It takes some mental gymnastics to wrap your head around a hi-z feedpoint where
the radial system is almost negligible vs. a low-z feedpoint (like a typical 30
ohm range transmit vertical) which is strongly dependent on the radial system.
I have the hi-z pro4-8 circle array and never thought at gut-level those short
verticals and 4’ ground rods would work as advertised - but the performance is
really fantastic. I guess that’s the march of technology moving the art
forward.
In addition to 80/160 (intended application) I have found the array very useful
on 30 and 17m as well. I have a vertical dipole on 30 for transmit so the
residual directivity of the circle is a benefit there. And on 17 it’s as good
or better than my 3-element monobander. I suspect the 17m improvement comes
from the relatively closer location of that beam (near the house) compared to
the circle (800’ away from anything).
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
From: James Rodenkirch
Sent: Tuesday, February 11, 2014 7:55 PM
To: Jeff Blaine ; Top Band Contesting
Subject: RE: Topband: Hi-Z Antennas Two Element Array Systems 2-LV2-5
Tnx, Jeff
> From: jeff@ac0c.com
> To: rodenkirch_llc@msn.com; topband@contesting.com
> Date: Tue, 11 Feb 2014 18:35:00 -0600
> Subject: Re: Topband: Hi-Z Antennas Two Element Array Systems 2-LV2-5
>
> The Hi-Z buffers have a feedpoint Z around 50K ohms. So a single 4' ground
> rod provides an adequate round system. No radials needed.
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
> -----Original Message-----
> From: James Rodenkirch
> Sent: Tuesday, February 11, 2014 3:20 PM
> To: Top Band Contesting
> Subject: Topband: Hi-Z Antennas Two Element Array Systems 2-LV2-5
>
> Do the two verticals require any type of radial system or can a simple
> "array" of 4 to 6 20' radials do the job??
> 72, Jim R. K9JWV
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|