HT Antenna Improvement

The handheld transceiver (HT) is likely a new ham’s first radio.  This VHF/UHF rig is relatively inexpensive, compact and fairly useful for local communication via repeater or simplex operation.

Unfortunately, HT  performance is typically limited by its low power and cheap factory antenna.

T9A04-2018

There are three easy ways to improve the HT antenna.  These ideas are from our post on Understanding Antennas but we wanted to elaborate a bit on them here.

The first improvement is to get a 2m ¼-wave or 5/8-wave whip antenna.

This 2m ¼-wave whip is much longer (~19″) compared to the factory antenna but gives dramatically better performance (roughly equivalent of 5x power):

QW whip

This telescoping 5/8-wave whip should (in theory) perform better than the ¼-wave monopole (shown with 5/8-wave mobile whip):

5_8 Whip

These two antennas can be purchased new in the $20-30 range; well worth the money.

While the antenna can be improved with a longer whip, vertical monopole performance is also limited by the HT’s indirect ground plane.

The counterpoise that makes the vertical monopole behave like a λ/2 dipole on a HT is the operator’s body.  It is capacitively coupled to the ham’s body through the plastic case and metal shell around the RF circuitry.

This indirect counterpoise coupling is not only weak but also highly variable and unpredictable.

The good news is that we can improve the counterpoise simply by adding a wire to the HT antenna connection.

By connecting a ¼-wave  wire (~19” for 146MHz) to the antenna connector outer terminal, we create a physical counterpoise in place of the indirect ground plane through the operator’s body.

This gives superior performance under difficult conditions and is easy to do.

These physical counterpoise wires are known as rat tails or tiger tails due to their appearance.

Rat tail counterpoise installation is quick and easy.  Simply unscrew the antenna, slip the rat tail over the connector and re-attach the antenna

tiger tail1

tiger tail2

tiger tail3

tiger tail4

The rat tail can simply hang down in a gentle arc where it won’t be much in the way of anything. Even better, you can hold the wire out  in the direction of communication.  Gain/directivity is achieved by pointing the rat tail.

The rat/tiger tail combined with a quality ¼-wave whip antenna achieves the best possible antenna performance with a HT while walking around.

You can buy a rat tail counterpoise or build your own fairly easily.  The hardest part of construction is determining the proper size of ring terminal to fit under the HT antenna; big enough to fit over the connector threads but not so big that it doesn’t make contact.

It’s also a good idea to cover the end of the wire with insulation to prevent RF burns from accidental contact.

Now there are some nay-sayers out there who insist that rat tails don’t help.  But there are many more web articles and videos which detail serious improvement.  I will share some links:

Our suggestion is to research this yourself and buy or build if it appeals to you.

Note that improvements are reported on the 2m band (VHF); while 2m antennas  antennas work well on 70cm (UHF) according to the 3rd harmonic principle, the rat tail counterpoise should be sized accordingly.

Finally, an overall improvement in HT antenna performance is available if you are stationary (not walking around).  Using a slim-Jim style J-pole antenna with your HT gives excellent results.  However, it requires you to hang the antenna up and you’re limited in mobility to the length of the coaxial cable.  Build or buy here or here.

 

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