Mark:
Geof was discussing LMDS vendors, where LMDS is used
primarily to refer to high operating frequencies
(NTRO's products are designed for the 10 to 40 GHz
range, with existing commercial LMDS bands at
24GHz, 28GHz and 38 GHz).
Hybrid is an MMDS equipment company. Other vendors
include Conifer, CAMP, Spike, and a few others.
The MMDS operating frequencies are much lower,
around 2 and 2.5Ghz. Components are much cheaper to design,
and wave propagation effects are different--
roughly, LMDS requires line of sight, while MMDS
is slightly less stringent in this regard (Clarity
Wireless, now part of CSCO, used signal processing
techniques to form a ``virtual' line of sight).
Also waves at LMDS frequencies attenuate much faster
than for MMDS, so that MMDS cells can be larger, but
signals from one cell interfere more severely with
other cells.
The bottomline is that there are significant differences
between the MMDS and LMDS markets.
Best regards,
Bernard Levy |
