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Re: Mode A: wanted?



Hi Richard,

When evaluating the responses you will be receiving, I believe it would
be well to bear in mind that, to the best of my knowledge at any rate,
a majority of existing Mode A users are not on the Internet, or at
least are not registered with <amsat.org> and hence have no
access to <amsat-bb>..

"How do you know this," you may ask.

As you know, I've been having fun for the last couple of years with my
Mode A "micro-station," which consists of a hand-held 2m transmitter
(actually an FM transceiver) and half-wavelength whip antenna for the
uplink, and a pocket-sized Sony ICF-SW100E receiver for the downlink,
generally with a wire antenna thrown out the window for 10m .  When I
work someone on RS-12 (or RS-10, when that was active), I normally
check the <amsat.org> list to see if he is listed; if so, I then send him
a "Tnx QSO" message informing him about the station he has worked.
From experience, I can tell you that at least two-thirds of the stations I
have worked on Mode A are not registered with <amsat.org>.

I have no easy way of determining how many of them are actually
members of an AMSAT organisation, but would be willing to wager
that many are not.  Indeed, Mode A operators who are not AMSAT
members have a persuasive argument on their side: to date, AMSAT
has done very little for them.  Except for the Russians, no AMSAT
organisation has built a Mode A satellite since 1978 (AO-8), and
even that was funded by ARRL (and built by AMSAT-NA under
contract to them).  In all of history there has been only one Mode A
satellite built and paid for by AMSAT (again, apart from the Russians),
AO-6 in 1972.  Twenty-six years is a long time to wait!

So, were AMSAT-UK to take the lead in building a new one, I
believe that there would be a significant new base of potential members
which may become available.  To find out how large it is, however,
one would have to ask them, and most of them are not on the Internet.
To try to reach this wider audience, perhaps articles might be written for
RadCom, Practical Wireless, etc, describing the proposition and asking
readers to respond.  

Turning now to my own personal opinions, I have two thoughts on this.

1.  Gerard, F6FAO, makes an excellent point.  The attractiveness of any
analogue bird is very much related to its orbit.  Specifically, much of the
attraction of the old Mode A satellites of the 1970s and early 1980s
derived directly from their DX potentialities.  Working DX on AO-6,
RS-6, RS-8 etc was challenging and, therefore, fun, something which
has largely gone out the window with the later Molniya-orbit spacecraft.
But, before something can be fun, it's got to be possible.  To be capable
of providing serious opportunities for DXers, the orbital altitude should
be higher than that of RS-12 today -- at least 1500 km (the altitude of
AO-6
and AO-7) and preferably even higher than that.  RS-15, for example,
is in an excellent orbit for DX operation.  Would that it had enough solar
power to permit consistent operation at reasonable output levels.

2.  When thinking about a bird with a 10m downlink, we should also 
consider the eventual need to replace RS-12 when it goes to the happy
hunting ground in the sky.  In addition to a Mode A uplink, I would like
to see the new bird have Mode K capability as well.  For the operator
who already owns an HF transceiver, Mode K has the advantage of
requiring him to purchase no new equipment at all.  In fact, due to the
extremely limited Doppler shift, his equipment need not even be 
capable of monitoring his downlink while transmitting.  The only
requirement would be for relatively easy bandswitching between
the transmit and receive frequencies, each of which would be stored
in memory with the added use of RIT.  For the DXer, Mode K provides
a combination of satellite and ionospheric propagation leading to 
fascinating opportunities, e.g., antipodal paths such as G-ZL which
are virtually impossible on AO-10.  Also, as John, GM4IHJ, has so
ably demonstrated, Mode K offers unique opportunities for serious
research into ionospheric phenomena.

I hope these comments prove helpful.

73, Ray
w2rs@amsat.org 



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