Posts Tagged ‘science’

July Greenland Trip

August 29th, 2015

Made a quick trip to Greenland for three days in July to work on some equipment there.  I did not get on the air due to work activities and operation of the incoherent scatter radar whose modulator trashes the HF bands if you’re close to it (i.e., same building).  A few photos, though.  These were all shot with an iPhone 5s, nothing fancy.

Signal and Noise

August 4th, 2014

“One man’s signal is another man’s noise,” began Dr. Kudeki as he derived incoherent scatter radar theory from Nyquist’s noise theorem in ECE458.  I think of that statement often, whether it be QRM on the ham bands or sifting through the pocket litter of web users looking for their consumption preferences.

This morning, I admired just such an example of signal and noise while watching the NOAA Doppler weather radar.  Undesired targets of a radar that return echoes are termed “clutter” in the radar parlance and one simplistic way of eliminating clutter, especially when you expect the desired scatterers (“targets”) to move, is to assume that all of the stationary returns are clutter.  In the weather radar, we get clutter from all sorts of stationary things like trees, hills, and buildings.  Of course, what causes the clutter to move?

You see, it was one of those humid August mornings when a ham’s mind wanders to…tropospheric ducting.  Yes, indeed the clutter returns were moving, intensifying before and after sunrise.  I was fixated on this and watched the loop over and over again before noticing an even more interesting bit of clutter!

3x2_scaled

Beginning at 0958 UT on 4 August 2014, there is a small ring forming out over the Elk River area.  The ring, which is indicated by the downward-pointing vertical arrows, expanded over the next >40 minutes.  I was puzzled and watched the loop over and over.  I considered and discarded a number of theories before resorting to Google.  Apparently, it’s very likely a flock of birds.  Sure enough, the epicenter of the ring is Elk Neck State Park.  Fascinating.

The slanted arrows in the figure above indicates the ground clutter that I was originally noticing as a signature of tropo ducting, obviously now of secondary interest in this sequence of images!

Epilogue:  I sent these frames to my father, who is an avid observer of the natural world.  He passed them along to two friends back home who are birders.  At press time, one reported that he had learned of these “bird circles” from Greg Miller, another birder from the area who got famous as one of the subjects of the book (and movie of the same title) The Big Year.  I haven’t read/seen it, but I guess they went to Adak, which has a special place in my heart.  Anyhow, it’s a funny small and interesting world in which we live.

 

Svalbard

June 1st, 2014

dogskiing_web

An annually-recurring professional meeting has started to put me in interesting DX locales.  This year was no different: the meeting was held at UNIS (University Centre in Svalbard) in Longyearbyen, Svalbard.  My friend and colleague, Nathaniel, W2NAF, did a semester of his graduate studies at UNIS and was excited to return for the meeting.  He suggested that the JW5E clubstation “hut” (depicted below) might be both an attractive lodging option for cost, location, and of course, radio.  The hut is a bit rustic with no running water but we did manage to maintain a nearly professional level of appearance and personal hygene due to Nathaniel’s insider knowledge.

jw5e_web

As is typical for the kind of travel I do, there was no straightforward way to get from A to B.  Nathaniel and my flight schedules put us into Longyearbyen (via London, Oslo, and Tromso, in my case) on Friday and Saturday, respectively, giving us a shot at the CQ WPX CW contest.  We elected to operate this under our own callsigns, which proved to be a bit of a limitation since for much of the contest 20 meters was the only band that produced rates.  So, we had to share 20m.  Nathaniel operated high power using the JW5E FT-1000MP mkV and Icom IC-2KL amplifier connected to the JW5E antenna system.  I operated low power with my K2/100 and the JW5E antennas.  He came out a little bit ahead on QSOs and pretty far ahead on points, mostly due to the day of head start and effectively exploiting 20m.  I also worked a lot of empty-calorie EU stations while he focused on 3-pt DX stations.  Despite our initial optimism, neither of us were particularly dedicated to a full effort in the contest.  We both had a bit of trouble adapting to polar day and slept through prime openings on Sunday.

