Re: [dstar_digital] Re: Limited access
That was the thinking for many years. However, after a lot of research, it was determined that Andrew was indeed a Cat 5 when it hit Florida. I place my trust in the National Hurricane Center: http://www.nhc.noaa.gov/NOAA_pr_8-21-02.html Wikipeida: http://en.wikipedia.org/wiki/Hurricane_andrew and a local newspaper: http://www.sun-sentinel.com/news/weather/hurricane/sfl-scane22aug22,0,1661757.story 73 de W4AS Sebastian
Re: [dstar_digital] Re: Limited access
On Jun 26, 2008, at 3:20 PM, nj902 wrote: Beg to differ, Nate. I know you computer gurus are all gaga about the world-wide call sign routed [Nextel Direct-Talk] D-Star model, but from the point of view of an Emergency Management Agency, we have no interest in having one of our communications resources tied to the entire planet during a local emergency. Hmm, how to respond to this to clear up misconceptions about what I'm saying... I'm not gaga about it, in fact I find it has serious flaws. Source- routing is great as long as there's always an ack system to prove you source-routed all the way to your destination. D-STAR has this (RPT vs UR back from the repeater) but it often disappears in practice, and I'm not sure why. The system could also benefit from real-time warnings about doubling (which would require a lot wider frequency split or a mobile duplexer built into the rig so you could listen at the same time as transmitting) etc. It's not perfect, by any means. But as I'm learning to say, It is what it is. A Gateway-equipped D-STAR system is instantly a fully- linked, source-routed system. If that's not what you wanted to use, why are you building a Gateway-equipped D-STAR system for your local use? It is what it is. Or another way to look at it, use the appropriate tool for the job. A local only net, probably shouldn't be on a D-STAR Gateway-equipped system, if there's some logical, serious concern, about interruptions from afar. We might be interested in regional networking or access from the State EOC - it depends on the circumstances. I understand completely. All I'm saying is that plenty of EmComm nets and activities happen on shared spectrum in both training (peacetime) and very trying times, and those Nets don't have the ability to block out other spectrum users. They have procedures and knowledge of how to adapt to an interloper, intentional or accidental. Actually, if D-Star really takes off, it is inevitable that there is no way everyone will play together and there will be separate networks, subnetworks, connect disconnect on demand, or whatever turns out to be the evolution of things. Perhaps. Right now it's bringing dissimilar groups together around the technology. And there ARE mechanisms built in to filter out things and/or people you don't want to hear, but not to force them not to timeshare on the repeater, really. Digital code squelch comes to mind here. The distinct user groups can agree to a code and only hear the other guys if they find/use the same code, press the EMR button and holler HELP or however that darn BK button works... I haven't quite figured that one out yet. Does anyone on an EmComm Net really need to run open squelch other than the Net Control? Food for thought. But... in order to take full advantage of that particular part of the technology, the participants need to pay attention to the displays on their rigs. Take that a step further. Do the participants in the event really need to hear each other? Could the Net Controller callsign route to everyone as needed? If folks go back to making sure they voice ID, could the radios be pre- programmed with RS1 RS2 MED1 MED2 for things like Rest Stop 1, Rest Stop 2, Medical 1, Medical 2, etc... and the Net controller's rig have all of those available as UR memories? Want to get less specific? RS for all Rest Stops. MED for all Medical. SAG for all Sag Wagons. Just to use one type of event as an example... a bike race. Change these as you see fit to match your needs. These are just rambling thoughts... your Net runs your way. That's how it goes. I'm just challenging folks to think about how to implement this new technology they've chosen. It will do a LOT of things, but few are pushing the envelope and trying them out as ways to make things better. But sticking to the old analog repeater ways is limiting, to some extent. Someone has to break ground and try some other methods. If they work well, great. If it sucks... call it a learning experience. Certainly real public safety dispatch has changed over the years. Trunking, Talk Groups, etc... all used regularly now. The Fire Chiefs may listen to all districts, but the grunts don't. Same with the police. And the garbage truck guys may be sharing the same repeater infrastructure too! New ideas don't automatically mean BETTER ideas. For proof just look at the glitzy, state-of-the-art, digital dashboard in the 84 Corvette. Others tried it too. Look into any car today - what do you see? Good old fashioned analog readouts. People found that the old model works best. Never said they did. Just saying instead of putting the load on the admin to try to tear down and reconnect a system at the whim of the users of the system, on a system that was never intended to be disconnected from the overall cooperative network,
