Build a Pennant Receive Antenna
The Pennant is a small triangular terminated loop — its full-loop shape (rather than the EWE's open two-post design) gives it a genuinely useful front-to-back ratio in a footprint that still fits in a modest back yard. Like every antenna in this receive-only family, it has essentially no gain of its own; its entire value is a directional pattern that helps you hear weak DX by rejecting noise and interference from unwanted directions. This guide covers the complete build from loop dimensions through the feedpoint transformer, termination resistor, and TX/RX switching.
A Full Loop Instead of an Open "U"
Where the EWE uses two vertical posts joined by a top wire (an open shape, electrically), the Pennant closes the loop entirely — a triangular wire loop, apex up, with the two bottom corners as the feedpoint and termination points. This closed-loop topology is one of the reasons the Pennant is often preferred over the EWE for a given site: the full loop tends to give a somewhat cleaner pattern and comparable or better front-to-back ratio for a similar footprint.
Feedpoint and Termination at the Base Corners
One bottom corner of the triangle connects to the feedpoint transformer; the other bottom corner connects to the termination resistor and a ground rod. The apex is simply the top point of the wire loop, with no electrical connection needed there beyond the wire itself continuing through.
The Termination Resistor — Found Empirically
As with the EWE and K9AY loop on this site, the termination resistor value is the single most important variable and depends on your specific loop dimensions and local ground conditions — treat published starting values as a starting point for on-site optimization, not a final answer.
Why This Isn't a Transmit Antenna
Exactly as with the EWE, the termination resistor and feedpoint transformer here are sized for receive-only signal levels, and the thin wire used isn't rated for transmit power. A TX/RX changeover relay that disconnects the Pennant from the receiver during transmit is mandatory, protecting both this antenna and your receiver's front end.
| Band | Apex height | Base width | Starting termination resistor |
|---|---|---|---|
| 160m | 22-25 ft | 28-30 ft | ~850 Ω starting point |
| 80m | 18-22 ft | 22-26 ft | ~750 Ω starting point |
| 40m | 16-18 ft | 18-20 ft | ~700 Ω starting point |
Pennant Antenna Starting-Point Calculator
Materials for a complete Pennant build
Building the Pennant Receive Antenna
A compact triangular loop build — most of the effort is in termination resistor optimization, same as this site's other small receive antennas.
Install the Apex Support
Set up the tall support pole or tree-limb anchor at the apex height from the dimensions table, oriented so the antenna's favored direction points toward your target listening direction.
Mark the Two Base Corner Anchors
Mark and install ground-level anchors at the base width spacing from the dimensions table, forming a triangle with the apex support.
Run the Triangular Loop Wire
Run a continuous wire from one base corner up to the apex, back down to the other base corner — a single unbroken triangular loop, with the two base corners left open for the feedpoint and termination connections.
Install the Termination Resistor and Ground
At one base corner, connect a variable resistor (for initial testing) between the wire ends and a ground rod driven at that location.
Install the Feedpoint Transformer
At the other base corner, wind and install the 9:1 unun on the ferrite toroid, connecting the loop wire ends to the transformer's high-impedance side and the coax to the 50Ω side.
Install the TX/RX Relay
Wire the relay so it disconnects the Pennant's coax from the receiver whenever your station keys up.
Route Coax and Optimize the Termination Resistor
Run the receive coax to your shack, ideally through a low-noise preamplifier. Using a known station in the "back" direction, adjust the variable termination resistor while listening for the setting that best minimizes back-direction signal while keeping the front strong, then replace it with a fixed resistor of that value.
| Symptom | Most likely cause | Diagnosis | Fix |
|---|---|---|---|
| No directional effect — sounds omnidirectional | Termination resistor missing, wrong value, or poor ground connection | Check the resistor value and ground rod connection at the termination corner | Verify and correct the ground connection; re-optimize the resistor value |
| Very weak signals in all directions | Feedpoint transformer wiring reversed, or normal expected low output | Check transformer winding sense against the reference diagram | Correct transformer wiring if reversed; otherwise add a low-noise preamp, which is normal for this antenna class |
| Front-to-back ratio worse than expected | Termination resistor not optimized for your specific site | Re-run the optimization procedure using a known back-direction station | Adjust the resistor value for your site's ground conditions |
| Loop shape distorted, apex sagging | Insufficient apex support height or tension | Sight the loop shape against the intended triangle | Re-tension or raise the apex support |
| Antenna damaged after operating | Transmitter power reached the Pennant, likely a relay fault | Check relay operation and switching timing relative to transmit keying | Repair or replace the relay; verify switching happens before RF is applied |
Can I transmit through this antenna if I keep the power low?
No. This is a receive-only design — the termination resistor, feedpoint transformer, and thin wire are not built to handle transmit power, and the antenna provides no meaningful radiated signal in return. Always switch to a separate transmit antenna before keying up.
How is a Pennant different from an EWE?
The Pennant closes the loop into a full triangle, while the EWE is an open "U" shape between two posts. The closed loop generally gives comparable or slightly better front-to-back performance for a similar footprint, though both designs need site-specific termination optimization to perform well.
How is a Pennant different from a Flag antenna?
Both are closed-loop terminated receive antennas from the same design family, differing mainly in loop shape (triangular for the Pennant, rectangular for the Flag) — see this site's Flag antenna guide for that variant.
Why is my received signal so much weaker than my transmit antenna?
Completely normal — the Pennant has essentially no gain, often meaningfully negative in dBi terms. Its value is the directional pattern that reduces unwanted noise, not signal strength. Pair it with a low-noise preamp if needed.
Can I build multiple Pennants for different directions?
Yes, switching between two or more Pennants aimed at different headings from a control box at the operating position is a common approach.
Do I need a preamp with this antenna?
Most operators find a low-noise preamp genuinely useful given how little signal this small loop captures compared to a full-size transmit antenna.