[FADCA] Antenna recommendations for the SNCP, BARTOW, 200 foot tower

Wed, 10 Mar 2004 06:23:17 -0500

Evans - That is a great recommendation but might be looked upon as quite
ambitious - I hope you can pull it off.

Here are some general comments.. (Not going to anyone except FADCA group)

I trust that single tower is well-fortified (has been standing for 20 years,
etc) as there are a lot of eggs in that one basket.  My personal feeling is
that if a site has been through the past 20 years of events in Central
Florida it is probably pretty hardened from weather.  Not that a brand new
tower properly engineered might not be - but no history! Of course, that
begs the question: How long does a tower have to stand before it can be
trusted? Har.

Item numbers for reference:

1.  Are any of these for ARES use?
2.  Is the ILRP antenna anticipated to be a dedicated one or can that
antenna be used for other VHF purposes when needed?
3.  Depending on how critical the UHF paths are to Tampa and Clermont,
consider putting the UHF backbone beams up at the highest level you are
allowed - the LAN antenna - if at 130-150 ft should cover much of the county
with 60w.  If the backbones can work at 136 ft then no problem putting the
LAN antenna up higher for more coverage.  There is a point at which a site
can have too much coverage on the 2M LAN (i.e. interfere with another LAN
beyond an 80 mile radio horizon.)- then it's time to reduce power.

4.  The primary purpose for HF voice at a County EOC would be to cover much
of the state of Florida - basically using 75, 60, and 40 meters.  In my
promotional work around the state, I'm also pressing for each EOC to have HF
PacTOR capability on 40M.  We have a dedicated 40M frequency that would be a
great back-up throughout the state for digital messaging.

In so far as ARES/RACES support is concerned -  HF below 80m and above 20
(or maybe 15m) is not all that important these days.  With the Internet
transport layer becoming more applicablable (on voice -Echolink/ILRP- and
Ham Radio e-mail messaging - WL2K) the need for any ham community to reach
out for help, or reach out to help much beyond 500 miles is likely out of
date. Most HF voice operation in support of in-state incidences will likely
be on 40, 60, and 75 meters, and lesser antennas than those required for DX
are much indicated.  To support Digital Messages, 30 meters is very
important, and a great HF digital band for e-mail messaging. 30M is digital
only, no 1.5KW phone stations splattering, and is not harmonically-related
to the other HF bands.  A five-band multiband inverted vee for 80,60,40, 30,
and 20m would be a good compromise between complexity and use.  (My
80,40,30, 20m coax-feed V with the apex at 68 ft works great and also does a
nominal job on 15m.)

On a related issue - we will soon learn that more and more EMCOMMs will be
carried on using vhf and HF digital messaging, and less and less HF voice.
It is a matter of Ham Radio EMCOMMs catching up with the 21st century.

5. I don't believe a sloper would be a very versatile antenna for HF ARES
work. Slopers are generally quite low Q, covering only one band. often not
much of that.   I've not had personal experiences with slopers but there is
likely a more appropriate antenna for ARES work.

ALL THAT SAID - If your group plans on having a general Ham Radio Club
station at the site, then go for as many bands as the club wants to sponsor.
Also, if it is possible for a WL2K PMBO to be running there 24/7, then a
resonant antenna covering 80,40,30,20 and perhaps 17, and 15M would be
great!

73,
bud N0IA

Then there is the issue of how much HF activity can be on-going at the same
time with antennas on the same tower? Is there a need for more than two HF
radios to be running at the same time - if not, then not much need for more
than one antenna to be available for each, providing needed bands are
covered.

----- Original Message ----- 
From: "Evans Mitchell kd4efm / afa2th fl" <[email protected]>
To: "Ben Holycross" <[email protected]>
Cc: <[email protected]>; "Polk County ARES" <[email protected]>;
"Lakeland Amateur Radio Club Remailer" <[email protected]>
Sent: Tuesday, March 09, 2004 21:59
Subject: [FADCA] Antenna recommendations for the SNCP, BARTOW, 200 foot
tower

From: Evans F. Mitchell, ARES EC, Polk County
To: Ben Holycross, Director of Communications, Polk County Emergency
Management
CC: Polk County Communicators Program Volunteers; Lakeland ARC, Polk ARES
Group
REF: Antenna recommendations for the SNCP, BARTOW, 200 foot tower.

Dear Mr. Holycross,
    I would like to share with you some of the site recommendations I have
received and
some that I, Evans,  have included for the 200 foot tower at the SNCP / HAM
EOC site.
These are the considerations, and only that, till you finalize and approve
the recommendations.

1) Your recommendation for the top is One Each; 800 MHz, UHF, EMWIN, and a
VHF (EMWIN left at current location)
    The 800, UHF and VHF would be mounted on 4 to 6 foot stand off's. ARES
agrees.

2)    At the 175 foot level, two side arms with one VHF and one 220 MHz
antenna on each, the vhf one would serve the IRLP
node, the 220 would serve as a communications antenna for a 220 rig at one
of the control stations.
(Evans added the antenna idea the IRLP node, ARES added line item 2B)

2B)    One note, a multi-banded antenna at the second stand has been
suggested that would cover VHF LOW (6 meter), 2
meter VHF HIGH, and 220 MHz. OR and antenna that would cover all bands, 6 m
2m 23cm 70 cm and 1.2 GHz.
Research will be done to locate such an antenna for this option.

3)    At the 150 foot spot, One VHF antenna for the Polk County area wide
packet station on a frequency of 145.570
    At the level of 136 to 140 foot (10 to 15 foot below the packet antenna)
3 UHF beams staggered, one points to
Clermont, (140') One to Tampa (138') and one to the south towards Arcadia at
the 136' spot. (4 to 10 element beam antennas)
recommended by members of the FADCA organization to provide seamless
coverage between EOC's, email can be forwarded
at your request.

4)    At the 125 foot mark, a WIDE BANDED HF ANTENNA, inverted "V",
recommendation, YES, should be able to use it
       for 160 meters (1,800 kHz to 2,000 kHz) Ideally being able to operate
from 1.8 MHz to 30 MHz General Coverage Tx / Rx.

5)    At the 100 foot mark, two pulleys with lines, recommended. Additions:
a second HF antenna called a SLOPPER
be added, the Shield (ground of the antenna) should be connected to the
tower at this spot also. The center conductor should
extend to the east towards the wooded area and secured from there.

These are the notes I have collected for your review and tower loading
studies as needed. Please advise should the loading
be too extreme for the tower, and need to be revised. It is also suggested
to have the stand offs not under each other, but offset
under each other.

Item number 3 is to support intra-state communications on a digital network
using
high speed back bone data links, UHF, and a 1200 baud LAN (the single VHF
antenna at 150") This system will
support NTS and EMCOMM traffic for the center of the state and will also
help support the SEDAN network during
an actual emergency. To find out more on the packet system the site may be
found at www.fadca.org as well as a map
showing Polk County as lacking digital communications between the East coast
and the West coast, and serving as a
Central packet zone for the packet system would be crucial to all hams. I
can provide you with more information if
needed at your request.

73 From,
KD4EFM / AFA2TH USAF MARS
Evans F. Mitchell
Polk County ARES Member / SkyWarn #POL-017
Polk County EC
Polk County Communications Program Volunteer

<http://www.kd4efm.org>
kd4efm at arrl dot net
kd4efm at hotmail.com
kd4efm at kd4efm dot org

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