Nonbovine Ruminations

Weather radios

2009-07-18T23:55:00.003-05:00

A friend recently sent a link to this desktop weather alert radio, which is manufactured by a company called Reecom. Reading through the manual, it has a few features that make it slightly nicer than the Midland WR-300 I'm using now, the most significant of which to me are the ability for it to turn off at the end of the alert message (the Midland continues to babble at you until you walk over and whack the 'silence' button, which is somewhat annoying) and the ability to select different audible alerts for different messages. I'm not immediately in the market for another weather radio (for no other reason than that my virtually nonexistent income at the moment doesn't support nondiscretionary spending), but this looks like it might be a good additional radio (I've wanted a second one so that the alerts can be heard through the entire house instead of just in the back, which is the effect with the current radio in its current location).

We originally got this radio because we realized that we cannot hear the alert sirens inside the house, and given that we rarely listen to broadcast radio and watch nearly all of our television via TiVo did not have any means to receive weather alerts in real time. I'd rather not find out about a tornado when it rips the roof off the house.

I'm also interested in options that will capture the message off the air and make it available to a computer. The Reecom radio (and the WR-300) can be used to detect that an alert is active, but without hacking the radio I don't know how to get the details of the alert (e.g. type of alert, duration, affected areas) into the computer. I could, of course, obtain this information from the NWS's website, but that's not much help if the network is down. I assume that there's a specification somewhere for decoding the EAS data bursts, and that someone has written code for this. Just haven't found it yet. Not to mention it'd be nice if I didn't have to dedicate a whole soundcard to that (that is, a hardware solution would be much nicer than a software one).

How Do Ten Meter Repeaters Work

2009-07-14T06:51:00.002-05:00

Here's another topic discovered from search engine referrals. I'm unclear whether the searcher is looking for information on how repeaters of any sort work, or the specific differences between ten meter repeaters and other types of repeater, so I'll cover both topics.

Just about anyone who's been involved in amateur radio for any time at all will have encountered a repeater, and for many hams (especially those in the US with Technician licenses) repeater operations are the majority of their activity, so it's probably safe to say that repeaters are at least somewhat important to hams. (They're also important to other radio services, but I won't get in to that in this article.) Fundamentally, a repeater is an automatically controlled station that receives a signal and immediately retransmits that same signal back out. The idea behind this is to enable two stations, each of which has relatively limited power, and more significantly, relatively limited antenna systems, to communicate with one another by way of the repeater station, which will typically have more power and, more importantly, a much better antenna system (where "better" in this situation means "installed at greater altitude").

As an example, a typical VHF mobile installation will have an antenna with center of radiation at perhaps six or eight feet above ground level and a power level of perhaps 50 watts. Two stations thus equipped will be able to communicate directly with one another at a range of about ten miles in relatively flat terrain. However, if the repeater is equipped with a 100 watt transmitter and an antenna installed at 200 feet above ground, it should be in range to mobile stations equipped as above within about 25 miles. Furthermore, any two mobile stations within this range will be able to communicate with one another via the repeater. This represents about a six-fold increase in the ability to communicate.

So how does the repeater accomplish this? Fundamentally, a repeater is a receiver connected to a transmitter, combined with various control circuits (e.g. to prevent the repeater from transmitting when there's nothing to transmit, and for other purposes, some obligatory, others not). Now, one of the things that confused me when I first heard about repeaters back in the early 90s is how the repeater could receive a signal and transmit it back out on the same frequency without interfering with itself. The simple answer to this is that repeater don't do this: virtually all repeaters receive on a different frequency than they transmit. (There are some "repeaters" that operate "simplex" by delaying the transmission until the receiver message is complete, but that's technically not a repeater; the definition of a repeater requires simultaneous retransmission. And there are other repeaters that do operate on the same frequency in and out by using separate antennas at well-separated locations; we'll come back to that later.) Because the receive frequency is different from the transmit frequency, the transmitter doesn't interfere with the receiver and both function can proceed simultaneously. The difference between the receive frequency (or "input") and the transmit frequency or ("output") is called the "offset". There are customary offsets for most repeater operations, which vary by region (for various reason). In the United States, the customary offset for two meters is 600 kHz, and for ten meters it typically 100 kHz.

And here's another aspect of repeaters I failed to get at first: most repeaters use the same antenna for both receive and transmit. Of course, this raises another question: how do you put a 100 watt signal onto an antenna to be sent out, and at the same time pull in a signal measuring often in the nanowatts without the receiver being overwhelmed by the transmitter's raw power even if it is on a (somewhat) different frequency? That was another one I didn't really get until I started studying for my Extra. The answer is, of course, filtering, and the two main techniques for doing this are the duplexer and the circulator.

A duplexer is a set of filters that are designed to pass signals on one frequency with very little loss, while at the same time rejecting signals on another (often nearby) frequency with very high attenuation. In the repeater case, you want a filter on the receiver side that passes the input frequency with as little loss as possible, and attenuates the output frequency as much as possible, while on the transmit side you want the exact opposite. Because of the very tight tolerances required (only 600 kilohertz separation for two meters), these filters have to be very tight, too tight to be built out of ordinary discrete components like capacitors and inductors, so for virtually all repeaters these are resonant cavity filters. Resonant cavities provide much tighter pass bands and reject bands than any discrete circuit could. Even so, two, three, or even four filter pairs are typically required to provide sufficient isolation.

The other component that is useful in providing this isolation is a little piece of electronic voodoo called a circulator. A circulator is a device, typically constructed out of ferrite disks, with three ports that allows a signal to pass from port 1 to port 2, from port 2 to port 3, and from port 3 to port 1, but not in any of the reverse directions. To be honest I still don't fully understand how they work; it has something to do with the signals setting up a rotating magnetic field in the ferrite disks that cancels the reverse signals; at this point I'm happy to call them "electronic voodoo" and leave it at that. In any case, connecting the transmitter's output to port 1, the antenna to port 2, and the receiver's input to port 3 will also provide a significant chunk of the signal isolation required to protect the receiver from the transmitter. Many stations use some combination of duplexing filters and circulators to achieve the required isolation (which is a mininum of at least 60 decibels, more if possible) between transmit and receive.

This is really the hard part of the repeater from an RF standpoint. The rest of the repeater is just a more or less ordinary receiver tuned to the receive frequency, a more or less ordinary transmitter tuned to the transmit frequency, a little bit of audio-frequency circuitry to ensure that the transmitted signal is well-balanced, and some control circuitry to do things like transmit the station's callsign periodically, and turn the transmitter on and off as required. Of course, nearly endless features can be added to a repeater, but these are ancillary functions, not the core of the repeater functionality.

