Communication options

[cnynrat]

You don't understand. Your attempt at comparing the probabilties for failure at a precise point in time are absurd. You can attempt to calculate the reliability of differing communication devices, but you can't reconcile or correlate their failures to a precise point in time....or an emergency event.
The likelihood of failure occurring at a precise time of need is incalculable. This isn't zealotry...it's reason, and I'm sorry I had to take on this issue with you.

You are the one trying to compare probabilities for failure at a precise point in time, not me. That question which you keep asking isn't even the relevant question. There is no need to calculate the probability of failure at a precise point in time. It is sufficient for the purposes of this discussion to know that HF radios do fail from time to time, and that the probability of failure of an HF radio is higher at any given time compared to the probability of failure of the simpler and lower power PLB.

You came on and made this statement:

A HF radio can summon help 100% of the time from anywhere on this continent.

That statement is patently absurd, and I'm sorry I had to call you on it. Aside from the fact that HF radios do in fact have finite MTBFs and are therefore subject to failure, there are any number of other reasons, all quite reasonable scenarios, by which you could fail to summon help with an HF radio.

[ratkin]

Thanks for chiming in Bob. This thread has confused me more than anything. I think the next outing I may just hang out and ask you questions. And I was wondering about all this SAR stuff. Maybe that happens out west since all the remarks about SAR were from people on that side, but it doesn't happen here. In Lumpkin County we had a backpack on the ambulance and would have to walk the AT if there was a call there. Hopefully you didn't get the 300lb guy on the truck that day. The wilderness calls out here always went to the local authorites. *Maybe*, just maybe, someone might contact the Ranger Camp to see if they could assist but that would be it.

Jeff,
If you're out and about this weekend, for a full 24 hours from 2:00 PM Saturday to 2:00 PM Sunday, there will be folks out practicing using their radios outdoors on emergency power. All of these groups encourage folks to stop by and try things out or just ask questions. Kids really have fun, once they get over being nervous talking into a microphone. You can check this website to find one closest to where you'll be. If you happen to be down kicking around 4 Wheel Parts in Norcross, I'll be at this location with my kids until around 5-5:30 PM Saturday. This one is a joint set-up between a club and Gwinnett ARES, which is probably the type of ham radio operation that you would be most interested in.

Hope this helps!

- Richard

[DreamingOfExpeditions]

Sorry dude, you clearly don't understand MTBF, or probability.

I'm afraid that the MTBF argument is tenuous at best. Most devices are measured in years, and given use and set up the REALITY is that they have 100% up time. You can always find an outlier, but you did say MEAN.

If I have my rig and put a HF rig with a meantime to failure of 10 years, chances are I'll replace the rig within that failure band, and so many good engineers like yourself designed that into the unit. Marketing and sales know exactly what the turnover of these units are and can engineer a product accordingly. Reality is its the heat sync we are talking about. It's always about heat. A quick search of the used market shows any number of units available in the 5 year old range. So that's insight into that failure rate. The PLB data I saw has a recommended replacement of 10 years (the makers recommendation) so that'll tell you what they think it is.

Calculating is easy. Engineers always have big calculators and fancy equations. But what does it matter if I tell you your 5 times my likely to get cancer with exposure to x material when the reality is 5 x .0000001 is still next to nothing.

I'd love to see your real data even on an analogous device. I know statistics quite well and think that would prove or disprove your point rather clearly.

[cnynrat]

I'm afraid that the MTBF argument is tenuous at best. Most devices are measured in years, and given use and set up the REALITY is that they have 100% up time. You can always find an outlier, but you did say MEAN.

No device built by man has 100% up time. None. Not in theory, or in reality.

Do modern electronics have very good reliability performance? Yes, in general they do. However, there are exceptions. Just to use one example, peruse the reviews of certain ICOM models on eham.com and it's not difficult to find people with complaints of early failures. Someone might say, well I don't own an ICOM model XYZ, but the problem is you sometimes don't find out about these product weaknesses until after you've made your purchase.

We characterize failure probabilities in terms of Mean Time Between Failures. Failures will typically occur in an approximately normal distribution about the mean. So, as a first order approximation a device with a lower MTBF has a higher probability of failure at any time during it's lifetime compared to a device with a lower MTBF.

I don't think I've suggested that anyone should stay away from HF ham radio as an emergency communications tool. You are correct that the reliability of most of these products is quite good, and shouldn't be a concern. I simply think it's incorrect to assert that any emergency communication tool has a 100% probability of success. There are way too many variables that can get in the way of that, only one of which is the failure of the electronics itself.

I also agree we're talking about a very fine point here. The difference between 100% and 99.99% may seem small, but among other things, the acceptance of that reality might lead one to take steps to be better prepared to deal with any emergencies on a self sufficient basis rather than assuming that they are absolutely guaranteed to be able to call for help.

