If you've gotten to this document, you've probably decided that you just can't live without an outdoor antenna, in spite of my suggestion in Minimal Antennas and Grounds that most people don't need them.
Antennas really aren't mysterious. Grounding your receiver
Antenna and Grounds probably will improve your
reception; possibly your reception will be improved enough so you
won't need an outdoor antenna. If you decide to put up an outdoor
antenna, any antenna that DOESN'T OVERLOAD YOUR RECEIVER probably
will help your reception to some degree.
It would be a good idea to solder and seal all outdoor connections.
Don't get too hung up on formulae for antenna lengths. Cutting an antenna to resonate at a given frequency makes it easier to match the antenna to your tranmitter (if you have one) sending on that frequency. Cutting a receiving antenna to resonate at a given frequency isn't necessarily useful for a shortwave receiver that listens on many frequencies. Furthermore, a resonant antenna could overload your receiver's front end, if there are strong signals present at or near the resonant frequency. Someone else once wrote that the three fundamental (:-) length rules for good reception are:
Hang your antenna as high as you can.
Make your antenna as long as you can.
If your receiver overloads, cut your antenna back, ten feet (3 meters) at a time, until the overloading stops.
Remember, you must take steps to protect yourself, your house, and your receiver from energy induced on your antenna by nearby, but, hopefully not too nearby (:-), lightning strikes. Some people use gas-discharge lightning arrestors, and heavy ground wires and ground rods for protection. (Life and property could be involved, so you might want to check with your local electrical inspector's office to find out what the code requirements are for lightning protection.)
Most of us disconnect our antennas when we're not listning and we NEVER LISTEN WHEN THERE'S A CHANCE OF LIGHTNING in the area.
I particularly like Easy Up Antennas for Radio Listeners
and Hams, by Edward M. Noll,
ISBN 0-672-2295-8. Noll's practical, nuts-and-bolts approach to antenna building is what I like most about his book. Inspired by instructions in Noll's book, I (by myself, and without a ladder) have erected two, 30-foot (or so), guyed antenna masts. The masts were built from lengths of plastic plumbing drain tubing, telescoped into each other and screwed together. The plastic masts were easily lifted and placed over ordinary, chicken-wire-fence anchors. (How much more nuts-and-bolts can you get?)
You might be able to find "The Radio Amateurs Handbook,"
American Radio Relay League,
West Hartford CT, at your Public Library. The edition I have has some advice about antennas in it. The League also has a book specifically about antennas. The "Antenna Book" might be worth a look if your Library has a copy.
The ultimate reason for bothering with an outdoor antenna is to move your antenna away from the electrical noise in your shack. The increased signal level from a longer antenna and the reduced noise level, TOGETHER, can increase the signal-to-noise ratio at your receiver's antenna terminals, and might make a weak signal more readable. Even if there were no increased signal strenth, the reduced noise level, by itself, would increase the signal-to-noise ratio and might make a weak signal more readable.
John Doty has a really great Low Noise Antenna article. John describes a method of feeding his 16-meter (52-foot) inverted-L antenna that gives him a substantial, signal-to-noise-ratio advantage. John uses low cost TV coax and other low cost TV components, including an inexpensive coax-to-twinlead matching transformer that he modifies. I've read and re-read John's article. I must admit that someday even I may be tempted to build John's antenna (:-).
This article was last updated on 1 April 1998.If you have any questions, feel freeto Email me firstname.lastname@example.org . I'll do my best to confuse you completely (:-). (Comments or corrections also are welcome.)