[TowerTalk] Re: TowerTalk Twin lead feedline
n8ug@juno.com
n8ug@juno.com
Sat, 11 Jul 1998 13:33:28 -0500
You got my curiosity up, Tom, so I fired up my 259B and ran a piece of
554 several times - .92 both times. I just removed 1/2 the insulation on
one side for 1/2 inch, all from a 1/2 inch on the other, shoved the first
into the ctr of the SO239 and held the other side to the threads. seemed
to work great. scrap was 15 feet long.
Try it again? I looped a piece of rope throiugh a" window" at the far
end, & hung it in a nail.
Glad you used the "good stuff" on all tjhe dip[oles!
Press Jones, N8UG, The Wireman, Inc., Landrum, SC, 29356
Sales (800)727-WIRE(9473) or orders@thewireman.com
Tech help (864)895-4195 or n8ug@thewireman.com
www.thewireman.com and the WIRELINE bargain page
Our 21st year!
On Sat, 11 Jul 1998 07:43:30 -0600 n4kg@juno.com (T A RUSSELL) writes:
>Hi Tom and Press,
>
>I measured a short piece of the stranded (mid size?) ladderline I
>purchased
>from Press, using an MFJ antenna analyzer, looking for minimum
>impedance,
>which I ASSUMED would indicate 1/4 WL. Based on the frequency at
>which
>the meter indicated minimum RESISTANCE, the computed velocity factor
>was 0.8 which surprised me a bit as I was expecting a little higher.
>
>Intuition tells me that the lower the VF, the higher the loss. I
>think that ARRL
>needs to make a clarification between true OPEN WIRE LINE (using
>widely
>spaced high quality insulators) vs. the dielectric insulated
>ladderline with
>large chunks cut out. I'm sure there are significant differences.
>
>For the record, I have 80, 60 (yes, 100 ft CF), and 20M 1/2 WL
>dipoles fed
>with ladderline from the Wireman which I use on 80, 40, and WARC
>bands.
>
>73, Tom N4KG
>.............................
>
>On Sat, 11 Jul 1998 00:31:52 -0400 "w8ji.tom" <w8ji.tom@MCIONE.com>
>writes:
>>
>>Hi Press,
>>----------
>>> From: n8ug@juno.com
>>> To: towertalk@contesting.com
>>> Subject: [TowerTalk] Re:TowerTalk Twin lead feedline
>>> Date: Friday, July 10, 1998 5:19 PM
>>
>>> The few designers and builders who required critical value had
>only
>>to
>>> alter length to suit, and a purist could still "roll his own"
>>> Keeping the cost down has made the resurge of balanced line use a
>>real
>>> exciting phenomenon, and the growth still escalates. Problems due
>to
>>the
>>> big stretch of the "nominal" expression on the 14 gauge model have
>>been
>>> rare.
>>
>>I wouldn't apologize for making the line better!
>>
>>1.) Larger conductors generally have less loss for a given spacing
>and
>>dielectric.
>>
>>2.) Lower impedance generally means less weather effects for a given
>>spacing
>>
>>3.) Lower impedance line often means less impedance extremes at the
>>far end
>>in many applications.
>>
>>4.) Larger conductors mean more power handling.
>>
>>5.) Larger conductors mean less breakage.
>>
>>This type of line is very poor at VHF, at least the samples I've
>>measured.
>>I'm sure you've seen the effects of periodically repeating "bumps" on
>
>>VHF
>>or UHF performance.
>>
>>IMO, the problem is misapplication of what amounts to a good line for
>
>>HF
>>(except for weather and routing problems) to VHF "matched"
>>applications.
>>Dean Straw seems to feel the new ARRL Chart is correct, and the old
>>one
>>wasn't that far off. My measurements disagree with that.
>>
>>When we sort that out off-line, I'll post a correction or
>>clarification.
>>
>>Have you ever measured VHF performance Press, and do you recommend
>>this
>>line over hardline? Since you sell the stuff, you see more than Dean
>>or I
>>do.
>>
>>73 Tom
>>
>>--
>>FAQ on WWW: http://www.contesting.com/towertalkfaq.html
>>Submissions: towertalk@contesting.com
>>Administrative requests: towertalk-REQUEST@contesting.com
>>Problems: owner-towertalk@contesting.com
>>Search: http://www.contesting.com/km9p/search.htm
>>
>>
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