Sun Outages on L-Band

As we approach the Spring Equinox in the Northern hemisphere some Sun interference on L-Band reception would be expected at a certain period in the day. I noticed at around 1600 UTC that the Safety Net signal on Inmarsat 3-F4 (54 W) had degraded considerably which led me to this website which can be used to calculate the affect of the Sun on reception from geostationary satellites (note that page hasn’t been updated for a while)

Would be interested in the experience others have had. Haven’t correlated this with the Outernet signal on 3-F4 yet but according to the webpage the maximum interference at this point would be at around 1830 UTC here at our location (109 W - Arizona).

2nd paragraph - when talking about the Outernet signal, I misstated the satellite at 98 W - should be 4-F3 not 3-F4. Never seem to be able to keep these names straight.

At your location does 1830 UTC become 1230 local time for you? I other words when the sun is behind 98W from your perspective? Ken

With the wide beam antenna that we have, does this have any special significance?
I thought these sun outages were significant on narrow-beam antennas like C and Ku band dishes
where the beam width may be 3 degrees and the sun being in the beam is a special event, but
in our case with the outernet patch the sun is in the beam a lot of the time, no matter how close it
is to the satellite. Of course this causes part of the received noise.

Good point, and based on readings I took yesterday there was only a small SNR loss in the 1-2 dB range when the Sun was in line and that could have been due to other factors. Being able to get a good signal from these patches certainly is a big plus over narrow angle antennas.

Interesting article on Wikipedia about Sun outages and issues in areas where there is a dependence on narrow angle antennas especially if there is limited satellite access.

At my location 1830 UTC is 1130 local (the State of Arizona doesn’t observe daylight savings time). That was yesterday’s closest alignment of the sun and the 98 W satellite. Didn’t notice much loss of SNR - see my response to pe1chl below.

May pay some attention on the actual equinox date of March 20th to see if the effect is more noticeable.