Boosting Your Vertical Antenna Performance: A Simple Parasitic Element Trick

Boosting Your Vertical Antenna Performance: A Simple Parasitic Element Trick


As ham radio enthusiasts, we're always on the lookout for ways to squeeze the most performance out of our antenna setups, especially when space is limited. The humble vertical antenna is a popular choice for many, particularly in suburban areas with small gardens. But what if you could add a little extra gain to your vertical without breaking the bank? Well, let me share an interesting technique that's been working wonders for a fellow operator, ZL3XDJ, and how you can try it for yourself.

The Versatile Vertical Antenna

The ground-mounted quarter-wave vertical antenna is a tried-and-true design that offers several advantages. It's omnidirectional, meaning your signal radiates equally in all directions, and the low-angle radiation pattern is well-suited for long-distance communication. However, the tradeoff is that you don't get the directional gain you'd find in a Yagi or other beam antenna .

But what if I told you there's a way to add a bit of directional gain to your vertical without a complete antenna overhaul? Enter the parasitic element – a simple addition that can make a big difference in your signal strength.

Introducing the Parasitic Reflector

The idea behind using a parasitic reflector with your vertical antenna is to create a two-element Yagi-like setup. By placing a reflector element behind your vertical, you can achieve some forward gain in the direction you want to focus your signal.

The key is to position the reflector element about a quarter-wavelength (5 meters for 20 meters) behind the vertical and tune it to a slightly lower frequency – around 2-3% below your operating frequency. This creates the reflector effect, which helps to concentrate the signal in the desired direction.

Putting it into Practice

One of the operators I've been chatting with, ZL3XDJ, has been experimenting with this exact setup, and the results are quite impressive. He's using a simple painter's pole as the vertical element and a portable antenna kit, the JPC-12 GP Portable 100W HF 40-6m Antenna, as the parasitic reflector.

By tuning the reflector element to a slightly lower frequency and positioning it about 5 meters behind the vertical, ZL3XDJ has been able to achieve noticeable forward gain, particularly on the 20-meter and 40-meter bands. He's been putting out a great signal into the UK, even with his minimalist setup.

I decided to give this a try myself, using my trusty Hustler 4BTV vertical as the driven element and the JPC-12 portable antenna as the reflector. After tuning the reflector to 13.7 MHz, about 2-3% below my 20-meter CW operating frequency, I noticed a significant reduction in the signal strength behind the reflector, indicating it was indeed creating a directional pattern.

On-air tests showed an improvement of around 3-4 dB in the forward direction, which can make a real difference in signal reports and overall performance. I'm eager to experiment further, perhaps by adjusting the spacing between the vertical and reflector to see if I can squeeze out even more gain.

The Beauty of Experimentation

One of the things I really admire about operators like ZL3XDJ is their willingness to experiment and not get bogged down in theoretical models or textbook recommendations. As he says, "Forget the modeling, forget what the textbooks say – try it for yourself and see what works."

This hands-on approach is precisely what led him to discover the benefits of using a parasitic reflector with his vertical antenna. And it's an approach I've always embraced as well. After all, the joy of ham radio is in the discovery, the tinkering, and the satisfaction of making something work, even if it defies conventional wisdom.

So, if you're a vertical antenna user, I encourage you to give this simple parasitic reflector trick a try. Check out ZL3XDJ's YouTube channel here.

Who knows, you might just find that a little bit of experimentation can breathe new life into your vertical antenna setup and take your DX capabilities to the next level. Happy tinkering, and I'll see you on the air!