Anyone with a VHF or UHF handheld transceiver (HT) probably uses the standard “rubber duck” antenna for casual use. I often refer to the rubber duck as The World’s Most Convenient Crappy Antenna. To be fair, all antennas are a compromise…the rubber duck optimizes small size and convenience at the expense of performance. The Wikipedia entry describes the rubber duck antenna as “an electrically short monopole antenna…[that] consists of a springy wire in the shape of a narrow helix, sealed in a rubber or plastic jacket to protect the antenna.“
Being curious about what really is hiding inside the typical rubber duck antenna, I decided to take a few of them apart. I did not try to assess the performance of the antennas but just examine their construction.
Baofeng UV-5R Stock Antenna
I started by dissecting a Baofeng UV-5R antenna, which took some aggressive action with a diagonal wire cutters to split the rubberized jacket near the bottom. After that, the jacket slid off to reveal the classic spiral antenna element inside. You can see some white adhesive near the top of the spiral element (upper right in the photo).
The Baofeng antenna had a female SMA connector.
Note: You can access high resolution versions of the photos in this article by clicking on them, allowing you to see lots of detail.
Yaesu FT-1DR Stock Antenna
The Yaesu antenna was easy to disassemble. In fact, I chose this antenna because I noticed that the outside jacket had come loose and was starting to slide off the antenna. A steady pull on the cover exposed the antenna elements without any further antenna abuse. (I plan to reinstall the cover with a few dabs of glue and expect that it will continue to work fine.)
The construction of this antenna is quite different from the Baofeng. The main element is a very tightly-wound spring…so tight that I expect that it acts like a solid wire electrically. In other words, it doesn’t have the spiral configuration that makes the antenna act longer electrically. At the bottom of the antenna, there is a coil inserted in series with the radiating element (connects radiating element with the center pin of the SMA connector).
The photo to the right shows a closeup view of the male SMA connector and the coil.
Laird VHF Antenna
Next, I wondered if antennas for commercial radios had different design or construction techniques. Laird makes high-quality antennas for the mobile radio and other commercial markets, so I purchased one of their VHF rubber duck antennas to dissect. This model is intended for use with Motorola radios requiring a threaded antenna stud.
This antenna was a challenge to cut open. I used a sharp knife and diagonal pliers to cut the rubberized jacket and peeled it back using a needle-nose pliers. The rubberized coating was embedded into the spiral antenna element, so it did not come apart easily. It took over an hour fighting with the antenna and I gave up before getting the entire spiral element exposed.
The Laird antenna is clearly the sturdiest of the three antennas. The spiral element is much thicker than the Baofeng and the rubberized coating is tougher and molded tightly into the spiral element.
The Baofeng and Laird antennas use the same design concept…just take a spiral antenna element and apply a protective cover. However, the Laird construction was far superior, but not a surprise given that Baofeng is a low-cost provider in the ham radio (consumer) market.
My disappointment is with the Yaesu antenna. The antenna came apart after one year of not very heavy use. I expect I can put it back together with some adhesive, improving on the design in the process.
Anyway, I found this interesting and wanted to share it with you. What’s in your rubber duck?
73, Bob KØNR