[taugust]

Keep in mind again, I have worked for years for this agency, I have the OK from Chief to access the channels they operate on if I happen upon an accident again, and I have the skills to help. If I accessed the channels for emergency traffic from an accident whould the FCC come after my license or would the Chief have to make a complaint? The last wreck I was on I started two helicopters and flew them out...and the on-duty guys were happy I made the decision and had them en-route. And this is something that may never even happen again, I am just wanting to confirm before I get one. I have already decided to get an InReach device too for anything other than life or death.

In this one county I have pulled a guy from a burning car...getting burned myself, made the decision to fly six different people out and followed through with it, accessed one patient via a rope system, and tended to about 10 critical patients from motorcycle accidents, all in about six years and OFF DUTY. I know these guys and they jokingly tell me to stay off the road because I am an obvious **** magnet. If I have a peice of equipment that can relay vital information to people that can make a difference I would think its the right thing to do. Are you saying if I did the FCC would pull a license?

Jeff,

From the reading I have done, if you contacted your own agency, the FCC probably would never know about it. If you contacted, say, the sheriff dept., they would not know who you are, and may register a complaint with the FCC. While the rules state that you can make an emergency call using any means available, licensed or not, you could still be subject to losing your license after the fact if some bureaucrat decides you should. In order to do what you want to do, you would have to modify the radio, and they could get you for that.

My suggestion would be to check out one of your agency handheld radios when going out, and making the call on that. Or get a surplus public service radio and mount in you vehicle. Then you would be completely legal, ham radio or not.

For the record, I am a ham radio enthusiast as well. I have made an emergency call when cell service was not available. I wrote about that incident here: http://www.expeditionportal.com/foru...-an-Emergency?

[Karma]

HI All,
I'm no expert on making MTBF (Mean Time Between Failure) calculations. But I have participated in these studies as a Subject Matter Expert representing the electronics design and components used in the design (I was the designer). There are many elements involved in MTBF studies. The most important and significant issue is the raw parts count. IOW, the more parts, the more likely a failure. Additionally, every part that is involved in the design have their own MTBF anylysis. So the final calculation takes into consideration the number of parts, the MTBF's of the individual parts, and finally the assembled system MTBF which considers the method of assembly (shock and vibration resistance, temperature resistance, circuit board techniques, soldering and attachment methods, etc.). Then, a suite of tests are performed to verify the MTBF studies. Usually the MTBF studies are pretty accurate. The tests use accelerated stress test methods so the time frame of the test processes is not beyond reason. The accelerated test methods are well characterized and widely used in space and military applications. Once the basic reliability of the item is established, the design proceeds into production and the test suits are simplified since the design has been qualified during the design phase. Consumer electronics are hardly ever tested in this way. I would say never but I'm not sufficiently familiar with all of the companies and their engineering goals to make such a statement.

A given electronics system can be designed with high reliability in mind or no reliability considerations at all. Both methods show up on the market. However, the systems that are designed with high reliability as a design goal are always more expensive because they are more expensive to design, build and more expensive to test. This is the reason that MIL spec products are considered the most desirable but tend to be expensive.

Ham products have no formal quality control requirements other than the ones imposed by the manufacturers themselves. Just what these are is unknown to me. Generally, the only way to have a clue is the cost of the product. This actually makes sense in a profit driven market. There is no advantage to building a more expensive product unless the customer gets something for the added expense. Reliability is one of those items that some people are willing to pay for. This answers the old saying that states that you get what you pay for.

PLB's have formalized reliability requirements the manufacturers must answer to. These have been defined by the federal government. MTBF analysis and testing is driven by rules, results and documentation. Ham radio, have none that I know of. This difference tips the reliability balance towards the PLB's. Remember, reliability is a statistical function. It reports the Probability of a failure not the actual failure itself. It's one of the reasons that PLB's have always been more expensive than competing, non-ham and ham, systems which have no formal reliability requirements.

So, PLB hardware should be theoretically (and practically too) more robust than others. For me, this is reason enough to go the PLB route. However, this is not enough if the human systems are deficient. But, the PLB system includes methods to ensure the human systems work and work every time. The main reason the PLB scheme is so reliable is that it is basically simple. KISS applies here as long as it is sufficient to get the job done. This can only be determined over time. Time and many successful results have shown emphatically that the PLB human systems work, every time. Competing methods have not shown this level of reliability. Until they do, PLB's remain the best method for emergency response.

Sparky

[11b4v]

Coming in late to the conversation, and I may repeat what others may have already said, so bear with me.

I got into ham specifically for having backwoods commo.

