In a message dated 9/17/06 3:08:03 PM Greenwich Standard Time, [email protected] writes:

Path loss is 15 dB less at 435 MHz than 2400 MHz and antenna gain is 13 dB less. However, the noise figure is 5 dB higher, so almost twice the EIRP wll be required on a U uplink than an S uplink. The 70 cm receiver has a 200 kHz bandwidth so some class 2 (4800 bps) uplinks could be accomodated. Since they will be BPSK and use FEC, I assume that they will occupy at least 15 kHz each and will have to be spaced at least 25 kHz apart. This could allow 4 uplinks. It's not good to increase the receiver bandwidth as it will let in more PAVE PAWS interference.

John,

I was thinking in terms of an additional 70 cm receiver to accommodate several conference-grade channels, for those users who may be prohibited from using BOTH L-band and S-band uplinks (think Europe). Yes, PAVE PAWS is there, sometimes, but it would still be better than no digital access at all. Also, it's not a certainty that PAVE PAWS will even be there in 2020.

73,

Ray