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HT Antenna Modification For Increased
Performance! When limited to "barefoot"
operation, with a "rubber duck", HT antennas are not very efficient
nor adequate for communications. They fail miserably as an effective
radiator due to their design! They are nothing more than an extended
dummy load acting as an antenna!
FACTS ABOUT HT ANTENNAS The National Bureau of
Standards tests of Public Safety high band and amateur 2-meter
antennas indicate that a "rubber duck" has -5db, "negative gain"
compared to a quarter wave held at face level. In terms of effective
radiated power (ERP), this means that a 5 watt HT with rubber
duck, radiates only 1 watt. Operating an HT on your belt results in
another -20db attenuation, reducing ERP to 50 milliwatts! That's
1/20 of one watt! Due to the design of the
factory installed HT antenna, you are effectively missing half of
the antenna! MODIFY THAT HT ANTENNA FOR BETTER
RESULTS
It should
be noted that if your HT is under warranty, the internal
modification may void that warranty...you have been
warned! If you want to
buy another HT antenna, rather than add the counterpoise
described in this article, then it is recommended that you shop
around. Don't be misled by the cheaper priced antennas. Buy
from a reputable dealer that will answer your questions. Try to
find an antenna with published gain figures compared to a
dipole or 1/4 wave vertical. Don't expect Yagi or similar
performance....have fun and get better performance than
you were! Easy HT Improvements by N6JSX 09/2013 We all know OEM (original equipment manufacture) HT rubber-ducky antennas are a dismal compromise, at best, facetiously called " helical-dummy-loads".There are a few ways to improve your HT'ing distance and experience. First and foremost consider buying an after-market antenna, like the Diamond SRH77CA-SMA or RC77CA-BNC, or make a more economical full 1/4 wave BNC Brass Whip and add a Tail. I found my 2m Brass Whip to work well on 70cm too.Second, is to improve the antenna's counterpoise; an HT body is a very poor counterpoise! A product I saw decades ago, called the "Tiger-Tail", seemed to have been the answer to this problem but it was just too easy for HAMs to reproduce, killing its sales. The Tail is a 1/4 wave + 5 percent counterpoise wire hung from the HT antenna connector creating a mock 1/2 wave dipole. The trick in making an affective Tail is to insure a good tight fit to the HT connector. I duplicated the Tail by using ring terminals but a problem with ring terminals are those darn BNC posts. I over came this by filing a small notch inside the ring to fit over one post, twist it around the BNC barrel and slip it over the other post. See photo below. But with the advent of HT's going to a SMA connector the BNC post issue disappears making this Tail a much simpler and far easier to attach.
The Tiger-Tail is a 1/4 wave +5 percent length of wire hung from the HT connector.Thomas & Betts ring-crimp-terminals: SMA = 1/4 inch eye for 14-16AWG wire (blue) T&B #14RB-14X BNC = 3/8 inch eye for 10-12 AWG wire (yellow) T&B #10RC-38X Black 14-16AWG
stranded wire is soldered to the ring. The hardest part of using this Tail is getting the wire to hang straight. 73~~~ N6JSX Download the complete pdf
file here for the entire project details and
enjoy!
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