40 meters and lower frequency bands were useless, as were 10 and 12 meters. Nathaniel and I did work each other on 160 with the power turned all the way down.  And, of course we worked each other in the contest for an easy prefix multiplier.  The 12m situation was a little disappointing since I know a lot of people needed JW there.  Had we been there in March, it probably would have been open.  I worked two CTs and that’s it.

During the week of the meetings, I only managed 1-2 of hours operating each day, and Nathaniel maybe a little more.  We developed a protocol of uploading to LoTW first thing in the morning when we got to the meeting (where we had free network access, versus roaming 3G on my phone at JW5E).  Since I don’t use ClubLog, this is a good way for DXers to see if they’re in the log and get a quick confirmation.  As I told a DXer who thanked me profusely for doing it, my employment covers the largest costs of my DX travel and my operating is secondary to my work.  Therefore, I feel no need to extract or solicit donations from DXers. I am ordering cards today and they will be ready to mail in a week or two.

On the last night, I put in a solid 6 hours of operating, making about 600 QSOs in one sitting.  30m was always a struggle with most signals right near the noise level.  The other bands (15/17/20) produced big signals and were pretty easy to work.  I’m always a bit slow to operate split because I don’t want to use more bandwidth than necessary.  With an amp, I could probably have operated simplex most of the time.  Usually once people stop coming back to my 599s or they start duping me mercilessly, I know it’s time to split the pile.

The pileups were generally very responsive to my instructions with only one station really raising my blood pressure to the point that I QRT’ed to cool off.  Based on his QRZ.com profile and how loud he was compared to all the stations he was obliterating, he was running as much as 4 kW on 30m.  Good show.

I heard that someone on a DX club e-mail list suggested that I go next to Jan Mayen (JX).  Please negotiate that with my wife and we can work something out. Don’t forget to include that Jan Mayen has one flight per month.  My Norwegian colleagues were amused by this and asked also about Bouvet (3Y).  Only scientists and hams know about Bouvet and Jan Mayen.  Seriously, if I didn’t have a young family, I would consider doing that sort of thing, but I miss them too much when I travel.  The next DX trip will be someplace warmer with regular commercial air service.

jw_k8gu_web

I’m still sort of converging on the best equipment for portable DX operating. While I like the K3 a lot, the K2 is a bit smaller.  In its flight case, it fits under all airliner seats and not just some of them like the K3.  Although it is a stupendous performer, the K2 has some idiosyncrasies occasionally cause me to notice that it’s not as well integrated as the K3 and modern JA radios.  The diminutive size and negligible RF emissions from the MRF-4125 switching power supply are big pros, but I noticed the fan making a particularly awful noise on this trip.  Need to look into that.  The K1EL WKUSB continues to be a star performer for computer and hand keying.  While I love the action of the Palm Mini paddle, the lack of a solid base can be frustrating.  I brought the recently-mounted Schurr Einbau and it sang. Although, it produces the best reactions from security screeners: “What is it?  Is it an antique?”  And, my favorite from a screener in Longyearbyen: “Is that the new iPhone?”

The real stars of this operation were the Etymotic Research MC5 in-ear monitor earphones.  Wow.  I’ve been using them for a couple of months now at the recommendation of someone on the Elecraft reflector and they are my new favorite headphones for travel.  They do excellent with noise isolation on long-haul flights and in noisy QTHs; they reproduce music flawlessly; you don’t have to turn the volume up to 11 to hear with them; and they fit in a tiny little pouch that’s smaller than a deck of playing cards.  And the best part?  They only cost 60 USD.

The GU Special came along on this trip but was not needed since I had access to an OptiBeam for 20/17/15 meters, dipoles for 30/40/80, and a Cushcraft R7 vertical for 40-10 meters.  I was tempted to take my gear on the 8-hr boat trip we took up another fjord.  However, I decided against it for a variety of reasons including the desire to do some birdwatching and look for polar bears—we saw some seals and an artic fox but no bears.  The seals and the fox amounted to no more than a couple of pixels in the photos I tried to shoot of them, even with a modest 200mm telephoto lens.  OK, that’s a short lens by wildlife photo standards.  Please accept this puffin photo in place of a bear photo.

