KC8AON's QRP PROJECTS

FIELD DEPLOYMENT FOR END FED HALF WAVE ANTENNAS

WAYS TO GET THE MOST FROM END FED HALF WAVE ANTENNAS

INVERTED V CONFIGURATION

Figure 1 shows the end fed half wave as an inverted V. It is shown using a 20' telescopic fishing (Crappie) pole as the main support, but any support can be used like available trees, existing poles, towers, or buildings etc. In the field, when I use it as an inverted V, I use the 20' crappie pole ground mounted and the center of the length of wire supported at the top of the pole. I usually try to keep the ends of the wires at least 3' above the ground. Mounted in this fashion, the end fed half wave makes an excellent NVIS (Near Vertical Incedent Skywave) antenna that gives good coverage out to around 300 miles on the low bands 30 thru 80 meters. On the higher bands 20 meters and up it will do a fair job at longer distance. The main advantage of the inverted V is the fact that you only need one support for the center of the wire, and a simple means of staking down the far end of the wire - I use a big nail and some nylon string.

INVERTED V CONFIGURATION

Figure 2 shows the end fed as an invert L antenna. Again, using the 20' crappie pole or tree or whatever, I like to get as much wire as possible in the vertical position and the balance of the wire in the horizontal position. The inverted L antenna will do a good job both in close and at a distance for DX due to the fact that it exhibits both horizontal and vertical radiation at fairly low angles. Unlike the inverted V, the inverted L needs 2 supports, so I usually use the crappie pole for the vertical support and try to find a good tree to support the horizontal section. The inverted L is actually my favorite way to deploy the end fed half wave because it is a great performer ! It's alittle harder to put up, but it does a much better job than the inverted V.

SLOPER CONFIGURATION

Figure 3 is the end fed half wave antenna deployed as a sloper, and I usually only use this antenna on 20 meters and up. On bands lower than 20 meters you really need a higher support than the 20' crappie pole to support the longer wires and still maintain a good angle on the wire. I try to get the sloper into a 45 degree angle, but this is not possible with a 20 meter wire (33') and a 20' support, so I just get it as close as possible. The sloper will exhibit a bit of directional radiation in line from the support to the radio (bottom support), so you must orient the wire in the desired direction for best operation. This means that if you want to shoot your signals to the east, you put the high support to your west with the bottom end of the wire to the east. Deployed this way, it is a good DX performer and is very easy to deploy in the field ! To change direction of your signal, simply pick up the radio and stretch the wire out into another direction !

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