I am sure you will get many of the same and better ideas from others, but
see below for my thoughts on your proposed installation. I have just ( I
almost said completed, but it is not, and may never be) built a fairly
elaborate remote station to escape restrictive covenants where I live.
-----Original Message-----
From: PBC [SMTP:paulc@mediaone.net]
Sent: Wednesday, January 27, 1999 5:57 PM
To: towertalk@contesting.com; topband@contesting.com
Subject: [TowerTalk] My Dream Station...
After reading several discussions on the Kachina reflector, I am ready to
embark upon my dream DX and contesting station: Kachina now offers the
ability to control its 505DSP transceiver from a remote control point using
a PC and high-speed dial-up modems. I invite comments on the following
ideas:
The host location is one of my company's fiber-optic central offices,
located in a remote area near the St. Johns River inlet on the Atlantic
Ocean. I have access to a prexisting 180'-foot PiRod tower, 24-inch
facing.
My thought is to install a Force 12 C-4XL on a 20-foot Chromoly mast. The
C-4XL will be mounted between 180' and 185', with the remaining 15' of mast
remaining above the antenna with a Verda static dissipation array located
atop the mast. I would prefer to mount the C-4XL at a height of 90-feet,
but I do not believe a ring-rotar will accomodate a 24-inch face. Correct?
Turning the tower by any means is not an option. The tower pre-exists; I
am
going to use it without heavy modification. Rotators: What shall I use to
reliably turn a C-4XL (assuming top tower mounting as descibed above)?
At 180 feet, over good ground to boot, the C4XL will have some wonderful
low angle lobes on 20 - 10, and should work great on 40, but you will have
a real hole in the mid to higher angles that will be needed for good
contest scores, and for working close in or mid-day DX stations. You might
consider a C3 or two fixed on EU and/or JA at lower levels for contesting.
Perhaps at the lower levels on a large tower face you could rotate a beam
90 degrees or so, say EU versus JA, or?
At this height, I will go through the FAA lighting/candy striping exercise
to be safe. In any event, the top-most portion of the structure will not
rise more than 200' AGL, and I do not believe any runways exist near the
site. I'm a pilot, so I have access to all FAA runway, airport, glider,
and
parachute operating areas. If I must reduce the mast height to avoid
obstruction lighting, so be it.
If the existing installation does not require lighting or striping, I would
not do anything to change that. Stay below 200' and do not rock the boat.
Once the lighting is on, it has to be kept working, and there are
penalties and potential civil liability if it fails, and all the entities
with antennas on the tower and/or the site will share in the liability. If
most lawyers representing the tower owner and/or other users got wind of
this, I bet they would try to shut you down in a hurry. I don't think the
potential benefits of going over 200' are at all comparable to the
detriments.
Next, I will use the modified, switched "vertical inverted Vee" sloper
system as described by A. Christman, and T. Duffy, K3LR, in mid-'90s issue
of QST. With a tower height near 1/2 w.l., located on the peninsula of a
salt marsh, I will keep the ground system to a minimum with perhaps eight
1/4w@160-M radials. The property easily allows the inclusion of the
radials, so why not? A total of four, perhaps five slopers will be used.
Question: now that I'm in the planning stage, to what areas of the world
would you choose for four possible main lobes? Europe, Japan, Australia,
Central Asia perhaps? I'm not too interested in South America. My 180'
tower uses steel guys, none of them broken up with insulators. Should I be
concerned about guy resonances at 160-m? I haven't done the trig with a
180' tower with 80% guying distance and three tower points, but I suspect
one of them may cause me trouble.
Will all those slopers and radials be an issue when it comes time to
maintain the other stuff on the tower? You would have to model the tower
with all the antennas on it to really check out guy wire resonances. I do
not' know any reliable rules of thumb. I used Phillystran. I have a single
sloper up at the 190' point of my tower, and it works well. I have the
three other slopers and the relay box made up, but snaking all those
slopers around the other antennas on the tower is a non-trivial task,
believe me! K3LR says there is no benefit to 5 slopers over 4. The lobes
are big, at least 50 degrees across at the 3 db down points, so orientation
in terms of direction is not that critical. It is important to get them
mutually perpendicular, though, and as symmetrical as possible. With the
ground as you describe, you may not need any radials: I would sure try it
without them first. Some people say use a Comtek box and feed them like a
four square, but others (including some pretty sharp contesters) have had
major troubles getting such an array tuned up and working.
Kachina also makes a nice remote antenna switch and rotor control unit.
All
antenna and amplifier switching functions appear to be possible with it.
This is one well-thought package.
I am using a Kachina 505 remote, and my 505 ARX just arrived today, but I
am not sure when I will install it. Looks good so far. In addition to the
rotor, I am switching 75/80M positions on one antenna, and hope to switch
between EU and JA beverages, and some stack switching. There is also the
possibity of either using the control functions in the Alpha 87a to do some
switching via RS232 and ASCII commands. There seem to be unused functions
there, but I haven't had time to play around with it yet.
My best guess is that I'm 60-90 days away from making this really happen.
A
lot of buying has to be done soon. Ouch!
If you think you are two months out, it will probably take you 18. That
was exactly my experience. I have already used the system over the
"traveling" 800# to work a Dxpedition while on a "must go" trip, and it
sure is nice to fire up to listen at home without a 50 mile round trip to
the site. Any chance you have lots of dark fiber you could light up between
your house and the site and run a Ethernet speed LAN to LAN connection to
your house? Then you could run something like multiple PC anywhere
sessions to PC's at the remote site, and the possibilities are endless. I
would be glad to discuss things further as you go down the raid on this
thing. I will be dabbling in the CQ WW 160 this weekend using the remote
and single sloper.
73 John N5CQ
Hey!, perhaps I can rent time on the system to anyone wanting to contest
from it for a weekend! Just kiddin.' Actually, all it requires to
operate
from anywhere is a laptop, modem, and Kachina's remote interface...I may
not mind going on those extended business trips any more! Thanks for the
input and I welcome all criticms and suggestions!
73,
-Paul, W9AC
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