puffin_web

And the Tempelfjorden glacier and sea ice shot from my phone…

tempelfjorden_web

This photo is looking back up Adventfjorden toward Longyearbyen and shows the JW5E tower right near the water in the center.  (The heftier one on the right.) Also in the background are the dishes for the EISCAT Svalbard incoherent scatter radar.
jw5e_eiscat_web

And a photo from our visit to EISCAT in tracked vehicles.  It was practically June and there was a lot of snow on the ground.

eiscat_visit_web

Finally, here are two YouTube videos related to our operation.  The first was shot by W2NAF and has a tour of the JW5E station.  The second was shot by KB9UWU during the WPX contest and shows pretty much what 15m was like for me: the band was obviously open but I didn’t have many callers.

 

Thanks to everybody who stopped by to say hi.  I worked lots of friends on the air from all over the world and received SWL reports from a few more.

A Summer Trip to Greenland

August 3rd, 2013

the_office

A professional colleague who is the principal investigator of the Sondrestrom incoherent scatter radar facility announced at a conference that they no longer had a scientific high-rate GPS receiver at the site for making ionospheric measurements.  I enthusiastically volunteered to ship them one that I had on the shelf.  She suggested that instead I should come install it myself and I found some support to do it (the National Science Foundation heavily subsidizes U.S. Greenland and Antarctic scientific travel during their respective summers, making this trip possible).  Therefore unlike my previous trip in the winter, this trip did not involve travel with the most perverse of arrangements flying to Copenhagen only to hop on another plane and fly half-way back to the States.  I set off for my second trip to Greenland, leaving Scotia, NY, early on Monday and returning mid-day on Friday.

On the past trip, conditions were really awful for radio with plenty of visible Aurora.  I didn’t really mind that because the auroras were beautiful, but with only a small chance of NLC/PMC (noctilucent/polar mesospheric cloud) sighting in the summer, I was eager for some good radio conditions to sate my appetite for other nerdy activities.  I set up the radio equipment almost right away the first evening to make sure that everything tuned up and immediately made 10 or so QSOs on 20-meter CW before heading to bed.

Instrument installation is always a hairy business, especially when you can’t just run to a hardware store, let alone going to RadioShack or calling McMaster-Carr.  Sometimes, everything works smoothly; other times it doesn’t.  In any case a flexible attitude (and some good old ham practicality) goes a long way.  Wind gusts of 40-50 mph (18-22 m/s) on top of the hill made for exciting work, but having a couple of helpers made it go smoothly.  Here is a photograph of the installed instrument on its hilltop (the box and green antenna on the right-hand side of the pole, which also held a weather station).

instrument
Work, especially some recalcitrant Windows 7 issues (At one point, I was running Windows 7 in a VirtualBox virtual machine on a Linux machine and logging into the Linux machine from a Mac!), kept me pretty busy on Tuesday and Wednesday and I only managed a few minutes of operating on each of those days.  But, by Thursday, my schedule broke loose a little and I was able to operate for a few solid hours in the afternoon and evening.  I had no idea that Greenland would be so popular on 30 meters!  Wow.  That’s definitely the most intense pileup I’ve ever experienced.  Thanks for being patient.

There was some about S3 hash on 20 and 30 meters that the K3’s NR function would take care of but the NB function wouldn’t.  NR is not good for running pileups, so I often had to get the caller isolated to use NR.  On the receiving end, there was a lot of fast QSB, with a period of a few seconds (this is consistent with magnetospheric and plasmaspheric waves that impinge upon the auroral and subauroral regions.)  In any case, callers were up and down, often in the span of a call.  You all on the other end may or may not have observed the same from me.

Per usual, the setup was an Elecraft K3 and the GU Special vertical with 2x 1/4-wavelength radials for each of 20 and 15 meters.  Everything else was tuned by adjusting the length of the radiating section.  This is a substantial improvement in performance-to-size ratio over the previous station I carried in January 2012, which was a Yaesu FT-840, DK9SQ 10-meter telescoping pole, and a variety of wire antennas.  Below is a photograph of the GU Special deployed (it’s in the center, unceremoniously ty-wrapped to a wooden sign post sticking out of a barrel).  The diesel Toyota HiLux pickups are the most popular vehicle in town.  We gave a visiting graduate student lessons in driving a manual transmission.  Great vehicle to teach/learn on with lots of torque and low gearing!

gu_special_sonde

Although I was unable to connect with them, we did drive past the OX2A/XP1AB site on Black Ridge that overlooks downtown Kangerlussuaq:

ox2a_xp1ab
Thanks for the QSOs.  The log has been uploaded to LoTW this morning and QSL cards are ordered.  I never ordered cards after the last trip, so it will be a shared card with a photograph of the aurora.

