Dave
will 75 ohm work for you rather than 72?
Dave
NR1DX
On 3/11/2021 8:57 AM, Dave Sublette wrote:
Good morning,
Each dipole of my 80 meter four square dipole array is fed with 72 ohm
coax. Yes, they are full length dipoles suspended vertially around a 150
foot tower. One end of each dipole is at the top. The centers are pulled
out until the feed points are 46.5 feet from the center. The other half of
the dipoles is allowed to droop and loop down with the ends tied 15 feet
above ground to allow mowing, etc... It ends up as a rough diamond shape.
And, yes it works. It has worked well for over 20 years. The control box
is the original Comtek that does work with dipoles. The new version manual
claims it doesn't. Perhaps they have altered it by now.
I gave a crude description to start because I figured there would be
questions. The point of this email, though, is to get your
recommendation for good quality 72 ohm coax with foam dielectric for a V/F
of 78% or so. It has to be foam in order that the feedline be long enough
to reach the center of the array where the control box is located. The
connectors on the box are SO-239. The PL259 can be soldered or crimped, I
don't care. But if soldered, shielding must be copper.
So 72 ohms, 78% v/f, good quality. Where to get it?
Googling yields all sorts of cable suppliers, but we all know the quality
varies. I would hope one or more of you has some real world experience to
share.
Thanks & 73,
Dave, K4TO
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