[TowerTalk] [Bulk] Coax cable economics. (was Mosley Antenna

[Patrick Greenlee]

Ed, Thanks for sharing your real world experience.  Good stuff.  I too 
have some pretty long runs to be installing soon and remembering your 
comments will serve as a reminder of what to do and why lest I stray 
from your example.  I have Andrew 1/2 inch hardline to use as much as is 
practical and LMR 400 (or ?) elsewhere with buryflex or (?) at the rotators.

Again, thanks for sharing and congrats on your achievement.  I haven't 
ever caught the contest bug but I can appreciate the efforts of those 
who have and who knows... maybe some day...

Patrick   NJ5G



On 2/19/2015 5:22 AM, Ed Sawyer wrote:
> As the reigning Low Power USA DX Contester(currently) in many of the popular
> DX contests, I think I can speak with some experience on this subject.  One
> year - I think it was 2009 - I was sick and knew I wouldn't be competitive
> for an ARRL DX contest.  I decided to try an experiment.  160 was not in
> great shape and 10M was having those "noise floor" big EU stations and
> that's it conditions.  I called stations using 100W in the contest (although
> the max limit is 150W).  I could work some with difficulty but not many -
> typical of those conditions with low power in this contest.  I remember
> multiple multiple times that at 100W they would CQ in my face.  At 150W you
> would start getting the "?" and at 200W I MADE about 50% of those Qs.  I
> might have been able to get through with the 150W (~1.8dB increase) of power
> with a lot of trying.
>
>   
>
> Bottom line, while 1dB in and of itself is admittedly not material.  2 and 3
> dB for sure are material in DXing and Contesting where the path is right on
> the edge of being made in HF.  And the 1dB is quickly passed with the wrong
> coax on top of bandpass filters and antennas.
>
>   
>
> Here at my QTH, I have my towers up on a ridge behind the house.  Its 250ft
> of coax from the back of the rig to the 2 x 8 switch at the base of Tower 1.
> 130 ft from there to the base of Tower 2.  And my top 10M antenna at 80 ft
> is on top of Tower 2.  That's about 450ft of coax from rig to 10M antenna.
> I run LDF5-50A to the 2x8 and from Tower 1 to Tower 2 and LMR600 to stack
> match on 10 at 50 ft.  The last 50ft of coax to the antenna is LMR400.  The
> total loss to that antenna is about 1.6dB.  If the whole run was LMR400 it
> would be about 4dB.  That 2.4dB power loss is the equivalent of doubling the
> size of the antenna roughly and clearly would affect weak signal work based
> on my tests.
>
>   
>
> Ed N1UR
>
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