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Re : Re: S-Band Newbies



>From: Estes Wayne-W10191 <W10191@motorola.com>
>James La Frieda wrote, about S-band newbies:
>
>The first thing that most of them need to do is: learn the fundamentals of
noise figure, gain, noise bandwidth, polarization loss - and how to compute
a link margin- for otherwise they will be wasting their time and money
using antennas with too little gain, downconverters with too high a noise
figure and not enough gain, and using front-end components with too much
insertion loss.
>
>Wayne replies:
>
>Newbies do NOT need to go through all the calculations.  They just need
good advice!  Getting on Mode-S can be made VERY SIMPLE if appropriate
information is available.  We need "real world" articles that explain in
simple terms that reliable mode-S reception requires XX antenna gain, YY
noise figure, good image rejection, and ZZ converter gain.  Those articles
should describe various low-cost sources for equipment that meets those
requirements.  Last but not least, the articles must explain that buildings
and trees severely attenuate microwave reception.

James and Wayne,

Both of you are correct.  Newbies do need to begin to learn the
fundamentals of what makes good microwave stations, and articles giving
them first of all simple advise on how to get on AO-40 mode-S which specify
needed equipment is a starting point.  Such articles ought to review
sources of such equipment and what sort of things are needed to put each on
the air.  Secondly a basic tutorial on microwaving for satellites would be
great.

I expect we will soon see some of these articles show up.  I have a
suspicion that Ed Krome, K9EK, may be authoring something like this.  He
may also come up with an AO-40 Update to his Mode-S book.  Hopefully,
others will be writing, too.  One place that these will show up will be at
ham conferences such as MW Update and the Amsat Symposium.

But we must realise that to write a good article [one that accurately tells
one what is needed], we need to experiment with the transponders themself.
The recent transponder operation [and the upcoming return of it] provide
this experience.  We who got to built for the initial telemetry beacon
operation and use of the transponder ARE the BETA group for the bird!
Certainly we don't want articles written that only speculate but have not
been tested in actual operations.  So here we are in the "twilight zone"
between commissioning and full operation ;-)

For us AO-40 "Pioneers" the Amsat-bb, Amsat [NA, DL,UK,...] and some
personal websites make due for the interim.

Ed

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