Why Comparing Antennas Is Like Comparing Apples and Oranges
Antenna comparisons are everywhere — forums, YouTube, field days. And yet most of them are as flawed as they are passionate. Saying “A GAP Titan is 2 S‑points stronger than my end‑fed” may feel like a data point, but without the full picture it’s often meaningless.
Context Is Everything
Antennas are not standalone devices. They interact with:
- Earth/ground: conductivity, permittivity, and radial system
- Height: changes take‑off angle and pattern
- Surroundings: buildings, trees, gutters, masts
- Feed system: coax length/route, choking, baluns/unun
Without these, you’re not comparing antennas — you’re comparing installations.
Polarization and Take‑Off Angle Matter
A GAP Titan is effectively a kind of vertical dipole, offering:
- Low‑angle radiation (great for DX paths)
- Vertical polarization (different noise coupling vs horizontal)
Compare that to a typical 26 m end‑fed with a loading coil, sloped/bent around a garden:
- Awkward, install‑dependent current distribution → mixed H/V polarization
- Often too high an elevation angle on low bands → poor DX
- Suffers from ground loss, common‑mode, and nearby structure coupling
- Coil insertion loss + detuned impedance transformation above its design point → reduced efficiency on higher bands
It may resonate, but it rarely excels. On some paths it’s stronger, on others much weaker — and always highly installation‑dependent.
Signal Strength Is Path‑Dependent
If a station is ~1 500 km away and the ionosphere supports a 10–15° take‑off angle, a vertical with a strong low‑angle lobe will shine. If your antenna radiates mainly at 40–60°, your signal overshoots the skip zone. The reverse can be true for closer NVIS paths.
S‑Points Are Not a Metric
- One S‑point is “supposed” to be 6 dB — most rigs don’t follow it consistently.
- AGC, mode, bandwidth, and firmware skew readings.
- SDR “S‑meters” are often scaled ornaments.
Use real metrics: SNR (dB), SINAD (FM/digital), and repeatable A/B measurements with identical conditions.
Item | Requirement |
---|---|
Height | Same apex/base height AGL for both systems |
Ground | Document soil/radials; don’t mix “with radials” vs “no radials” |
Feed system | Same coax type/length; same choke/balun strategy |
Time & band | Same band, same time window; ionosphere is time‑variant |
Direction | Measure A/B toward fixed azimuths (DX, regional, NVIS) |
Metric | Use SNR or dBFS, not S‑points; log multiple samples |
Recommended methods: WSPR / Reverse Beacon Network (RBN) with synchronized A/B switching; or a dual‑antenna RF switch into the same receiver chain and identical bandwidth/AGC settings.
Apples to Apples, Please
To make a valid comparison, you must control variables:
- Identical height above ground and similar surroundings
- Known ground quality and radial/counterpoise strategy
- Same feedline length/route, choking, and balance
- Same band, time, and azimuth
- Preferably modeled patterns or measured field strength to explain differences
Otherwise, it’s an anecdote — not evidence.
Takeaway
Antennas aren’t just wires and tubes. They’re systems. Unless you understand and control:
- Polarization (H vs V and mix)
- Elevation‑angle distribution (take‑off lobe vs the path)
- Surroundings & ground (loss, detuning)
- Current distribution (and whether your feedline is radiating)
you’re comparing apples to oranges — or apples to bowling balls.
Bonus Tip
For practical, path‑aware comparisons, use WSPR and/or RBN over several hours with an A/B switch feeding the same receiver. Aggregate dB‑relative reports by distance/azimuth, then repeat on another day. That’s how you build a meaningful picture.
Mini-FAQ
- Are S‑meter reports useful? — Only when carefully controlled. Prefer SNR or dB‑relative reports from WSPR/RBN.
- Why does my end‑fed beat a vertical sometimes? — Path and installation. If the path favors higher angles or your vertical has ground loss/CMC, the end‑fed may win on that path.
- How do I fix unfair comparisons? — Equalize height, add proper chokes, document ground/radials, and test on the same band/time/azimuth.
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