[TowerTalk] Questions

[Rudy Bakalov]

Julio,
I'd try to answer some of your questions. Although my tower is permanent (vs. crank up), I think some aspects of my experience are relevant to what you are doing.
First, as I mentioned in my private email, I exclusively use Jefa Tech coax. They offer their own version of LMR600 which is considerably cheaper than the branded LMR600. In addition, they have been been offering very reasonably priced custom cables so I chose to order all cables cut to size and with connectors rather than build them myself.
So, that said, this is what my coax setup  is:
1) Two 50' LMR600 runs from the shack inside the barn to the corner of the barn where the coax enters the barn. At that point I have lightning arresters and two 8' ground rods2) Two 100' LMR600 runs from the corner of the barn to the base of the tower, connecting to the remote 2x8 SO2R antenna switch3) Individual runs of LMR600 from the SO2R box to the individual antennas. Each run ends into a bulk UHF connector so that I can ground the coax to the top of the tower. Then from the bulk connector I use anywhere between 15 and 25' of LMR400 Flex (similar to DXE 400MAX) for rotator loops
So, the bottom line is that I run LMR600 for everything except the last 15-25' needed for rorator loops where LMR400Flex is being used.
I have zero experience with crank up towers. My assumption is that only a portion of the crank up tower goes down. So if this assumption is correct, I would run LMR600 to that point and run LMR400Flex up the remaining including the rotator loops.
IMHO, every db of loss counts.
Rudy N2WQ      From: Julio Peralta <jperalta4 at verizon.net>
 To: john at kk9a.com; towertalk at contesting.com 
 Sent: Wednesday, August 31, 2016 10:24 AM
 Subject: Re: [TowerTalk] Questions
   
Thanks for the comments.  

Because more than 100 feet of the 270 foot run will be up a crank up tower I
don't think the loss savings in 150 feet of hard line which I think will be
less than 1dB is worth the extra cost and trouble. I currently run the coax
from the operating position over the roof to the tower which is the shortest
route. I would probably have to run the hardline on the ground all the way
around the house which would almost double the length of the run to reach
the tower. Not worth the cost and problems in my opinion.

What I was really asking was if anyone had any experience with the DXE
400MAX cable since it cost less and has the same specs as most of the other
LMR-400 type cables. However no one has responded with any comments either
positive or negative about 400MAX.

Nor has anyone commented on the availability of replacement sheaves for UST
crank-ups.

Julio, W4HY

 

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
john at kk9a.com
Sent: Wednesday, August 31, 2016 8:29 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Questions

I concur that using the same cable from the radio to the antenna 270 feet
away is a poor choice. Some cables are flexible and some have lower losses.
I was going to make a similar suggestion when I initially read the post. I
have many very different cables going from the shack to the antenna.

It sounds like your stacking relays are mounted up the tower.  While
slightly more costly to install, I think that they are better at ground
level.  It is much easier to check for individual antenna problems and relay
issues while standing on the ground.

John KK9A


To:    <towertalk at contesting.com>
Subject:    Re: [TowerTalk] Questions
From:    "Ed Sawyer" <sawyered at earthlink.net>
Reply-to:    sawyered at earthlink.net
Date:    Wed, 31 Aug 2016 01:23:52 -0400


I think it's a mistake to run the same cable for 270ft for this application.
I would run the lowest loss you can afford for the main run - LDF4 or LMR600
and then shift to a more flexible cable at the tower - LMR400flex or worst
case RG213.



I run 3 sets of coaxes for my systems.  LDF5 from the shack to the switching
at the towers.  LDF4 from there to the stack matches and them LMR400flex
from the stack matches to the beams.



Ed  N1UR

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