Re: [dstar_digital] Re: Limited access
At 05:36 PM 6/27/2008, you wrote: I was told the that the Internet was still available in parts of New Orleans after Katrina eventhough the power and the telephones were out. Yes, that's what I heard as well (read my notes on the most common failure mode for Internet linked repeaters). http://www.renesys.com/tech/presentations/pdf/Renesys-Katrina-Report- 9sep2005.pdf I wonder how many internet users THINK the internet is out but its only because their cable modem went dark when the AC power quit at their location. A simple car battery and a $39 12 volt to 120 volt inverter from Wallmart would have solved that problem. Should part of every ham's emergency kit contain a way to operate their cable modem from battery power? Yes, my experience here is that cable Internet often does survive power outages, provided you have a means to power your equipment. My current cable modem could be run directly off 13.8V, so I could even ditch the inverter. :) I haven't bothered yet, because I haven't decided how best to manage the IRLP PC (which is also the router at that site), so there's no point keeping the cable modem up. The repeater will stay up though, as it has battery backup available. 73 de VK3JED http://vkradio.com
Re: [dstar_digital] Re: Limited access
Thank you all for your responses. I now have a better perspective of things. Matt / N3WNX
Re: [dstar_digital] Re: Limited access
On Fri, 27 Jun 2008, Jack wrote: I was in Lafayette, LA for this event, our cable Internet was only as good as there batteries and gas powered generators, then there was also the lines that were down. The short COX had limited or no coverage for 3 days in some areas and in the rural area I lived in it was 9 days till the cable was restored. DSL around here seems to be the best bet. I've had 20 minutes of downtime since April 2001. -- ...DOUG KD4MOJ Tallahassee, FL
Re: Re: [dstar_digital] Re: Limited access
Tony and all, Here in Tampa Bay, Florida, area we have a number of cable providers that offer cable, internet, phone, etc. on one cable. I have Verizon FIOS which is a fiber optics to the home and I subscribe to cable TV, internet at 3 Mb and phone. The phone is high, but the others are competive with others. When home power is lost the only thing working is the phone and on a battery. The battery is good for about 4 hours. No cable TV or internet even though you might have gen/battery power for computer. Just the way it is done. For New Orleans after Katrina it would not be a good test to compare DSL or any other serice in normal operation as we all know. For a Katrina one can expect most all services to be down except the sat stuff like Direct TV or other sat services we now have with our EOCs. Unless you have this sat service you will probably be down. My Verizon I think is in Texas with some type of connection servers here. 73, ron, n9ee/r
Re: RE: [dstar_digital] Re: Limited access
As stated access to the internet from your local connection will probably not be aviable if a Katrina or the like hits. The internet will be there, just the last mile will not. Some here with D-Star are thinking of RF linking to distant city DSTar repeaters for the gate way; a link or remote base using DStar rigs on the repeater. We provide the local repeaters with a link to another 100 miles away DStar repeater that has the gate way. No guarantee, there is never is, but some reasonable back up is needed. If one is really concerned do as most EOCs do, have the internet via a satelite connection. The EOCs have expensive systems with even portable flip up antennas on the emergency comm vehicles. As Hams we can do the same with something like Direct TV. Be prepared to do the install after the storm, not the one you are using now. 73, ron, n9ee/r From: Woodrick, Ed [EMAIL PROTECTED] Date: 2008/06/26 Thu PM 11:07:01 EDT To: dstar_digital@yahoogroups.com dstar_digital@yahoogroups.com Subject: RE: [dstar_digital] Re: Limited access Matt, Since its inception, the Internet has never gone down.
