[TowerTalk] LMR 400 UF issue and Low Loss cables in general

[Grant Saviers]

I am using Buryflex for all of my around the rotator jumpers to yagi 
feedpoints.  Pretty happy with it in all applications, the jacket is 
much tougher than current 9913F7.  The DX Eng Max400 seems to be the 
same as Buryflex and am using it also.  Loss for all three is about the 
same.

One thing I decided was to have no coax connectors on any boom, so the 
loop near the feedpoint goes into a j-box thru a watertight gland and 
the #31 choke output 10ga leads exit through two small glands to the 
driven element.  The hardline DIN to N transition connector is inside 
the tower. (N since PL to DIN are $$ and hard to find). The Andrew 
waterproofing kits for all WX exposed connections.

Grant KZ1W

On 11/13/2019 6:46 AM, john at kk9a.com wrote:
> I was going to ask a question on towertalk what is the best coax to go 
> around a rotator but had not gotten around to doing so. Your post is 
> very interesting. For decades I have used Belden 8267 and it has held up 
> very well, even at my station in Aruba. I know that there are less lossy 
> cables but I felt that 8267 was tough as nails. My concern is that the 
> newer Belden 8267 that I put up five years ago has turned white on my NC 
> tower and the older version on the tower is still basically black. Did 
> the jacket change? I use Heliax up the tower which holds up well. I am 
> making many monoband antenna changes next years and I am revisiting what 
> I use for antenna coax leaders.?? LMR400 appears to be too stiff, 
> LMR400UF seems flexible enough and I considered using it until I read 
> the UV posts. I tired Belden 9913 in the 80's and it was the worst coax 
> that I have ever used,?? Does 9913F7 hold up well and not have the same 
> water ingress issues? If cost is not a concern what is the best coax for 
> a rotating HF antenna?
> 
> John KK9A
> 
> 
> 
> Steve Davis wrote:
> 
> 
> 
> 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.
> 
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