In a disaster, a basic D-STAR repeater can be just as reliable as a FM
repeater. The gateway is not required for operation. So as long as the
repeater continues to work, it provides the same capabilities that an FM
repeater would, PLUS. The PLUS is the ability to send slow speed data and
voice over the same links, even at the same time. So it actually combines
the functionality of a packet node and FM repeater in one package. And even
if the repeater dies, this same capability exists on simplex.



-->Reliability - I don't think there is any data to present regarding the
reliability of the all in one repeater in a box concept over a commercial
analog repeater.  The Icom 'repeater' is clearly two mobiles stuck in a box.
However, can you keep it running and repair it if needed?  With a typical
analog FM repeater, I can fix or replace most parts, in fact we have parts
on site, a complete spare for most of them.  With the Dstar repeater, you
either replace it with a spare (assuming you have one or more) or ship it
back to Icom.  So while it may continue to operate under normal conditions,
it is nowhere near as serviceable or 'reliable' as commercial analog gear.
I can get almost any two way technician to restore service after a disaster
on our analog gear, good luck with the D-star.

 

-->Same as FM - sounds like you have swallowed the blue pill from Icom.  Our
'terrain' includes very few locations that are line of sight to the site.
We have a VHF Dstar repeater with a 6dB antenna, and 1000' horizontally away
a VHF analog repeater with 6dB antenna.  Hands down, absolutely no question,
tested it for months, the Dstar is usable for reliable (non-garbled
communications) for mobiles about 10% or less of the coverage area of the
Analog FM and for base stations about 80%.  This is largely due to the
picket fencing of a mobile signal, multipath for non line of sight, etc.  On
a high peak in the desert with line of sight, I can see them being
comparable, but not in the real world of trees and buildings.

 

-->Voice and slow speed data 'over the same links' - this one has me
wondering.  Assuming the gateway is down, what links are you referring to?
Sure, I can talk to you via the repeater and while I'm transmitting send
some text.   There is simply no way that it combines the functionality of a
packet node and FM repeater into one package.  Can you get into a 'network'
with your data if the gateway is down? Nope. Can you connect to the 'node'
and get telemetry from the site? Nope.  Can you go into the 'node' and come
out somewhere else if the gateway is down?  Nope.   Can you listen to a net
and transfer data at the same time?  Nope, the net has to stop if you intend
to transmit your data because there is only one channel and either voice or
data require it.  In fact, going from an analog FM radio for voice and a
radio for packet.to the Dstar single radio, cuts your throughput in half
UNLESS you are simultaneously reading a message to the same destination that
you are sending the data to.

 

So with a handheld or mobile and a computer, I can send voice and data.



-->Yup.with my D7 and a laptop, I can carry on a voice conversation or send
and receive email or download lists of data via packet.  I don't tie up the
net control discussion when I send and receive email.


BUT, if Internet access IS available, then I can provide all of the above,
as well as direct communications with remote locations such a State EOCs,
FEMA EOCs, and other government organizations in DC such as the Red Cross.

-->Yes, assuming all those agencies have Dstar (all of those agencies by
default quite likely already have analog FM)

 

So if I compare the common non-linked FM repeater to the commonly Internet
connected D-STAR repeater, the D-STAR repeater at it's worst does a heck of
a lot more, and at the best, just blows the functionality of a FM repeater
away.

 

-->Hmmm..you do get NOAA weather alerts over your D-Star repeater?  We do on
analog.  You get site telemetry (battery voltage, VSWR, etc.) over your
D-star?  We do with analog.  You have remote control of any of the site
features like turning the power down, switching to the backup antenna,
manually starting the generator, etc on your D-Star repeater?  We do with
analog.  And guess what, with data on a separate network, I can send and
receive email at the same time I'm listening to the emergency net without
having to occupy their channel for data.

 

If I have D-STAR radios, then I have the option to use both. If I don't then
I CAN'T use the advanced functionality.

Oh, and for getting Internet connected D-STAR access in disaster areas,
that's where a couple of us have portable repeaters available for
deployment. For my repeater, I travel as close to the area as I can get
Internet, whether it is via cellular modem, hotel Internet, or even a WiFi
Hot Spot, the repeater gets setup and that then gives 20 or so miles of
coverage into the impacted area, which is often all that is needed.



-->Awesome.  PLEASE explain to me how you have been able to make the gateway
work via cellular modem and wifi.  Having only done one installation and
worked hard to get the Icom required addressing scheme implemented and
having to be very close to the backbone to keep the jitter down enough to
provide reliable communications I would be in awe if you have managed to
make it actually work as simply as you make it sound.

You just roll in, connect to a wifi hot spot, and you are authenticated with
the trust server and the gateway just hums along?  Please Share!

 

-->I'm not saying D-star isn't novel and fun.  I'm saying that there are
many pitfalls in implementing it, servicing it, fixing it and actually doing
what the brochures lead you to believe it does.  I would MUCH rather have a
voice radio so I can monitor a couple of nets during the emergency and a
radio/TNC to send data WHEN I want to WHERE I want (i.e. winlink) rather
than be trapped on the Dstar 'network' with no onramp to the email system
(except what Dan has done with Drats which is awesome!).  My tool box
includes both, todate the analog side get's 99% of the usage because it
meets the need even if the internet backbone is down.

 

73

Daron N7HQR





 



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