Re: [dstar_digital] Re: Limited access
And I was in the eye of a CAT5 hurricane and the internet, the electricity, the REPEATERS, the Cell towers and commercial towers were down. Even the hospital (Fletcher-Allen) had no electricity. The generator got whacked too. The EOC in Punta Gorda was out of service and the Sarasota EOC filled in until they got up and running 24 hours later. I recall having this conversation once before, Hams were heavily relied upon that week. There is a thing called line of sight! In other words, simplex operations or non repeater operation. Every excercise should be carried out as though these services are not there and then migrate those services back into the excercise. Start at the top of the emergency rather than at the bottom. But what do I know So it does happen... 2004 Hurricane Chalie, Punta Gorda, Port Charlotte Florida. de N1TAI -Original Message- From: Woodrick, Ed [EMAIL PROTECTED] To: dstar_digital@yahoogroups.com dstar_digital@yahoogroups.com Sent: Fri, 27 Jun 2008 10:19 am Subject: RE: RE: [dstar_digital] Re: Limited access I have walked into a location where the eye of a hurricane has passed and Internet was available. And don’t forget that we seldom locate repeaters in valleys that are prone to flooding, I like my repeaters on top of the hill. Not all repeaters are connected with DSL service, some have very high reliability connections. No, I’m not going to count on the fact that Internet is going to always be available. But I’m not going to say that it never will be available. History has shown that the Internet is much more survivable than some hams think. [Non-text portions of this message have been removed]
Re: Re: [dstar_digital] Re: Limited access
Not sure what Cat 5 hurricane you were in. There has never been a Cat 5 hurricane hit Florida going back over 100 years. Sure there has been one, maybe within last 100,000 yrs, hi. Kertina was Cat 5, but down to Cat 4 before hitting New Orlenes. I remember Charley in 2004. Was headed right up the west coast headed right for us in Tampa area. A few of my friends went to Orlando to wait it out. Got to about Sarasota and made right turn and followed my friends to Orlando. They spent the next week operating a chain saw, 73, ron, n9ee/r
RE: [dstar_digital] Re: Limited access
Ed WA4YIH wrote: Since its inception, the Internet has never gone down. There are places where access has been unavailable, but the Internet has never gone down. Except for the last mile, most Internet connections are highly redundant. In the middle of Katrina, in the middle of the biggest California Earthquakes, the Internet has been available. (snip) Well worked, Ed. As we're building out a few D-STAR systems ... we're making sure that they are designed to be as reliable as possible - including the gateways and network connection. In what I've drawn up so far - one of the weakest points in our whole configuration is the D-STAR repeater controller itself! Its easy to configure redundancy in that last mile network connection ... and setup a reliable gateway including maybe even a backup system. We can sustain the failure of a band module - which would leave other modules available. But if we lose the controller itself ... ugh! (Sorry if this thread is getting a bit off-topic ...) Bob W1QA [Assistant Moderator - This is on topic.]
Building redundant D-STAR Systems (was: Re: [dstar_digital] Re: Limited access)
Bob McCormick W1QA wrote: In what I've drawn up so far - one of the weakest points in our whole configuration is the D-STAR repeater controller itself! Its easy to configure redundancy in that last mile network connection ... and setup a reliable gateway including maybe even a backup system. We can sustain the failure of a band module - which would leave other modules available. But if we lose the controller itself ... ugh! Bob, this is actually a very interesting topic. One thing I've heard some groups have done is bypass that power bus topology of the controller altogether. It really does nothing more than turn power distribution into a single-point-of-failure. Plugging the modules into power directly would not (as far as I can tell) suffer any ill effects, unless they were accidentally hooked to floating grounds that didn't tie together. That could make the serial protocol between the controller and the modules unhappy if current were flowing. The brains of the controller is harder. One could buy two of them and build a complex switching system for the four module cables and the Ethernet... but that device probably introduces more possible points of failure than the controller itself does. Hmm... interesting topic. There's also been some discussion about how to harden the Gateway server properly, but those are generally well-known best-practices that any server admin who understands Linux could accomplish pretty easily. Same with the network gear, kinda... at least there's some commercial class networking gear that could be pressed into service and probably never show a fault in many years of operating time. Even some semi-commercial quality gear will do that nowadays. What else would need to be considered? Obviously a power source... automatic generator, if really paranoid a battery plant (and figure out some way to alert over D-STAR itself that the battery is online and site power is off... h... another side project...), etc. Nate WY0X
RE: [dstar_digital] Re: Limited access
