UHF is more robust than VHF (was Re: Digital TV receptionproblem)

Garrett Wollman wollman@bimajority.org
Sat Jun 20 22:54:21 EDT 2009

<<On Sat, 20 Jun 2009 22:07:09 -0400, "Dan.Strassberg" <dan.strassberg@att.net> said:

> I read that WHDH has applied to double its ERP on Channel 7
> (presumably by diplexing its main and about-to-be-installed
> auxiliary VHF DTV transmitters).

They might be thinking about doing so, but they have not applied to do
so yet.

The channel 7 transmitter they have now can do at least 4 kW TPO (I
can't find the actual specs on the Harris Web site), so I'd expect
them to try increasing that first.  The existing antenna does about
9.6 dB.

> haven't heard that analog power was peak and digital is average, so
> it doesn't necessarily follow at all that 60 kW digital is less than
> 300 kW analog." Does anybody have a conversion formula?

Multiply by 5 is the rule of thumb; I'm not sure how accurate it is,
or why the FCC didn't apply it in setting the power limits for VHF.

I can't seem to find where in the rules the power limits are actually
defined.  I know I've read them in some official source (maybe one of
the DTV Reports).


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