I have a 2.3m dish with 2 dual output (V/H) C-band 5150LO LNBs on it, one aimed at Asiasat 3S (centre) and the other at Chinasat 6B (side). The 4 output cables are ~4m and go into a Zinwell SAM-6802 DIRECTV Approved 6x8 Flexport Multiswitch (not using the flexports).
Asiasat 3S is connected to the 0Khz inputs and Chinasat 6B to the 22Khz inputs.
receivers are connected, a Strong SRT4990 (weakest), a old Dion (also cheap nasty tuner) and a Mediastar HDX9100 (very sensitive tuner). These 3 can get just about all the c-band channels. The setup has been going strong for 6 years and was recently (~2 months) realigned to improve signal qaulity for a few weak stations (TVB8 and hnstv).
I just setup a spare Intel E8400, G41 chipset PC as a MythTV backend an ubuntu 10.04 with 1xWinfast DTV1000S (NXP/TDA chipset) and 1x TBS 8920. Initially the DTV1000s did not work due to kernel support (2.6.32) so I upgraded to a 2.6.33-realtime kernel from the ubuntu studio repo. This allowed both cards to work, with the DTV1000s working fine but the TBS 8920 only working well for the Asiasat 3S channels (0Khz). Initially I thought this was a bug in MythTV's Tone Switch, but then discovered that 2-3 transponders out of the 20+ on Chinasat 6B were okay (CCTV mainly, including 4100V CCTV-HD).
I after going back to the official kernel and upgrading to the latest v4l-dvb linuxtv repo drivers, everything was working well and I was getting all the channels. However, a week later, after powering down the machine and restarted (for installation of a graphics card that turned out to be too thick), the situation turned back to when I was on the 2.6.33-realtime, in that most transponders on the 22khz LNB do not get a signal. I have checked that all other kernels and there headers have been purged and also tried the 2.6.32 drivers dated 201006 from TBS website with the same results.
It appears to be similar to this (but different, in that the asiasat 3s = no problem):viewtopic.php?f=11&t=36&start=10
I have tried to switch slots (only have 2 on this MSI G41M-P33) but not difference.
Is there something about the way the TBS 8920 is generating the 22Khz tone that is causing this problem. Is anyone else using a tone switch (0/22Khz) with this card? For sone reason I can only pick the CCTV (all 10+) and most asiasat 3S (except FTV, some others). IF it is a weak signal condition surely TVB8 and Sun TV would go first (they are the weakest according to the other receivers.