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Repeater Coverage
Below is repeater RF coverage plot for the
Tombstone, AZ UHF & VHF repeaters. The RF coverage plot is for the
current repeater installation site based on a 20 watt repeaters at a
antenna height of 42 feet. Unless you're part of lined repeater
network, your repeater has limitations, however, the Tombstone 440
repeater is now part of a linked repeater system with umlimited
coverage potential, please read the IMRS
Repeaters Page on this website.
The RF 2 meter repeater coverage plot is for
42 feet, centered on my Tombstone, AZ repeater site
location. The RF coverage plot shows that power isn't always the
solution, elevation and tower height help to overcome some line of sight issues,
but not always. Building obstructions and shadows caused by ridges, hills, and
mountains all contribute to the ability of a repeater, mobile or base, to
communicate with repeaters. The gain and location of a mobile antenna, the
power output of a transceiver, and the sensitivity of a station,
mobile or base, all contribute to the overall performance of a mobile
or repeater base station.
Although Tombstone resides at an elevation of approximately
4600 feet, it also sits in a sort of a bowl or mesa and is surrounded by
mountains or hills (the same thing), back home they would call them mountains,
out here they call them hills. The point is, that RF signals don't go
through mountains, they just stop short there and are blocked and bounce
around.
Please keep this in mind, the Tombstone repeater at this
moment is functioning as a "local area repeater", not a wide area
coverage repeater, more details follow below.
The repeater incorporates both 110 volt AC and
12V DC power supplies for emergency purposes, it's all backed up by a
generator that power our home, if the need arises and will keep the repeater
online during emergencies..
Some of the factors used in plotting RF coverage are:
1. Location
2. Antenna Height Above Ground
3. Frequency
4. Output Power
5. Antenna Gain (Dbi)
6. Polarization
7. Surface Refractivity (N-Units)
8. Direlectric Constant Of Ground
9. Conductivity Of Ground
10. Climate Zone
The "blue" shaded variations in the RF
plots indicate the dbuV/m (Decibels Relative To One
MicroVolt / Field Strength). Field strength ranges from 100 (darkest
shade of blue) to 45 (lightest shade of
blue).
The most important part of the RF plots has to due with the
areas south, southwest and east of Tombstone. The "Tombstone
Hills" to the southwest, the mountains south to Herford, AZ and
Bisbee, AZ, and coverage overall to the the east is affected
considerably. This has always been a troublesome area for RF
communications. The mountainous topography in Arizona presents problems for
RF communications, shadows and line of sight obstacles are a common
occurrence and difficult to manage unless you have a mountain
top site at a very high elevation with a tower of sufficient height. Even
then, line of sight in certain directions, can still present
communications difficulties from the tower to mobiles, or to
portables (hand helds). Once one passes though the Tombstone Hills, and gets
father down stream the signals improve considerable due to an improved line
of sight, as you enter into Sierra Vista the signal will be near full quieting,
I know, I've run this test as I visit Sierra Vista weekly.
KG7DOG (Ron) and myself ran signal tests using FM voice
audio while maintaining communications to and from the Tombstone VHF &
UHF repeaters and Sierra Vista, AZ while using his HT and 5
watts. Further testing, while using mobile rigs and 10 - 20
watts, we have been able to maintain full quieting communication to
and from the Tombstone, AZ repeater all the way along highway 90 between Sierra
Vista, AZ and Interstate 10 at Benson reliably. In some directions range is
30 - 40 miles, in others it limited to 8 - 10 miles. If We're
successful with establishing LAN Links range will change dramatically.
The new Yaesu DR-2X Fusion repeaters now allow LAN linking of up to 100
repeaters, if we can develope relationships with other DR-2X LAN link repeaters
owners and clubs wide area coverage will become a reality. It's all up to
DR-2X repeater owners with LAN boards installed to take advantage of this
tremendous feature of the DR-2X repeater. LAN linking is direct not dependant on
a Japanese server like WIRES-X and eliminates lag time in the
connection.
Current GPS
Location:
31. 43. 44
North
-110. 02. 48
West
30 Watts @ 42
Feet Antenna Height @ 8.6 Dbi Gain
The AB7CQ & W9RIC Repeaters Are
IMRS LAN
Linked Between Arizona & Wisconsin.
First Lan Linked Repeaters In North
America.
Bob Krueger,
AB7CQ
Web
Administrator
146.920/146.320 PL
123.0
444.600 / 449.600 PL
100 Repeater
IRLP Node: 7515 PL
114.8
ab7cqradio@ebidpal.com |