loss of TV signal at around 11.30 am each day for approx 15- 30 minutes

Possible loss of TV signal at around 11.30 am each day reference TV signals on the Costa Blanca from Astra 28.2ºE

Possible cause Autumnal Equinox

We have tested the dishes and at 11.30 am the sun is directly behind the LNB  and causes a shadow to be projected to the "centre" of the dish, this will support the theory below as the LNB will amplify any electromagetic noise that is concentrated on the centre of the dish and cause the LNB to produce a signal that crash it's output, hence signal loss (outage). The LNBs used on the Costa Blanca are high gain, usually coupled to large high gain Satellite dishes  1.8m, 2.4m and 3.1m. Even then the average signal is only 10 watts as opposed to 50 watts in the UK, these signals are vulnerable to any interference.

An equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator. These Satellite dishes (earth stations) at around noon every day will be in a straight line between the Sun and the Earth,  so  strong electromagnetic waves generated by the sun directly shine on the earth station (dish)antenna. 

 Scientific Quote
"The elevated temperature of the sun causes it to transmit a high-level electrical noise signal to receiving systems whenever it passes behind the satellite and comes within the beams of the receiver antennas. The increase in noise is so severe that a signal outage usually results. The length and number of the outages depends on the latitude of the earth station and the diameter of the antenna. A 3-metre antenna, the outages occur over 15 - 20 days, with a duration of  approx. 30 minutes."