[TowerTalk] LMR 600 UF options ?

[Grant Saviers]

Some time ago I asked DavisRF to make some Buryflex with 600 specs, but 
no go.  I have two crank ups, so Burylex for me is ok for HF, but even 
LMR-600 has too much loss 2m & 70cm (besides the cover problem)

The CW is hardline will fatigue fail, but I think that chance is greatly 
reduced when a number of cables are taped together as they currently are 
on my HDX-589s.  Now 2 or 3 Buryflex, rotator, SteppIR controls, plus a 
spare control taped every 2ft.  I use the loop slide thru cable 
standoffs from KF7P.  Changing out one Buryflex to LDF4-50A would be the 
plan (someday, I have a lot).

My tower raise and lower frequency is pretty limited to maintenance, 
lubrication, and expected storms, 6 +/- round trips per year.  With big 
loop figure eight flaking of the bundle when lowering, the bend radius 
is way larger than the multiple bend spec for LDF4. I can do that 
looping by myself when lowering the tower, simple guiding when raising.

Obviously, a Buryflex jumper is needed at the rotator and maybe at the 
base.  Another approach with several helpers would be to pivot the 
bundle out from the base and keep it straight. If somebody wanted to try 
7/8 hardline, I think that might work as the bend radius would be about 
the height of the lowest cable guide, 23 ft.

There are larger RG cables, eg RG19/RG220/RG218, I think all are solid 
conductor, heavy and very expensive.  At least hardline is relatively 
light weight and LDF4 and copies are very available and lower loss.

Grant KZ1W

On 12/24/2019 01:49, Robert Harmon wrote:
> Hi Rick,
> 
> I want the low loss of LMR-600.  (.3dB /100ft on 14Mhz)
> There are several choices.
> * Regular LMR-600  has a nice PE jacket but solid center conductor (aluminum/copperclad)  not that flexible.
> * LMR-600 ultra flex which has a poor TPE jacket, but the center conducter is stranded copper, nice and flexible.
> 
> I would like LMR-600 UF with a PE jacket but not available.
> 
> I am planning to run 7/8"  hardline out to the top of the first section of my HDX589MDPL  (crank up tower) and then go with as low
> loss as I can find "flexible" coax from there on up to the antenna.  I thought with LMR-600 I may not need a separate rotor loop either.
> 
> I will see if I can find loss info for RG-218 on 14Mhz    I found one table but it is for 50Mhz.
> 
> It would be a lot simpler if I didn't have a crank up tower hihi
> 
> 
> Bob
> K6UJ
> 
> 
> 
> 
>> On Dec 23, 2019, at 5:21 PM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
>>
>>
>>
>> On 12/23/2019 2:47 PM, Robert Harmon wrote:
>>> I would like to use LMR-600 UF on my crank up tower all the way up to the antenna without a rotor loop.  From what I understand
>>> the UF (ultraflex) has a stranded center conductor and would have the flexibility needed.   The only problem is that it has a TPE jaket
>>> which is only good for 7 years or so.  The reguar LMR-600 has a  solid center condutor (aluminum/copper clad) not stranded, but
>>> has the good TP jacket like Bury Flex has.
>>> I can't have the UF with TP jacket.  :-(
>>> Any other options that you know of for a low loss feedline (like the LMR-600) that is flexible and has a good jacket ?
>>> Bob
>>> K6UJ
>>
>> I don't completely understand your question, but what I
>> use on my HDX-5106 is RG-218 to go to the top of the tower,
>> and then a rotor loop consisting of a short section of Bury-Flex.
>> The rotor loop is connected to the RG-218 with a rigid
>> 90 degree adapter.  It works for me.
>>
>> Rick N6RK
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