Topband: The 4SQR for 160m a'la K8UR

[David Raymond]

Jarda:

My original 160 mtr 4 sq was in K8UR (bent dipole) configuration.  When
using classic 0/-90/180 phasing, the F/B was only about 10 db (close to
what the modeling shows at about 12 db).  A couple of seasons ago I
attempted to switch to 0/-137/-237 phasing using the Lahlum method.  I
spent quite a lot of time with it but had no luck (actual F/B was only
about 12 db).  It's entirely possible my methodology, expertise, or test
equipment (or all of the above) was not up to the task.  I did not have
access to a good network analyzer and only had a modest scope with which to
measure phase delays.  In any case, I could not achieve anything near the
theoretical modeled performance (which is outstanding).   Having a 190'
tower to work with, I reconfigured the K8UR array to a classic system using
ground mounted 1/4 wave elements hung off of catenary ropes (the elements
slope in toward the tower slightly) using 0/-90/180 phasing (Comtek).  I
immediately saw a consistent 6 db improvement in F/B.  After detuning the
bottom 100' of tower, I picked up another 4 db of F/B (for a total of about
20 db).  At this point, the array seems to have achieved its theoretical
performance.  

I would be interested in hearing more about how you handled
matching/tuning/phasing/current distribution/etc. to achieve the full
performance of a K8UR array with 0/-137/-237 phasing, what kind of
bandwidth the array has, etc.  Please feel free to reply direct if you wish.

73 to all. . .Dave
W0FLS 



> From: Jarda OK1RD <ok1rd at ok1rd.com>
> To: Topband Digest <topband at contesting.com>
> Date: 10/21/2006 11:59:13 AM
> Subject: Topband: The 4SQR for 160m a'la K8UR
>
> Dear Topbander, 
> as having got more than several requests for information about my full
size
> dipoles 4SQR for 160m a'la K8UR which photos  . . . .