Now, on to the more specific question of ten meter repeaters. One of the characteristics of resonant filters is that one of the factors that determines their size is the wavelength of the pass frequency (the other, of course, is the filter sharpness, or Q, required). This is why two meter "cans" (as they're called, as they really do look like cans) are typically about the size of two paint cans stacked on top of one another, while cans for 70 centimeters are much smaller, about the size of a can of spray paint. This is because 70 cm is a third the wavelength of 2 meters, and in addition the customary offset in 70 cm is 5 megahertz, instead of the much smaller 600 kilohertz used in 2 meters. As a result, 70 cm machines (hams often refer to repeaters as "machines") can use physically much smaller cans. For ten meters, this goes the other way: ten meters has five times the wavelength of two meters, and the customary offset of only 100 kHz is even more demanding than the 600 kHz of two meters. A set of cans for ten meters capable of providing a reasonable degree of isolation would be at least the size of hot water heater tanks. If you read the article I linked above you'll note that the designer of those filters silver-plated the interior of the cavity filters to minimize loss; the cost of silver-plating that much surface would be quite substantial. Also, the very narrow offset would necessitate very finicky tuning.

Mainly because of this, it's more practical for 10 meter repeaters to use "diversity antennas" instead of filtering to achieve the necessary isolation. Separating the antennas by a mile or so will achieve as much signal isolation as would even the best possible filtering arrangement. In this approach, the receiver and the transmitter are at different locations, and the audio received at the receiver is conveyed to the transmitter's location either by a landline link (a physical hardline cable, a dedicated telephone circuit, or some other non-radio connection including possibly a VoIP circuit), or alternatively by transmitting the audio via a radio link operating in some other band. Typically these links are in the 70cm band and use very directional antennas that are carefully aimed at one another. (The same approach is use for multi-input repeater systems, but that's beyond the scope of this article.)

This same approach can be used in any band, but using diversity receive in any band other than ten meters (and perhaps six meters, where it is also occasionally seen) creates the problem that the coverage area where the repeater can be heard (which is based on transmitter location) may not correspond well to the area where the repeater can hear remote stations (which is based on receiver location). This is less of a problem for ten meters because ten meters has much broader propagation, due to skywave propagation modes including near-vertical incidence skywave (NVIS), and so the nonoverlap areas are likely to be smaller.

The "Syfy" Channel

2009-07-13T23:35:00.003-05:00

So, this past week the Sci Fi Channel recently changed its name to the just atrociously misspelled name of "Syfy" Channel. The ostensible reason? Apparently there's this nagging feeling at NBC Universal (who owns the Sci Fi Channel) that the name "Sci Fi" is holding them back, because that term is associated with nerds in basements and such not. The alternate spelling of "Syfy" is supposed to be more appealing to women.

Well, ok, whatever. They sound the same and for most people that's going to evoke the same feeling. Won't affect my tendency to watch their channel: I have almost no idea what channel anything in particular is on because I have been a TiVo user now for almost ten years. I just tell my TiVo what to record and it finds it and records it whatever channel it's on. (Besides, I watch maybe three hours of TV a week these days.)

That said, I miss the old Sci Fi channel, in the days before the new Battlestar Galactica (which I detest). They used to have much more science-fictiony content, but lately've they've definitely moved much closer to the mainstream perception of "sci-fi", such as the new BG. Frankly "Lost" is more science-fictiony than BG. So while I do occasionally watch some of their content, it's not often, and I don't seek it out.

Still, the real reason they changed their name? Branding. You can't trademark "sci fi" as a universal mark; it's a common phrase and trademark protection in common phrases is always limited in scope. But "Syfy" isn't a common phrase or term, and so the trademark they can get for that is exclusive; this gives them a much more powerful trademark and much broader branding opportunities. (This is why so many products have deliberately misspelled names.) That, dear friends, is the real reason for the name change.

The Philadelphia Experiment

2009-07-11T13:11:00.002-05:00

This is one of the odder things I've seen pop up on the Google Hot Searches list. The "Philadelphia Experiment" refers to supposed research done by the United States Navy in World War Two into the teleportation of warships, and more specifically the USS Eldridge, which, according to legend, was teleported from Philadelphia to Norfolk sometime during 1943. This apparently comes up often enough that the Naval Historical Center has a FAQ sheet on it.

Of course, conspiracy-minded individuals (of which I'm sure I have a few in my regular readership) will be inclined to find obvious proof in the Navy's denial of involvement. Can you imagine, though, being assigned to the Naval Historical Center and being given the assignment to research the records to provide proof that the Navy has never attempted to teleport a 1240 ton destroyer over 200 miles away by purportedly eldritch means? I wonder how many times the requesting officer had to explain to whoever he ordered to do this research just what it was he wanted.

(It also amuses me that the ship's name is so close to "eldritch", which any reader of Terry Pratchett will know actually means "oblong".)

The supposed incident was memorialized (if such is possible regarding an event which never occured) into an eponymous movie, which I have never seen (and not even heard of before yesterday). Apparently the movie and the underlying hoax are recurring elements in government conspiracy theories, especially those popular with ufologists.

Just had to share this, being one of the stranger things I've read about lately.

Change we don't quite know what to make of

2009-07-08T15:12:00.003-05:00

So the big question on everyone's mind right now (now that we're done with the Michael Jackson funeral, which occupied way too much of our collective attention, thank you very much) seems to be "Why did Sarah Palin resign as governor of Alaska?" It's not like she got caught having sex with a hot Argentinian (e.g. Sanford), or just generally being a prick (e.g. Blagojevich). Yeah, Palin's commitment to ethics does seem to have been a bit soft, but she's in a group of people that includes Rod Blagojevich, and in that company just about anything seems reasonable.

The title of this blog post was the caption of a political cartoon I saw today by Chip Bok. It really captured my bestartlement at hearing that she had resigned, and the complete lack of understanding that can be gleaned from her subsequent statements.

On a related note, Language Log has an interesting article today on the odd use of "I know that I know that I know" (or similar formations) that occurs in recent speeches by both Mark Sanford and Sarah Palin. Apparently this is yet another example of linguistic divergence within the American evangelical community; see also "dogwhistling", a common practice for Bush's speechwriters when he was President. To me it is somewhat scary that, to a large fraction of our country, ordinary sequences of words have special, nonobvious meanings. We risk becoming a country divided by a common language.

