Android's UTC vs GPS Clock Error

Official Blog: Time, technology and leaping seconds

Google's Site Reliability Team blogged back in 2011 that "Having accurate time is critical to everything we do at Google."  This is an interesting statement, in light of the known issue with Android (i.e. Google) having a known clock error which equates to the difference between GPS Time and UTC Time. 

First reported back in 2009, the Android clock error is the result of the device's date/time being locked to the GPS time signals, but as I discovered and reported in 2010 the GPS driver fails to apply the time correction.  As of this writing the error is on the order of 15 seconds, and will increase over time.  The reason that GPS and UTC time differ is due to various factors, but the largest is that the two time systems are increasingly divergent due to "leap seconds" which are small corrections applied every couple of years to UTC time which attempt to keep the UTC year aligned with the "Solar year". 

You might argue that 15 seconds is not an issue, and for the majority of users this is true.  However for scientists, some professionals, and even amateur radio operators the error can cause huge problems.  In the amateur radio world we use smartphones to track the location of satellites and the International Space Station.  Depending on their orbit, most sats are visible in the sky for at most 15 minutes.  So the error in time means that an antenna pointed at the satellite will be incorrect by at least 3 degrees, possibly more. 

The thread on Android Google Code about this issue has grown quite long over the years.  I asked for users to report if their devices had the bug; over the years every post has been a "yes" with the one exception being a Nexus 4 running Android 4.2.1.  A response from the Android team has never been posted.  It would seem that "Having accurate time is critical to everything we do at Google" is a bit of a stretch - because clearly it's not even worth talking about when the inaccuracy is on Android.

Update: I picked up a Nexus 7 running Android 4.2.2 and find that the time issue is resolved!  So to be fair, the issue existed for a long time but "Jelly Bean" seems to have resolved the issue. 

Spectrum Analysis of a Smart Meter

We got our smart meter installed this past week, so of course I had to take a look at the RF signals coming from it. The results were very interesting!  I used the spectrum analyzer on an Anritsu S412E LMR Master™, which is fast enough to capture the 20 - 200 millisecond pulses in the 902 - 928 MHz ISM band coming from the PG&E electric smart meter (the meter itself was actually made by GE).

Summary of my findings?  As I expected, there's far more RF energy in the air from the TV and FM broadcast bands and cellular signals than from the smart meter's short-duration pulses.  You have to really hunt for the smart meter signals, which are buried underneath a lot of other stronger signals. 

The Un-Club: Validation

At ARRL Pacificon 2012 I presented "Club is a Four Letter Word" - during which I set forth the idea that most amateur radio clubs are hurting more than helping our hobby.  The thesis of my presentation was that, in the modern world where membership can be obtained by simply clicking the Like button on a Facebook page, and information on innumerable subjects can be obtained from YouTube and other sources, a traditional club structure is often not needed.  A recent article on the ARRL website entitled "The Un-Club" talked about many of these same ideas, and gave examples of how their group has rejected the traditional club model and the positive benefits from that approach. 

Consider Bay-Net in the San Francisco Bay Area.  It's increasingly one of the more popular amateur radio groups in the region, with a popular linked analog repeater system and D-Star node.  Bay-Net has no members; if you're on the email list, you're in the group.  Bay-Net doesn't hold regular meetings, except for a once-per-year gathering at which goals for the coming year are set forth for consideration and an informal expo is held where members bring in projects to share and discuss.  There are three "board members" (required to maintain the Bay-Net vanity callsign WW6BAY) but they're not treated any differently than anyone else and most of them group doesn't even know who they are.  We host a Field Day site every year and usually come in last place because we spend all of our time playing around with radios and gadgets instead of making contacts, but we always learn something. There are no dues; if we need to buy something we ask for donations and people step up. 

One of the great things about Bay-Net has been that it's attracted a lot of younger operators, which I credit in part to the "not a club" approach.  I encourage you to consider whether your club might be more efficient, more effective, and more inviting if it wasn't a club at all.

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Update: As if to yet again validate this idea, I received an email from a local club that allows non-members to monitor their mailing list:

We are having an election to make a change in the By-Laws. The proposed change is shown in RED LINE in the attached petition and adds the words "more than once" to the end of Article IV, Section 1 of the By-Laws. In essence the proposal is that the By-Laws be amended in order to allow officers to serve up to two one year terms in a row rather than only one term as presently provided. It would not extend officer terms and all officers would still stand for election each year at the April meeting.

Gaaahhhhh.....

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Update, Part II: I keep getting comments (here and on my G+ post) about the importance of f2f interaction and why clubs provide that.  Let me clarify: I'm not saying that Bay-Net never interacts f2f.  We meet up all the time, for a variety of reasons.  We just don't do it *formally*.  If we need or want to meet, we do.  What we don't do is waste time with minutes, financial reports, committee reports, voting, etc.

