I was just reading EN 50121-3-2 (Railway Applications – Electromagnetic compatibility – Part 3-2: Rolling stock – Apparatus) and noticed in Table 5 that there is a gap in the test frequency between 2.7 GHz and 5.1 GHz.
In the remarks for the test it states that the tests are intended to simulate disturbances from digital communication devices, which made me think maybe the frequency range is unallocated. But I checked the ACMA spectrum allocation chart, and there are a lot of different uses allocated between 2.7 and 5.1 GHZ, so I don’t think that is the reason.
The test reference EN61000-4-3 as the basic standard. I checked EN 61000-4-3 (EMC Part 4.3: Testing and measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test) and was unable to find any information that may explain the frequency gap.
Why did they choose to not conduct a radiated immunity test between 2.7 GHz and 5.1 GHz?