[opendtv] Re: News: FCC Floats Cash-For-TV-Spectrum Scheme

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 30 Oct 2009 13:31:31 -0400

Craig,

I bet if you add up all of the electricity used by the broadcasters in our market, then add up all the electricity for all of the cell towers in the same coverage area, the difference in electricity use would not be significant.

I know cooling costs alone for all of those cell phone doghouses would far exceed the cooling costs of our transmitter building.

As for the SFN, very high power TV transmitters for the most part are using IOTs while lower power transmitters are using FETs. The efficiency of IOTs is greater than FETs, so the reduction in power does not necessarily equate to a reduction in electricity use.

Further, the single big stick use relatively large and high gain antennas, while the smaller SFNs also use smaller, lower gain antennas, requiring more input power for the same ERP.

Add it all up, several buildings needing cooling, several buildings using less efficient solid state MosFET final amps, feeding lower gain antennas, and you haven't saved very much, at least in terms of electricity use. You may have gained a lot in signal density uniformity within your market, but that is another matter.

And for the SFN, let's not forget the "greenhouse gasses" emitted by the lone engineer driving from transmitter to transmitter for maintenance.

John

----- Original Message ----- From: "Craig Birkmaier" <craig@xxxxxxxxx>

The input power levels for the big sticks are still huge compared to what a properly designed SFN would consume.




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