Improve the performance of your rubber duck with a rat tailBTECH Radios
Hams often complain about the performance of the “rubber duck” antennas that come with their handhelds. There’s even a question in the Technician Class question pool about rubber duck antennas. Question T9A04 reads, “What is a disadvantage of the “rubber duck” antenna supplied with most handheld radio transceivers when compared to a full-sized quarter-wave antenna?” The answer is, “It does not transmit or receive as effectively.”
Usually, the solution is to buy a better antenna. Here at BTECH, we sell the Nagoya line of HT antennas (https://baofengtech.com/accessories). These antennas are fantastic accessories for our BTECH radios.
Another way to improve the efficiency of your handheld antenna is to add a counterpoise, also known as a “rat tail” or “tiger tail,” to your antenna. As shown in the figure at right, the rat tail is simply a short piece of wire that connects to the ground side of the antenna connector. In normal use, the radio’s whip antenna operates against whatever kind of ground it can find. It works, but isn’t very efficient. With a rat tail, however, the rubber duck becomes much more efficient, meaning that you’ll be able to get out farther and receive weaker signals.
They couldn’t be any easier to build. For a 2m rat tail, simply cut a 19.5-in. piece of hookup wire, strip one of the ends, then form a loop that will go over the antenna connector where the rubber duck screws in. You can solder the spot where the end of the wire forms the loop so that the loop stays intact. Another option is to use a crimp-on ring terminal at the radio end of the rat tail. Before crimping on the terminal, make sure that it will fit over the stud.
Now, all you have to do is slide the loop or the terminal over the stud and screw in the antenna.
Keep in mind that the rat tail will be shorter on other bands. For the 1.25 m (220 MHz) band, the rat tail should be about 11.5 inches. For the 70 cm (440 MHz) band, the rat tail should be about 6.5 inches.
Finally, keep in mind that the rat tail makes whatever antenna you’re using more efficient. What this means is that you’ll get even more of a performance boost if you use a rat tail with a Nagoya antenna. This combination may be just what you need if you find that you’re only making a repeater marginally.
Working for me. I can now hit the local repeater from a spot where I couldn’t
What is the best gauge of wire to use?
Even the worst counterpoise in the world is better than nothing.
Be sure not to let the wire touch the center conductor. If you key it with that short present you can make “magic smoke” while you fry your final output stage.
Please work with Nayoga to build this as a product for all bands – especially C variants – 155, 220, 440 use. Many radios have a “collar” that make it difficult to use a ring terminal around the ground…maybe a add an external screw on the base of the antenna where the collar can be easily attached – the screw would of course connect to the antenna ground.
You might be able to find a screw on the HT case that has conductivity to the chassis and antenna connection collar. This “may” have to be considered part of the rat tail overall actual length.
Ring connector works well with 18 gadge wire with shrink wrap to cover the connector/wire.
Could you simply have one wire 11.5” and another 6.5” and solder them both to the terminal and cover them both in shrink tubing? That way whether you’re in UHF or VHF it’ll take advantage of the double tail.
Two rat tails significantly separated should work. Keeping the two different lengths closely together will most likely negate the shorter one due to capacitive coupling between the two wires.
I did this for my UV-5R, and it works. Thanks for the update.