After Astra 2E and F replaced Astra 2D, the reception of British free to air channels got more problematic in Central and Eastern Europe. However, a good chance of solid reception still exists in Prague. I've done a test with a prime focus 1.8 dish equipped with an Invacom feedhorn and Inverto Black Pro quad LNB.
During my tests, all frequencies were receivable between 20:00 - 23:00. Even though I've tried optimizing the reception for Astra 2E, the signal is still significantly lower by 1-2 dB, compared to Astra 2F where the signal would range from 7.5 to 8.5 dB on a typical day without rain. All transponders in the UK beam on Astra 2F seem to be receivable 24/7, while Astra 2E UK beam signals change during the day and sometimes even fade out completely.
From this experience, I could conclude that for a 24/7 Astra 2E/F UK beam reception, a 200-220 cm dish would be required. On the other hand, 180 cm dish is almost perfect for fringe reception tests in this area. With careful tweaks of the LNB, I believe the signal could still be improved. I've already ordered Invacom quad LNB to give it another try.
The following signal levels (SNR) were measured using Vu+ Solo2.
The LNB is connected through approximately 50 meters of cable and 2 diseqc switches. The picture starts to break up at SNR of 5.8 dB (FEC 5/6) on DVB-S transponders and at 7.2 dB on DVB-S2/8PSK (FEC 2/3) transponders on the Vu+. Any lower signal than this and the signal is not locked at all so it's difficult to tell the acual signal strength without a proper satellite meter. On a Dreambox 500 HD, the margins were at 6.3 dB and 7 dB respecively. What's interesting is that while Vu+ does significantly better with DVB-S signals than DM500 HD, the situation is equal, maybe even in favor of the DM500HD when it comes to DVB-S2 signal processing.
The signal then keeps quite steady till midnight, when all transponders go down in power by approximately 1 dB, resulting in no lock on most of Astra 2E transponders.