Speaking from personal experience, and I have wheeled just about every FS road in N. Ga., I have never had a problem hitting somebody's 2m repeater no matter where Im at. You are almost guaranteed to be able to hit either the Jasper Ga. club machine or the Sawnee Mtn/Cumming Ga. machine(ham slang for repeater) from just about everywhere in N. Ga. I have a favorite spot in Rabun county and have hit a repeater in Fayette County once under some unusual, 'ducting' conditions.

One good thing about the Ham community that Ive learned and enjoyed is that if you're friends with a group of hams you regularly speak with locally, say your "drive time commute folks" and you put the word out you're heading to the mountains for the week/weekend, most will monitor for you, and basically act as your personal base station for any possible, emergency.

Ive got a friend, fellow ham, who lives in Kennesaw, and will monitor for me 24hrs, when Im solo in N Ga. Many a time he has relayed "Im OK doing fine" messages to the wife back home when there is no cell signal.

As an aside, you can hike out of anyplace your wheeling in N Ga and be on a paved road in little time. Get the Tech license, super easy. A 50 plus watt mobile rig such as Yaesu and Icom, with a good antenna, can be had for less than $200.00

[Mtn Mike]

I'm new to the conversation too but will throw in some comments. This is my vote for becoming a ham operator and learning more about communication. Ham radio is primarily a hobby and hams are in it because they enjoy the study of communications. One of the advantages to being a ham is that you learn principles that apply to ALL forms of radio communication; commercial radio, ham, CB, GMRS, cell, satellite, whatever. They all use radio waves. A theme of this thread has been that communications are a complex science. No form of communication is fool proof, and all have failure potential. Your best chance of "getting out" in an emergency is to learn the science and practice behind various systems. Going out and purchasing $1000 in equipment does not guarantee you'll get help. Purchasing a satellite phone and a monthly plan, or a SPOT does not guarantee you'll get help. You need to know what communication systems will work best for your particular situation and why. Ham radio also involves experimenting by trial and error in NON-EMERGENCY situations so that you'll be prepared to communicate when it really counts. That's what it's all about.

I got into ham radio because I spend a fair amount of time out of the cell-phone grid. I can hit 2M repeaters from anywhere in Eastern-Central Washington. Whether or not someone is monitoring those repeaters is a different story. So it helps to have multiple repeaters programs for a specific area and then know which ones are the most active. 2 Meter simplex is also really good. In this area there are always people monitoring the 146.52 national calling frequency. I haven't gotten into HF yet but it's on my list of things to do

73

Mike
KF7EHT

[Mashurst]

Mike I think you're right on about understanding how a variety of systems work. It's all radio.
I question the following:

I can hit 2M repeaters from anywhere in Eastern-Central Washington.

Without any personal experience operating in the area I don't know for sure but I imagine there are 'holes' and damned ol' Murphy will be sure you are in one when you find yourself in real trouble. I know eastern WA is kinda flat but I'd be willing to bet there are some good sized holes and I bet those holes are in neat places to visit, like river gorges and such. To me this is the realm of the PLB. They dominate when UP is the only way to get a signal out.
I love my 2m as much as the next ham. The risk is to become over confident in them. On a resent hike up Lundy Lake canyon near Mono lake I was a bit surprised that there was very little repeater coverage in the area and none up the canyon. I also tried a few calls on 146.52 with no result. A course, folks may chime in if it was emergency traffic that would sit out a simple friendly QSO.
Anyway you are right on...

[Mtn Mike]

Mike I think you're right on about understanding how a variety of systems work. It's all radio.
I question the following:

Without any personal experience operating in the area I don't know for sure but I imagine there are 'holes' and damned ol' Murphy will be sure you are in one when you find yourself in real trouble. I know eastern WA is kinda flat but I'd be willing to bet there are some good sized holes and I bet those holes are in neat places to visit, like river gorges and such. To me this is the realm of the PLB. They dominate when UP is the only way to get a signal out.
I love my 2m as much as the next ham. The risk is to become over confident in them. On a resent hike up Lundy Lake canyon near Mono lake I was a bit surprised that there was very little repeater coverage in the area and none up the canyon. I also tried a few calls on 146.52 with no result. A course, folks may chime in if it was emergency traffic that would sit out a simple friendly QSO.
Anyway you are right on...

Yeah I'm sure you're right. There are probably plenty of isolated valleys or canyons with no 2M coverage. What's more is that if one is out of a vehicle, they probably only have a 5 watt hand held radio, which is very limited. In those cases Sat is your best bet. I wasn't trying to say the 2M is the be all and end all of communications. The point I was trying to make is that learning about how communication works is just as important as the band and system you use. And ham radio is a good way to learn and experiment.