Minimum Path Length
- Jonathan Brewer
RSM conserves spectrum that’s good for long distances by setting minimum path lengths. Engineers are not allowed to certify licenses that don’t meet the minimum length.
This table is a summary from Radio Licence Certification Rules (PIB 38) - Issue 12 (March 2021) p 47-48.
Bands | Frequencies | Minimum Length |
|---|---|---|
5 GHz | 4.4-5.0 GHz | 30 km |
6, 7, 8 GHz | 5.925-8.500 GHz | 20 km |
10,11,13,15 GHz | 10.5-15.35 GHz | 5 km |
18 GHz | 17.7-19.7 GHz | 2 km |
Exceptions (dispensations) can be granted by the RSM licensing team in special circumstances, but RSM has no obligation to do so. Examples where exceptions have been granted in the past:
The license was for one part of a longer path that involves a passive repeater
The license was in a remote area where there’s no possibility of spectrum exhaustion - and extended a system in the same frequency band.