[Dstar] D-Star and emergencies

[Tony Langdon]

At 12:40 AM 9/11/2008, you wrote:
>Hi Peter, agreed that the range of DSTAR is better than analogue FM 
>at the same power levels. I have a very difficult simplex path to a 
>mate of mine when operating from the parents place in Melbourne. I 
>always have problems using analogue, but when we went to DSTAR, no 
>problems, made it through without an issue.

I have seen similar performance between fixed stations.  D-STAR 
between fixed stations works extremely well.  Mobile operation is a 
lot harder to judge.

However, a lot of the issues raised were that the reliance of the 
D-STAR on Internet infrastructure for out of area linking was a 
liability.  Well, as someone who has been using IRLP and Echolink 
(which have the same issues re infrastructure) for several years 
under hurricane conditions across the US, the conclusion is that 
these systems are extremely valuable under these conditions, and I 
believe D-STAR will also prove to be valuable, perhaps more so, given 
its feature set, and also the fact we're not retrofitting a legacy FM 
system with links, so we don't have to deal with IDs, etc getting 
into the links.

Now to debunk the myth that D-STAR/IRLP/Echolink will be useless in 
an emergency...

1.  The Internet will not be available during an emergency.  Well, 
depends on the emergency, but experience (at least in the US, don't 
know how well it will translate here) suggests that the Internet 
actually holds up rather well.  The most common failure mode is lack 
of standby power at the repeater or link site.  Systems that have 
backup power tend to remain on the network well into the storm.  This 
would affect a standalone repeater, and the fix is a case of suitable 
planning and investing in appropriate standby systems for the radio, 
computer, routers and other equipment at the repeater site.

2.  No one is an island, use a combination of tools.  The VoIP WX 
Net, for example, even in the event of worst case, with total 
Internet and VHF/UHF blackout in the affected area (artificially 
induced by a lack of systems in the case of Cuba), can still pass 
traffic by making use of HF stations with propagation into the 
affected area.  In other words, good old fashioned manual 
relays.  Works in an emergency for me.  D-STAR actually offers more 
options, for example, linking D-RATS chat to a PSK-31 HF link in the 
affected area.

I hope that's debunked the myth that Internet based technologies are 
useless during a disaster.

The SE D-STAR WX Net was starting to sound nice the other week.  At 
this point, the main limitation of D-STAR is that it's early days, so 
the penetration isn't anywhere near that of IRLP/Echolink/FM, but 
time will change that.  I for one look forward to using D-STAR more, 
and I believe new functionality will come along to extend and enhance 
the system in the future.

>There seems to be a fair amount of DSTAR bashing - I wasn't around 
>when FM was introduced, but would imagine some of the hysteria 
>experienced then is probably similar to that with the new mode 
>DSTAR. The biggest stumbling block I see with DSAR is the cost of 
>the system compared to the more numerous analogue "hand me down" 
>systems we amateurs often put into service, but until the volume of 
>sales increases, I guess that there is not much slack to move in 
>that area. Congratulations and thanks to Icom for all the assistance 
>they have provided with DSTAR to the VK amateur scene.

It's early days yet.  D-STAR has a LOT of future ahead of it, and it 
all looks rather exciting from here.

73 de VK3JED
http://vkradio.com