[TowerTalk] How to run my 400' feedlines?

[donovanf at starpower.net]

Dan,

I've used thousands of feet LDF4-50, LDF5-50 and LDF7-50 Heliax without issue, both direct buried and on dozens of tower runs of up to 200 feet.  Its safe to say that many, many millions of feet of such cables are in use.

You should have no difficulty with Heliax cable installation if you handle the cables in accordance with the manufacturer's recommendations.  You just need to give a little thought in advance: "could this operation kink the cable?"  If it could, you need to consider an alternative handling approach.  If you're used to handling flexible coaxial cable, you'll need to learn to be more careful with Heliax.

That said, Heliax is much easier to handle than CATV or other hardline cables with smooth aluminum shields.  It should never be used without rigid support, and its completely unacceptable to use Heliax -- of any kind -- in a rotator loop.

73



---- Original message ----
>Date: Tue, 29 Apr 2008 01:37:44 -0400
>From: "Roger (K8RI)" <K8RI-on-TowerTalk at tm.net>  
>Subject: Re: [TowerTalk] How to run my 400' feedlines?  
>To: Dan Levin <djl at andlev.com>
>Cc: towertalk at contesting.com
>
>Dan Levin wrote:
>> I am in the process of moving my tower, which requires me to re-cable the
>> feedlines.  The new runs will be roughly 400', and I think I am going to use
>> LDF5-50A Heliax
>> The question is how to run the cable.  The options are:
>>
>> 1) Direct burial in a ~18" deep trench.  I don't think that running conduit
>> is going to be an option.  Is Heliax "rated" for direct burial?  Does it
>> matter?
>>   
>Although the loss in 400 feet of LDF-50 would certainly be low even on 
>VHF, I've found LDF-50 to be a tad fragile when it comes to mechanical 
>things.  I started to install it and changed to LMR-600. Over 400 feet 
>the 600 only has a few tenths of a db more loss and is not nearly so 
>sensitive to kinking while being handled.  It's probably a bit more than 
>the LDF-50 at $1.29 a foot which is what I paid last year.  I don't know 
>what it is now. Crip connectors are much cheaper for the LMR-600 as well 
>although http://www.surplusserver.com/products/Antennas-Coax/index.html 
>has some pretty good prices.
>> 2) Run the cables through the trees at about 8' up in the air.  This is
>> obviously not as good aesthetically, and I've had some problems with current
>> on the shield of previous "hung in the air" feedlines - but it may be the
>> only option if direct burial is out...
>>   
>Although I'd be uncomfortable running LDF-50 underground, I'd be more 
>uncomfortable running it through the trees.  For Andrew coax my choice 
>would be the 7/8" Heliax although it's usually quite a bit more, or I'd 
>go for a cable designed for direct burial.  The extra cost  is good 
>insurance.
>
>Good Luck,
>
>Roger (K8RI)
>> Thoughts, suggestions, comments?
>>
>>                     ***dan, K6IF
>>
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