[amsat-bb] Re: Help sought - amateur satellite service vs D-star

Tony Langdon vk3jed at gmail.com
Tue Sep 8 23:39:20 PDT 2009

At 07:24 AM 9/9/2009, Geert Jan de Groot wrote:

>In the Netherlands, 436-440 MHz is secondary to the amateur
>and amateur sat service. The folk experimenting with D-star
>on 70cms use a fairly large shift of 9.4 Mhz, resulting in
>a typical setup of 430.400-430.600 in and 439.800-440.000 out.
>Unattended stations (like D-star repeaters) do require a special
>license here.

OK, so what do FM repeater owners do?  Asking that, to see if there's 
any other places the D-STAR systems can be put.  Over here, D-STAR 
repeater allocations are in the same parts of the bands as FM ones.

>The D-star community, having fear of not being able to use their equipment,
>is now proposing to use a shift of 7.4 MHz shift: input ~430.400-430.600,
>output 437.800-438.000.
>The output obviously collides with the amateur radio satellite service,
>but the proposal does not mention this at all, nor does it mention
>any remedy for this interference, which the amateur radio service
>would inflict on itself, on a worldwide (at least European) scale.

This could create significant QRM across Europe, as any satellite 
with an input on those frequencies and within range of an operating 
D-STAR system would suffer QRM.  Satellites with downlinks in this 
range would be unusable within the coverage area of a D-STAR system 
on the same frequency, though in a lot of cases, Doppler shift would 
allow at least some of the pass to be worked.

>I believe this plan is very poorly thought-out and should be
>rejected and complained upon on an International scale.

I'm not sure what can be done about the DGPS issue, given the 
relative status of amateur radio and commercial interests in most 
countries, but the issue of allocating repeater outputs in a 
satellite subband is something that goes beyond national borders, 
especially in Europe, where many countries are very small.

73 de VK3JED / VK3IRL

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