Narrowbanding: A Retrospective

The FCC-mandated deadline for narrowbanding is less than 100 hours away, and as was predicted many license holders will not make the deadline.  (e.g. New York City, Philadelphia, and Chicago)

Starting with a Notice of Inquiry in 1991, and ordered in 2004 (yes, it really took over 13 years for the gears of governmental progress to get from "should we do this?" to "we're going to do this") narrowbanding refers to the conversion of land mobile radio systems from 25 kHz channel spacing to 12.5 kHz spacing.  It was first formally considered in the 1991 NOI because, before cellular phones became affordable and widely available, land mobile radio spectrum in some areas was very scarce.  In many major cities during the 1980's and 1990's it was often impossible to add new channels. 

Dissolve (as they say in the movies) to late 2012.  Many commercial land mobile radio users have switched over to cellular, cellular push-to-talk, or even smartphone push-to-talk apps.  It doesn't make sense to pay an LMR repeater provider for something that has limited coverage, limited flexibility, and requires professional installation in a vehicle.  Yes, LMR works when disaster strikes, which is one of the reasons why amateur radio has kept non-cellular radio in its arsenal of disaster communication solutions.  For the average commercial user, cellular makes more sense operationally and financially.  So there's a lot more LMR spectrum to be had, and yet the narrowbanding mandate continues; a 2013 solution to a 1986 problem.

Why are we even bothering to continue?  There are a wide variety of possible reasons, the sum of which probably answers the question.  The government doesn't like to admit it made a mistake, or that its thinking is two decades behind the technology curve.  It wouldn't be fair to let some people off the hook, when others have already made the change.  (Although this doesn't hold up, because obviously big cities mentioned above ARE being let off the hook.)  And of course there's big money to be made in narrowbanding; the government charges a fee to modify a license, and the radio manufacturers charge taxes on sales of new radio equipment.

All of the above reasons would be perhaps excusable if the end result were something desirable like interoperability, but we're farther away from interoperability than we were 20 years ago.  (Ref: "Meeting the Interoperability Challenge", Witkowski, CMU DMI Workshop 2012)  At the same time the FCC has been beating the narrowbanding drum, it's also allowed proliferation of incompatible radio technologies into public safety communications.  So where before we had everyone on analog FM but at different frequencies, we now have FM, P25, NXDN, DMR, etc and the frequencies are still not aligned.  God forbid these people get hold of our healthcare system.  Oh wait...

Dynamic Spectrum Sharing & Amateur Radio

Update: My prediction has come true.  I eagerly await the opportunity to tell the ARRL they should have listened to me 10 years ago.

FierceWireless reported yesterday that the US FCC has issued a Notice of Proposed Rulemaking (FCC 12-148) that if enacted into law would allocate the 3550-3650 MHz band for use by small-cells.  Heralded by industry groups such as Wireless Internet Service Providers Association (WISPA) and the High Tech Spectrum Coalition (whose members include Apple, Alcatel-Lucent, Cisco, Ericsson, Intel, Nokia, Qualcomm, Research in Motion, and Samsung) the rulemaking will implement a dynamic spectrum-sharing architecture similar to that proposed for TV white space users.

Not discussed, but likely to become relevant over time, is the fact that the 3550-3650 MHz band sits right next to the Amateur Radio Service's 3300-3500 MHz allocation.  I've been saying for years that amateur radio is very likely to lose this band because it's almost never used.  Even here in the Silicon Valley, where hams tend to push the technology envelope, the band lies dormant.  I think we're seeing the beginnings of the end for amateur's "ownership" of the 3300 GHz band.  If FCC 12-148 moves to law, and the dynamic spectrum sharing model proves to be successful, it's not unlikely that the FCC will move to expand the allocation.

On the other hand this could wind up being a windfall to amateur radio, because dynamic spectrum sharing works both ways.  It could be that the amateur radio of the future will leverage spectrum sharing and allow operators to use frequencies currently unavailable.  This is more likely to be true in data networks than voice networks, but of course digital voice could also make use of dynamic spectrum sharing. 

Apple won't enable LTE until system is vetted - by Apple

Last week Telecoms.com reported that Apple is not releasing the iPhone 5 for sale by mobile operators until they've confirmed the system's performance.  Originally rumored back in October, and now confirmed by Swisscom; it puts Apple into a unique and unprecedented position of essentially holding an operator hostage until their network is up to Apple standards.

In a way this is understandable.  The days when you bought a phone from a carrier and then got support from that carrier are long gone.  If you're operating an iPhone 5 on Verizon and encounter problems, you're more likely to call Apple than Verizon for support.  So Apple, wanting to reduce support calls, needs to insist that the network perform adequately before approving products.  The operators may not like this (maybe even for ego reasons) but it makes sense.

