FIrst, let me say the topic question isn't meant disparagingly. Everyone has their favourite bands to operate on, but I think our amateur spectrum is a "use it or lose it" proposition, so I want to use as much of it as I can.
I've never used 33cm (900Mhz band) for anything, but it's right there, available to use. I have a good grasp on the utility of the other VHF/UHF bands, propagation-wise. In a forest environment I'd use 6m, in open terrain I'd use 2m, in an urban environment I use 70cm for its better penetration of structures and its tendency to reflect off many structures. 1.25m has an advantage in a lower noise floor and is a good compromise between 2m and 70cm. (these are mostly with regards to FM voice; I know 440 is also used for ATV and higher-speed data because of the available bandwidth)
But what about 33cm? At 900MHz, foliage absorption begins to be a factor, and my body more readily absorbs RF energy. This is countered somewhat by the smaller physical dimensions of higher-gain antennas; I can have a 5/8 wave on my HT and a 3dB gain colinear on my car without taking up any more space than a lower-frequency quarter-wave or helical antenna.
Most public safety systems seem to have moved to 700/800/900MHz, and I always assumed that was due to greater channel availablity on those bands, but is there a task or situation that high-UHF wavelengths are particularly suited to?
I've never used 33cm (900Mhz band) for anything, but it's right there, available to use. I have a good grasp on the utility of the other VHF/UHF bands, propagation-wise. In a forest environment I'd use 6m, in open terrain I'd use 2m, in an urban environment I use 70cm for its better penetration of structures and its tendency to reflect off many structures. 1.25m has an advantage in a lower noise floor and is a good compromise between 2m and 70cm. (these are mostly with regards to FM voice; I know 440 is also used for ATV and higher-speed data because of the available bandwidth)
But what about 33cm? At 900MHz, foliage absorption begins to be a factor, and my body more readily absorbs RF energy. This is countered somewhat by the smaller physical dimensions of higher-gain antennas; I can have a 5/8 wave on my HT and a 3dB gain colinear on my car without taking up any more space than a lower-frequency quarter-wave or helical antenna.
Most public safety systems seem to have moved to 700/800/900MHz, and I always assumed that was due to greater channel availablity on those bands, but is there a task or situation that high-UHF wavelengths are particularly suited to?
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