Wednesday, December 18, 2013

What's Wrong with CT? (telephone edition)

This article in the Hartford Courant lays it out:

The independent phone company known as 
Southern New England Telephone (SNET)
was bought out by
Southwestern Bell Company (SBC)
was then bought out by
American Telephone & Telegraph (AT&T)
which is now being bought out by
Frontier Communications
doing business as (possibly) 
South New England Telephone (SNET)



SNET was independent for a long time and never fully part of the original AT&T.  In the new deal, AT&T will retain only its wireless phone service in CT.

All in all, the wired telecom business is sinking pretty fast as a fraction of the telecom market.  I suppose a smaller and more agile company should be managing it;  maybe that's Frontier.  On the other hand, if it is locked out of the wireless business and it doesn't have lots of capital available, will it ever be at the forefront of technology?  Will CT residents resume their status as a telecom backwater? Will there be more or less competition in this market?

State approval is needed, but I'm not feeling optimistic.  On the bright side, we dumped AT&T U-verse service in favor of Comcast for phone, data, and video a year ago.

Saturday, October 26, 2013

Data Footprint Control -- Your own email server!

Lately I've been talking up the idea of "data footprint".  It's a fact that we're spreading all kinds of personal data around the Internet in the course of our modern electronic and financial lives.   Our bank, Facebook, Google, Yahoo, Comcast and essentially everyone we do business with is collecting data about us. The data get bought and sold and snooped no matter what our wishes may be.

One concrete thing I could do, while having a bit of fun, was to move my Google email back to a server computer under my own control.  That's (a) a rather old-fashioned thing to do, (b) rather complicated to set up correctly, and (c) a losing game in terms of functionality.  No doubt Google Mail sets the standard for usability, especially for power users.  It also has the best anti-spam technology I've come across.  So if we step back to a local server, we will be losing some useful features.

It happens I have an older Raspberry Pi (256 MB Model B) which hasn't had a particular mission.  So now it is the household IMAP server, with my 1.6 GB email stash on a 16 GB SD card.  It would have been easier to use a big PC for this function, but I wanted a platform that I could leave on 24/7 without eco-guilt.  It uses just a couple of watts of power.

I am temporarily (until I forget all the details) an expert on Postfix, Dovecot, and SSH, allowing me to access the e-mail from any machine on the home network and (securely) from external machines. Fortunately, I have an external SMTP relay that is part of my web hosting service, so outgoing e-mail should be treated with proper respect by the big services.  (A user PC directly sending out SMTP mail is often shunned as a likely source of spam.)

It's a just a symbolic step. We have a long way to go before we get control of all our data.

UPDATE 1: The dirty little secret they don't tell you at e-mail school is that most e-mail is spam, and an e-mail server without spam filtering is ... not worth a lot.  On the client side, Thunderbird and some others make a valiant attempt, but it wasn't going to work for me.  Especially since I want to use an Android client like Kaitin (no spam filtering) for mobile e-mailing.  So I consulted  https://help.ubuntu.com/community/PostfixAmavisNew. (Ubuntu is close enough to Raspian.) Everything installed OK until it became clear that my 256 MB Pi might not support a big freshclam update.  OK, we don't need antivirus for Linux/Android, do we?  Anyway, the server has started bouncing spam pretty well now.  And the Pi can feel virtuous as it crunches on each message for a second or two.

UPDATE 2:  ClamAV is hopeless, taking way too much RAM and CPU.  Fortunately Amavis doesn't need antivirus, so it's OK just to remove it from the system.  Even so, Amavis & co. take a lot of RAM and just fit in the 256 MB machine along with Linux.  If I start doing package updates, for example, there is a lot of "disk" thrashing -- swap utilization climbs, and things go very slow for a while.  (But no crashes!) A 512 MB machine would be much better.  Spam scanning and message handling seem to take 5 to 15 seconds per message.  This is not a high volume solution, but it handles my load OK.

UPDATE 3: This project was a success technically, but Comcast woke up to it (maybe they read my blog?) and they blocked port 25 on my service. Maybe I could have argued my case, but I didn't pursue it. Instead, I moved my email action to Pobox.com, a commercial outfit that specializes in email - and doesn't sell my info to the highest bidder, hopefully.

Wednesday, October 23, 2013

ARRL Handbook: Cool, but Heavy Reading


Yesterday, I got my engraved hardbound copy of the 2014 (Centennial) Handbook.  It's the Ham Bible, they say, but it's big!


