The Formula
The Antenna Value Index™
The Antenna Value Index is, at first glance, entirely reasonable.
It has the comforting geometry of an equation, the presence of authority implied by capital letters, and — perhaps most reassuringly — a division by cost.
One feels immediately that no money is being wasted here.
AVI = (Band Performance × Power × Usability × Ground Efficiency × QRM Behaviour) ÷ Cost
It reads rather like something that has been thought about.
Which is often all one really wants.
According to Dave — G3LRC, here’s what matters. Watch his breakdown below:
A Note on the Inputs
Each term is thoughtfully chosen.
They are the sort of words everyone agrees are important, without the awkwardness of defining them.
- Band Performance — satisfactory across the usual bands
- Power — adequate for most purposes
- Usability — not difficult, once familiar
- Ground Efficiency — dependent on conditions
- QRM Behaviour — acceptable, considering everything
None of these are burdened with units, reference conditions, or specific measurement procedures.
Which keeps the discussion pleasantly accessible.
It also avoids arguments.
Why Multiplication Is Reassuring
Multiplication conveys seriousness.
It suggests that the parameters are cooperating, contributing their part, and then standing politely aside.
In practice, antenna parameters have a tendency to overlap, interact, and occasionally sabotage one another.
Ground coupling alters current distribution. Current alters loss. Loss alters radiation. Radiation alters received noise.
The formula assumes these relationships are either negligible or have agreed not to be difficult.
This is an optimistic position.
Cost, Sensibly Placed at the End
Dividing by cost is perhaps the most elegant feature of the index.
It ensures that affordability is never overshadowed by performance.
Once cost enters the denominator, differences in radiation efficiency become less… pressing.
Pattern control becomes contextual.
Loss resistance becomes something that can be discussed later, if at all.
The cheaper antenna tends to emerge as the better choice, which is both economical and decisive.
A Small Matter of Frequency
Antennas, inconveniently, behave differently across frequency.
The AVI resolves this by not dwelling on it.
80 metres, 20 metres, and 10 metres are treated as variations of the same general experience.
This simplifies comparison considerably.
It also removes the need to ask which band one is actually interested in.
The Result
The output of the Antenna Value Index is not expressed in dB, ohms, watts, or any other distracting unit.
It produces something more durable.
A sense of having made a sensible choice.
This should not be underestimated.
Many antennas perform worse while inspiring far less confidence.
Why It Feels Right
Because it is tidy.
Because it produces a single answer.
And because it removes the need for follow-up questions involving environment, installation, or physics.
It allows one to proceed without lingering doubt.
Which is, in many cases, the real requirement.
RF.Guru Verdict
The Antenna Value Index is not misleading.
It simply measures something other than antenna performance.
Specifically, it measures how comfortable one feels having stopped thinking about the problem.
In that respect, it is extremely effective.
Final Observation
If antennas could genuinely be reduced to a single number…
…the Antenna Handbook would be very short, and electromagnetics would be a hobby.
Anyway.
Kettle’s on. ☕
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