Ideal when you don't have anough space, this simple loaded dipole, 10 meters (total) long, is a good compromise in order to work 40 meters band.
Bill of material:
- 1,5 mm² electrical wire for domestic installation;
- two pvc pipe 16 cm long and 40 mm outer diameter.
On the PVC support, drill a 3 mm hole at the distance of one cm from the edge. Insert the electrical wire into the hole just practiced and pull out three meters. This will be the central section of the antenna.
Wrap 49 turns on the PVC pipe and drill a 3 mm hole near the end of the winding and insert the electrical wire to stop the winding. Measure two meters of electrical wire from the end of the coil (leave 10 cm more for tuning operations). One side of the dipole is finished.
Now, do the same for the other half dipole. If desired, you can cover the coil with tape or heat shrink (the latter is much lighter).
Using two fishing rods, 5 meters long as support, it can become a compact rotatable dipole very light.
- The loading coil fixed on a fishing rod to obtain a rotatable dipole -
The use of a choke balun is recommended, as always, to adapt the unbalanced coax cable to the balanced antenna, and to prevent RF feed back along the coax shield. The bandwidth referred to an SWR of 2:1 close to the extremes, is on the order of 50 KHz. The use of a tuner is essential if you want to work both the CW and SSB portion.