In fact, it weighs in over 6 lbs (2.7 kg). This makes it rather difficult for reading in bed, especially for us geezer types.  (Note for reflection: the actual Bible, as usually printed, is much more user-friendly!)

My solution: upload the CD right away to Google Drive.  (privately) That makes it available wherever I'm likely to be.  And with the Nexus 7, it's quite manageable while reclining!

So apart from the cool-factor of having this tome on my bookshelf, it would be just as well to get my Handbook via Google Drive directly -- or some other network based solution.

(We might ask what it would be like if each chapter of the Handbook had an accompanying online wiki where readers could add their material.  Mixing curated and non-curated content would be a challenge, but a worthy one!)

At right is the classic ARRL graphic (ca 1975) that I seem to carry around in my head.  A very nice portrayal of the then-modern ham!

And strangely enough, it must be one reason while I frequently go up to HQ, and why I'm thinking about the Second Century Campaign.

Sunday, October 20, 2013

Station Computer Upgrade

I had enough!  My creaky Intel Atom-based computer had enough oomph with Ubuntu to run fldigi, but just barely.  It couldn't handle a browser and logging program running alongside very well. So the D945GCLF motherboard supporting an Atom 230 processor and 1 GB of RAM is now surplus. (See right.) Note that it has on-board serial and parallel I/O ports - a rarity now! (I originally chose the Atom board as an experiment to see how small a processor was really necessary. I answered that question.)
Upgrading was straightforward.  I could keep the power supply, case, DVD drive, etc.  The board is an MSI B75MA-P45, which will run many current Intel chips.  (Left) I selected the "Celeron" G1610 (2.6 GHz, 2 cores) to run with a "mere" 2 GB of RAM.  Choosing the configuration was helped quite a bit by Ars Technica's "Bargain Box" System Guide. My logic was that any new system, even a "bargain" system, would be way better than what I had been using.  And that has proven correct.

The hardware change went smoothly enough.  The real work (no surprise) was building the new Ubuntu environment with needed development tools and Amateur Radio applications. It will be some weeks before we get all the way back to equilibrium.

Added: I ran the BOINC Whetstone and Dhrystone benchmarks on the G1610 and then on my "big" i7-920 machine.  For 2 cores, the G1610 gives 2768 floating point and 16928 integer MIPS per core. For 2 cores (of 4), the i7-920 delivers 2869 floating and 16577 integer per core.  So core for core, today's "budget" CPU is comparable to a premium chip of a few years ago.  Such is Moore's Law. The '920 will run 8 independent execution threads across 4 cores, giving it 2-4 times more potential in terms of throughput. In practice, that throughput is only realized when I'm cranking 8 threads of BOINC apps, which is a nice thing to do, if your tastes run to extraterrestrial intelligence, pulsars, or gravity waves.

Purists will note that Whetstone and Dhrystone aren't great benchmarks, and I'd have to agree. All I will say is, they came easily to hand, and they're better than BogoMIPS.

Monday, September 09, 2013

Let's hear it for AM radio!

NYTimes: A Quest to Save AM Before It’s Lost in the Static http://nyti.ms/1aX6J4Y

Friday, August 16, 2013

So *you* have radio interference problems?


If you want to work at the National Radio Astronomy Observatory at Green Bank, WV (my stomping ground in ancient times), you better be prepared to leave your technology behind.  It's a little ironic, because they have some of the most powerful computers, receivers, and electronics you would ever hope to use, but all the local equipment is rigorously RFI-suppressed and tested in anechoic chambers before it is installed.

Check out "The Enemy Is Us" (pdf).

Added: NRAO Green Bank is near the center of the National Radio Quiet Zone.  This is a much larger area (13,000 sq. miles) where all radio emitters by law have to be coordinated to minimize impact at NRAO.

Thursday, August 08, 2013

Luddite Cellphone Report


For a few years, I've been telling folks about how I've gone from a $100/mo. smart phone service to  $10-15, non contract, on a barebones Tracfone device.  I don't need e-mail and Internet connectivity when on the hoof, and I have a Nexus 7 tablet for navigation and portable use. Lately, we've had a weird sequence of events that got me to re-evaluate, but the situation is stabilizing now.

