Manfredi, Albert E wrote: >Craig Birkmaier wrote: > > > >>here we go again... >> >> > >Sorry, Craig. You ain't no Ronald Reagan "great >communicator." > > > >>So I take it Bert was involved in the development >>of this system >> >> > >No, I merely read what is written with the intention >of understanding, rather than reading with the >intention on twisting my previous political >platforms to try to prove that I was right before, >as you seem to enjoy doing (but fail). > > > >>however they are just what you would expect for a >>COFDM-based Single Frequency Network. >> >> > >You mean, like the 200 KW big sticks (for *one* of >the nine DTT channels) in Berlin. Sure. That is in >line with many big sticks the TV transmitters use now, >even here. > >Remember that a 3 dB difference (doubling power) does >not amount to much difference in range. You have to >think in orders of magnitude. A 200 or 500 KW >transmitter and 600' tower *is* a big stick, by any >definition. > >Big sticks in the US now, depending on frequency, >range from the single or tens of KW to 1 MW. Many >big sticks are in the 100s of KW. In line with >the Berlin SFN approach. > > > >>You obviously did not read the links I provided. >>These networks have been designed to work >>together to maximize the potential for both. >> >> > >When we talked about this infrastructure, I >explained that you could mix and match any >modulation scheme and different transmitters >entirely. Remember? You were instead pushing this >imprecise concept of an all-COFDM mesh of small >sticks. Need I remind you? Was it 10-30 KW per >stick? Or less? It made no sense then, and it >doesn't make sense now either. > >Well, what I described is what they are proposing. >They are talking separate transmitters for the two >services, with a cell approach for the unicast >2-way service. > >The IP (or other) encapsulation is purely optional >with *any* infrastructure you care to build. Don't >make more of a big deal out of it than it deserves. >IP over 8-VSB or over QAM works too. > > > >>COFDM is simply a more efficient way to deliver >>this data to CDMA enabled appliances, especially as >>it relates to power consumption. >> >> > >This is jibberish. What does "CDMA-enabled >appliances" mean? The truth is that COFDM is >more spectrally efficient, at 16-QAM or 64-QAM, >than CDMA is. So they use COFDM for the TV >broadcast, potentially, instead of cdma2000. >They propose either scheme, though. > >And if the COFDM transmissions are high enough in >power, the greater spectral efficiency will still >provide enough robustness. > >The appliance would simply incorporate both >tuners. This is a CDMA *and* COFDM enabled >appliance, if that terminology makes you happy.=20 > > > >>You missed it again Bert. >> >>The channels are 1.25 MHz. They can be used to >>deliver any kind of packet data including audio >>and video. But this has nothing to do with what I >>wrote. >> >> > >Narrowband CDMA was always specified for 1.25 MHz >channels. cdma2000 was always specified to fit in 5 >MHz bands or in separate 1.25 MHz bands, for backward >compatibility with narrowband CDMA. The COFDM they >would introduce, unlike the COFDM used in DVB-T, >would also be made to fit in something less than 6 >MHz. Guess what? You can do the same thing with any >modulation scheme. It's simply a different >modulation technique used in the same 6 MHz band. >Which is exactly what you were *not* proposing back >when, in your spectrum utility. > >I explained to you (i.e. to deaf ears) back then >that although your notion of small sticks and all >COFDM was essentially unworkable, a viable utility >was still possible, and by the way, 8-VSB could be >in there as well. You just can't be too dogmatic >about these things. > > > >>This approach moves most of the IP Multicast >>traffic OFF of the CDMA network, freeing up >>bandwidth for more unicast and phone transactions. >> >> > >It moves the high bit rate TV channel traffic off >the 2-way infrastructure. Wow. Isn't that how >DOCSIS and cable TV works? > >In fact, you need use no IP overhead at all. The >broadcast TV traffic can use MPEG-2 TS without IP >overhead, and the two-way traffic can use normal >circuits as defined in CDMA. Or IP overhead can be >added to the data circuits of the CDMA 2-way >unicast service. And/or IP overhead can be added >to the MPEG-2 TS in the broadcast service. This >is all very interesting, but let's not over-hype. > > > >>I did provided two references that verified the >>notion that these would be COFDM SFNs. >> >> > >Your references said high power towers. They did >not even hint at 10-30 KW towers you had mentioned >previously. The arithmetic never did work for >those small sticks, Craig, and no amount of >obfuscation can change that fact. > >As far as I can tell, none of the above is >remotely similar to your previous utility >concepts. But I am gratified that maybe you're >starting to get it? > >Bert > First this is an overlay network that works with current carrier CDMA networks. They are not proposing to build both a COFDM and CDMA network. Second they are limited to 50 kW so if that is big stick it is but I would think big stick high power starts at 200 kW and over. LPTV is definitely 15 kW and lower. I would expect most of the transmitters that Qualcomm uses to be in the 1 to 30 kW especially in cities. That is if they use towers at all. If not the power levels could fall to a kW or even less. Bob Miller ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.