I remember hearing about these though I'd consider these to be somewhat of an oddity. again why 70cm, only 30MHZ wide & already filled with other users? Why is everyone so damn scared and afraid of moving to the amateur microwave bands where we have 1555MHZ of mostly unused spectrum from 1.2-47.2GHz? Why must we recreate the wheel so much of the time when it may be better, faster, easier, & cheaper to use directly or adapt a solution already in use in another service.
Eric AF6EP
Well, partly because the availability of solutions in other services puts our band in danger.
For example, the presence of WiFi in the 13cm band (we have 2320-2450) already resulted in a ban to use 2400-2450 because of WiFi interference. The same will probably happen on the 5.7 GHz band now that it is becoming more popular for WiFi. 70cm is only 10 MHz here and part of that is already allocated to other services and we are only secondary to them. 1240-1300 we are going to lose when Galileo (the European GPS) is becoming deployed. Only a small segment for DX will probably be left (1296)
The more a band is attractive for other services, the more likely we are going to lose it soon. The much higher bands will remain availble for now, but they are not as attractive.
Rob