The story outline:

  1. Noticed that my car's Bluetooth hands-free system isn't functioning.  After a few days,
  2. Leaning over to check my pool water, and my Tracfone fell out of my pocket into the deep end.
  3. Phone is retrieved after 5 minutes and placed aside to dry out.  Not much hope, as my last Tracfone suffered the same fate and never came back.
  4. Recalled that at least one smart phone is now being advertised as waterproof (or resistant?).  Maybe that would be a good one to have?  It would be nice to have mobile yelp and other services like my friends all seem to have...
  5. Trying to do some banking business, I discover that I'm blocked because I signed up for 2-factor authentication.  I can't add my wife's phone to the list without receiving a code on my dead phone.  (I could call the bank about this, but that's a last resort.)
  6. Google's 2-factor process at least allows me to use one of my one-time pass codes since, thankfully, I haven't lost my wallet.  Anyway, I better get a phone back with my old number asap.
  7. The quickest and easiest way to get my number working again is to go back to Tracfone.  I ordered a reconditioned LG.
  8. Phone arrives, costing a little over $20 including overnight air.  It wants me to charge for "5 hours", but charging is complete after about 2 hours.
  9. Now to the T'phone website to register the new unit and hopefully snag my old number back. End up with a human operator of uncertain nationality talking through a horrendous phone circuit.  She said many things that I did not understand, but finally it seemed we agreed on the basics.  (I hope I did not agree to sell my firstborn.) My number should be effective overnight.  Actually, it only took an hour or so.
  10. The new phone became registered in stages.  At first, I could dial out, but not receive calls.  Then it seemed I could send text message, but not receive them.  After 1-2 days, we seem to be fully registered wherever cellphones get registered.
  11. Car's hands free Bluetooth is still bust.  I'm guessing that repair will either be free (find the right reset button) or probably 10X the cost of the new phone.
So I'm outfitted with a new (old) phone that is rather snazzier than my previous Motorola W376g.   Still no email, no yelp, etc. but it's a phone.

Tuesday, May 07, 2013

Raspberry/Beagle/Core Benchmarks

Measured the other day using iPython:

iPython's "timeit" function is hardly the last word in benchmarking, but it can be very useful if you're thinking about Python applications.  Raspberry Pi is very powerful compared to Arduino, say, but very slow compared to modern desktop machines.   No surprises, but I haven't seen relative benchmarks before.

Saturday, May 04, 2013

Lousy Saturday on 40 meters


Solar weather (M class flare) makes the low HF bands very quiet this morning! Some day I have to dig in and understand the scale on this map.  It says we're affected by "1 dB" on 40 meters, but I'd say it's more like 30 dB from listening on the band.

Check http://www.swpc.noaa.gov/drap/global.html for the latest.

Tuesday, April 30, 2013

Raspberry Pi - 30X more time for coffee

alliedelec.com
My Raspberry Pi is benchmarking about 30X slower than one thread (out of 8) on my desktop Core i7 processor. It's an interesting challenge to do real-time Python / wxWidgets programming on the little guy, but we're making progress.

Thursday, April 18, 2013

Cable to U-Verse and back again

Executive summary: AT&T U-Verse out, Comcast cable in.

I've been living as an Amateur Radio operator with AT&T's U-Verse service for about 18 months.  It was a great experiment, to see whether ham HF operation could be compatible with U-Verse's VDSL2 signalling.

VDSL2 delivers a bit stream over channels stretching from a low frequency to over 8 MHz, so it was a challenge to work at power levels over 50 W or so in the 160, 80, or 40 M bands.  We tried lots of things -- ferrites everywhere, shielding, etc.  At the same time, AT&T's technology improved, with higher bit rates and more tolerant modems.  We weren't too unhappy as U-Verse customers -- but that was only because I don't spend a lot of time on the air (especially QRO) during TV viewing hours.

Still, I have grown tired of having to think too much about my TV, Internet and phone service.  They should just work!  Even for radio amateurs.  Back to the cable world -- Comcast.

The problems with Comcast will undoubtedly come.  Maybe they'll throttle me if I don't watch enough NBC shows. But in 2 years, maybe we'll see Google or Verizon or somebody offering something more attractive?  Stand by.

Tuesday, March 26, 2013

KX3 IQ & Python SDR

It's a work in progress, but here's a shot of my Python / wxPython / Numpy "panadapter" display for the Electraft KX3.  The KX3 provides a very nice IQ output (wideband, quadrature audio), covering +/- 24 kHz around the VFO tuning frequency.

I have long been interested in building an SDR software backend using Python et al.   Two principles: (1) You don't understand it if you haven't coded it, and (2) Python is the quickest and often best way to put together complicated software.  It's most at home on Linux systems, but it is not hard to port most applications to Windows.  (Not quite so easy to port: hardware-oriented stuff like audio and Ethernet.)

