VHF (Band 2) propagation tests across the Irish Sea
Abstract
Measurements of Band II transmissions across the Irish Sea over a 13 month period between 1983 and 1984 were analyzed and compared with prediction methods normally used to calculate interference from broadcast transmissions (BBC and CCIR methods). They were also compared with North Sea measurements made in 1954. The measurements show that both methods predict interference levels which are not seriously in error, any differences which do exist tending to allow a slightly greater degree of protection than may be necessary. Considering how different the two methods are in approach to field strength prediction, it is encouraging to note how closely they agree with each other. When compared with the earlier North Sea measurements, the results show a possible anomaly regarding the effect of transmitter height on received field strength for trans-horizon paths. While not a serious problem, it does raise questions concerning the mechanism of trans-horizon propagation at VHF which cannot be fully explained.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- 1991
- Bibcode:
- 1991STIN...9218250M
- Keywords:
-
- Broadcasting;
- Electromagnetic Interference;
- Field Strength;
- Geopotential Height;
- Very High Frequencies;
- Anomalies;
- Errors;
- North Sea;
- Protection;
- Transmitters;
- Wave Propagation;
- Communications and Radar