The Voice/Data Divide

2009-06-29T19:09:00.003-05:00

There's a discussion over on K3NG's blog over the legality of D*STAR, given that D*STAR uses AMBE, a proprietary vocoder the details of which are not publicly known. K3NG raised, reasonably, the FCC's prohibition (in §97.309) on the use of data encoding methods which are not publicly documented. I've previously mentioned this here in this blog, discussing APCO-25, which uses AMBE's sister protocol IMBE. The reason why §309 doesn't apply is that D*STAR transmissions (at least those using AMBE) are regulated as voice, not data, and §309 applies only to data transmissions. There is nothing anywhere in Part 97 that regulates what encodings we can use for voice transmissions; the only limitations presented to us by the FCC relate to bandwidth.

The FCC and Congress (and for that matter, the ITU) persist in maintaining an artificial divide between the voice and data regulatory regimes that has not been logically sustainable since digitization of voice became widespread in the late 1990s. Perhaps the best expression of this inanity is Rep. Ed Markey's proposed amendment to the Freedom and Broadband Deployment Act of 2001 (the Tauzin-Dingell Bill):

The term 'high speed data service' includes any telecommunications service delivering data, represented by a string of binary bits transmitted digitally as a series of zeroes and ones, but such data services do not include, under any circumstances, bits representing voice communications, even though such voice services are also expressed digitally as a series of zeros and ones, data services being digital bits of special importance. Someone, preferably a senior corporate employee with years of experience in analyzing zeroes and ones, shall posses authority to determine which bits are which as they zip through a network literally at light speed. All decisions of such employee may be challenged and brought to the attention of government officials, but only after a wee bit, and only bit by bit.

Rep. Markey's proposal was, sadly, ruled out of order by the committee chair. This amendment (which was clearly offered for comic value) underscores the fact that, at least in 2001, while telecommunication providers could not meaningfully distinguish between digitized voice data and other forms of data passing through their network, Congress (and therefore also the FCC) continued to operate under the assumption that they could. (For more on the Tauzin-Dingell bill, see this interesting article from llrx.com.)

Sadly, neither Congress nor the FCC appears to have learned anything in this regard since 2001; even as the FCC (and also Homeland Security) pushes commercial and public safety licensees into digital voice, the FCC continues to be burdened by an obsolete voice/data regulatory dichotomy. To be fair, much of this is forced on them by Congress, and even to some degree by the ITU (emission designators, which drive the regulatory picture at a very deep level, are based only on the superficial RF modulation technique and the ultimate payload, without regard to any intermediate encoding).

As to D*STAR itself, and its reliance on AMBE, I'll simply repeat what I said back in October: "We need to encourage the development of open digital voice standards, not make excuses for perpetuating existing closed ones just because they already exist."

Field Day 2009

2009-06-29T10:27:00.003-05:00

This weekend was my first Field Day, at least the first that I went to (I got my license in April 2008, but I didn't have any connections with any group, nor any radios of my own save a simple HT, in June of 2008 so I didn't participate in the event then). I must admit that I had a great time and look forward to doing it next year.

I had originally planned to mainly be a support person at this year's event, helping with setup, food, and so forth over the course of the event. At the last planning meeting I volunteered to co-captain the GOTA station this year (since my license is barely a year old I'm a good candidate for that) but my co-captain came down ill, leaving us with no station to operate. So I was back to helping with antenna lifts and such. No big deal.

I should mention that the club I worked Field Day with is the Du Page Amateur Radio Club, W9DUP, in northeastern Illinois. We ran 7A this year out of our usual site, the Hawthorne Hill Woods, a relatively undeveloped property owned by the Woodridge Park District. Running 7 stations means there's a lot of antennas to go up.

I reported to the site a little after 6pm Friday and helped with the first erection of the minibeam that one of the CW stations was going to use. Getting that up took most of the available daylight that evening. We took two shots at putting up the 40m/15m dipole for the other CW station but couldn't get a good position in the trees before it got too dark. That would have to wait until morning. I went home around 9pm and went to bed.

Saturday morning I headed back into the site arriving just before 9am. By this time it had been determined that we needed to take down the minibeam because there was a configuration problem with it and it wasn't tuning up. I missed the takedown, though. Most of my time that morning was spent helping get the previously mentioned 40m/15m dipole, the 80m dipole for the first CW station, and the G7 longwire that the digital station would be using up. One of our members has an air launcher that works really well and we got very good placements for all these antennas.

We got the last of these up around 12 noon, giving me just enough time to grab something to eat. After that I went over to the digital (PSK) tent because this was the mode I was most interested in anyway, and watched Bob KA9BHD try to work digital for about an hour, without a lot of luck; band conditions weren't very good, and there was just too much traffic to have much luck at working anything. I wandered around for a while, helping out with little things here and there, and ended up at at the 75m SSB table where I logged for a half hour or so for Pat K9PPP and then operated for a half hour or so before we decided that the impending storms to the west were generating too much QRN to make many more contacts and took a break. I went back after a bit and managed to work a couple more stations but the storm-related QRN was continuing to build. I wanted to go back home for a bit anyway, so I left the site again around 5:30 to go home for a few hours.

I returned to the site around 9pm just as the rain from the storm system that mercifully passed mostly south of us hit in earnest. After putting a couple of tarps over the digital tent to keep water out and deciding that the dangerous part of the storms were past, we decided to bring the PSK station back up. Marianne KC9JLK worked the station for about an hour making some contacts, then I took over around 10pm and worked it until midnight with Bryan KC9GRH logging for me until he went to bed around midnight. Activity was poor to moderate until around 11:30, then it finally started to take off.

I had not planned on working the station all night, but shortly after Bryan went to bed the bands really started to pick up. We had three antennas configured for this station, a longwire dipole that Marty got way far up in the trees for us that would tune on just about anything that I was using, which was mainly 80m, 40m, and 20m (I also tried 15m and 10m but didn't find anything to work), plus a pair of horizontal dipoles on a mast, one tuned for 40m and the other for 20m. The longwire was by far the best of the three, but it was much more suspectible to QRM from the CW operators, especially on 40m when they would turn their beam to point at my antenna and swamp me with S9+80 dB QRM.

Anyway, between midnight and about 5am I managed to work about 50 stations across all three bands, logging my own QSOs as I went and switching from band to band as the CW QRM got to be too bad or when I'd worked out the selection of who there was to work on any particular band. I took a short nap around 5am, at the operating position, then woke up in time for East Coast sunrise, which heralded a great opening on 20m and another 30 contacts over the next 90 minutes along the east coast. At 8am, when I finally broke for breakfast, we had logged 102 contacts, two over our 24-hour goal of 100. I did go back after breakfast and worked one more contact, then decided that if I didn't go home then I'd be too tired to drive safely at the end of the day, packed up and went home.

