I hate rubber duck antennas.

I got so sick of mine, in fact, that I lost it. Completely on accident!

This was my excuse to build a new antenna.

Goals -

• Little. It's for an HT, after all.
• Cheap. I built mine for about $8, plus solder and time.
• Good performance. The big reason for hating rubber ducks is that they're not particularly good antennas... Fortunately, just about anything (everything!) else will work better.
• All parts available at RadioShack. This means that I could build it at work.
• DUAL BAND. I decided that since I have a Dual-Band HT (an HTX-245), I should be able to use it with my antenna. I decided that I WOULD be ok adjusting the antenna length before transmits - Pull antenna out to maximum length for 2m, compress to minimum length for .70m.

Pictures will be coming soon, once I actually decide to build a second one.

Parts list:

• BNC-Motorola plug adapter. This has a female BNC on one end, and a male Motorola plug on the other. A Motorola plug looks a whole lot like an RCA plug, but with a much longer center conductor. (An RCA plug would work too, but be harder to solder).
• A replacement extension antenna. Has to be about 6.5" long when contracted, and about 20.5" long when extended, WHEN MOUNTED ON THE BNC ADAPTER. The 22.25" antenna replacement worked pretty well.

Construction Instructions.

• Using a hacksaw, high speed rotary tool, or file, cut off the base of the antenna. About .25" above the crimps at the base seems right. When you get it open, it should be JUST ABOVE the solid part of the base.
• Pull out the inner tube, by compressing the antenna slightly more than you could before. This pushes the tube out the bottom of the antenna, and a 2" tube falls out.
• Push this tube over then center pin on the Motorola plug. Solder it in place. (Use a "gun style" soldering iron, "hook" the tube inside the heating tip, pull the trigger. Stuff solder on the inside until it melts to fill the gap.)
• File/Sand off the chrome on the outside of this tube. Tin the brassy/coppery looking metal. Tin it a little heavy, as you won't be able to add more solder to fill in once you push the rest of the antenna on. Don't tin it too heavily, or it won't fit inside the antenna....
• Fully extend the antenna. Measure 1/4 wavelength at 144Mhz from the tip (20.5" - tip is where the metal stops, probably about halfway between the top and bottom of the "red ball" plastic tip). This is the point you want to be even with the "shield" of the Motorola connector.
• Cut the antenna so that when inserted fully, this point will line up with the shield.
• Compress the antenna. Measure from the shield edge 1/4 wavelength at 450Mhz (6.56"). You should need to extend the antenna to get to this point. Extend ONLY the topmost (thinnest) section to make this length. At the point where the top section meets the next section, wrap a piece of tape around the antenna, to prevent the antenna from getting too short.
• Place the antenna over the Motorola plug. Solder in place, using above "hook" technique.

The very astute of you will have noticed that this does NOT provide the typical SMA-BNC adapter that is necessary. These can be ordered from RadioShack (ask at the counter to see the Commercial Catalog, then get to the adapters section, you want an adapter that is SMA male on one side, BNC male on the other - this is the common variety of SMA-BNC adapter).

Performance - I don't have an SWR meter to test it with. HOWEVER.... I did notice about a 2 point increase in receive strength over the duck. Where before I was lucky to hit 1 repeater from my living room (had to do the Rabbit-Ear dance and pray...), I can now hit all 5 local repeaters that I know about, casually, with the antenna in any orientation, with .7 Watts.

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