[amsat-bb] Re: Is Wi-Fi Headed toward an Early Grave?

Bruce Robertson broberts at mta.ca
Wed Dec 13 04:28:02 PST 2006

Quoting David Barber <david.barber at dbelectronics.co.uk>:

> Could I perhaps just highlight an unwanted side effect of all the
> discussion
> regarding Wi-Fi and its impact on "our" frequencies.
> Any newcomer reading all the gloom and despondency may well reach the
> conclusion that 2.4GHz is not worthy of their investment.  Surely if we
> are
> not careful this becomes self defeating as potential new users shy away
> and
> we end up with another under utilised band.

To any beginner, I'd say that, with today's satellites, 2.4 GHz is great
fun, but rarely operational. Certainly not a high priority for a new
satellite operator, but wonderful to experiment with once the basics of
operating through AO-51 are in hand. 

> The recent scheduling of AO-51 with downlink on 2.4GHz has been
> interesting.
> I live in a highly populated urban area with a number of locally active
> home
> and commercial Wi-Fi's however using just a K5GNA down converter and
> corner
> reflector (hand held) huge interference free signals are easily
> received.

Looking at future birds, S-band comes into its own on the HEO missions of
P3-E, SSETI-ESEO and, now, Eagle. The beginner should be equally warned
that, due to the far greater path losses from those satellites, an
experiment such as the above does not ensure that QRM won't seriously
degrade future S-band reception from HEO.

Can anybody work out a simple experiment that would simulate these
conditions? In a previous letter, I'd recommended using lossy cable between
the antenna and preamp/dc as an attenuator (simulating the pass loss), but
I now realize that that will drop the QRM along with the satellite signal. 

Hoping for a return to HEO in 2007 (but content to wait until 2008),

73, Bruce VE9QRP

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