Dave,
One needs to distinguish between CATV style and Video style cable.
CATV coax, whether RG59 or RG6, has an aluminum foil with aluminum braid
shield with either copper or copper clad steel center conductor and foam
dielectric.
Video coax - again either RG59 or RG6 - has copper braid and copper
center conductor. The dielectric will be either solid or foam, the foam
style usually having VF in the mid 70's.
I'm a little confused about your experience with F connectors. I'm sure
you are using compression style rather than crimp style, right?
One thing I used to see quite often is folks didn't understand that
proper prep requires the braid to be folded back over the jacket rather
than trimmed to the same length as the jacket. Otherwise it can be
pushed back under the jacket when inserting the connector which is the
recipe for a poor connection.
-Steve K8LX
On 3/11/2021 9:28 AM, Artek Manuals wrote:
Dave
I am in the process of rebuilding my array of Coax Reversible BOGs and I
just bought a large quantity of RG-59U from Davis RF .
http://www.davisrf.com/rgcoax.php
The measured velelocity factor was around 79 ( probably really 78 my
measurement technique was quick and dirty)
The reason I chose RG59 over RG6 was :
1) It is near impossible to find quality female F connectors that wont
become intermittent
2) It is equally as hard to find crimp on PL259 Males of the right size
for RG6. (I am switching all my F connections over the PL259)
3) RG6 is NOT Solderable, RG-59 is SOLDERABLE
4) You can find appropriate good quality crimp on or solder connectors
with the appropriate reducers for RG59 from a number of sources
Dave NR1DX
On 3/11/2021 9:11 AM, Artek Manuals wrote:
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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