Yes, you're correct, .357dB/100 feet at 30 Mhz is better, but IMHO I consider
that .529 is also a very good spec too for the HF bands. Heck, even good 'ole
Buryflex at .7 dB loss is fine for many hams on HF. I show from a 100 watt
input 92.1 watts reaching the end of a 100 foot run for the LDF4-50A and for
the smoothwall 1/2" 88.5 watts; a difference of 3.6 watts and the converse
could be applied to receive attenuation. It can be argued that nearly every
loss or gain in any spec is theoretically noticeable per se, but I'd think one
would be hard pressed to accurately choose one over another via a true A/B
test. And even if one could, the difference would be very small. .17 dB, we
need 6 dB to swing the S meter one notch. And that's all at 30 Mhz. I'd
consider around 14 Megs and lower where most spend most of their time operating.
If both cables were priced similar, I'd naturally choose the LDF, but when you
can get new stock 475' roll at for just about the same price as shipping vs.
around $2.50/ft (almost $1,200) plus shipping for the LDF, then for my amateur
station the 1/2" smoothwall wins. And yes, I now see the connectors for the
smoothwall might be a PIA vs. the connectors for LDF, but I think (fingers
crossed) I have devised a solution making easy to make dies from 1/4" steel and
pressing it all together in a hand operated standup hydraulic press. I even
considered using one of my injection molding machines clamps (max 238 tons),
but that might get out of hand!
Rick Wheeler
K4LX
________________________________
------------------------------
Message: 3
Date: Fri, 2 Feb 2018 10:10:12 -0500
From: "john@kk9a.com" <john@kk9a.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Install Type N connector to 1/2" Smoothwall
Message-ID: <aefdfdbd068b0ea73a1d4fbc3039ad76.squirrel@www11.qth.com>
Content-Type: text/plain;charset=utf-8
The smoothwall specs are not that great. LDF4-50A is also 1/2" and its
loss is .357dB per 100 feet at that frequency. Also connectors are easy to
install with a few hand tools.
John KK9A
To: "towertalk@contesting.com"
From: Rick Wheeler <info@omalley.com>
Date: Wed, 31 Jan 2018 01:31:40 +0000
It is smoothwall but the description from Tessco was this:
CommScope - 1/2" HELIAX Superflexible Smoothwall Aluminum
TESSCO SKU: 473138
QTY/UOM: 1 FOOT
UPC: 646444731386
MFG Part #: SFX-500
They describe it as heliax but it is smoothwall. It has good specs; .529 db
loss at 30 MHz/100 ft. You find the tech specs at Tessco's website searching
sku No. 473138. Still don't know where the 'Superflexible' term came into
play.
It's stiff!
Think that would work?
Rick Wheeler
K4LX
------------------------------
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End of TowerTalk Digest, Vol 182, Issue 3
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