There’s been a surge of new antennas hitting the market lately—many of them verticals. And in my opinion, vertical antennas are fantastic, especially for portable operations.
When I head out to a park, I don’t always have a convenient tree available to hang an EFHW. Even when I do, time matters. I don’t want to spend half my activation wrestling with a throw bag, trying to get it over the right branch, and carefully positioning the antenna. EFHWs are excellent—but they take time. That’s why I often turn to verticals.
I’m not alone. Many activators are coming to the same conclusion, which explains the growing number of portable verticals on the market. Along with them comes a popular idea: using “resonant” or “tuned” radials. The logic usually goes something like this—use a certain number of radials for 20 meters, but when you switch to 40 meters, you need to add more.
At first glance, that sounds reasonable. But flip the logic around, and it starts to fall apart. If that were true, then when moving from 40 meters back to 20 meters, you would need to remove radials. And that should raise some red flags.
Rudy Severns, N6LF, addressed this very question in a QEX article (May/June 2009) titled *“How many radials does my vertical really need?”* His conclusion was simple: more radials are better. Period.
Now, there is a point of diminishing returns. As Severns notes, “You gain perhaps another fraction of a dB going to 32 radials, but by the time you reach 64 radials there isn’t much change. The broadcast standard of 120 radials, each 0.4 wavelengths long, is hard to justify for amateur use—especially at today’s copper prices”.
Still, the principle holds: additional radials continue to improve performance, even if the gains become small. Which means that once you’ve laid out radials for a lower band like 40 meters, removing some when switching to a higher band like 20 meters is actually counterproductive.
So don’t buy into the marketing hype. The idea that ground radials need to be “resonant” or “tuned” is largely a myth. And when someone asks how many radials your vertical needs, the simplest answer is still the best:
More.
Note: This article is discussing ground radials only. Elevated radials, which play a different role in the antenna system, is a different beast all-together. Rudy Severns, N6LF, discusses these differences in another article written for QEX magazine Mar/Apr 2009. To gain a firm understanding of various ground systems and access to all his test data, I recommend all seven of his articles that can be found (for free) at “https://www.antennasbyn6lf.com/“
