[amsat-bb] Re: [psk31] PSK31 Satellite Uplink on 10m

[Bob Bruninga <bruninga@xxxxxxxx>]

On Tue, 19 Nov 2002, Peter Martinez wrote:

> Bob says that wideband modes are not permitted on 28120.  THIS IS NOT
> TRUE IN EUROPE,... I don't think it's true anywhere except the USA.

Ah, thats good to know.  But there must be some reserved CW/Digital
narrowband spectrum in Europe for the 10m band?  Maybe it is below 28.100?
My original objective was to find a freq that was bandplanned everywhere
for narrow band modes only.

> Maybe the region 28117-28120 would be an option?

Is that narrowband only in Europe?  Maybe you could fill me in on the
European band plan with regards to the digital subbands and the license
class boundaries (if any) on 10m so I can see the big picture.. Here is
the USA issues:

28.000 to 28.100 CW/digital General and above operators only
28.100 to 28.300 CW/digital Noivce, Technician+, general and above
28.300 to 29.300 mostly all modes Generals and above only
29.300 to 29.510 Satellite downlinks
29.510 to 29.700 Mostly FM.

I was trying to find a slice with CW/digital only and as many license
classes as possible... and that would have some PSK-31 activity on it.

> Bob argues on the one hand that the terrestrial activity will be so low
> during a sunspot minimum that there won't be any QRM, and on the other
> hand says that the high activity on 28120-28123 will boost the number of
> signals heard through the satellite. The activity cannot be
> simultaneously low and high at the same time.

I meant in "relative terms"...

> Either terrestrial activity is going to be low and there is no point in
> choosing 28120 and any other channel would do, or activity is going to
> be high and there will therefore be mutual QRM between terestrial and
> satellite traffic.

In the case of "low" activity, I was thinking below say a dozen
simultaneous terrestrial PSK-31 QSO's would be low and would allow plenty
of room for another dozen or so people during the 8 minutes of the
satellite pass...

In my use of the term "high" activity for the purpose of their being
something to listen to, I was referring to any numbers of signals greater
than 0 as being "high" enough to guarantee that there was at least one
signal on the band to tune in... THere are an awful lot of times when the
activity is zero across the entire band and the presence of a single
signal for an extended period of time can be considered "high" channel
occupancy...

So it all boils down to how "crowded" the 28.120 slice of spectrum is and
whether a few more users can be accomodated a few times a day for under 8
minutes at a time for a one year mission in 2003-2004.

I certainly want to avoid QRM, but by the same token, if we exclude the
PSK-31 satellite uplink from this place where the PSK-31 operators
congregate, then is there anyone else to talk to or listen to?  It is kind
of a tradeoff, If you chop up the PSK-31 operating segment into multiple
bands, you can spread activity below the critical mass and then there is
never enough people on either slice of spectrum to make it interesting
enough to causepeople to switch back and forth all the time...

The beauty of PSK-31 is that you never touch the radio dial. Requiring the
few operators for the 8 minutes of a satellite pass to go elsewhere would
almost guarantee lack of use...

I don't think I am as concerned over someone using SSB in the designated
PSK-31 bandwidth for satellite any more so than for terrestrial use.  I
believe that if the intentions of a piece of spectrum is published as a
PSK-31 or other narrow band mode only, that other HAMS will respect
that...  or are you saying that in Europe, you see SSB QRMing the 28.120
PSK-31 frequency?

I'm just trying to understand how that slice of spectrum is used in Europe
and how best to make this exciting PSK-31 Satellite capability (only
usable 8 minutes a few times a day) viable and useful to PSK-31 users.

de WB4APR@amsat.org, Bob



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