If you worked W9DUP on PSK during Field Day, the chances are good that you worked me. I had a great deal of fun, and you can bet that I'll be doing this again next year. About the only thing I think we need to do is work something out between digital and CW stations so we don't interfere with each other as much. And maybe add a second digital station.

Not dead yet!

2009-06-24T20:18:00.003-05:00

I know, I haven't posted in a while. I've been otherwise occupied, by a whole host of other things:

I've returned to working on my rewrite of MediaWiki into Java. The work is progressing much better this time. I've discovered some really glaring bugs, too, although probably most of them are uncommon code paths and so don't often affect anything. Unfortunately, the way I'm using phc as part of the translation process strips comments and destroys line number relationships, so it's difficult for me to back-relate the logic errors to the original PHP.
Sims 3 has occupied some not insignificant part of my time lately. I'm not going to comment a lot here about the Sims; suffice it to say that I think this release is an interesting addition to the franchise with enough difference from Sims 2 (which I also enjoyed) to seriously capture my interest.
It's the warm season again, and that means it's time for household projects of all stripes.

I just haven't had a lot to say here, and so I haven't said much.

See you all at Field Day.

TLS blackhole?

2009-05-28T20:23:00.003-05:00

So today I was called by one of my clients to assist with a problem they were having accessing a secured website operated by a major business data processing company (you know, those big companies that do payroll, that sort of thing). One of their accountants reported that he could access the site from home, but not from the office, and the behavior suggested to them that the issue was a firewall issue of some sort, and since I do their firewall consulting they called me.

Now, I strongly doubted that it was a firewall issue, but the facts did fit that pattern (as they had tested accessing the site from a laptop on the outside of the firewall and that worked), so I made a trip to the client site to investigate further.

Investigation determined that the laptop in question actually worked from inside the firewall as well as outside, which flatly ruled out firewall issues. I noted that the laptop was not in the domain while the computers being used to test were inside, and suggested that we remove one of the nonfunctioning computers from the domain. This did not help, and we pursued other options. I also noted that the functioning machine was running IE6, while the nonfunctioning one was running IE7. (The complaining user states that he was using the same computer at home as at work, a traveling laptop, but I believe he misrepresented that fact to us and was actually using a different home computer, which caused me to waste considerable time investigating whether there was a domain authentication issue going on). Further investigation showed that the site could be accessed with Firefox, Opera, and IE6, but not with IE7, Google's Chrome, or Apple's Safari. (No machine with IE8 was available.) After using Process Monitor (which is a most excellent tool, although it does generate great gobs of output that takes some effort to sort through) to understand what was causing the hang. This having led to the determination that the web server not responding for some reason, I decided to sniff packets using Wireshark, freshly installed on the laptop. The network traces for sessions using IE6, Firefox, and Chrome were quite illuminating.

The site in question was hanging when being presented with an https session using TLS 1.0. TLS 1.0 is enabled by default and used preferentially by IE 7, Chrome, and Safari, but is not enabled by default in IE 6. Since the remote server's response to an attempt to negotiate a TLS 1.0 session is to hang (it sends a TCP ack to the TLS "hello" packet, but no further traffic), these browsers will wait indefinitely on the stuck connection. Firefox (and apparently also Opera) apparently have programmers who have run into sites like this and have coded defensively around them: Firefox also tries to use TLS 1.0, but when the TLS session times out, it retries the session with SSL 2.0/3.0, which the web server was happy to accept. IE 6, on the other hand, works merely because TLS 1.0 isn't enabled by default in this browser.

The "solution" for my client was to disable TLS 1.0 on the affected user's computer; not ideal, but it works. It would be nice if Microsoft made IE smarter (like Firefox), or if they gave me a way to disable TLS 1.0 only for this site; or if the Large Data Processing Company would just fix their server....

Dayton approaches

2009-05-12T09:34:00.002-05:00

It's time again for the Dayton Hamvention; once again, I will not be going. I don't have the funds this year to spare for the trip and admission. And the main point of going to Hamvention (as far as I can tell) is to buy stuff, another thing I can't readily do with limited funds.

For those who will be passing through the Chicago area on the way to Hamvention, some driving advice: Do not follow I-90 all the way through Chicago. You will run into the badly congested O'Hare Toll Plaza at the end of the Jane Addams if you do this, not to mention I've heard that the west end of the Indiana Toll Road is a mess as well. You'll be better off bypassing around the city with a combination of I-290, I-294, and I-80. If you need help, there will be, no doubt, plenty of local hams monitoring on the local VHF and UHF repeaters; for example, I'm almost always monitoring the DuPage Amateur Radio Club's 2m repeater at 145.43(-) PL 107.2, and I'll be monitoring 146.52 as well starting tomorrow or so.

Oregon to ban mobile amateur radio

2009-04-24T13:31:00.002-05:00

I've discovered another state seeking to ban mobile amateur radio operation. This time, it's Oregon (link courtesy BikePortland.org). As with several other attempts by state legislatures to ban cellphone operation while driving (for example, Virginia's), this bill reaches far beyond just cell phones to ban the use of any "mobile communication device", presumably because they want to ban texting as well as talking, and using a laptop. What's especially interesting is the exemptions (quoted from the text):

(3) This section does not apply:
(a) To a person who is summoning medical or other emergency
help if no other person in the vehicle is capable of summoning
help;
(b) To a person using a mobile communication device for the
purpose of farming or agricultural operations
(c) To a person operating an ambulance or emergency vehicle; or
(d) To a person using a hands-free accessory.

So ambulance drivers, firetruck drivers, and marked (but not unmarked) police car drivers are excluded, but truckers, taxi drivers, volunteer firemen (in their personal vehicles), and amateur radio operators are not. What's interesting to me is the exemption for farmers, which makes no sense from any public safety purpose, but is clearly there merely because the farmers got to the committee before the bill got out. From various comments by legislators and others behind this bill, it's obvious they haven't thought about this much at all.

I've dropped a note to Bonnie Altus (AB7ZQ), the ARRL Oregon Section Chair, asking her what the ARRL is doing to ensure that Oregon doesn't ban mobile amateur operation.

World Amateur Radio Day

2009-04-18T14:05:00.001-05:00

Today, April 18th, is World Amateur Radio Day. Did you notice? I didn't. It's mentioned on the IARU calendar, and the ARRL ran a press release back in February, but the only press outside of the ham radio world (and even there it's getting far less attention that the fiber cut in San Jose) is a mention in the Times of India, and I can't even find that now.

