fdant2.art

一个很小和天线计算程序

Antennas and Field Day kits.

Antennas:  A wide range of antennas have been used for field day from
simple wire antennas to full sized yagis. I'll list the different types
of HF antennas that I have seen, used and set-up, rating them on 
portability, set-up, performance, survivability, multi-band, & overall 
average.

    portability: How easy can the antenna be transported by vehicle 
    and/or hand carried to the site.

    set-up: Once at the site, how easy is the antenna to set-up and 
    tune.

    performance: Does the antenna punch through the crowd and hear 
    well? Does the antenna need a tuner?

    survivability: How does it hold up to the weather.  Does the SWR 
    change when it gets wet? Can it take a crash and be set right back 
    up again?  Can it handle a strong lighning storm with high gusty 
    winds and rain?

    multi-band use: How well does the antenna work on more than two 
    bands with or without a tuner?

    Overall average: total of each area divided by five.

Scale is 1 to 5 with 5 being the best.

ANTENNA       PORT.     SU        PERF.     SUR       MBU       OAA
===================================================================
Whip          4         4         2         5         1         3.2
Groundplane   3         3         2         4         1         2.6
Bigstick      3         5         3         5         1         3.4
A-99          5         5         3         5         1         3.8
Hustler vert  3         1         3         4         4         3.0
R5 & R7       3         2         3         4         5         3.4Cs
Vert Dipole   3         3         3         4         2         3.0E
Inv.Vee       5         5         3         4         2         3.8E
Slopers       5         5         3         4         2         3.8E
Wire Dipole   5         4         3         4         2         3.6E
Wire Loops    5         3         3         3         2         3.2
Cubical Quad  3         3         5         2         2         3.0Cm
Yagi          3         2         5         3         2         3.0Cm
LPDA          2         1         5         3         5         3.2Cs

Recommendation code
E:Emergency antenna for the real thing
Cs:Single Rig Antenna (1A, 1B, 1C Stations)
Cm:Multi-Rig Antenna (Stations operating more than one rig)

The recommendation codes are there for you to use as a guide rather 
than law. You can use E antennas on field day and most do.  If you are 
a point chaser, the Cs and Cm antennas will do the job better but 
require more work. Cs are designed for the single station in mind, one 
antenna, one rig, one to four operators, multi-band output. Cm antennas 
are designed for the multi-rig, multi-antenna, multi-everything 
station with multi-band output.

Kits:  Kits can come in a wide range of flavors.  But just what is a 
kit?  A kit is a prepared package constisting of at least the 
following:

            o  An antenna that can be assembled and installed in under 
               30 minutes.
            o  Coax with connectors at least 50-ft in length that can 
               handle at least 100w continuous.
            o  A small tool pouch including spare connectors and 
               adaptors.
            o  A small first aid kit.
            o  A flashlight with spare batteries.
            o  A cheap rain poncho.
            o  A 3-ft coax jumper.
            o  An inexpensive but fairly accurate SWR/PWR meter.
            o  Three #2 pencils and small note book.
            o  50-ft extension cord.
            o  Rope or cord to hang the antenna.
            o  Cheap plastic tarp.
            o  A low wattage 12vdc lamp.

    All this should be in a bag or perferably in a foot locker to go. 
The footlocker can double as a table and also leaves room for your rig, 
mic, a 12vdc deep cycle battery and small power supply.

    There is always the possibility that you will be located near a 
command center which will probably have a generator. Or there maybe a 
generator near you which will allow you to plug in the power supply, 
place the battery between the rig and the power supply incase you loose 
power during a communication. It will act as an UPS. Run the minimum 
power needed to make the contact to conserve your power.

    Kits can be larger and have many more antennas.  You can setup kits 
for emergency use and/or field day.  A four inch diameter PVC pipe, 10
feet long with screw on caps can serve to hold a pushup mast and beam
antenna.  This can also hold two supports.  Where there is no cover for 
a station, the PVC pipe and supports can be set up with a tarp covering 
them as such:

              ========================================== PVC pipe
             /==========================================\
           /  ||                                      ||  \
         /    ||                                      ||    \
       /      ||                                      ||      \ guys
     /        ||                                      ||        \
   /          ||                                      ||          \
 /            ||                                      ||            \
              ||                                      ||  support     \


Handles can be placed on the PVC pipe for easy carrying.

    Designs are endless and I'll continue on next time with some 
antenna mods for quick set-up and use next time.


-WS