[TowerTalk] Routing Ladder with Parallel Coax?

[Richard Cariello]

Tony,
A friend of mine used twin coax lines for the entire run from his shack to the antenna locations on the towers. I recall he used a Johnson Match Box (balanced tuner) at the shack end soldering both coax shields together and then connecting them to the ground lug of the tuner which was also connected to the station ground system. The two center conductors of each coax line went to the match box inputs. It worked perfectly also allowing him to tune out any reflected power making his equipment happier. I am not sure what he did with the coax shields at the antenna end. I would solder them together which I believe would stabilize the coax lines impedance with less effects from the surrounding area. I would also tape the two coax line together at points to prevent the coax lines from separating. I would NOT connect the antenna end coax shield to the tower or anything else. Just seal it from any weather. Also you would no longer need a Balun to connect to the antenna. Another point is the system should be allot more stable from changes from the weather and much easier to install then any twin lead open wire line installation. On the negative side it will cost you double for the coax and additional cost for the tuner.
Rich AA2MF
P.S. Two lines of RG-11, 75/2=37.5 ohms. Two lines of RG-8, 50/2=25 ohms. Not much of a difference to worry about.



 
On Apr 6, 2014, at 2:43 AM, Tony wrote:

> All:
> 
> My shacks location makes it difficult to keep ladder line away from other cables that enter the house. Someone suggested I use 2 runs of RG-11 coax in parallel to route the coax inside the house and then connect the two to the ladder line outside.
> 
> The coax shields would connect to the tuner ground and the center conductors to the tuner output terminals. The shields are left open at the end where the coax center conductors connect to the ladder line.
> 
> Has anyone tried this with a doublet?
> 
> Tony
> 
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