Aerial Installation Report Page 3
Aerial Installation Report
Signal Analysis, The Results.
The figures highlighted in red are the minimum and maximum recommended published levels at the receiver.
Signal results from the new aerial installed by Woking Aerials. These measurements in Table 'A' were taken at the wall outlet in the lounge, after all cable losses.
Table 'A' |
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| Analogue | Level 60 – 80dBµV | C/N >43dB |
| BBC1 | 72.8dBµV | >51.3dB |
| BBC2 | 69.4dBµV | >47.1dB |
| ITV | 73.6dBµV | >49.7dB |
| CH4 | 71.1dBµV | >49.3dB |
| CH5 | 67.1dBµV | >50.1dB |
| Digital 64 QAM | Level 45 – 60dBµV | C/N >26dB |
| Mux 2 | 57.6dBµV | >32.7dB |
| Mux A | 54.9dBµV | >39.9dB |
| Digital 16 QAM | Level 42 – 60dBµV | C/N >23dB |
| Mux 1 | 58.2dBµV | >42.5dB |
| Mux B | 57.6dBµV | >43.6dB |
| Mux C | 53.7dBµV | >40.1dB |
| Mux D | 56.2dBµV | >39.5dB |
Table 'B' shows the signal results from the same position in the lounge after the attachment of the alleged ‘weak booster’. Every channel showed an increase in signal levels.
Table 'B' |
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| Analogue | Level 60 – 80dBµV |
| BBC1 | 87.0dBµV |
| BBC2 | 81.5dBµV |
| ITV | 85.7dBµV |
| CH4 | 84.3dBµV |
| CH5 | 79.9dBµV |
| Digital 64 QAM | Level 45 – 60dBµV |
| Mux 2 | 68.5dBµV |
| Mux A | 65.0dBµV |
| Digital 16 QAM | Level 42 – 60dBµV |
| Mux 1 | 71.1dBµV |
| Mux B | 69.0dBµV |
| Mux C | 63.5dBµV |
| Mux D | 65.3dBµV |
Table 'C' shows the signal levels taken from the aerial, still in situ, in the loft as installed by XXXXX Aerials, this measurement has been taken before losses for the cable run are added.
Being as the existing downlead was as old as the house, about 30 – 35 years, the cable loss would have been a minimum of 2dB, but realistically 3 – 4dB or possibly more.
This would put BBC2, CH4, CH5, Mux A & Mux C below the recommended published signal level and Muxes B & D borderline at the receiver.
Table 'C' |
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| Analogue | Level 60 – 80dBµV | C/N >43dB |
| BBC1 | 65.9dBµV | >49.7dB |
| BBC2 | 60.8dBµV | >49.0dB |
| ITV | 65.8dBµV | >46.0dB |
| CH4 | 58.0dBµV | >45.2dB |
| CH5 | 57.3dBµV | >46.1dB |
| Digital 64 QAM | Level 45 – 60dBµV | C/N >26dB |
| Mux 2 | 63.5dBµV | >36.5dB |
| Mux A | 44.3dBµV | >30.7dB |
| Digital 16 QAM | Level 42 – 60dBµV | C/N >23dB |
| Mux 1 | 51.7dBµV | >38.0dB |
| Mux B | 47.4dBµV | >34.0dB |
| Mux C | 43.2dBµV | 6.7dB |
| Mux D | 47.3dBµV | >34.0dB |
Signal levels taken using the 30 year old aerial for a comparison as an exercise.
Whilst any aerial installation engineer would agree that the old aerial is not suitable for stable digital reception by comparison the old aerial performed better than the new aerial on the analogue channels and it matched the new aerial 50/50 on the digital muxes, as shown in Table 'D'.
Table 'D' |
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| Analogue | Level 60 – 80dBµV | C/N >43dB |
| BBC1 | 59.7dBµV | >44.7dB |
| BBC2 | 64.0dBµV | >52.3dB |
| ITV | 63.0dBµV | >44.8dB |
| CH4 | 59.2dBµV | >47.2dB |
| CH5 | 59.7dBµV | >48.4dB |
| Digital 64 QAM | Level 45 – 60dBµV | C/N >26dB |
| Mux 2 | 49.4dBµV | >26.1dB |
| Mux A | 46.1dBµV | >32.0dB |
| Digital 16 QAM | Level 42 – 60dBµV | C/N >23dB |
| Mux 1 | 48.6dBµV | >33.8dB |
| Mux B | 46.1dBµV | >34.0dB |
| Mux C | 46.6dBµV | 9.2dB |
| Mux D | 47.4dBµV | >33.2dB |