Interesting annex to the ofcom consultation document submitted by Astrium.

http://www.ofcom.org.uk/consult/condocs/dttfuture/responses/astriumannex.pdf

Ben  wrote:

>Interesting annex to the ofcom consultation document submitted by Astrium.
>
>http://www.ofcom.org.uk/consult/condocs/dttfuture/responses/astriumannex.pdf

I see.  That's a possibility that they've floated at the end of the
document.  The idea being that you could receive a satellite broadcast
with a simple Yagi.

The downside being that there's going to be very little space for
channels left in the UHF spectrum -- compared to the usual satellite
band, the Ku band, which has relatively huge bandwidth.  And since Ku
band satellite dishes have much better gain than Yagis, a UHF satellite
would have to transmit at significantly higher power.

I'd have thought that it'd be better to launch higher power Ku band
satellites instead, in which case the Ku band equivalent of a Yagi aerial
could be used:

http://tinyurl.com/fmrzu 

That's a tube antenna, and the end points at the satellite.  Although
that reviewer guesses at how the thing works, the guess has to be wrong,
because he assumes that the signal is received via the tiny
cross-sectional area at the end of the tube, which in fact is far too
small.  My own guess is that it contains a dual-polarized Yagi in an
RF-transparent shell, thus the Fresnel-zone all around the tube must be
clear of obstructions.  That antenna is not popular because its reception
is marginal in the UK, but it should have worked fine if the satellites
had broadcast at a higher power.

-- 
Dave Farrance