vrijdag 15 februari 2019

Here is an other analysis of a spot made by Paul PA0K on February 1st 2019. He was spotted by W4HOD over 7200 km with a SNR of -23 dB. This spot reveals, that the propagation, between Paul's station and W4HOD, was not good, at that moment. But never the less, Paul's signal was received, with a bit of luck, as we will see.

Spots sorted by propagation
The table shows all the stations, that were received by W4HOD in Alabama in the time slot of 13:12 UTC. I have sorted the spots by propagation, using the Lowest Possible Power (LPP). The lower the Lowest Possible Power, the better the propagation. The propagation to W4HOD was good, or even very good, for the first 9 stations in the table. This are the stations that have been spotted with a LPP of 50 milliwatt or less.

The propagation from Paul's QTH to W4HOD was poor with a LPP of 500 mW.

W4HOD also received PA1OSF over a distance of  7200 km from The Netherlands. PA1OSF was received with a LPP of 20 mW. The propagation from PA1OSF was 17 dB better than from PA0K. The distance between PA0K and PA1OSF is 71 km (44 mi). The difference can be caused by propagation, antenna direction and the antenna.

Spots received by W4HOD
The propagation between VE3KAE and W4HOD shows the best propagation with a LPP (lowest possible power) of 0.5 mW. Luckely for Paul, VE3KAE used 100 mW. Believe it or not, if VE3KAE had used 5 W, in stead of 100 mW, this signal would have used a large part of the dynamic range of the receiver of W4HOD and Paul's signal would probably not have been spotted.

I noticed that W4HOD received twice the number of spots compared other stations. In an analysis of frequencies that were used, I saw, that W4HOD received  two signals a few Hz apart. This suggests that there are more than one WSPR receiver at W4HOD.

The dynamic range of the SNR is +1 -(-26) = 27 dB.
The dynamic range in LPP is 1000/0.5 =2000, which is 33 dB.

woensdag 13 februari 2019

PA0K spotted by EU2AAH

Here is a further analysis of spots made by Paul PA0K on February 1st 2019. The propagation was not that good. But Paul's signal was earsplitting into Belarus. He was spotted by EU2AAH over 1500 km with a SNR of -3 dB. This spot reveals, that the propagation, between Paul's station and EU2AAH, was very good, at that moment.

Lowest Possible Power diagram
I developed the Lowest Possible Power diagram, to compare spots, that are made with different power. The Lowest Possible Power diagram shows instantly, how good the propagation is.
A spot is placed on the diagonal line of the power, that is used by the transmitting station. The height of the spot in the diagram is determined by the SNR of that spot. You can read the Lowest Possible Power of a spot, on the horizontal axis.
The better the propagation, the lower the value of the Lowest Possible Power.

Spots by EU2AAH
This diagram shows all stations, that were spotted by EU2AAH in the time slot of 13:52 UTC. It can be seen instantly that 3 station were received with good propagation and 2 with very good propagation. The letter gives the DXCC of the spot.
Paul's signal (PA0K) was the strongest signal, with a SNR of -3 dB. The arrow to the horizontal axis points to a  Lowest Possible Power of 5 milliwatt. The LPP of 5 mW is in the area of  very good propagation.
The propagation between F6KOP (F in the diagram) and EU2AAH is even better, with a LPP (lowest possible power) of 2 mW.

Lowest Possible Power diagram of spots received by EU2AAH
The line of 10 milliwatt
The dashed line in the LPP diagram is the diagonal line for a power of 10 milliwatt. PA0K and F6KOP could also be spotted if they would use a power of 10 milliwatt. If PA0K would reduce from 2 Watt to 10 milliwatt, his signal would be received with a SNR of -26 dB. F6KOP would be received with a SNR of -22 dB with a power of 10 milliwatt.

Table of spots received by EU2AAH
This is the table, that I used to draw the LPP diagram.

zaterdag 9 februari 2019

Very Good Propagation with WSPR

With this table you can immediately judge the propagation from your WSPR spots.
For example, when your 1 Watt WSPR signal is spotted with a SNR of  -9 dB,
or higher, the propagation is very good.
If you notice that the propagation is very good, consider to reduce your power.

Judge the Propagation with your WSPR signal
A WSPR beacon with a power of 10 milliwatt, will ONLY be spotted, when the propagation is very good. WSPR with 10 milliwatt can be compared with a CW beacon with a power of  200 milliwatt.

donderdag 7 februari 2019

Good propagation for PA0K

My fellow Blogger Paul (PA0K) used WSPR for an hour, on on February 1st 2019. His 2 watt WSPR signal has been spotted 31 times, in one hour. For Paul the most interesting spot was made by W4HOD, over a distance of 7200 km. In many spots you can see, that the propagation was not that good.

I noticed an other very interesting spot, that was made by EU2AAH over 1500 km. Paul's signal was earsplitting into Belarus. When I made an analysis of the spots, this spot came up, as the spot with the best propagation. This spot reveals, that the propagation, between Paul station and EU2AAH, was very good, on that moment.
To compare the propagation, I use  the Lowest Possible Power, that I calculate from the used power and the SNR. A Lowest Possible power of 5 mW, can be compared to 100 mW with CW or 2 watt with SSB. Thus very good propagation.

PA0K - WSPR spots with 2 watt on 20 meter
The table also shows that the propagation was good to TF3GZ on Iceland, R3TJP in Russia and EA8BFK on the Canary Islands.

The second table shows the propagation, in the successive time slots, in which Paul was transmitting.
Notice that, the better the propagation, the lower the Lowest Possible Power.

The spots made by R3TJP start with good propagation with a Lowest Possible Power (LPP) of 50 mW. In time slot 13:30 utc the signal is drops 10 dB with a LPP of 500 mW. In the last time slot the signal is up again to good propagation. LPP 50 mW.

The signal received by EA8BFK is first strong, with a LPP of 20 mW, but later the signal gets a bit weaker.

The signal that is received by W4HOD, shows a LPP of 500 mW in the first two time slots. In the time slot of 13:30 UTC the SNR is -29 dB, so all the power is needed to be spotted. Hi.

PA0K with WSPR on 20 mtr in 5 time slots
Thanks Paul, for the interesting spots.
Paul placed the tables, that I sent him on his Blog.