[TowerTalk] LMR 400 UF issue and Low Loss cables in general Re: TowerTalk Digest, Vol 203, Issue 15

Tue Nov 12 14:50:20 EST 2019

Hi Steve,

Regarding Buryflex, what is the anticipated lifespan of Buryflex under “normal” use cndx?   How long can it be stored inside (prior to use) without significant degradation?

Tnx & 73

Bob  KQ2M

From: Steve Davis | Davis RF 
Sent: Tuesday, November 12, 2019 1:20 PM
To: towertalk at contesting.com 
Cc: wa6tla at icloud.com ; W4EF at dellroy.com 
Subject: [TowerTalk] LMR 400 UF issue and Low Loss cables in general Re: TowerTalk Digest, Vol 203, Issue 15

Hi Elliot

Mike, W4EF, hits it on the head ref. potential degradation of LMR 400 UF, in outdoor environments vs. UV impact.

My firm, DAVIS RF Co., sells various RF cables, as well as control cables, and provides government, military and numerous industries, with cable design and solutions, not only in the RF spectrum.  We are not just wholesalers, we are cable design engineers fulfilling many custom needs.     One cable I designed, which many hams recognize, is Bury-Flex Tm, used also by Lockhead Northrup and NASA ground stations.

In the past on T Talk, I have pointed out the issue with LMR-400 UF, and suggested alternatives. 

We sell a lot of Times LMR sizes, and in fairness to them, their cables in general are superb.  However, in order to max out flexibility of UF's, they chose to use a TPE jacket (Thermoplastic elastomer).
This outer jacket material does not hold up well to UV, over the longer term (depending on where  in the world it is used). Times latest specs have deleted ref. to the potential life of the cable.  And W4EF'S experience, as noted, confirms the problem. 

So, what is the alternative??:  Belden 9913F7, which has excellent flexibility, and same attenuation specs (only slightly different at and over 2 GHz).   And, 9913F7  is LESS expensive than 400 UF.  
Why is it better vs. UV??  Because they use their own formulated "Belflex" Tm outer jacket material.  It is a highly flexible hybrid PVC.   NOTE: do not mix this cable up with Belden 9913, which at least in the ham market has had a bad reputation.   9913F7 is a totally different build. And I highly recommend it.

I will just add also that many customers come to me thinking they need to run their entire length of a cable using a UF type, where there are alternatives to that which results in our sale being less, but that also means saving the customer his $$, which is what we want to do for our fellow hams , without sacrificing performance and application sense. 

Lastly,  we have very low prices on Low Loss cables, hardline, Andrew Heliax and RFS Cablewave Heliax Tm equivalent.  And we do the assemblies using mfr. Certified installers.  We provide our fellow hams with the same low wholesale pricing as we do  all other commercial customers.  And we provide free application consulting, unlike any other commercial or ham dealer that I am aware of. 

Contact me anytime with any questions.  73,  Steve Davis,   DAVIS RF Co.  

On 11/12/19, 12:01 PM, "TowerTalk on behalf of towertalk-request at contesting.com" <towertalk-bounces at contesting.com on behalf of towertalk-request at contesting.com> wrote:

    Today's Topics:

       1. Re: Times Microwave LMR-400 UltraFlex Cable (Michael Tope)

    ----------------------------------------------------------------------

    Message: 1
    Date: Mon, 11 Nov 2019 20:56:47 -0800
    From: Michael Tope <W4EF at dellroy.com>
    To: towertalk at contesting.com
    Subject: Re: [TowerTalk] Times Microwave LMR-400 UltraFlex Cable
    Message-ID: <3199f5a5-9526-3649-f146-36c4a06d8d64 at dellroy.com>
    Content-Type: text/plain; charset=utf-8; format=flowed

    Are you planning on using the TM cable outdoors, Elliot? I had really 
    bad luck using LMR400UF in an outdoor application. While it was indeed 
    very flexible, the jacket essentially disintegrated in the Southern 
    California sun. Regular LMR400 by contrast holds up extremely well in 
    the SoCal sun. Apparently the UF variety uses a TPE (thermoplastic 
    elastomer) jacket whereas the regular LMR400 uses a PE (polyethylene) 
    jacket.

    Unless Times improved the formulation of the UF jacket material, I would 
    be cautious about using it outdoors without some additional protection 
    for the jacket (for a short rotor loop, a layer of 3M tape might do the 
    trick). For indoor service, it should be fine.

    73, Mike W4EF

    On 11/10/2019 12:28 PM, Elliott Lawrence via TowerTalk wrote:
    > I?m looking for a source of Times Microwave LMR-400 UltraFlex cable assemblies.  I have found one company, Field Components in Florida, that specifically states that they use this cable.  Other suppliers,  ABR, DX Engineering etc have preassembled cables but do not specific Times Microwave.  Based on the pricing by those suppliers I doubt that the TM cable is used.
    >
    > Recommendations, suggestions etc would be appreciated.
    >
    > 73
    > Elliott WA6TLA
    >
    >
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