[NLRS] [BC'ers] Coax to antenna feedpoints: an unbroken run or a rotor loop transition connection?

[n8pum1]

I have for sale a M Squared 23CM35ez antenna. 35 element yagi for 1296mhz. New they are $279.  Antenna is in excellent condition. Asking $200obo. 9062505500   de N8PUM


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-------- Original message --------
From: David Palm <thepalmhq at gmail.com> 
Date: 08/31/2015  9:42 AM  (GMT-05:00) 
To: NLRS Reflector <NLRS at mailman.qth.net>, Badger Contesters List <badgercontesters at mailman.qth.net> 
Subject: Re: [NLRS] [BC'ers] Coax to antenna feedpoints: an unbroken run or
  a rotor loop transition connection? 



Thanks again for all of the great feedback on coax runs for my set up
here.  The advantages of shorter rotor loops seem to outweigh any connector
loss disadvantage.  At the very least I can see from my weekend's
experience that it's a heck of a lot easier to manhandle an antenna with
just a short rotor loop attached, versus trying to get it into place with a
whole length of coax dangling off.

My coax run is not very long, maybe 60 feet maximum, so I'm just going to
do LMR400 from the lightning arrestors to the top of the roof tower, then
Buryflex for the rotor loops and the jumpers from arrestors up into the
shack.

I made great progress this weekend.  On Saturday I built a new platform for
my new (well, rebuilt by Norm's Rotors) rotor and set that in place.  I
still need to make all those new coax runs, but I was so anxious to have
something to play with that I put the K1FO yagi for 432 into place and used
an existing length I already had here.  I saw that Steve, N4PZ was
monitoring 432.110 so I gave him a call, got his attention and had a very
nice chat.  So with just 20 watts into the K1FO, I seem to be getting out
very well on 432.

Then Sunday morning I saw that there was a band opening, so I scurried out
to the barn, grabbed the Cushcraft A148-10S for 144 MHz and set that just
below the 432 antenna.  They seemed to play fine together and I was able to
work several stations out west on 144 and last night worked VE4MA on 432
(518 miles from my QTH), so that was pretty sweet.

At the very least it should be easy to have my new antennas up for 50, 144,
and 432 in time for the September contest.  The wildcard is 222 MHz.  My
antenna on that band is a homebrew N6NB quagi and it needs shoring up
before it can go into the stack.  And during the UHF contest my transverter
kept tripping out, complaining of IF over-power, so there's something wrong
there as well.

But, if all goes well I'll be solid on the bottom four bands for September
from EN43.  And for at least portions of the contest we'll hand out triple
points, from KC9MRX and KC9VEM as well.

73,

David  W9HQ



On Mon, Aug 31, 2015 at 12:31 AM, Doug Reed <n0nas at amsat.org> wrote:

>
>
> I agree with the comments about rotor loops at the tower top. But I'd
> also consider the total line loss versus added connector losses for
> each junction when deciding what cable to use. Short runs it doesn't
> matter much, for long runs you'll want the best cable you can afford.
>
> My personal favorite for waterproofing coax connectors is the
> self-fusing rubber splicing tape that is sold for sealing underground
> electrical connections. I usually just use one or two layers of it
> over the connector, following the directions, i.e. stretch to half
> width and overlap each turn by half. Since it isn't UV resistant, I
> usually cover it with a couple layers of black electrical tape, 3M
> type 33 or 88 is best if you have it. I usually don't get more
> complicated than that.
>
> I have the sticky gooey sheets and gooey tape that is shipped with
> hardline connectors, but I prefer to use the rubber splicing tape as
> the first layer because it comes off and leaves the connectors
> perfectly clean. Use the other stuff on top of the rubber tape if you
> want to but I refuse to use the gooey stuff as the first layer on the
> connectors because it makes a heck of a mess.
>
> If you expect the coax to hang on the tower more than a few years,
> DON'T use plain plastic zip ties to attach the cable to the tower.
> Even the black zip ties get brittle with age and fail, often within 10
> years. Possible options include a layer of black tape over the black
> tie wraps, it might last longer. Otherwise, hose clamps, lengths of
> 12ga or 14ga solid copper wire, or stainless-steel zip ties (Harbor
> Freight) should last longer. Commercial tower installations usually
> have stainless steel clamps that go around the hardline and clip into
> the cable race going up the side of the tower.
>
> I've only used 9913 at home once, and found it in a roof-top packet
> installation one time. In both cases it acted more like a garden hose
> than like coax. I prefer to use a coax with a filled dielectric
> center, not air dielectric. But that is just my opinion, YMMV....
>
> 73, Doug Reed, N0NAS.
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