[d-star] Fw: D-STAR using Analogue SSB

[Mark Thompson]

----- Forwarded Message ---- 
From: jk1zrw <7m3tjz at jk1zrw.ampr.org> 
Sent: Thursday, October 25, 2007 9:56:15 PM 
Subject:  Re: UT118 Adaptor 

--- Tony Langdon <vk3jed at ...> wrote: 
> 
> At 10:45 AM 10/26/2007, you wrote: 
> 
> >Yes, it works any band. Only requirement is AF bandwidth of your 
rig. 
> >If SBB of HF has above requirement, we can use D-STAR in HF. (I ma 
> >nore sure now.) 
> 
> SSB radios typically don't have the bandwidth, as they cut off 
> sharply around 300 Hz on the lower edge of the passband, due to the 
> crystal filters used in 99.99% of radios. You would normally use 
FM 
> mode in any case, resulting in the same 6.25 kHz wide signal as 
used 
> on VHF (which would be legal on any amateur band in Australia, as 
it 
> fits within the 8 kHz bandwidth limit). However, the performance 
is 
> likely to be lousy, and any attempt to use D-STAR based systems on 
HF 
> would require a more appropriate modem for HF conditions in my 
opinion. 

Yes, your are right now. SSB radios typically used crystal filter. 
But recent tequnical development are too fast, so we can make the 
ssb signal using Software (like SDR). For example, JH1DTX successed 
to modulate/demodulate from 50Hz to 3000Hz with PSN-SSB method 
(this is not SD mnethod). So, I think we can make the D-STAR rign 
in HF near future. The bandwidth(in AF) of D-STAR is 20Hz to 2400Hz. 
If future SBB rig has this bandwidth, we can. 

Satoshi 7m3tjz

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