An antenna tuner is one of the first pieces of equipment in everyone’s shack. And it’s probably one of the most used, and probably one of the misunderstood pieces of equipment.
Yes, you can tune a wet noodle, but that does not mean it will radiate efficiently.
People often assume that if an antenna tuner achieves a low SWR, the system is “good” because they misunderstand what the tuner actually does. A tuner does not fix an inefficient antenna—it just makes the radio see a 50-ohm load so it can operate safely. Here are a few reasons why this misconception persists:
1. Focus on SWR Instead of Efficiency
Many hams and radio operators are taught that a low SWR (Standing Wave Ratio) means a good match, but SWR only tells you the impedance match between the radio and the tuner—not how well the antenna is actually radiating power. A perfect 1:1 SWR can still mean most of your power is lost as heat in the tuner or feedline.
2. Tuners Hide the Real Problem
A tuner can “match” almost anything, even a completely terrible antenna. If an antenna is too short, lossy, or improperly installed, the tuner can adjust the impedance seen by the radio, but the actual radiated signal may be weak.
3. Losses in the Feedline
If the mismatch is happening far from the tuner (e.g., at the antenna), and you’re using coaxial cable, high SWR leads to major transmission line losses. The tuner fixes what the radio sees, but it doesn’t recover the lost power. This is why it’s better to place a tuner near the antenna rather than at the radio.
4. Psychological Bias: “If It Works, It Must Be Good”
If a station hears them or if they make a contact, many assume their system is working well. But they might be wasting a significant portion of their power in tuner and feedline losses.
5. Built-in Tuners Reinforce the Misconception
Many modern radios have internal tuners that only adjust small mismatches. If an internal tuner “tunes” a bad antenna, it’s often just making the radio happy, not improving performance.
The Right Way to Think About It
- A tuner is not a fix-all—it should be the last resort after ensuring the antenna and feedline are efficient.
- Check for radiation efficiency, not just a good SWR.
- Use a tuner at the feedpoint for long-wire or open-wire-fed antennas instead of at the radio.
- Measure actual power output and performance instead of relying purely on SWR.
Generally speaking there are two types of tuners that most hams will come across.
- The “inside” tuner. This is the tuner, in the shack, right after the radio. This tuner is good for “matching” an already well tuned antenna.
- The remote “outside” tuner. This is the tuner that is located next to the feed point of the antenna. This tuner is good for matching multi-band antennas or random wire antennas, or non-resonant antennas.
It is also not a good idea to use both an internal tuner and an external tuner to try and “tune an antenna”. You are adding way too much complication and additional losses. The two tuners may compete with each other and in some cases may cause damage to your equipment.
To summarize, use an inside or internal tuner when the match is already close and you only need a small adjustment to get a 1:1 match. Use an external tuner when the antenna is broad band or multiband or non-resonant.
Finally, a well-tuned system should not just “tune”—it should radiate effectively with minimal loss.