[TowerTalk] Rotator Loop Suggestions-Response DAVIS RF Co.

[Stephen Davis]

Hi TT'rs, 

Any of the Times UltraFlex outer jackets use TPE (thermoplastic elastomer). TPE is not good in UV for much 
more than 6-9 years, depending on the ambient.  That's too short for effective/cost efficiency. Even the Times literature states "life expectancy in excess of 10 years" (discount the "in excess of" ! )    The std. LMR  jackets are PE and so is Bury-Flex Tm (Tm and design of our company).  The PE formula I use is best and it is not subject to UV degradation.  Also, it is highly abrasive resistant due to its sufficiently high durometer, unlike PVC.  Bury-Flex Tm (Low loss) has a life of 30 + years.   A good PVC jacket should be UV resistant and a life of 18 + years.

There often is way over -concern and overkill as far as use of Ultra Flex for rotator loops.  Substitute in a loop of Bury Flex Tm or even 9913F7 ( Bellflex Tm blend of PVC which is highly UV resistant).  Why use LMR 400UF or 600 UF at the loop and certainly not all the way up the tower from the shack?  An excellent grade PVC, such as Mil Type IIA used in our RG-213 is fine for a long life and more than adequate flexibility for a loop.    

PE outer jackets like Bury-Flex Tm can be laid in water, also highly rodent resistant, and makes the best cable that I could provide anybody for coiling around crank up towers...and I sell any cable or wire made, or will design to your special need.

Hope this is of some help,
73,   Steve,    K1PEK 

DAVIS RF Co.,  Div. of Orion Wire Co., Inc.

Wire, Cable, RF Connectors and wire aerial parts.  

LMR, Heliax, Eupen

Commercial / Military

Custom Cable Design

tel:  978-369-1738     Fax:  978-369-3484
www.DavisRF.com

       

> 
> Message: 1
> Date: Tue, 29 Mar 2011 21:31:31 -0400
> From: "Kevin Adam" <n9iww at msn.com>
> Subject: Re: [TowerTalk] Rotator Loop Suggestions
> To: "K8RI on TT" <k8ri-on-towertalk at tm.net>,
> 	<towertalk at contesting.com>
> Message-ID: <SNT131-ds173AE2A4594F868359432FFBBC0 at phx.gbl>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
> 
> Heres a good idea you put an protector on the coax like plastic black pipe 
> or auto heater hose to act as protector
> 
> Kevin Adam
> N9IWW
> 
> -----Original Message----- 
> From: K8RI on TT
> Sent: Tuesday, March 29, 2011 9:17 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Rotator Loop Suggestions
> 
> On 3/29/2011 8:12 PM, Robert Harmon wrote:
>> Roger,
>> I have some LMR 600 ultra flex that I will need to do a turning loop 
>> arrangemet with.
>> I am wondering if it is possible to do a 3 or 4 turn coil that is in a 
>> spiral configuration
>> around the mast, then there would be little abrasion  Just 
>> thinking.........
> 
>   I had the 400UF as you describe laying on the flat top plate of the
> 45G for about 5 or 6 years (give or take). It actually had braid showing
> in one spot and many flat spots.  OTOH it had a number of cracks (up to
> an inch long) along the length apparently from exposure to the
> elements.  I had two pieces that looked good so I was making flexible
> station jumpers out of them.   I had already made several jumpers before
> I found a section where the braid was corroded  for several feet
> apparently from moisture.  I never did find where it got in.   This was
> pretty much in the middle of a 28' section that was good on both ends.
> 
>  Possibly had the top plate been painted so it was smooth the jacket
> would not have abraded like it did, but that still would not have
> stopped the weathering.
> 
> In my opinion, the UF cables NEED a cover over the jacket to protect
> them/it, particularly in rotator loops but that would reduce the
> flexibility.  Even several layers of tape *might* work.  Yes, I know how
> much the 600 UF costs as I have 2, 200 foot coils of unused LMR-600 UF
> left...some where. It has the same rubber like jacket as the lMR-400
> UF.  I have one run of the 600 UF  in the conduit between the tower and
> den where it's out of the elements.  I'll likely use the rest of it for
> additional runs in the conduit. I'd use it to the shop as well, but I
> already have multiple runs of regular LMR-600 in that conduit.
> 
> Had I removed the pigtails *before* I purchased the LMR-600UF I would
> never have purchased another batch of the UF.  It's a great low loss and
> very flexible coax, but it does not stand up well to UV light or
> mechanical abrasion.  It also seems a waste to put N-type connectors on
> the large cable, but most UHF connectors for it cost a small fortune.
> 
> 73
> 
> Roger (K8RI)
> <snip>
> 
> _______________________________________________
> 
> 
> 
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> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 29 Mar 2011 21:36:06 -0400
> From: "WA3GIN" <wa3gin at comcast.net>
> Subject: Re: [TowerTalk] Rotator Loop Suggestions
> To: "K8RI on TT" <k8ri-on-towertalk at tm.net>,
> 	<towertalk at contesting.com>
> Message-ID: <B4795D8340504F3391511ABBAA9EA108 at ToughBookLaptop>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
> 
> I like slipping the flex gas line copper or aluminum tubing.  It keeps the 
> UV off the PVC and prevents, to a degree, wear spots on the PVC ... Can be 
> sprayed flat black. of left with the yellow PVC...
> 
> wa3gin
> 
> ----- Original Message ----- 
> From: "K8RI on TT" <k8ri-on-towertalk at tm.net>
> To: <towertalk at contesting.com>
> Sent: Tuesday, March 29, 2011 9:17 PM
> Subject: Re: [TowerTalk] Rotator Loop Suggestions
> 
> 
>> On 3/29/2011 8:12 PM, Robert Harmon wrote:
>>> Roger,
>>> I have some LMR 600 ultra flex that I will need to do a turning loop 
>>> arrangemet ... 
> 
> 
> 
> ------------------------------
>