Disturbing GMRS Trend

Went it Frys to buy some walkie-talkies for the neighborhood kids. My girls often loan theirs out, and since I went high-end for them I wanted something less painful should they get damaged.

Problem is that it seems like most of the radios now don't come with CTCSS/DCS support. You have to go up into the > $50 range to get tone squelch. Midland seems to have more models at the lower range; from what I saw Uniden had almost none. The premium price seems like a lot, given that the code squelch support is likely already in the radio's ASIC. (It would make zero sense for the radio vendors to design more than one radio ASIC.)

I should probably note that I can understand the business motivation behind this. Most people who don't work with radio as amateurs or professionals are likely confused by CTCSS/DCS. The vendors made this problem worse by marketing it as a "privacy code" - customers likely call tech support all the time complaining that people can monitor their "private" transmissions. Eliminate the code, support call rates will go down. That doesn't mean it's a good idea.

Are Church Steeples the Answer to Cellular's Prayers?

CBS5 in San Francisco recently ran a story about how churches are allowing cellular carriers to locate cell sites in their buildings and steeples.  It's a seemingly win-win solution - churches are usually in need of supplemental funding, and carriers are faced with the dilemma of adding coverage while also dealing with community rejection of towers/poles due to aesthetics and/or concerns about RF radiation safety.  Win-win?  Maybe not...

Over the past few years there have been a lot of new stories about problems with police radio systems.  Complaints about noise, drop-outs, and sometimes a complete failure of the system are often cited in these articles.  In some cases, the issues are caused by substandard equipment, poor planning, and poor installation.  But other times all of these are ruled out, and yet the system remains problematic.

What then is the cause?  A while back the City of Oakland, which has been plagued for years by failures of their police radio system, pointed the finger at cellular carriers as the culprit.  Oakland PD's radios are very close in frequency to some of the cellular bands, so it makes sense to investigate this.  And in fact, when the cell sites were turned off the problem went away.  So is the problem with the cell site, the police radios, or both?  Certainly there are some radios on the market which have poor receivers and are likely to pull in radio signals from cellular bands.  But lately I've been working with a team of consultants on analysis of these cases which shows that over-crowded cell sites may in fact be contributing to the problem.

Securing the permits, regulatory approvals, and community support for cell site construction is a huge problem for the cellular carriers.  So when they find a site, they tend to load it up with as many systems as they can.  The problem is that the signals can mix with each other and create very fast transient high noise floors near the sites, even outside the cellular bands.  The more systems sited close together, the more likely it is that this will occur.  So while cellular may seem like a God-send to churches, they should be careful to avoid overcrowding - or there might be hell to pay in the long run.

Pacificon 2012 : Club is a Four Letter Word

Had a great time at Pacificon 2012 today.  This was the first year I brought the kids.  It may have been a bit over Tara's head, but Nora enjoyed hearing from NASA Astronaut Lee Morin about life aboard the International Space Station, and soldering her own Morse Code Sounder at the ARRL's Youth Program area. 

My presentation this year was on organizing in the 21st century, and how to reorganize existing organizations to attract and retain people born after 1980 (termed "Millennials").  I think it was well received, and in fact the audience started asking so many questions that I didn't get through all my slides.  For anyone interested here's the presentation.

Field Day 2012 is almost here!

Getting ready for next weekend.  Are you attending Field Day?  Check the ARRL Field Day locator for a site near you and join us!

Kids and Morse Code

About three years ago my youngest daughter Tara took an interest in Morse Code.  I think she just liked the sound it made, but the way she sat there so intent when she was pretending to send was cute, so I took a video and posted it to YouTube.  It got picked up by a few amateur radio blogs, worked its way around the world, and as of today has just under 10,000 views.  In fact, it's my most watched video.  Not exactly the Dramatic Chipmunk, but still...  I had no idea it would be so popular.

JT65 Articles from CQ Magazine

Last year (October and November 2010) I co-authored with Tomas NW7US a two-part article "Communicating Under the Noise" about JT65A on HF which was published in CQ Magazine.  Thanks to Rich Moseson for agreeing to make the articles available in digital form.  PDF copies of the articles can be obtained here: Download (PDF)

Enjoy.

You're doing it wrong

The ARRL kicked off 2011 with a news item that hopefully is not a harbinger of more retro-tech lameness to come during the new year.  (Hint: It is.)  "Ring in the New Year with Morse Code Ringtones" started off well enough; make your cellphone ring with CQ CQ CQ or some such.  I did this almost two years ago and it's great fun; I even made ringtones with my wife's name, the callsigns of hams in the Bay-Net group, etc.  I got lots of good comments on my ringtones from folks at the 2010 Dayton Hamvention; a few even requested that I email them copies of my MP3 files for their phones.

