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Technology Stocks : Winstar Comm. (WCII) -- Ignore unavailable to you. Want to Upgrade?

To: Bernard Levy who wrote (10014)	1/18/1999 5:44:00 PM
From: SteveG	Respond to of 12468

Hi Bernard- <..So, the increased attenuation at higher frequencies is more than compensated by increased antenna gains..> Ah right, the gain factor. I knew there was SOME kind of tradeoff (as there always is). I just couldn't remember specifics.. [a meandering aside: I remembered some years back when developing a non-invasive technique to measure regional cerebral bloodflow using rheoencephalography. In a "quad" montage, we had two outer placed field establishing electrodes and two inner placed impedance detecting trodes. With blood (water/electrolytes) as an electrical conductor, a greater volume/time under the detectors indicated greater flow and inferred greater regional metabolic activation. I remembered that using higher frequencies (~100khz) allowed the signal to transmit ("see") through lesser conductors like skull. In fact, we had problems with the higher, more "penetrating" frequencies as they tended to wander, establishing a field well beyond the head. In trying to remember the tradeoff, I incorrectly extrapolated from this that a higher freq was more resilient to impediments like water. I realize now that it's water's conductance which absorbs the signal, and not some electrical lesser-conductor which limits the field for lower freqs. In any case, responding to Perry's showing of his chart on the reach for 38, vs 28 vs 24, emphasizing how much bigger NXLK's service area was compared to WCII, I smugly thought I'd "expose" the converse side of reach by (erroneously) questioning 38's greater resistance to rain fade than 28 or 24. But I had to slink back when he responded that in addition to shorter reach, 38 was more susceptible to rain fade, hoist by my own petard (how you say - "moteur"?) So, given the same sized antennas (and is this a given, or are the antennas designed to be the smallest possible for whatever freq they carry?), you are saying that an increase in gain (but same SNR) MORE than offsets the reach attenuation? In the real world of antenna sizes (and the 28Ghz antenna he displayed was small <12 inches dia.), and assuming same power out, since one way to deal with rain fade is increasing gain, wouldn't this offset 38's relative sensitivity to rain fade? BTW, NXLK plans on using Bosch radios. <..So this factor tends to be larger in places like Florida than in dry areas of the Southwest...> Perry made an interesting point. Arizona rates higher on a rain fade index than Seattle, due to the larger size of the drops in Arizona. <..When I did my analysis for the TGNT BW transfer, I had concluded that 100MHz at 18GHz was worth about 125MHz at 24GHz...> I remember your discussion of this. Since then, I have read something about TGNT needing to share 24Ghz with police radios, hence the need for more spectrum. What's your take on this justification? BTW, I asked Mandl in the Q&A if this issue was fully resolved or if there was any residual concerns about the swap. He (somewhat huffily) said it was long since approved and finalized. Any word on McCain's continued interest in pursuing this beyond the FCC and into congress? And did you see this: Message 7064633 ? And whaddya think of these rad-hardened Pentiums being put into gov satellites, and the potential susceptibility of comm satellites to nuclear explosions? Rad-hardening the chips purportedly close to doubles the cost of a satellite.