It's amazing that there's no commemorative contest or something. I did find mention of one special event station (A60WARD, operated by the Emirates Amateur Radio Society, UAE), but given that people will use just about any excuse for a contest, you'd think the anniversary of the IARU would be good for one.

It seems that as a collective group, hams just aren't that good at PR.

In any case, happy World Amateur Radio Day, wherever you might be.

Always back up your data loss

2009-04-10T09:34:00.001-05:00

I bought a SATA card for an older computer I am trying to make useful here yesterday. On the front page of its manual is this choice gem:

Before installing and activating RAID function, please make sure you have a complete backup of your existing data loss due to abuse, misuse, or neglect.

Here's what I'm not clear on: if I have a complete backup of my data loss, is it really lost?

Punished for passing a code test?

2009-04-03T21:57:00.001-05:00

I was looking at the Part 97 regulations relating to transmitter power the other day, when I noticed something odd. The operative regulation here is § 97.313, which I'm going to reproduce in part below because it's hard to link to ecfr searches:

(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.
(b) No station may transmit with a transmitter power exceeding 1.5 kW PEP.
(c) No station may transmit with a transmitter power exceeding 200 W PEP:
(1) On the 10.10–10.15 MHz segment;
(2) When the control operator is a Novice Class operator or a Technician Class operator who has received credit for proficiency in telegraphy in accordance with the international requirements; or
(3) The 7.050-7.075 MHz segment when the station is within ITU Regions 1 or 3.

(I left out the sections past (c); they relate to the various bands on which everyone has power limits.) The section of interest here is (c), and specifically (c)(2), which limits Novices and Technicians who have passed a code test to 200 W. Since the regulation doesn't specify any bands, it applies everywhere. Technicians who have not passed a code test are unaffected and therefore have the same power privileges as any other operator.

In effect, this means that Tech Plus licensees (a dwindling lot, to be sure) actually lost power privileges even as they gained emission privileges. And since there is now no other distinction in the regulations between Tech and Tech Plus, the net result of this drafting error is to limit the power privileges of Tech Plus licensees.

I am sure this is not what the FCC intended; I assume they intended to limit the power of Technicians and Novices operating in HF to 200 W. Clearly § 97.313 should be amended, to clarify that section subsection (c)(2) only applies below 30 MHz (or whatever the FCC actually intended) and to remove the reference to "proficiency in telegraphy" language that is now obsolete.

Of course, they could amend it to restrict Technicians to not exceed the powers set forth in § 97.13(c)(1). Those power limits (the limits above which the licensee must conduct an environmental evaluation) have been established as limits to ensure safety, and it would be reasonable to assume that a Technican-class licensee may not possess sufficient expertise to conduct such an evaluation properly, and on that basis restrict power levels that might endanger the public to General-class licensees or higher. But that's just an idea.

Amateur Radio Licensing Exams

2009-03-22T11:58:00.001-05:00

The ham radio sector of the blogosphere is all agog over the FCC's recent decision to deny KI4NGN's petition to expand the minimum question pool size from 10 times the number of questions on each exam, to 50 times. As best as I can figure, the argument for expanding the pool is to make it impossible for candidates to memorize the entire question pool, enabling them to pass the exam without actually learning anything. The FCC denied the petition because the petitioner did not provide evidence that the current practice was, in fact, leading to there being a large number of operators who did not possess the necessary skills to operate their stations correctly.

First, I'm one of those people who at least partially memorized the question pools, with enough success that I managed to pass all three elements at one go. I also publish study decks (derived directly from the NCVEC published pools) that, used in conjunction with readily available software, will assist others in using this technique to prepare for the exams, if they so choose. I don't have a problem with people using this approach; I want to see as many interested people in ham radio as possible. (Unlike some people. More on this later.)

Second, many of the commentators state that Mr. Mancuso's proposal would make it much harder for candidates to pass. That is something of a reach. While it would make memorizing the pools much harder (the Technician and General pools would be forced to increase to at least 1750 questions from their current 392 and 486, respectively, and the Extra pool to at least 2500 questions from its current 738), it would be entirely up to the NCVEC to decide whether the additional questions would actually cover additional material, or merely involve more permutations of the same material requiring no additional study.

Either way, however, it would have a dramatic impact on the NCVEC. The NCVEC, as the body currently charged with producing and maintaining the question pools, is, as far as I know, organized entirely on a voluntary basis. Accepting Mr. Mancuso's petition would have forced the NCVEC to come up with four to five times as many questions on each of the three pools; this would have strained the capabilities of what is presently an all-volunteer organization and would likely have required the NCVEC to hire staff, which would force them to solicit contributions from, or even charge dues to, their member organizations, which would in turn force them to increase testing fees. There are enough people complaining about the ARRL/VEC charging $15 per session; just imagine how loudly they'd screech if that went up to $30. And, of course, any increase in fees will incrementally exclude some candidates.

More importantly, however, is that Mr. Mancuso's petition underlies a misunderstanding of the purpose of the licensing examinations. The exams do not, by any reasonable standard, test candidates on whether they have the skills they need to successfully operate an amateur radio station. Some of the questions are, in fact, somewhat relevant, but a passing grade on the current exams, whether obtained "honestly" through actually learning the material, or merely by memorizing the pool, does not in any way insure that the licensee has any clue how to successfully operate their station. There is no practical test of operating procedures anywhere in the licensing process.

And that's a good thing. Why? Because such a test would invariably involve subjective judgments by the examiners. The nice thing about the examination structure we have now is that the tests are objective. The answer is right, or wrong, and there is little wiggle-room for a VE to fail a candidate for "inappropriate" reasons. There's no real way to do a practical operation test that doesn't involve subjective judgments by the VEs on whether the candidate passed or not, and as soon as you allow subjective judgments you allow for the possibility of prejudice. And that's something we just can't afford to have.

And anyway, the purpose of the tests isn't to ensure that every ham radio operator is competent at electrical engineering. The purpose of the test is to filter out people who aren't willing to take the time (in some way or another) to learn the minimum material required for the tests. The idea is that we put on the test material that we want newcomers to our hobby to be at least passingly familiar with, so that they will learn at least some of it, and by passing the test they demonstrate at least a passing commitment to learning these things as well as an understanding that our hobby has rules that everyone is expected to follow. For this purpose, the size of the pool is almost completely irrelevant; all that matters is that the questions cover the range of material that we want newcomers to be exposed to.

