Howdy y'all, I am thinking of our new friends and all of the folks with constrained spaces. I have just the thing!
The 'flowerpot antenna' is an end-loaded, half-wave vertical. It takes up no space at all, may be deployed for use and hidden away after, is easy to build, and it is cheap! The parts list is simple: - 10' or longer 1/2" PVC pipe - 10' or longer 50 Ohm RG-58 coax feed cable - electrical tape and boxcutter knife. The antenna itself may be threaded inside the PVC at the end load coil, or taped to the outside, depending on just how stealthy you need to be. A premade coax feedline is a great way to start, as the pesky BNC is already fitted. Lop off the end you don't need. The wavelength of 2-meter frequencies is 2 meters. A half wave is 1 meter, and a 1/4 wave is 50 cm. Simple math! Measure down 1/4 wavelength. That's almost exactly 50 cm. Longer is better. We will tune for length. Cut around the outside and through the braid, and strip off 50 cm of the shield braid and the 'outside' insulator. Leave the inner insulator for protection from the elements. Tape the stripped end to the end of the PVC, leaving 3" or so for tuning. Add tape along the length of the stripped portion and at the next 50 cm. Then, make several turns of tape 1 meter down to anchor the antenna part of the coax. You should see 1 meter of coax tapped to the PVC, longways! At this point, wrap nine (9) turns of coax tightly for the end-load. Wrap this all in plenty of tape to keep the turns from separating. Add several turns of tape at the end of the coil to anchor the coil. Done. That was easy. It actually took longer to read than it does to make. One cut is all you need. Using our handy, dandy SWR meter, tune the stripped portion to length. Mine ended up shorter than 50 cm, but with a very nice 50 Ohm matching resistance. The 10 feet of PVC makes for a suitably tall mast; the tail of the coax can reach the HT, or you can extend PVC and coax as necessary. The performance easily beats the antenna shipped with the HT. I hope it lights a fire in you to build another antenna! ;-) 73 Dan KJ5IZK
________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list [email protected] http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/[email protected]/
