The McGyver(tm) special
From The RadioReference Wiki
This antenna was originally introduced to me by NASWAn Ed Insinger, who needed a quick and dirty way to get a relatively small HF antenna to work reasonably well across the HF spectrum, given its small size. I call it the 'McGyver(tm) antenna' because of one of the items you need to build it, made famous by the fictional character of the same name, portrayed by actor Richard Dean Anderson . Only simple tools and a soldering iron is required.
Items required for construction
- Aluminum duct tape
- A large cardboard tube, the kind used in shipping carpets. Cut it down in size to fit wherever you plan to mount the antenna - an outdoor facing closet, crawlspace, ect. The larger the tube, the more wire you can easily fit
- Insulated wire, antenna wire of just about any type will do. #16 or #18 is easy to work with. I started off with about 70 feet, but increased it later to 90 foot or so.
- A length of coax (I used some old RG174U, but others will work too).
- An appropriate connector for your receiver
- Start by measuring out the wire. At about 1/3 of the length, strip the wire, twist it to make a very small loop, then tin it.
- Wrap the entire length of the tube with the aluminum duct tape, sticky side out. This will help hold the wire in place
- Punch 2 parallel holes in the now-taped up tube.
- Put 1 end of the wire through one of the holes and tie a knot so it won't come out. Wrap the wire around the tube - the spacing really isn't critical, but be as consistent as you can. The sticky tape will hold the wire in place.
- Make sure that the wire loop you made in 1.is secure. You may need to put an additional piece of tape on either side of the loop to insure it won't move
- When you've finished winding, put the remaining wire through the other hole and tie a knot.
- Strip whatever coax you have, exposing only the center conductor. Tin the center conductor and solder it to the wire loop you made in 1.
- Solder the connector for your receiver to the other end of the coax.
- Put the antenna in the desired location. Try to keep it away from metallic objects as much as possible.
It might be interesting to put a magnetic longwire balun (MLB) at the feedpoint to see if it will quiet down the noise pickup. You can wind your own using plans found in the Shortwave SWL Antenna Yahoo group, or you can buy them rather inexpensively. See our HF Antennas article for more on this topic.
I've used various kinds of antenna tuners over the years on this antenna - everything from a L/Series combo to the MFJ-901, to the Grove TUN-2 (no longer in production). The use of a tuner is somewhat controversial - most suggest that if the antenna is allowing you to hear signals at a reasonable level, then no tuner is needed. However, it can be helpful in situations where the antenna is not quite working on certain bands as well as you would like. Experimentation, and experience, is the key here.