Clay
LMR-400 is probably the best compromise , I doubt you will see any
useful improvement in system performance as a result of the improved
1.5db loss characteristics of the larger cables. Losses due to
atmospherics, ionospherics and multi-path will be an orders of
magnitude higher than the additional 1.5 db of signal improvement with
the larger cables. We are not talking comms with some guy in a space
suit on Mars here :-)
AS for walking the mast up I have done a number of installations of
this sort and the use of a block and tackle at the eve point is not
difficult, and will be appreciated more and more the older you get .
Mechanical multiplicative advantages are easy to implement. Don't use
block & tackles which can pivot since depending on the weave/braid of
the rope they will twist around and bind.
Dave
[email protected]
On 9/2/2017 7:48 PM, Clay Autery wrote:
Thanks for the response...
Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp.... And then adding N to F adapters?
Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc... but I specifically stated that $$
is not a top priority.... Not really even in the top 5 or 10...
The whole point of this exercise is to put up a semi-permanent SINGLE
antenna/feed-line install that will supply all 4 ports of the HP amp
with the least compromised signal within reason.... 4 now, and 8
whenever I can find the HP 8-way distro amp with external power input.
Strain relief solution: Really depends upon which cable stock I end up
using.... Obviously, the larger the cable, the more weight will be
suspended under the antenna (approx. 38 feet, depending on where I pull
the cable out of the mast at the bottom. (The mast is on a tilt-base of
my own construction.... which brings up a valid consideration. it is
already a chore to walk the mast up manually. The more weight added at
the top and inside the mast, the more difficult a manual walk-up will
be. I'd prefer to keep this a manual tilt for now... at least until I
add the tri-band vertical dipole)
LMR-400 would be less than 4 lbs total weight... I'd likely suspend the
cable by the connector alone. (although, it wouldn't be JUST the
crimp... The connector would have at a minimum, 1 layer of
adhesive-lined shrink tube... probably 2, with the second, overlapping.
Then a nice wrap of self-fusing tape and then electrical tape over that.
Even LMR-600 could be suspended by the connector alone, at 5 lbs max in
the 38 foot max vertical section.
I do have several methods of secondary suspension within the top (and/or
second) mast section though if I decide I need it.
Also prefer to keep all the connectors N-type as much as possible since
that is the station standard.
73,
______________________
Clay Autery, KY5G
On 9/2/2017 6:07 PM, Mike Naruta AA8K wrote:
Clay, you may wish to consider using a quality RG-6 with F
connectors. Grounding blocks are readily available for the base of
your mast and the entrance to your house. Also, off-the-shelf
over-voltage protectors (Zap-Tech) are available. I even found an
F-to-N adapter for the antenna on Amazon. Watch out for the ones with
metric N threads though.
For my 25 meter run I was going to use an existing one inch Heliax,
but pulled a run of Belden RG-6 instead after learning that Trimble
used RG-6.
It worked well directly connected to a Trimble Thunderbolt; now it is
connected to a Symmetricon 58535A GPS L1 distribution amplifier.
My Blitzortung System Red station has been running fine in my attic
(Michigan) on a Motorola 97 Oncore patch antenna fastened against the
roof underside. It is looking through wood, shingles, and nails (and
a tree and antennas and utility lines).
How are you planning to do strain-relief on the vertical run of coax
inside of your mast?
Mike - AA8K
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Dave
[email protected]
www.ArtekManuals.com
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