What Happened When I Added a Counterpoise to My HT


The problem of an electrically short antenna is familiar to anyone operating in medium-wave bands. One solution is the counterpoise ground system, which is a series of radial wires that act as a low-resistance ground connection.

Broadcast Engineers use counterpoise systems to improve AM radio station coverage. Coastal Maritime Stations with limited space use them in conjunction with capacitance hats as a tuning method. HF Backpackers even tie a long radial to their whip antenna to improve their own signal as they hike.

When I read an article about applying the concept to handhelds, I was intrigued.

The antenna on a typical handheld is a vertical monopole with the radio chassis serving as a ground plane. This configuration is terribly inefficient because the antenna is a fraction of a wavelength it should be. Your radio may be rated for 5 watts, but you’d be lucky to have a third of that power radiate from the antenna.

By adding a 1/4-wave counterpoise, you, in effect, turn the antenna into an off-center-fed, vertically polarized 1/2-wave dipole. The modification should improve antenna efficiency so more transmitter power radiates from the antenna than it would without a counterpoise.

Theoretically, it should work.

As an experiment, I added a half-wave counterpoise to my Yaesu VX-8DR during a recent Boy Scout camping trip.

The Communication Challenge

Our Scout Camp is a 700-acre facility on flat elevation. The archery range, fishing dam, and swimming beach are exceptions. They drop 30-35 feet below average terrain over short distances; and it is difficult reaching those sites with 5-watt radios, even though they are less than a mile from most camp sites.

First Test Result

My first test was to see if I could reach a local VHF repeater in nearby Morris, Illinois. Under most conditions, I am fully quiet into this repeater with 1 watt.

I talked with my wife back at our home over the repeater, and she confirmed that my signal was good both at 1-watt and 5-watts.

When I added the VHF counterpoise, I couldn’t kerchunck the repeater on full power.

I was very surprised because the VHF counterpoise, at 19-inches, was nearly as long as the stock VX-8DR antenna. It should behave like a center-fed, 1/2-wave dipole and be 60% to 70% efficient.

I checked my connection and tried again.

Nothing.

I move to a simplex frequency to make sure the counterpoise hadn’t shorted the antenna system.

It did work, but I was 20 feet from the receiver on high power.

Second Test Result

Armed with the knowledge that I had a signal, the next test was a short distance check of 175 yards between our campsite and the dining hall.

Nothing.

When I removed the counterpoise and tried again, the operator on the other end thought I was using the counterpoise and transmitting my test.

I reduced power to 1-watt and carried on the conversation without a problem.

We then tried a UHF counterpoise to see if the fault lay in the construction of the VHF counterpoise.

Again, no signal over the short distance.

Thoughts and Opinions

Without any test equipment, I can’t determine the reason for signal loss. Either the antenna was terribly out of tune and had a SWR greater than 3:1, or the counterpoise I built worked as a shunt away from the antenna. I don’t plan to spend any more time chasing this birdie down.

The antenna theory is logical, but didn’t work for me in practice.

I wouldn’t recommend using a counterpoise on an HT. If you want to improve your signal, construct a better antenna such as a Roll-Up J-Pole.

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13 thoughts on “What Happened When I Added a Counterpoise to My HT

  1. Likely adding it shifted the feed point impedance and antenna resonance (electrical length,) so it would need to be adjusted to compensate. That typically happens when adding ground radials to vertical antennas on HF. — Mike, AL7KC

    Liked by 1 person

    • hello Mike, AL7KC you with radiant floor creates obstacles, if you’re camping or on a scooter, and even on a roof of the car, the roof of the car for example being sheet reflects the radiant and not in a capacity that is receiving transmission, and the same for the scooter, and camping you have to raise it the antenna 3 meters or 3,5mt for a good signal especially if you’re in the high mountains (on the top of the mountain where it ends) so for a good haul to the valley

      Like

  2. Rich C. says:

    I experienced the same problem when adding a counterpoise to my HT. My solution is to get a longer 2 meter/440 antenna and replace the shorter one now in use.

    Like

  3. pentrus says:

    Where did you connect the counterpoise. I do not mean to be impertinent, but was it attached directly below the antenna or to the chassis of the radio such that it did not make contact with the antenna?

    Like

  4. I’m curious if that ring was thick enough to break the center conductor connection on your HT antenna. The SMA connectors on the HTs and scanners I have, that would be too thick and the center radiator would no longer be seated properly if I put that ring in there.

    Also depending on the antenna, this applies to all antennas, adding wire to a design may detune the intended performance. If an antenna is designed as a balanced design, adding anything to it will break it’s intended resonance. This is seen often with people ‘grounding’ antennas that aren’t designed to be grounded.

    Like

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