When it comes to Parks on the Air (POTA) activations, choosing the right antenna can significantly impact your operating experience. Traditionally, aside from resonate dipoles the debate centers on the classic End-Fed Half-Wave (EFHW) versus the Resonant Vertical. However, there is a third contender that combines the best of both worlds: the End-Fed Vertical. By using a vertical radiator fed through a 9:1 unun and an antenna tuner, you create a versatile, high-performance system that excels in the unpredictable environments of state and national parks.
1. The End-Fed Antenna (Horizontal/Sloper)
End-fed antennas—typically deployed as horizontal wires or "slopers"—are a staple for portable ops.
Pros: Lightweight, multiband capability with a tuner, and simple "one-tree" setup.
Cons: Prone to RF grounding issues, tuner dependency, and a radiation pattern that often favors NVIS (local) over DX.
2. The Traditional Vertical Antenna
Standard verticals (like a 1/4 wave whip) are the go-to for distance.
Pros: Efficient low-angle radiation pattern and an omnidirectional footprint.
Cons: "Radial Fatigue"—they require a dense network of ground radials to work efficiently. They are also usually single-band without manual adjustment.
3. The New Contender: The End-Fed Vertical
The End-Fed Vertical is essentially a vertical wire supported by a telescoping pole, fed at the base through a 9:1 Unun.
The Pros:
- Minimalist Footprint: Much more forgiving than a traditional vertical. A single counterpoise wire is often enough, keeping the "tripping hazards" to a minimum in public parks.
- DX Take-off Angle: You retain the low take-off angle of a vertical, essential for reaching distant "hunters."
- Lightning-Fast Band Hopping: The 9:1 unun brings high impedance down to a manageable range, allowing a wide-range tuner to switch from 40m to 10m in seconds.
The Cons:
- Common Mode Current: RF can travel back down the coax. A 1:1 choke (line isolator) is often necessary to prevent interference.
- Efficiency Trade-off: You lose a small amount of power to heat in the unun. However, for POTA, the versatility usually outweighs the minor loss.
Converting a Standard Wire to an End-Fed System
If you currently use a standard resonant vertical, "converting" it to an end-fed system with an unun and tuner can revolutionize your POTA flow:
- Band Agility: Stay in your chair. If 20m dies, you’re on 40m instantly via the tuner.
- Length Flexibility: Use "random" wire lengths (like 29' or 41') that aren't resonant on any one band but are tunable on all of them.
- Deploy Anywhere: Perfect for rocky soil or high-traffic areas where laying out 16 radials is impossible.
Summary Comparison
Feature - End-Fed Sloper - Traditional Vertical - End-Fed Vertical
Setup Time - Fast - Slow (Radials) - Fastest
Band Swaps -Tuner-based -Manual/Coils - Tuner-based
DX Potential - Moderate - High - High
Ground Needs- Low - High - Low
Conclusion: If you want the ultimate balance of portability and multi-band performance, the end-fed vertical is hard to beat. Experimenting with a 9:1 unun on your next activation might just be the upgrade your POTA kit needs. -KB3CMT