Interesting viewpoint (BTW, why do you never identify who you are?) If you don't want anyone transiting your gateway, then it is really easy just to stop the services on the gateway, or block the inbound ports. But from the point of view of many of us and our Emergency Management Agencies, communications outside of the local area is a very important capability. No area is an island. Many events escalate to the point where cities ask counties ask states ask federal (pick one or more) for help. And once you ask for help from above, the folks in that remote EOC are going to want to know what is going on. Here in Atlanta, we are the home of the State EOC and the FEMA Region EOC. We recognize that there will be times where any county in the state or state in the region will want to talk to our area. But if you don't want anyone to talk to you, just stop the services or block the ports. Ed WA4YIH
Re: [dstar_digital] Re: Limited access
At 10:20 AM 6/27/2008, you wrote: As far as communications outside of the local area - we have HF rigs in our EOC and lots of local volunteers who are willing to show up with HF capabilities as needed. You might be surprised at how out of area communications can be used. The VoIP WX Net offers a few examples, which would also translate well into the D-STAR world as well. Firstly, need a 24x7 NCO schedule? Easy, outsource the role, train up some hams around the world. I am one such NCO, usually heard in the hours 2-8AM (US EDT) during hurricanes. Secondly, HF doesn't always go where you want it to. There may not be a path between the affected area and where information needs to go. This is quite common for hurricanes in the Carribean or Mexico. We have used (good old fashioned manual) HF relays from the affected area to an intermediate station who had propagation in their favour, as well as Echolink/IRLP. From there, it's direct to VoIP NCO and/or the NHC itself - Bingo! Another piece of traffic that wouldn't have otherwise been passed. The general feeling is that if the disaster is big enough to take down wide area public communications carriers we wouldn't count on the internet or any internet linked system - D-Star or otherwise - plus - there are sat phones for communications with FEMA. You might be surprised. Our experience is that the repeaters themselves are the most vulnerable during hurricanes, and by far the most common mode of failure is power failure at the site. Sites which have emergency power often remain on air (and on the Internet) during a hurricane. A suitably hardent D-STAR node is likely to be useful during an emergency as well. As significant parts of the US are already going D-STAR for SKYWARN nets, I will be keeping my Dongle on standby, to take traffic from those nets during hurricanes. It's just a matter of being prepared. As I said earlier, time will tell and D-Star as well as other amateur communications modes will keep evolving - the journey is where the fun is - I simply have pointed out that acceptance of the world-wide-routed D-Star model isn't universal. I'm sure there will be changes. However, D-STAR avoids the worst issues we have on FM/VoIP, namely misconfigured nodes and audio levels. There are no tails or CWIDs on D-STAR, and audio levels are much more consistent across the network. There goes 80% of our problems. The next 15% is those stations that just blast away with long CQ calls. The routed model of D-STAR does encourage this, because the routed model doesn't allow you to listen for traffic before hitting the PTT, and if you're lucky to get in between other traffic, you have no idea. A good Net Control can help here, of course. But then again, Net Control may not be operating from the system receiving the call. The routed design of D-STAR's traditional mode of operation leads to many uncertain states across the network and a lot of blind operating. It would be nice to be able to, for instance, turn off routing and still be able to link to reflectors for wide area nets. It's a new system and there's still teething issues we need to work on. :) 73 de VK3JED http://vkradio.com
RE: [dstar_digital] Re: Limited access
At 01:07 PM 6/27/2008, you wrote: Matt, Since its inception, the Internet has never gone down. There are places where access has been unavailable, but the Internet has never gone down. Except for the last mile, most Internet connections are highly redundant. In the middle of Katrina, in the middle of the biggest California Earthquakes, the Internet has been available. That's what I've seen as well. As I have said previously, the single biggest cause of VoIP links in the past has been lack of standby power at the site(s). D-STAR would be subject to the same issues. But that's not to say that the Internet will always be available at all locations. D-STAR is primarily another tool in the tool belt. At its best, it provides capabilities that haven't been readily available. If it loses the Internet connection, it can still act as a repeater, it can still send data, and it can still relay position reports. Exactly. I like to have as many tools as possible. Even HF can go down - I have had HF nets (80 metres after dark when the band should be good) where's we've had to QSY to VHF and UHF, because HF wouldn't go more than 10 miles due to unusual ionospheric conditions. Nothing is 100% reliable, but the more options we have, the better odds that at least one of them will work on the day. D-STAR doesn't replace any technologies, it only gives us a better opportunity to solve problems. Diversity is our strong card, and D-STAR enhances that. 73 de VK3JED http://vkradio.com
