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

[Steve Maki]

Corrugated hardline and larger cables in general *try* to not kink when 
piled on itself or wrapped around a mast, and they usually suceeed.

The key is to watch it (or have someone experienced watch it) as the 
maneuver is initially attempted to verify that the bending is 
distributed over enough cable length.

-Steve K8LX

On 1/1/2021 6:08 PM, Grant Saviers wrote:

> 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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