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EH Antenna for the 20- meter Band

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ANTENTOP- 01- 2012, # 016

EH Antenna for the 20- meter Band

 

 

Fist copper sheet turns around of the Polypropylene Tube and temporary hold by a length of wire. Distance from the upper end of the tube to the foil should be 15- 20-mm. Take hot soldering iron and solder the sheet in 3- places. You need to do it fast because the plastic tube may be melted. Take wire for the phase inductor. Put wire to the seam and do soldering the foil on the full length.

Phase inductor has 2- 3 (3 better) turns of the insulated wire. Turn around the tube coils of the inductor. Lower end of the inductor is inserted into the hole in dia 2-mm onto the tube. Do not forget to tin the end. Figure 2 shows soldering of the inductor to the upper copper cylinder. Figure 3 shows the ready phase inductor.

 

 

Figure 2 Soldering of the Inductor to the Upper Copper Cylinder

 

Figure 3 Ready Phase Inductor

   

Take the second copper sheet. Do with it the same things as with the first one (to turn around of the plastic tube hold by pieces of wire and do soldering in several places). Pay attention that the second (lower) cylinder should be placed on the distance apart of the first cylinder equal to diameter of the tube. At our case it is 32- mm (see Figure 1).

Next step is to measure the capacity between the cylinders. I used to a surplus Russian device E9- 5. Figure 4 shows the measurement. At the design of the EH- Antenna the capacity between the cylinders should be near 7- pF. Knowing of the value is needed for us to calculate (according to W5QJR reference book) a tuning inductor. Below I give you a calculated by me data for the inductor.

Next step is to make the tuning inductor. The inductor is coiled by enamel strand wire in diameter 2- mm (12- AWG). Numbers of turns are 26 (calculated value) but I recommend to coil 28- 29 turns.

 

Figure 4 Measure the Capacity between the Cylinders

It should be done for purpose of the tuning of the EH Antenna because it is easy to remove the coils then to add those ones.

 

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