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VSAT technology and installation >> LinkStar Forum: VSAT hubs and terminals >> BER vs RX power and EsNo https://www.satsig.net/cgi-bin/yabb/YaBB.pl?num=1238226422 Message started by c9jfb on Mar 28th, 2009 at 7:47am |
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Title: BER vs RX power and EsNo Post by c9jfb on Mar 28th, 2009 at 7:47am
Hi Eric,
My Linkstar S2 RCST with 2.4m dish is receiving the hub with stronger signal compared with 1,2m dish (rx power -44dBm, EsNo 14) . The 1,2m placed on same site receives hub with -51dBm, EsNo 9.6 However, the BER on ACM transport read by command tcmx shows that the 2,4m is having very bad BER compared with 1,2m, which does not make sense( 0,01XXX against 0,001xx). The BER on 1,2m seems not to be a typical value on linkstar also. This two antennas are place on same hub location. Any clue for this problem? |
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Title: Re: BER vs RX power and EsNo Post by Eric Johnston on Mar 28th, 2009 at 9:31am
Try swapping the LNBs over as well. It is possible that one LNB has bad phase noise or is significantly off frequency. DRO LNBs can be +/- 2 MHz error.
These problems might be evident with a low bit rate outlink like 2 Msps, but it unlikely with a large outlink like 27.5 Msps, which is more tolerant of phase noise and frequency error. Best regards, Eric. |
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