Antennas
Perhaps the most popular topic of discussion on my web site is my antenna situation. I get countless emails asking me to describe this antenna, that antenna, my ground system, tuner, etc. As a result, I've decided to describe as completely as possible my antennas, ground, and tuner mostly with pictures and a few words. Keep in mind the antennas are somewhat 'stealth' and not all that easy to see in places. To preserve my bandwidth on Cahaba Internet, my antenna pictures are now on Microsoft's OneDrive cloud storage web site. When you click a link in the text below, it will take you to an album containing a group of pictures of that particular subject. You can view the pictures individually by clicking the thumbnail or there is an option to view them all in a slide show.
Random Wire
I use my random wire on 160, 80, 60, 40, and 30M where the ICOM IC705 and AH705 tuner matches it very well. It will also load on 20, 17, 15, 12, 10, and 6, but since I have other antennas for those bands, I seldom use it there. The wire is about 110 feet long. At its highest point in the attic, it is about 30 feet above ground (brick) level. The 21 pictures here follow it from where it now leaves an antenna switch connected to the ICOM 705 setup instead of the homebrew antenna tuner shown in the picture, out the shack window, in the attic window, through the attic, out the back attic window down the wall of the house, around a corner of the house where it ends fastened to the frame of a cellar window. Pretty much all of the antenna is shown except the section between the shack window and the attic window. It just blends in too well with the brick wall to get a good picture of it there.
20 Meter Dipole
This antenna resides in the front room on the third floor as shown in four pictures here. The center 12 feet of it is a flat top mounted on the ceiling. Both ends then run down the walls first at a 45 degree angle where the walls are sloped to accomodate the sloping roof, then vertically down to the floor. The center is about 30 feet above ground (brick) level. So it is more or less an inverted vee with a flat top and vertical ends. It's fed with 72 ohm coax out the window, down the outside wall and through a hole in the wall to my shack. It's connected to a switch that is there for quick switching among my antennas. The ICOM AH705 tuner handles whatever tuning may be needed. The dipole consists of #18 stranded insulated wire. Since the picture was taken, I've added a coax balun at the feed point similar to that shown in the ten meters antenna pictures.
15M Dipole
A vertical dipole that is mounted on the outside wall of my house as you can see in three pictures here. The center at the sill of my third floor window as shown there is about 24 feet above ground (brick) level. It is fed with 72 ohm coax running down the wall through the same hole in the wall as the 20M coax into my shack. It is matched with the ICOM AH705 tuner not only on 15, but on 17 and 12 as well. So this one antenna serves me well on 3 bands. The neighboring house is only 6 feet away from my house at the place where the dipole is mounted. This shows clearly in the pictures. I used #16 stranded bare wire for this dipole.
10M Dipole
A sloping dipole with one end at the front third floor window and the other end at the edge of my front porch roof. See two pictures here. It makes about a 30 degree angle with vertical. Like my other dipoles, it is fed with 72 ohm coax, but this time with a few turns of the coax rolled into a coil at the central feed point to act as a coax balun. The balun can be seen clearly in one picture. This coax simply runs in the shack window through a hole in the storm window frame and a notch in the bottom of the window itself. It then goes to the switch in my tuner. It also is matched with the ICOM AH705 tuner to a low SWR. This dipole is made of #16 stranded bare wire.
6M Dipole
The latest addition to my antenna 'farm' is a 6M rotatable dipole in my attic as shown here. It's made from some old aluminum tubing left over from a former TV antenna, and fed with some cable TV coax. The mount is constructed from wood from my 'woodpile' in the basement. Currently it must be rotated manually by going to the attic. Perhaps some day I will come up with some sort of remote rotation capability.
Ground System
When you look at the two pictures starting here you'll agree it doesn't really deserve a name like 'Ground System'. All it consists of is some #16 stranded bare wire running from a bus in my shack to which all my equipment grounds are connected through a hole in the wall down to a couple of ground rods via a connection to the cold water faucet shown in the picture. The ground rods are perhaps 3-4 feet long as best as I can recall. They were put in back in the 60's and I sometimes have trouble remembering things that happened yesterday let alone that long ago. HI. Two random length radials that run along the ground are connected to the top of the rod. One is perhaps 17 feet long. The other is around 50 feet and connects to the power company ground in my basement.
Tuner:
Although the ICOM AH705 tuner handles all the matching now, I'll describe the tuner I needed to use with my previous rigs in case anyone is still interested in a homebrew external tuner.
It's a C-L-C type setup with a series connected capacitor, a parallel coil, and another series connected capacitor. The switch and the tuner are mounted as one unit as shown in the five pictures here that include a simple schematic diagram. All the parts are very very non-critical, including the switch which is just a cheap rotary switch salvaged from the junk box. One rule of thumb is that as you go lower in frequency, the caps and coil will need to be larger, so if you plan to use it down to 1.8 MHz you'll need something similar to the values shown in the picture. But if you only plan to use it for the higher bands, you can get away with using smaller values. Once you initially find the correct settings for the coil and caps on each band, you can quickly return to those settings. Initially to find the correct settings, I start with the caps at mid range and change the taps on the coil for the lowest SWR. This may get you anywhere from 1:1 up to 5:1 or so. Then, if you're not already there, change the tuning of the caps to get down to 1:1. Mark those settings, and you're all ready for some quick band changes in the next contest, especially if you use a multi-pole switch to change the coil taps as I do. Remember these tune-ups must be done on the air, so take every precaution not to interfere with someone. NOTE: The schematic pictured is of an older tuner and indicates a different coil, but the general idea is the same.
Bottom Line
Unless you live in an underground cave or a solid metal apartment building, you can be successful on the ham bands with very minimal antennas. Analyze your situation, decide what can fit into the space, hang the wire, hook it to your transmitter, get a good match, and you'll be successful. You don't need to follow exactly every last little detail in the antenna books. Those are there for the person who has unlimited space and unlimited funds for an antenna farm. A wire strung around your apartment, properly matched to your transmitter will yield you countless hours of pleasure on the ham bands. One note of caution. Don't plan on running a KW into that apartment antenna unless you want to fry your brains with RF. Be careful even at 100W. That is why QRP and simple indoor antennas work so well together. They perform, and they are safe from an RF radiation standpoint. And as an added bonus, no RFI, TVI, etc. to worry about. I can watch TV in my shack and not be able to tell from the TV set when I am transmitting.
