad-shield flooded (buryable) F-6
with CCS conductor and a bonded inner shield in 1000' spools off eBay. I
even
use F connectors at 1500 watts (as do other hams). Neither the coax nor
the F connectors get the least bit warm, even after several minutes of
key-down at 1500 watts.
The loss of RG-6 is about the same as RG-213. And it will handle over 3000
watts all day long in the hot sun.
73, Mike
www.w0btu.com
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