Date: Mon, 29 Mar 2010 11:57:24 -0400
From: Roger <sub1@rogerhalstead.com>
Subject: Re: [Amps] 'good engineering'
Zeitler, Lane LT, FST-1 wrote:
> Better get busy constructing some heavy duty open wire feeders while you
> are at to feed your antenna. I am thinking 8 gauge stranded would work
> great, say, with 3 to 4 inch spacing.
>
LMR-600 and 7/16ths connectors should do it through HF, or get some
surplus 7/8" heliax. More than likely even PL259's would be sufficient
for 5KW.
73
Roger (K8RI)
> Lane
> Ku7i
## for the record... it's called a '7-16 DIN' connector. It is NOT a '7/16"
connector!
The 7-16 means 7mm /16mm. The OD of the FEMALE that the PIN plugs into
is 7mm [.284" ] The solid MALE PIN itself is of course, LESS than 7mm
OD.
## There is No RF on the male pin anyway. Once mated, all the RF travels
down
the outside of the mating 7mm female. The braid /shield portion goes to the
collet fingers of the mating FEMALE. The ID of this collet is a whopping
16mm.
## Then there is the actual threads.. which are way bigger than the inner
collet.
No rf on the big threads. The threads + inner female collet are ZERO DC ohms
between em.
## years ago, Andrews announced they stopped making UHF connectors for
7/8" heliax !
The only connector that is readily available for 7/8" heliax, and also
LMR-1200 is
either a type N.... Or a 7-16 DIN.... take ur pick. I hate type N's with a
passion,most
useless bloody thing devised for bigger cable. A 7-16 Din is a mid 60's
German military
design, that caught on fast. It's now used exclusively on all North American
cell sites.
We dumped the last of the type N's as of last summer. All the new gear has
7-16 dins.
All our competitor's had already been using 7-16 dins. A 7-16 male plug
for 7/8"...
1.25" or 1 5/8" heliax doesn't cost much more, if any.. compared to a Type N
for the
same size cable. What really looks silly, is a type N on a 1 5/8 heliax
cable ! Here
you have a connector the size of a coffee mug... with this tiny type N pin in
the middle..
which imo.. is just glorified BNC crap. The pin in a bnc is the same size as
a type N.
## You can easily apply 5 x the torque on a 7-16 Din connector vs a type
N for the
same size cable. A 7-16 is good to 6 ghz. A type N is good to 12 ghz... and
that's abt the
only advantage of the type N. 2900 v rms vs 500 v rms.
## they make a bigger din too.. called a '13-30'
## The old LC connectors are going out of vogue. The LC chassis female
connector is 2" square
and uses 4 x 1/4-20 bolts. A 7-16 din is only 1.25" square.. and uses 4
x 8-32 machine screws.
The type N / SO-239 is 1" square.
## 7-16 connector's are readily available on the surplus market these days.
Lightning protection
devices use a pair of 7-16 chassis dins in a box.. with a gas discharge tube
inside. When the protector is
doa, they toss em. You can buy the blown ones for $2.00...and remove the
pair of 7-16 din female chassis
connectors.
later... Jim VE7RF
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