[FLARES] Portable Antennas for Shelters

[Paul Toth-NA4AR]

Ron....

Many of the shelters in your county and most others are what are considered
"well  built structures".  Translated in Florida-ese, concrete and steel.
It is a well documented fact that 70 cm signals (UHF) penetrate the exterior
of
concrete and steel structures much better than signals at lower frequencies
(VHF), unless, of course, the local two meter repeater is nearby.  It is
also a norm that most two band antennas (VHF/UHF), including the ones
designed for use on handheld portable radios, have more gain on the UHF side
of the operation.

I would like to suggest focusing your Shelter Communications efforts on UHF
and equipping your Shelter Operators with high gain, after-market antennas
for their radios.  Diamond makes several really good V/U antennas for H/Ts
that enable communications where the standard H/T antenna hasn't got a
prayer of working.  To complement the units in the field, make sure your
repeater antennas (when possible) are commercial grade, high gain (6db or
greater) gear.  Equip the repeater(s) with low noise PHEMP pre-amps that
will help pull in weak signals with a very low moise profile.  The Angle
Linear pre-amps we are using on the NI4CE repeaters are doing a great job.

To support my suggest, I offer this.  Several years ago, I was involved in
an EComm exercise at Newark (NJ) International Airport.  The local
ARES/RACES repeater (VHF) was located 10 air miles from the facility.  There
was a comparable UHF repeater (same TPO, antenna height and Super Station
Master antenna) also located at the repeater site.  When the exercise
commenced, the Ham Radio communicators were ushered into a steel quanset hut
to work with the other agencies we were supporting.  The minute the main
door on the building was closed, we lost all access to the VHF repeater.  We
switched to the non-ARES UHF repeater and worked the remainder of the
exercise with no difficulty on UHF.  The following Monday, all ARES and
SKYWARN communications for that county was moved to the UHF repeater, based
on its performance under real operating conditions.

73 de Paul-NA4AR
----- Original Message ----- 
From: "Ron Wetjen" <wd4ahz at gte.net>
To: "Florida ARES/RACES list" <flares at mailman.qth.net>
Sent: Saturday, January 29, 2005 9:07 AM
Subject: [FLARES] Portable Antennas for Shelters


> We've been trying to get permanent antennas installed at several of our
> shelters here in Sarasota County, but have been unsuccessful.  The
> latest attempt yesterday, also did not work, for various reasons.
>
> I think we'll probably have to give up that idea for good, and go with
> some kind of temporary or portable arrangement that can be set up when a
> shelter is activated.  What are other folks using as a temporary or
> portable antenna solution at shelters?
>
> Thanks, Ron
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