[TowerTalk] [Bulk] Re: LMR600 up to the top of tower ?

Robert Harmon k6uj at pacbell.net
Sat Aug 1 13:43:41 EDT 2015


Grant,

 I will have a stack on my HDX589 consisting of  40/20  on the bottom and a new 17/15/12/10 on top.  
 I see your point on LMR600UF for the swing arm loops not holding up.  
 So lets see if I have your arrangement right.  You are running 7/8 and 1/2 LDF from the shack to the tower top section,
 then they connect to Buryflex for the swing arm loops for rotation, and the Buryflex cables continue up the mast and connect to the
 beams.  Is that correct ?

Bob
K6UJ




> On Aug 1, 2015, at 7:16 AM, Grant Saviers <grants2 at pacbell.net> wrote:
> 
> I second Roger's comment.  Coax I removed from a large stack were 7/8 hardline to LMR600UF swing arm loops, and the 600 was in bad shape after 7 years.  Several cuts, one complete tear of the braid, water inside.  I'm using Buryflex service loops and with 7/8 LDF5 for 20/15/10 and 1/2 LDF4 80 & 40  have less than 0.8db loss Yagi feedpoint to amp on all bands.  Buryflex is very tough stuff and flexible enough for service loops.  With the long runs (140' tower, 125' to shack) in hardline the slight additional loss for the short service loop is within the loss budget.
> 
> Grant KZ1W
> 
> 
> On 7/31/2015 23:44 PM, Roger (K8RI) on TT wrote:
>> I use, or have used a lot of LMR 600. I much prefer the crimp on connectors...HOWEVER LMR 600 UF is not recommended for exterior use.  I have used the UF versions of LMR 400 and 600.  The best life I've gotten out of them has been 6 years although it's rated at 10 years.  The jacket is rubber like, easily abraded, and does not stick to the shield.  A three turn coil of LMR 400UF laying on the flat plate top of a 45G wore through to expose several sections of shield 3 or more inches long.  It does not appear to stand up well to UV light and that is at 43', 37" N.  OTOH it is the most flexible large coax I've used
>> 
>> 73
>> 
>> Roger (K8RI)
>> 
>> 
>> 
>> On 7/31/2015 8:43 PM, Robert Harmon wrote:
>>> I have a 380 foot coax run to the top section of my motorized tower when it is fully extended.
>>> 
>>> I am changing out all my old RG213 and thinking of saving a few db by going to LMR600 up to the top section then
>>> LMR400UF up from there for the rotor loop and up to the 40 meter beam and triband/warc beam on the mast.
>>> What do you think of LMR600 for this run from the shack up to the top section for a motorized tower ?
>>> When I lower the tower I am thinking I could coil the LMR600 into maybe 5 foot diameter coils on the ground.
>>> BTW the tower is 90 feet to the top of the top section when all the way up.
>>> Is this a bad idea ?  (I am hoping to avoid the cost of the flex LMR600UF if I can.)
>>> A side issue is I understand I have to be very careful not to nick the copper clad on the center conductor
>>> when installing a connector on the non flex LMR600.   I would use the Davis PL259 connectors for LMR600.   Anyway maybe this usage of the
>>> LMR600 is not a good idea, what do you think ?
>>> 
>>> Bob
>>> K6UJ
>>> _______________________________________________
>>> 
>>> 
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>> 
>> 
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