2004 ARRL FIELD DAY
2 PM SATURDAY, JUNE 26TH THROUGH 2 PM SUNDAY, JUNE 27TH
RULES ON PAGE 107 OF MAY QST
GET ON THE AIR DURING FIELD DAY JUNE 26-27
NOFARS members are encouraged to participate in the 2004 ARRL Field Day.
For NOFARS, the focus this year will be on operating from each member’s home neighborhood.
Instead of a centralized Field Day, we hope to have a half-dozen or more single transmitter operations spread around the area–a much more likely emergency response situation than a big communications central operation.
A transceiver on a picnic table powered by a battery or small generator at a campsite, a park, the beach, from a mobile station or from the back yard is sufficient to participate. A simple wire antenna will allow contact with some of the 3,000+ other participants.
For a single transmitter operation on backup power using a makeshift antenna, the exchange will be 1A NFL. A mobile station uses a 1C exchange. A commercial power category also is available (1D) as is a home station on emergency power (1E). Rules are listed on page 107 of May QST magazine. The Field Day information package can be downloaded via http://www.arrl.org/contests/announcements/fd/
FIELD DAY PROVIDES OPPORTUNITY FOR HAMS TO DEMONSTRATE SERVICE TO PUBLIC
On Saturday, June 26th and Sunday, June 27th–individuals and groups of hams throughout the Americas will make contact with each other during ARRL Field Day. Most installations will be powered independent of commercial power sources and will demonstrate possibly the biggest unique advantage of Amateur Radio.
Commercial communications systems such as cellular telephones and trunked radio systems rely on a complex infrastructure network to function. When this network is disrupted, communications collapses. Even during panics, cellular telephones become jammed and unusable.
In contrast, Amateur Radio communications can be established quickly by trained and dedicated ham operators. No infrastructure is needed. Field Day provides training to those hams who wish to serve their neighbors and the general public.
The North Florida Amateur Radio Society urges all area hams to plan to operate at least a few hours using backup power. A Field Day station can be as simple as a mobile transceiver in the driveway or parked in an advantageous location. Also, a small generator can power a station set up in a public place such as a park or at a campsite. Even a station on a picnic table in ones back yard using a portable antenna can participate.
Make plans now to be a part of Field Day by getting on the air for the entire 24 hour operating period or just for a while.
Watch this web page as Field Day approaches. Learn more about Good Neighbor Field Day 2004 which will tie in with the North Florida Amateur Radio Society Good Neighbor Radio Operator Program (Neighborhood Ham).
PORTABLE HF ANTENNAS
The sloping dipole (sloper) is a cheap and simple antenna for both base and portable use. It stores very easily and consists of a center insulator and two wire segments. It can be hung from a tree branch or most any support. Only one support is needed, the other end is attached close to the ground.
Use RG-8, RG58 type of 50-52 ohm coax. Even RG-59 cable TV coax (72-75 ohms) can be used with little degradation, especially if a tuner is used. Nylon twine can be used to secure the two ends of the sloper. Be sure and mark any low wires or ropes well to provide a warning.
A 40 meter sloper usually will also cover 15 meters, so this is the first one to consider. Each wire segment should be around 33 feet long. Total length is around 66 feet. It is good to include an extra three inches or so on each wire segment to facilitate end and center connection loops.
Wire can be copperweld type stranded bare wire or scrap electrical cable. Even unshielded speaker wire is satisfactory. Aluminum wire can be used but may cause complications with making connections.
Unless you are running high power (over 250 watts), the wire diameter is not of much importance. The main consideration about wire thickness is being sufficient to keep the wire from stretching or breaking easily from stress.
Both wire segments should be exactly the same length. Cut one segment with a ruler/tape measure. Then cut the second segment using the first as a guide.
A drilled segment of PVC pipe can be used as a center insulator. A 3 inch segment of 3/4 or 1 inch diameter PVC works well.
Pig tail the two coax conductors to the two center leg connections. The wire segment to be hoisted the highest should be electrically connected to the coaxial cable center conductor. See the diagram below.
You can dog leg the wire segments to fit in a small lot, although this should not be done unless such is unavoidable.
Field Day is a good time to construct your own sloper. And then try it out on the air.
If you live in a restricted area, portable antennas may be legal for a short duration. After FD is over, roll up your sloper and store in a plastic box. Or set up in a park or operate from your car parked near the beach.
You’ll be ready to go even if your normal antenna is damaged during a storm. If you also have a source of backup power, then you may be of valuable service to your neighbors when serious utility disruptions occur.
Other sloper lengths include:
80 meters (3.9 MHz)——60 ft. for each wire segment (120 ft. total wire length)
20 Meters (14.2 MHz)—–16 ft. 6 inches for each wire segment (33 ft. total wire length)
10 Meters (28.4 MHz)—–8 ft. 3 inches for each wire segment (16 ft. 6 inches total length)
6 Meters (50.2 MHz)——4 ft. 7 inches for each wire segment (9 ft. 2 inches total length)
Formula for total wire length (X to Z): 468 divided by the frequency in Megahertz
Above: XY and YZ are wire segments. Attach nylon rope or twine to points X and Z..
Y is the feedpoint. Attach 50 or 75 ohm coaxial cable.
The X ended wire segment should attach to the center conductor of the coaxial cable at the Y feedpoint.
The Z ended wire segment should attach to the outer shield of the coaxial cable at the Y feedpoint.
The X end nylon twine should be placed as high as possible such using a tree branch, mast or other support. 20 to 30 feet of elevation is ideal.
The Z end nylon twine should be attached to a point near the ground. Or if a second support structure is available, both ends can be raised to form a basic dipole configuration.
Some hams have used wire dipole antennas in their attic with reasonable results when band conditions are above average.
There are sloper configurations that provide directionality and gain. Consult a search engine for sources of information.