Communication options

[the_g_man]

My apologies, in advance, for not reading every reply prior to posting mine. As far as amateur radio being merely a "high power CB," that is much like saying that an automobile is a high power go-cart. The options made available by moving up to amateur radio are way too countless to get into here. CB is pretty much demoted to a) truckers b) trail rides and c) "hobbyists" who are just "into" cb. For these apps, it's great. For serious communications, when "it counts," not so much. For making emergency phone calls and contacts, you have autopatch (no, it's not difficult or mysterious... usually just an input code) and the MULTITUDES of HAMs who are monitoring your local frequencies, pretty much all the time. There are many places I frequent that have NO cell signal but it's nearly impossible to be out of reach to an amateur repeater. For a small investment in money and study time, it's probably your best option. Good luck!

[xtatik]

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

Basically, PLB circuitry is no more robust than found in any of a number of consumer and commercial products. The federally "adopted" standards are only in place to ensure that quality doesn't drift below a mean level. They do not ensure a build quality above that which is already commercially available in many other electronic devices. Usually the components are surface and/or through mounted to boards using either wave or reflow soldering methods ..usually the latter. There can be different specs given for weight (thickness) and composition of the boards, but it's unlikely given the relatively inexpensive price of theses PLB units. By simply looking at them and holding them in my hand, I can tell you they are of less substantial build than any other radio equipment I own. This is very obvious, and I would also say there is a huge disparity in the apparent build quality between the marine EPIRB I own and the small handheld PLB .

Basically, most handheld amateur radio equipment will be built to newer commercial standards.......same-same with modern MilSpec circuitry. Most commercial and amateur handhelds will be built by mounting the circuitry inside a die-cast aluminum/zinc chassis that gets surrounded in high impact plastics. Most of the larger radio manufacturers are in the business of manufacturing amateur, amateur marine, commercial marine, and land commercial units and will do so with the same assembly methods, machinery and personnel. It doesn't make financial sense to do so any other way.

http://en.wikipedia.org/wiki/Wave_soldering
http://en.wikipedia.org/wiki/Reflow_soldering

In all likelihood, it's done with the same brand of machinery.
http://www.ersa.com/reflow-soldering-en.html

Now, taking it a step further.....what amounts to "MilSpec" has undergone significant change since the mid 90's with the introduction of COTS (Commercial Off The Shelf) principles and mandates that govern military electronics contracts.
Essentially, in the world of electronics...all things are melding into one...and this has been happening for at least two decades. The inefficiencies presented by having differing grade components and assembly methods are being done away with. Actually, it's been going on in electronics for even longer. I've got NOS JAN (Joint Army Navy) 6L6WGC tubes mfr'd by Phillips that were used in 50's and early 60's era military cockpits. I use them in the guitar amps I've built. But, these "MilSpec" tubes were no different than the ones my Dad was putting in our TV sets back then. I'm sure Phillips billed the Navy at a higher price than what my dad paid.
http://en.wikipedia.org/wiki/Commercial_off-the-shelf
http://www.militaryaerospace.com/new...2012-2022.html
http://www2.l-3com.com/tw/index.htm Search "COTS" or "COTS Initiative" on this site. This is one of the largest military electronics systems contractors.

PLB's are a very worthy addition to the kit, but are more limited in overall utility (to the overlander...er, whatever). They are a last ditch device to be used only in situations where there is risk of great physical harm or death and/or when other communication means have been attempted/exhausted without success. For most emergencies (non-life threatening), other communication devices should be used first.