In short, the exams are, pretty much explicitly, a barrier to entry. Barriers to entry are always a challenge. Set them too high and you don't get enough participants; set them too low and you get people who lack sufficient attachment to the common goals and purpose of the community to feel bound to follow its rules. I think for the moment we set a pretty good balance on this issue with the current examination practices, both with the Technician (entry-level) license and with the somewhat harder General license. The more rigorous study required for General increases the likelihood that the licensee will have come to understand the importance of following the rules, which is more important for licensees with access to HF because of the worldwide propagation and much more restricted spectrum to share.

The much higher requirements for the Extra actually make sense because this is a "prestige" license; not being able to get Extra doesn't substantially exclude the licensee from much of anything (mostly, access to short callsigns, access to some of the more valuable contesting spectrum, full privileges as a volunteer examiner, and broader reciprocal privileges when traveling abroad), and so making this license substantially harder will limit it to those who show substantial commitment to the hobby, which is exactly what we want.

In my opinion, the testing system we have now is pretty close to the best one we can really hope for. We could lower standards further in the hopes of getting more hams, but I suspect we'd not get that many more active hams, just more people with licenses who don't actually use them. We could "increase standards" further by increasing the number of questions on the tests, increasing the size of the pools, or broadening the content being tested for, but that runs the risk of merely excluding people who might otherwise become licensees, without actually improving the competency of current licensees. We could institute "practical testing", but that introduces a huge opportunity for prejudicial administration of the examinations that would exclude people from the hobby for illegitimate reasons. It's certainly important that the NCVEC consistently revise the pools to ensure that the questions asked continue to expose licensees to the issues they need to be aware of, but I do not believe that any significant change to the process as it exists now would materially benefit the hobby.

Other posts on this topic that may have inspired this one:

K3NG's Just What Is the "Dumbing Down" of Amateur Radio?
KB6NU's FCC Denies Petition to Increase Size of Amateur Radio Question Pools
Various discussions on Twitter and IRC
An email from Will Sperling K9WSS that I don't think Will has posted online anywhere

Running a PC off batteries

2009-03-14T20:11:00.001-05:00

This (well, actually next) month's QST has an article on DC-to-AC inverters targeted toward the specific purpose of running a shack computer off the shack battery backup supply. While DC-to-AC inverters can be useful, there's a better solution to this problem and the QST article completely ignored it: replacing the PC's supply with a direct DC-to-DC converter.

Powerstream (a company with which I have no experience or connection) offers several DC-to-DC power supplies in the ATX form factor for very reasonable prices. Laptops and other devices with "brick" or "wall-wart" supplies typically have low-voltage DC inputs that can be accommodated either by adapting a car adapter (recall that 13.6 VDC "shack" power is essentially the same as automotive accessory power) or by homebrewing a DC-to-DC converter (buck/boost converters are one option for this). About the only devices that cannot be easily run by a DC-to-DC converter are CRT monitors and laser printers. CRT monitors should be replaced by LCDs anyway as the latter have far lower power consumption, and laser printers have such high startup currents that they probably can't be run off a DC-to-AC inverter either unless the inverter has a very high surge capacity. I've known more than one IT operation that had UPS problems caused by plugging a laser printer into the UPS.

Of course, most DC-to-DC converters use pulse-width modulation to generate the desired voltage(s), and hams will have to be careful to ensure that any RFI generated by such approaches is managed with care, and it might be difficult to do this. My main beef with the QST article is that it presented DC-to-AC inverters as the solution to the "how to power a computer off batteries" problem without even mentioning in passing that there are other solutions that at least deserve some consideration.

Battery backup for ham radio gear

2009-03-11T00:05:00.001-05:00

The second issue I heard on last Monday's TechNet (a weekly net held by the club I'm a member of) was on the topic of battery backup for repeaters and other ham radio gear. This issue was raised by Ryan (KC9OFF), and as it happens his specific situation is not going to be that interesting to hams as he is trying to provide power to an Icom FR3000 series repeater, which is not ham gear (it's business band gear) and that particular repeater already has a built-in battery controller so setting up a backup battery on it is just a matter of connecting a battery to the terminals on the repeater in the correct polarity. (I really should charge him a professional fee for researching this for him, but hey, whatever.) However, us hams tend to use gear with slightly fewer "creature comforts", which means we have to roll our own (or at least put together from components) power controllers for such thing. Not that that's a problem: rolling our own is part of what we do, right?

During the net I asserted that there was an article in November's QST on battery backup systems for ham shacks; fortunately, I was right: the article in question is on page 76 in the regular "Getting on the Air" column. That column describes two approaches to battery backup. The first approach is use an inline charger and a boost/buck regulator to provide regulated 13.8 volts to the radio no matter what voltage is provided by the charger/battery combination (which could be as high as 16 volts when the charger ramps up, or as low as 10 volts as the battery runs down). The second is to use a switching power controller that has separate inputs for charging power and the battery; the difference is that the power controller will not draw from the battery unless the main power is down, while the inline design draws from the battery and the line power (charger) to the extent that each can provide power at any time.

In the inline design, you will likely draw from the battery while transmitting, because the charger probably only provides 5 amps at most and cannot provide the full 20 amps or more that a typical rig pulls while transmitting. As long as your transmit duty cycle is low enough, the charger will have enough time to recharge the battery between transmissions. The main problem with boost/buck regulators is that the majority of regulators out there generate "noisy" DC; virtually all of them use pulse-width modulation for power control, which generates RF noise and will require significant filtration to avoid RFI issues. The switching power controller does not do this, but will present a variable voltage to the radio when switchover occurs and as the battery discharges (unless it also contains a boost regulator, in which case all the issues with those again arise).

Several people on the net noted the need to include protective hardware (mainly fuses and diodes) to prevent the battery from draining through the power supply and to protect against various sorts of possible failures that could lead to shorts. The inadvisibility of using an ordinary car batteries (which are optimized for short high drains, not for extended low drains) was also mentioned. Car batteries should never be used for backup power. There are a variety of deep-cycle options for this purpose which are designed for long-term moderate-power draws. Many are also engineered to avoid venting hydrogen gas, which would create an explosion risk when used in an enclosed space.

The solution I'm still looking for I haven't found yet in commercially available gear, and involves using solar as primary power and a battery rack as backup during the night, with line power being used to charge the batteries only if they drop below the point that they aren't expected to recharge in the sun the next day. I think I've seen a controller that supports multiple power sources, so if I put the solar panel on one input and a line supply on another, but use a switch/relay to only provide AC to the line supply when the battery voltage is below the threshold, (with some hysteresis to avoid chugging) then the system would perform in the manner I desire.

