Antenna testing is hard

Antennas – hams can’t stop talking about them. We all have our favorites, and we all seem to feel an urge to defend our choice by wielding flaming swords and by submitting (mostly anecdotal) evidence.

What I learned after more than 50 years on the air is that a given antenna can work great here, but might really suck when used at someone else’s QTH. This convinced me to tell new hams that they have to find out for themselves which antenna works best for them instead of saying ‘This is the one!’

Hand held antennas
The focus of this blog is Chinese equipment, mostly hand held. Antennas are often the closing entry for manufacturers, something Baofeng proves with their short stock antenna. I even suspect Baofeng to promote this inefficient antenna because its deafness masks certain flaws, such as an easily overloading receiver.

During testing hams quickly found out that there are better antennas out there such as Diamond, Nagoya, the longer Baofeng UV-B5 antenna or the brand-less $3.79 one. I tested this by going into the field and check repeaters which should be just in range.

Stay put, change antennas, and make notes of the results. That’s all there’s to it.

$3.79 antenna 3

The $3.79 (now $2 or so) antenna mystery
I resold two of these antennas to Teun PA0TBS as a replacement for the short antenna found on the Baofeng BF-666S and equivalent radios. A few days later he checked in on our ‘Tech channel’ and reported that the new antenna performed worse than the original one. The difference wasn’t only obvious during field tests, but also when he used a field strength meter.

Going for a train ride
I went for a train ride with my Quansheng TG-UV2 (no Baofeng as I wanted to rule out receiver issues) and took both the short and the $3.79 antenna with me. It didn’t take long to find out that the after market antenna outperformed the BF-666S antenna by a wide margin — the range basically doubled.

We were puzzled. Teun’s results were completely opposite to mine, and we both wanted to know why. Thanks to a QSO with Fred PA4TIM, a guru when it comes to scientific measurements, one of the first things we looked into was the circumstances of our tests. Tests like this, Fred argued, should always be done in the open, with no obstructions anywhere in sight. Teun did his initial test in his shack, and I was in a train. Just too may variables.

A day in the park
Teun and I met in the local park and repeated the test with the field strength meter. When using the Baofeng BF-666S Teun had no trouble replicating his results: the $3.79 antenna was clearly inferior. When we repeated the test with the Quansheng TG-UV2 however, the cheap after market antenna ruled. Interesting, but very confusing. It’s clear that this story ain’t finished yet.


Maybe we should construct something like this..

Preliminary conclusions
It seems obvious now that an antenna which does great on hand held radio X doesn’t necessarily mean that it will also do great on hand held radio Y or Z. What we will do next is to take the radio out of the equation by constructing a mounting plate for these antennas. We’re still debating whether we should use a simple 50cm by 50cm aluminum plate, or construct something with radials. The latter system (ground plane alike) would enable us to get as close to 50 Ohms as possible. Maybe we’ll do both.


9 comments on “Antenna testing is hard

  1. If a given antenna does not perform predictably in various environments, it’s usually a bad design. The infamous 1:9 transformer with any length of wire, for example. Brrrr…….

  2. Yes many various reasons given ..
    1) The radio itself is part of the antenna .. Or acts with the antenna affecting tune.
    So if this is the case , then obviously different antenna on different radio will behave differently . So no one antenna can be all things to all radios .
    2) The person holding the radio affects the tune ..
    Ok ,
    3) Obviously the environment ..

    Baofeng antenna . Actually the ones I have test rather well for what they are ..
    And the best one I have ( Factory) came of my TYT UV8R. Easily as good as the UV-B5 antenna , if not better .

    One thing I have noticed , how tightly you screw on the antenna seems to affect how it performs , I have one Baofeng UV-5r ( I have 2 ) and it will actually stop transmitting if the antenna is not on right .. I think quality control has a lot to do with whats going on as well . ( Not just the antenna ) .. ( My Tonfa is equally squirrely about antenna and tension )

    So if you don’t pay your dollars , you may end up with issues ..
    + You may want a small sample lot of the same radio ( UV-5r ) for example and then test .. Comparing apples and Oranges is ( ? )

  3. Let’s see, your typical HT antenna is trying to be a 1/4-wave monopole without the benefit of a ground plane while being held by a human in an uncontrolled manner. What could possible go wrong? 🙂

  4. While my wife was on one of her trips to Tibet, I tested a bunch of HT anyennas with expensive Motorola equient. Tested more than 20. Bottom line: Total waste of time (grin). For 2m and 440 handheld work, longer antennas work better – period. Do not trust ANY manufacturers’ claims of “gain” – what is much more important is build quality and how the antennas “mate” with the radio. SMA connectors are rated at far fewer connects-disconnects than their BNC counterparts. So if you are planning to play with several antennas – or will be swapping out often – you may want to obtain a “SMA-to-BNC” adapter that properly mates to your SMA HT, thereby protecting your radio’s antenna connector.

    • Heh, thanks for the remark regarding SMA-BNC connector, will definitely look into it!
      Its not that Im frequently swapping antennas, but SMA-F looks pretty fragile and will eventuall wear out quite easily.

  5. We are too obsessed with the notion that all antennas must be 50 ohms with no reactance to be “right”. It is perfectly sound engineering to have a non 50 ohm antenna in order to properly match the receiver or transmitter in question.

  6. Hello All, Is it possible to determine what the output impedance is of a radio? Is it really 50 ohms or is it lower like 12.5 ohms which when using an antenna analyzer with a uv-8hp stock antenna is where the antenna tunes up best in the amateur bands.

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