Wednesday, 11 February 2015

WSPR - Antenna performance evaluation

I believe WSPR is a great tool to evaluate station/antenna performance.

I used the WSPRnet’s data base and downloaded the 10m WSPR data for all stations decoded by myself and a fellow amateur, Kevin ZS6KMD located some 20 km north of me yesterday.

The graphic below reveals quite a lot of detail: Number of decodes, strength of decodes (min and max).

I was using a simple dipole beaming E/W at 8m agl, I think Kevin also uses a dipole, but I am not sure of the orientation and height agl.

IMHO this is a sure fire way of comparing apples with apples.

Info gleamed from this test:

The band opened and closed at about the same time (Duh...)

I decoded a few more stations than he did, 569 vs. 468.
The strongest signal decoded by me was +2 dB vs. -5 dB by Kevin.
Weakest signal decoded was -32 dB !!
It appears as if my antenna was performing slightly better (between 2 and 13 dB)

I should stop playing and build my Ultimate 3S WSPR beacon.....

WSPR ZS6A vs ZS6KMD 10m decodes


  1. Interesting analysis. There is a large difference in the total decodes. Could be the orientation of the antenna and surroundings or Kevin has more QRM/QRN?
    Computer soundcard, different radios could also be the case? Could be interesting to find out why things are different. 73, Bas

  2. Hi Bas,
    I believe Kevin also uses a rigid rotatable dipole for 10m at 12m agl. I will check with him, but I assume he would be pointing north to Europe.
    There are many variables as you pointed out and one must guard against jumping to incorrect conclusions. It could be due to feed line losses, lossy balun, QRM, or receiver performance etc.
    I still believe this method of using WSPR data provides us with a means to compare one setup with another in a real world situation.
    In my all 40 years of amateur radio have I never seen a conscious effort to test antennas using real world data. Everything is based on math modelling and hearsay….

    73. Pierre ZS6A

  3. What software did you use to plot them on a time:strength graph?

  4. Hi John,

    I imported the data into Excel and created my own scatter graphs.

    73, Pierre ZS6A