First things first, if you have a beam or more than one, on a mast or tower that nearly reaches the sky you might want to move on as this is more a process for us mere mortals that live in suburbia and have to live with a piece of wire.
I've been trying to get a "feel" for "how my current antenna is performing at my current QTH"! The antenna in question is a 40m Delta Loop, which is slopping from the roofline into the backyard. Now I can model the antenna with one of the many Antenna Modeling programs and using the results I can evaluate if the antenna will perform to my satisfaction. However, it is a model and it will show the antenna to work in an environment that is not indicative to the real environment.
So the next best thing I've done in the past use data from my logbook to get an understanding of the performance of my antenna. However, all this can be speed up these days in using WSPR. I'm not here to explain how WSPR works, except I will reuse the description given by the good folk at WSPRNet.
The Weak Signal Propagation Reporter Network is a group of amateur radio operators using K1JT's MEPT_JT digital mode to probe radio frequency propagation conditions using very low power (QRP/QRPp) transmissions.
So basically I've setup a WSPR receiver over a period and reported the data to WSPRNet. I could also store the data in my own database, but why reinvent the wheel. Having all the received station data available we could now download all of the data and run it through a graphing/data analysing tool like grafana, gnuplot or Octave.
But why if we have a first class tool written by VK7JJ online directly getting the data from WSPRNet so I don't have to bother with anything else but look at WSPR ROCKS!
As I mentioned I setup a WSPR receiver to monitor the Amateur Radio WSPR frequencies from LF (136kHz) to end of HF (28MHz) and send the collected results to the WSPRNet. I then use the WSPR rocks website to filter out the Band of interest, use the biggest amount of data sets (limited at 5000), select unique calls and select an appropriate time frame.
Lets use the above selected dataset. Initially, the data will be displayed as text first. And to graph the dataset I select <charts> and then <SNR compass>. The result can be seen at the below graph. It is the result from all unique calls which my WSPR receiver heard over a three (3) day period on the 20m WSPR frequency.
I can already see that my antenna is favoring only two directions, more than any other direction.
The question is, can I be sure?
It sure is a good start to visualise the real receive pattern but there is another dataset we can check and then compare it to my recorded dataset. That dataset is the <everyone> dataset. We can select that dataset for a comparison check by setting the <RX call> value (currently set to vk5hw) to everyone. And voila we get ...
This tells me that from 0° to 360°, i.e. around the globe stations where reported for the same time period. Comparing this graph with the graph from my dataset confirms my initial observation. It shows that I have two good and one sort of ok direction were the antenna is performing. The directions between 60° - 110° and 270° - 300° are pretty good. 315° - 25°, well I do receive signals but it seems to be a struggle. There are additional single signals around the 240° and 135° mark but they would be the exceptions due to ... maybe enhanced propagation wich I could find out with a propagation tool (Voacap or GWPS). Now there could have been por or no propagation between me and all those other stations. But even so, I'm confident that this is a good profile of my 20m receive capability at my QTH with the current (40m Delta Loop) antenna.
There might be the ocasion opening that might give me a better path into those regions which I've received no signal from but those are more likely the exceptions and not the rule.
Since antennas are a reciprocal passive device, meaning they work the same on receive (RX) and transmit (TX) I'll know which areas of the globe I'll be making easy contact to and were I would have a difficult time to work stations.
So this is the profile for 20m on the 40m delta loop, and since I use the antenna for 40m, 20m, 15m and 10m as a TRX antenna I need to run profiles for at least 40m, 15m and 10m. Of course I'm also interested in the bands that I only use the antenna as a RX antenna so a few more graphs to compare. However, all I wanted to show is how easy and quick it is these days to profile, i.e. get a good feel, for ones antenna installation at ones QTH.
Well, most of this is not new to me, but it confirms that I could have done this in three (3) days rather then in 24 month. That's how long it took me to to get to the same conclusion by operating FT8 and SSB from this QTH.
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