Like most "friendly" apps, you find that 95% of the work goes into the display and user interface.  The numerical part is almost trivial, using Numpy:

    data = np.array(iqdata[::2] + iqdata[1::2]*1j)
    z = np.roll( fft.fft(data), SIZEC/2)  # place center freq in center
    pwrwork = pwrwork + np.square( np.absolute(z) )

The total code size is about 590 lines at this point.

This application (kx3iq.py) is really a remote control app.  I "beam" the IQ data from the KX3 via my Beagleboard XM and a UDP Ethernet stream to the Python app across the room, with Hamlib rigctld provide rig control.  Using 16 bit 48 kHz sampling, that's a data rate of ~200 kB/s without any compression -- doable over most ISP's these days, if you want a long distance remote.

Wednesday, February 27, 2013

#SteppIR down


It was the last straw.  Today, we had a "normal" Nor'easter storm, with NE winds gusting to ~25 mph, they said.  The antennas at AA6E had largely sailed through two hurricane / tropical storms and a few other major wind events.  But this "mild" one pushed us over the edge.  One of the reflector tubes popped off.  Fortunately, my policy of routinely retracting the SteppIR elements has paid off.  You can see a bit of the tape sticking out, but it looks OK from my vantage point at least.


This is where the tube fell, apparently without much damage in the front patio.  (The tree branch is from an earlier wind storm.)


Here is where things separated.  It looks like the rubber boot has separated, but the tube itself is probably OK.  The storm is still on, so I'm going to wait to do a more careful check.

The SteppIR is one of the original 3-element type.  It went up in 2004 IIRC, and has been trouble-free until now.  I'm not complaining.  We will probably have to bring it all down and replace the silicone rubber bits.

Tuesday, February 12, 2013

Best spam lately

Today's Spam
My candidate for most educational spam is above.  Checking with http://en.wikipedia.org/wiki/South_Asian_numbering_system and current exchange rates, I find I am being offered something like US $ 1.5M.

I won't bite.  They seemed to have missed their demographic. (Note to Centurylink!)

Sunday, January 27, 2013

Cutting the cord: FB

My Facebook account is now "suspended".  It was a long time coming.  The many problems of being on Facebook are well known among internet-literate folk, but hard to explain to casual users.

As someone said, "if you can't figure out what the product is, the product is you."  FB makes money by advertising and by using tricky ways to get you to disclose lots of marketable facts about yourself.

The same facts can be used by almost anyone who wants to know something about you.  The most notorious case would be prospective employers, who are known to require you to give up your FB password, so they can see all your history.  No doubt the Federal government has similar interests in your politics or your research into exothermic chemical reactions.

We need to pull out of Facebook.  It's painful, because FB provides some very useful networking with people you want to connect with -- classmates, family, etc.  But it's not enough for me.

There are quite a few other social networking sites.  Yes, they're mostly free and they all share some of the same problems as FB, but that's where I am now.  Try me on Google+ (Martin Ewing) or on Twitter (@AA6E) or talk back to my blog.  I'm active on the ARRL member forum (AA6E), too.

You can suspend your FB account -- a kind of trial separation.  If it still seems wise in a week or two, you can have all your info deleted.

Saturday, January 19, 2013

Hams allocated 23,350 MHz

The good news: U.S. Radio Amateurs have frequency allocations (primary and secondary) of 23,350 MHz. (Primary allocations add up to 4,791 MHz.)

The less good news: 23,300 MHz of the total is allocated above 1 GHz, but 22,700 MHz of that is above 10 GHz, and 16,750 MHz is above 100 GHz.  Little day-to-day amateur activity takes place above even 1 GHz, but there is important experimentation in these regions.

Just a few tidbits from www.spectrumwiki.com.

By the way, these allocations would support about 7.8 million simultaneous SSB conversations at any given location.

Wednesday, January 02, 2013

Antenna Woe

I upgraded the AA6E antenna installation just before SuperStorm Sandy.  We pinned the beam to the mast and the mast to the rotator to prevent the slippage that occurred in Irene.  We also put up a Joel Hallas W1ZR style dual band skeleton sleeve-coupled dipole for 80 and 30 M, made from 450 ohm ladder line. (QST May and Oct 2011) All seemed well after Sandy's 60+ mph winds.

I haven't been on the air much since Sandy, while there have been a few biggish wind events and some snow and freezing.  When I went to work 80 and 30 on SKN on New Year's, I found SWRs of 7 and 8 to one.  The antenna is defunct.  But why?  I took photos from the ground, and no problem is yet visible.  (It is most likely an open or a short in the connection to the balun.)

The tower is hard for me to access (20 ft above a 20 ft roof), and I'd like to have a better idea of what has gone wrong before I bring in the work crew.








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