When it is better to try ( or avoid) a sked EME on 50 MHz?


        Avoid the days just before or after the apogee

When the Moon is at his perigee the signal we potentially receive is about 2.2 db stronger than the one we get when the Moon is at the apogee (the average signal loss on 50 Mhz EME path is around 242 db). So it is preferable to set up a sked during days around the perigee. Moonsked is capable display in real time the exstimated degradation of the signal due to the distance of the Moon from the Earth.

        Avoid days with high cosmic noise behind the Moon

During the monthly trip, the Moon crosses zones of the space with a high noise level which, naturally, seriously interferes with the very weak moonbounced signal we are waiting for. So it is very important to avoid sked during this period. Nova for Windows and Traker have a very usefull option to calculate the cosmic noise level for every day of the month.

        Avoid days and time with potential ionosferic propagation

At 50 MHz it is quite easy to run across ionosferic propagation (TEP, F2, ES ...). If this is the optimum for people who use these reflections to get a good qso or an excellent dx, for radio-hams who want to try EME these phenomenons are absolutly negative because they absorb or scatter the signal that, in this case, can't reach the surface of the Moon with the power needed to be bounced. That's the reason why we must avoid running sked when our antennas will beam zones potentially involved in these ionosferic situations.

        It is very useful to run a sked just after rained

I experimented that running skeds just after the rain it was absolutly profitable. The wet ground, infact, increases his capability to reflect the wave radio and ground-gain, naturally if you are not elevating the antennas, results stronger than when the ground is dry. The problem is that usually it is difficult to forecast rain (at least here in Italy!).


Due to the very weak signals we can receive off the Moon, it could be very useful to try a sked when the propagation condition is theoretically good.

W5LUU releases every year an useful table were you can easily find the good days for a try.


 

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