The ARRL article fails on two fronts; first off it talks about creating Morse Code ringtones like it's a completely new thing (clearly it's not), and secondly it goes into detail about the horribly convoluted process Tom AD1B used to create his tones.  Tom actually used his Ten-Tec rig and a keyer paddle to generate the Morse Code, recorded the audio (article is unspecific on how he did this; my money is on "8-Track Tape Deck"), massaged the audio files in Audacity, and then generated MP3 files.  Talk about using a bazooka to kill a mosquito.

Clever.  And completely unnecessary.  I generated my MP3 files by going to LWCO.net, a website created by Fabian Kurz, DJ1YFK.  Fabian's website (the URL is an acronym for "Learn CW Online") offers a number of useful tools, many of which are based on Fabian's excellent open source "ebook2cw" library.  One of the tools on LCWO is "Convert text to CW".  You type in text.  It generates an MP3 file for download.  You put the file on your phone.  Done.  I can generate a library of unique ringtones for twenty people in the time it takes Tom to record and process one.

And even my method is now somewhat obsolete with the advent of apps for smartphones that convert text to Morse Code on the fly.  MorseRing for Android is available in the Android Market for 99 cents.  It converts Caller ID strings to Morse Code.  The beauty of MorseRing is that I now know who's calling me even if my phone is 25 feet away.  I'm sure there is similar apps for the iPhone, possibly one for Palm, likely not for Blackberry.

You can't fix stupid

This post has nothing to do with wireless.

Somewhere, out there on the Internet, is a stupid family.  Quelle surprise, non?  Tell us something we don't know, you say.  But this is no ordinary stupid family.

Many years ago (back when the Internet was powered by steam engines which ran on barrels of kerosene) I signed up for a Yahoo account.  I chose my username based on a nickname given to me by a friend, and one I had used for my circa 1996 "homepage" which was a sophomoric collection of links, graphics, and sounds used to stake my claim to a corner of the nascent Internet.  Unfortunately my Yahoo username happens to be the last name of a stupid family.  I'll refer to them as "The Stupids". 

A few years later I started getting junk mail at my Yahoo address from a variety of sources; car dealerships, online car broker services, etc.  Apparently the Mama Stupid wanted to buy a new car, and had given my Yahoo address as hers.  The emails had a lot of information about Mama Stupid; her name, street address, phone, etc.  The amount of junk mail became painful, over a dozen messages a day; I had to activate a filter in Yahoo Mail to look for keywords and dump them straight to Trash.  10 years later, if I look in my Yahoo Mail trash folder, there are still car dealerships trying to contact Mama Stupid.

Papa Stupid has done likewise.  I've received over the years email from online shopping, stock brokers, get-rich-quick scammers, insurance brokers, magazine publishers, requests for donations, links to photos of newly-arrived Baby Stupid.  Again; I get a LOT of personal info on the Stupids from this.  A while back Mama Stupid decided she needed some spice in her life, so she signed up for an online casual fling hook-up service.  (I'm not kidding.)  She (I) started getting email from middle-aged men looking for some "Afternoon Delight", complete with photos intended to "sell the product" if you get my meaning.  Icanhazeyebleach?

In many cases I get requests to confirm my address for an account on whatever system the Stupids have tried to sign up for, I can then reset the password and basically do as I please.  Most of the time I change the password and then close the account. 

I've watched the Stupids build a family.  Their son (Stupid Junior) started out years ago using my Yahoo address as his "parental permission" email to sign up for online games.  As time's gone on I've watched his game interests evolve into more mature themes. Once he hits puberty I fully expect a lot of porn site account confirmation emails.  Their oldest daughter Missy Stupid just went to college in Florida.  I got some pictures from Disneyworld.  She looks happy.

You can imagine the amount of spam I receive because of the Stupids.  I've given up using Yahoo for email, simply because 99% of what I get is spam caused by the Stupids inability to figure out that lastname@something.com doesn't automatically route to their house.  I've been tempted to close the account, but in some bizarre way I feel like I need to continue.  What will happen next?  Will Papa Stupid have a midlife crisis and go looking for a red sports car?  Will Missy Stupid get knocked up and have to come home from college?  It's like my own private soap opera.

Pacificon 2010 Wrap Up

This past weekend the Mount Diablo Amateur Radio Club hosted ARRL Pacificon at the San Ramon Marriott.  I was glad to see the event back this year, after last year's debacle which forced the organizers to move the event to Reno in conjunction with EMCOMM West.

This year's event was well-attended.  There were some great presentations, I got a chance to see some folks I don't often see, and I was given the chance to speak twice; including delivering the final keynote on Sunday.

I promised several people that I would post my presentations, so here they are:

   Weak Signal HF with JT65A

   Ham Radio Must Die!