To end my posting about my HAM radio project, I finished up my installation of lightning protection this weekend, and spent the day yesterday installing my antenna. I have been experimenting with different antenna designs for the past few months. For this round, I bought myself a 500 foot spool of 14 gauge black THHN wire to make my antenna for $43 from Home Depot. I measured out 275 feet of wire, and ran it around the outer edge of the roof. I used hooks on the eaves to attach my insulating anchors, which are just short loops of parachute cord. I cut off the end, and this left me with a 260 foot antenna in a rectangular shape, about 10 feet off the ground. It is nearly invisible from the street.
I soldered the ends to a 20 foot section of 450 ohm ladder line, and attached the other end to a 4:1 balun. Antenna complete.
Do the math by dividing the number 1005 by the total footage of the antenna (260) and you get the resonant frequency of the antenna, 3.865 mHz. That means that I have an antenna that will resonate right in the center of the phone section of the 80 meter band. In theory, I have an 80 meter full wave horizontal loop. The problem here is that these antennas are supposed to be placed 30-40 feet above the ground. So we moved on to testing.
Receiving was greatly improved. Swapping back and forth between my old and new antennas, the difference was amazing. Frequencies that sounded dead with the old antenna had faint but readable signals. Signals that used to be audible but unreadable were crystal clear. I got a 3-4 S meter improvement in all bands.
Transmitting is amazing. The antenna works so well that I have disconnected my auto tuner. Hooked directly from the balun to the receiver, I get a 1:1 SWR in the 160, 80, 40, 30, 20, 17, 15, 12, 10, and 6 meter bands. That's right: EVERY amateur band from 160 meters all the way up to the 6 meter band. Within 10 minutes of starting, I had made contact with the Hatteras Lighthouse 600 miles from my house.
For anyone that is a HAM operator, I would recommend trying this antenna.
2 comments:
Outstanding!
Your angle of radiation should come down as you go up in frequency and it will behave differently. On 80, it will be more of a local antenna, but on higher bands, your pattern will drop, making it a better DX antenna.
6m was pretty wide open this past weekend. On Sunday afternoon, most of Florida was "connected" into the Carribean and South America for hours. Later in the day, we had a virtual pipeline into Southern California, with moderate stations easily hitting an honest S9 on my meter. There's a major contest on VHF this weekend, so there will be much more activity than usual.
SiGraybeard @ work
Wow! That's impressive. I'm tempted to try it.
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