MFSK Idle Tones

2009-03-09T22:32:00.001-05:00

In tonight's TechNet (a weekly net held by the club I'm a member of) one caller (Ed, K9EW) asked about the idle tones that various MFSK implementations, given that he's noticed that different MFSK generators seem to generate different idle patterns. No clear answer was given on the net, although the discussion came to the conclusion that it was, at least to some degree, up to the programmer to decide how to do this.

The ARRL publishes formal technical specifications for some common digital modes, including MFSK. According to section 3.8 of this specification, compliant MFSK implementations must inject a non-printing character every 20 symbol periods, in order to avoid sending an extended period of a single tone. The standard does not specify which nonprinting character must be sent (although ASCII NUL, 0x00, is suggested). A programmer could elect to send any of several nonprinting characters, which would result in different bitstreams.

The reason for not allowing a extended single tone is that this would allow the symbol clock between the sender and the receiver to desynchronize. The specification requires that receivers maintain clock for at least 50 cycles, so sending a character every 20 cycles guarantees that sync is maintained as the receiver will resync its clock with each "diddle".

For more on the technical specifications of digital modes, see fldigi's excellent Digital Modes page.

The Right to Receive: Police Scanners and the Internet

2009-03-06T17:21:00.001-06:00

Last night, I ran across this entry on a blog for the communities of Clayton and Concord in California. In this entry, the publisher of the blog announced his intent to put up a live internet stream of his scanner, which is tuned to receive various police frequencies in the "ClayCord" (Clayton/Concord) area. The comments on the thread are, to be certain, very interesting, as well as rather disturbing.

The idea of streaming scanners is pretty well established. There's a whole organized system for picking up live ATC streams (LiveATC.net), which got some significant attention because the site was able to produce a recording of the communications related to the crash of Continental 3407 in Buffalo within hours of the crash. There are also quite a large number of sites offering live and recorded police radio streams for much of the United States.

And apparently the police aren't too happy about this. Several states have laws that attempt to limit people's right to receive police radio, even though the Communications Act of 1934 granted a virtually unlimited right for any person to receive any signal they can hear. Apparently the police don't want people listening to their radio signals, and rather than taking the obvious step of encrypting them to prevent people from usefully listening to them, they prefer to try to make it illegal, and when that fails, harass those who do listen to them anyway and make it easier for others to listen to them.

Some of this is evident in the linked thread: witness the several comments (probably all from the same person) declaring that the "FCC has regulations that prohibit streaming a police scanner" (they don't) and declaring other laws that make this sort of thing illegal, or which create criminal liability for the streamer should someone use their stream in the commission of a crime. Why, one wonders, are the police so insistent that the public not listen into their conversations?

Then there's the recent issue with the Indianapolis Metropolitan Police Department, which recently got itself in hot water because citizens (reportedly, amateur radio operators) recorded IMPD officers using profane language to exchange vulgar and inappropriate comments, using frequencies the police do not have permission to use. The use of unlicensed frequencies is especially concerning; the use of "unexpected" frequencies for such inappropriate commentary suggests that the officers in question knew that what they had to say was improper, but thought that, because it was being said on a "nonofficial" channel, would go unnoticed by supervisors and observers and thus not lead to repercussions. Unfortunately for them, there are people who listen to everything, and someone took enough offense to report it to the FCC.

I've heard rumors that the FCC is withholding the identities of the people reporting the unauthorized transmissions because there is a real concern that the IMPD, or members thereof, will seek retribution against the reporters. The fact that they were reported as "amateur radio operators" is especially interesting because of Indiana's mobile scanner law, which explicitly exempts amateur radio operators; by identifying the reporters as amateur radio operators that makes it impossible for IMPD to demand disclosure of identities so they can investigate whether Indiana's mobile scanning law was broken. Those of us in Chicagoland know just how bad it can be when you cross a cop: just ask Mike Geinosky, who has received 24 parking tickets in 16 months, several of them for a car he no longer owns. And that's mild for Chicago.

The clincher in that ClayCord thread was when the anonymous coward responded to my post explaining why the ECPA doesn't prohibit republishing police radio transmissions with posting somebody's address (not mine; I don't live in Concord) and encouraging people to go there and "protest" me. Fortunately, someone (probably the blog owner) quickly deleted that comment. Pretty blatant attempt at intimidation, there.

So, while there's little question in my mind that while police scanners can be used for socially unredeeming purposes, the socially positive purpose of allowing the public to better keep tabs on how well the police (who are supposedly their servants) are performing their duties overwhelms that.

Lunar repeater

2009-02-28T22:25:00.000-06:00

Image via
Wikimedia Commons

Today's outlandish ham radio idea: plop a repeater on the surface of the moon.

This came up during a discussion on Twitter, of course. The main challenge would, of course, be getting to the moon. Also, the repeater would be have to significantly larger than a satellite repeater because it would have to have a significantly higher power budget. Path loss from the earth to the moon (one way) is between 190 and 200 decibels, so a transmitter power of at least a couple hundred watts would be desired, more than can be handled in your typical cubesat.

In order to power this device, a substantial solar array will be needed, and the lander will have be developed to self-deploy the array on landing. The station's antennas will also need some way to track the earth, as we'd want to use relatively highly directional antennas for best results. Presumably all the signals will be coming from the earth, and so an antenna whose beamwidth is only slightly wider than the earth's apparent size from the moon's surface (how big is that, anyway?) would make sense. At the very least the deployment system has to find the earth initially; since the moon is tidally locked once you've found it it shouldn't move a whole lot, but I think libration movement probably exceeds one earth diameter when seen from the moon's surface and so active tracking would probably be a net gain.

This is, of course, completely impractical, but it would be fun. And probably very expensive. And the EME people would probably complain to high heaven if we ever did it.

South Carolina middle school cuts ham radio, astronomy clubs

2009-02-20T13:31:00.001-06:00

I got word today that a middle school in South Carolina has cut its ham radio and astronomy clubs, apparently in the interest of cost-cutting, even though the ham radio club operated at no expense to the school. These two clubs were the only non-sports clubs at the school.

No word on whether they cut any of the sports clubs; I'm still hoping to get more information on this.

Can someone explain to me, in the meantime, why we spend so much public money on sports for our kids, and so little on giving them opportunities to excel in science, math, and engineering?

Repeater maps!

