[TowerTalk] Lowest loss coax that can be run up a crank up tower

[Grant Saviers]

It's a problem no supplier has tackled.  Perhaps the market is too small 
to get interest.    I have same issue on a HDX589.  Your 7/8 hardline to 
the base will be a few db improvement though.

I think it is possible to make LDF4-50 reliable as the up the tower with 
a crank up.  Three things need done IMO to make it reliable- bundle it 
with all other cables, taped every 2 ft or so to reduce the flexing, use 
cable guide standoffs at the top of each section, and figure 8 flake the 
bundle in at least an 8ft long figure eight when lowering the tower.

The flaking keeps out the twist and the bend radius is larger than the 
repeat bending spec for LDF4.  This assumes the tower isn't going up and 
down more than a few times a year.  The fiber optic conduit pull teams 
I've observed flake the fiber in about a 20ft figure 8.

If this works for LDF4 then it should work for LMR600 but I am not a fan 
of the jacket.  Then transition to Buryflex etc for the rotator loop.

I've wanted to try this, maybe this summer.

Grant KZ1W

On 1/1/2021 12:43, Don Solberg wrote:
> I have installed a US Tower HDX-572 crank-up tower.  I have two antennas
> currently on the tower: 40 M rotatable dipole, and a 2M/70CM antenna for
> satellite operation.  My shack is in the middle of a pine forest so the
> only way I can get a good view of the sky is to put my satellite antennas
> on the top of the mast, which puts it up about 82 feet.
> 
> My shack is about 140 feet from the tower.  Currently I have 150 feet for
> 75 ohm 1/2" CATV hardline running to the base of the tower, and then DX
> Engineering's DXE-400MAX running up the tower.  At the top of the tower I
> am running RG-213 for the rotator loop and up the mast to a diplexer.  From
> the diplexer to a mast mounted 70 CM preamp and to the antenna's I am using
> LMR 240.  At the moment I am using a Cushcraft A27010S, mounted at a fixed
> 15 degree elevation.
> 
> I estimate that I have at least 8db of total coax loss.  This also includes
> a short jumper from the CATV hardline to a diplexer, the diplexer losses,
> and adapters.
> 
> While I can work all of the FM and Linear satellites, I would like to
> reduce my coax loss.
> 
> I ambuyin 7/8" 50 ohm hardline to replace the CATV hardline.  I am also
> going to switch to all N connectors and eliminate some PL259 connectors and
> adapters.  My plan is also to replace the Cushcraft A27010S with individual
> 2M and 70CM yagis on a fiberglass cross boom.  When I do that I want to use
> lower loss jumpers at the top of the mast, replacing the LMR-240.
> 
> My question for the group is what is the lowest loss line that I can run up
> the tower and also use as the rotator loop. Is DXE-400Max flexible enough
> for the rotator loop?
> 
> Is there a better coax to use going up the crank up tower?
> 
> Thanks for your recommendations?
> 
> 73,
> 
> Don K9AQ
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