2009-02-17T16:40:00.001-06:00

Mainly out of curiosity, I decided to map the repeaters in my repeater database coded by CTCSS. This was a bit of fun, because I had to clean the data (it's amazing how many repeaters are listed with silly CTCSS tone values like "961" or "Yes") and then figure out how to generate a map and put the data onto the map. The last bit was aided immensely by the Generic Mapping Tools, a nice little set of tools very much in the UNIX spirit. As K6HX put it to me, "it's quirky, but does a good job once you figure it out".

Click on the thumbnail to go to the full size image on my wiki.

I was kinda hoping that you could see the way some coordination councils use CTCSS tones regionally, but it's not very obvious except for a couple places, like Western Pennsyvlania, Michigan, and Wisconsin. A different color code might help here; I'll have to explore that later. I might also do another map, coloring by the majority CTCSS tone in each grid square, but first I'll have to figure out how to plot regions.

By the way, the most popular CTCSS tone is 100.0, with the next four (which trail by quite a lot) being 103.5, 123.0, 107.2, and 88.5.

I'm also really curious about the repeater out in the waters off the coast of North Carolina.

Conspiring to control space weather

2009-02-15T00:36:00.000-06:00

There's a pretty good discussion over on Watts Up With That? regarding the failure of Solar Cycle 24 to get up and go yet, something which has somewhat confounded stellar physicists so far. Given the relatively high importance of the solar cycle to amateur radio operators, or at least those who operate in HF, we tend to be aware of the solar cycle, and talk about it quite a bit.

However, what got me was the discussion about vested interests lobbying scientists to predict higher solar activity levels than the data would otherwise support; in short, the allegation that elements (at NASA or elsewhere) are being influenced to predict relatively high solar activity levels. Is there nothing that big business won't stick its big fat nose into and tamper with just to make a few extra bucks?

End of the rabbit ear era?

2009-02-13T14:19:00.001-06:00

Image by PiKimage.com via Flickr

I ran into this discussion on a blog the other day (thanks to Backtype, which I use to monitor for interesting discussions in places I might otherwise not see them). It's interesting to me how ill-informed the general population is about the analog TV sunset (which is semi-delayed now, although many places will still go dark in just a few days). The most interesting one to me is the apparently widespread belief that the converter box somehow replaces the antenna, rendering it obsolete, instead of acting in concert with the antenna.

I suspect a lot of people think that using a DTV converter box to receive TV is something akin to cable or satellite TV, probably because digital TV converter boxes resemble cable TV converter boxes in many ways. There seems to be a lack of understanding that the DTV box is receiving signals transmitted over the air in the same manner as traditional analog TV, just in a different modulation that their old TVs aren't capable of understanding. All the DTV box does is convert the signal to one that is comprehensible to an older TV that lacks the digital decoding hardware. You still need the rabbit ears or rooftop antenna; the DTV box doesn't eliminate those at all.

Another comment in that discussion I found interesting was the notion that "I don't way to pay to watch TV". Well, you presumably paid for your TV, right?

In my experience, the DTV box in conjunction with an existing antenna will actually work better than that same antenna did in analog. Of course, my experience is limited to the relatively signal-rich Chicagoland area; your mileage may vary.

Emergency preparedness doesn't just mean disaster-proofing

2009-02-09T13:22:00.001-06:00

The recent ice storm in Kentucky left hundreds of thousands without power or telephone service, as nearly everyone reading the news is probably aware by now. It also took out cell phone towers and wireless communication systems used by public safety agencies, by toppling their towers, taking out their power supplies, or taking down the landlines that connect the towers with the control points. Several western counties had no effective communication within or without the county for several days. This despite the expenditure of tens of millions of dollars to improve emergency communications across Kentucky, as reported by the Lexington Herald-Leader.

The problem is that we are taking the wrong approach to disaster preparedness. Much of that money was spent on upgrading public safety communication systems to newer (often digital) technologies. These technologies do not make those systems more disaster-resistant themselves, and in fact can make them less robust because they are often locked to use gear by a specific vendor, which means you can't grab some other brand of radio and just retune it to the right frequency. More importantly, a fancy digital trunked radio doesn't come with a superstrength antenna that can't be blown down by wind or pulled down by ice, and it's just a pretty shiny box if it doesn't have power.

The Herald-Leader article notes that the state did make satellite phones available to its regional emergency managers, but those phones are expensive to buy and to operate, and are therefore not available in a dense enough distribution to be helpful in a disaster (like an ice storm) that makes travel difficult. At least this is evidence of the recognition that having backup communications is important, but obviously enough wasn't done, both in material distribution and in training.

The problem, however, seems to be that there is no recognition that the best way to deal with disasters like ice storms, tornados, hurricanes, and earthquakes is not to build you primary infrastructure to resist destruction. That's foolish. No comm antenna is going to survive a direct strike by a Force 5 tornado; that mast is going to be either prezteled into uselessness, or else it'll be blown into the next county. Either way, you won't be using it for communications. Same deal if your mast is snapped in two by ice, or falls over because of an earthquake. The way you prepare for disasters like this is to have "ready-reserve" equipment in bunkers that you can pull out and set up when the time comes. And more importantly, people need to know where this equipment is and how to use it.

And because you want a lot of these bunkers (which by rights should also be stocked with food, water, medical supplies, blankets, fuel, and other such emergency-type things), the equipment should be cheap. None of these insanely expensive fancy digital radios that only work with one another and cost a bundle. What you want is a portable antenna mast with a simple antenna that connects to a VHF or UHF analog FM radio preloaded with designated emergency frequencies, and a nice book that explains how to set it up and some information on the designated emergency communication procedures to be used. In many areas, especially those with rugged terrain or low population densities where VHF line-of-sight communications may not be adequate, an HF radio would be a good addition. Even so, the portable tower is the most expensive part of this; you'd probably spend about $3000 per site for a basic configuration.

You simply cannot build your infrastructure up so that you won't have a loss-of-communication disaster; even if you had satellite phones at every location, there's the chance that the phones, or even the satellite itself, will fail. The key here is in providing recovery resources, and in training people in how to use those resources to effect a recovery. Too many counties in Kentucky had to make it up as they went, and that delayed relief efforts.

Personally, I'm hoping that the Kentucky experience leads to emergency management officials making more of an effort to reach out to amateur radio groups in their areas, and at the same time leads to amateur radio groups making a more concerted effort to organize themselves for preparedness and to communicate with emergency management officials what their capabilities are and how to call upon them. It seems that both sides have been letting it slide a lot in recent years.

(Updated 2/13 to add link to Iridium satellite collision event.)