Aurora 15 July 2012

July 16th, 2012

I was enjoying a leisurely sweltering summer Sunday afternoon in the back yard with Evan, Sarah, two Adirondack chairs, a kiddie pool, and the schematics for an IC-290A I have on the bench.  I came in to get a glass of water and while I was inside, I checked my e-mail (since I have some equipment for sale).  No prospective buyers, but I did have a message from Sean, KX9X, that he was working aurora on 6 and 2 meters.  I quickly plugged in the 2-meter rig and swung the beam around to the north.  Sure enough, there were raspy aurora signals all over two meters.  I quickly put N9GX (EN60) in the log for my first ever aurora QSO.  This was at least as cool as working K5QE on 2-meter Es with 10 watts.

So, I fumbled around a drawer and pulled out a cable to connect the TS-700S to the computer and fired up Audacity.  I made this interesting recording of KA1ZE/3.  I started out with the beam to the NE (45 degrees azimuth) with a strong auroral buzz on Stan’s signal.  Then I swung the beam around to the NNW direct path (345 degrees azimuth).  I’m in FM19la and he’s in FN01xt, which is exactly 200 miles (322 km) direct path.  On the direct (forward tropo scatter) path, there is still a hint of aurora, but the tone is a bit purer.  When I turn the rotor there is pretty bad hum from a (not unexpected) ground loop.

In order to better visualize a few things, I ran a short-time Fourier transform (this is the actual technical term for a “waterfall”) on the audio file.  I need to code-up a polyphase implementation of the FFT like that used in Rocky, but there are only so many hours in a day.  Click on the image for full-size.

There are lots of interesting details here.  First, you can see that the auroral scatter is both Doppler-shifted (lower in frequency) and Doppler-broadened (spread out from the central frequency) compared with the direct tropo scatter signal.  Second, you can see the ground-loop-induced hum at the low-frequency end.  Auroral backscatter comes from field-aligned plasma density irregularities embedded in the auroral convection flow.  Because most readers will be allergic to the vector math, we make the (somewhat gross) approximation that KA1ZE and I are transmitting and receiving from the same location.  Now, we can take a stab at estimating the flow velocity from the following equation:

Where delta-f is the Doppler shifted frequency (about 300-Hz from these data), c0 is the speed of light (300,000,000 m/s), f is the carrier frequency (144 MHz), and vflow is the flow velocity.  While we’re making approximations, if we round f up to 150 MHz, the twos cancel and we get the Doppler shift of 300 Hz corresponding to a flow velocity of 300 m/s (670 mi/hr).  Fast!  Because it is lower in frequency than the direct signal, we can also infer that the flow was directed away from us.

There you have it!  Science fair projects with your ham radio.

OAx/K8GU

April 3rd, 2012

Loyal readers know that from time to time, I am fortunate to travel to interesting and exotic locales for work—they usually come in pairs, so Greenland and Peru are it for a while.  Although the motivation is usually field work, occasionally a conference pops up.  The International Symposium on Equatorial Aeronomy occurs every three to four years and can be counted on for an exotic locale.  Sarah had such a good time when we attended the 12th ISEA in Crete in 2008 that she insisted on attending the 13th in Peru with me this year.  Of course, Evan complicated that a bit, and so we evaluated the pros and cons of leaving him with grandparents or bringing grandparents along, eventually finding a willing pair of grandparents to come along.  If you’re interested in a general travelogue (and following posts) and some photographs, you might check out my father’s blogs.  This short post is mostly focused on radio aspects of the adventure.

In retrospect, it may not have been such a good idea to bring ham gear to this meeting.  Between being the most seasoned traveler in my family and the only one with a functional command of the Spanish language, plus Evan, plus hours of meetings and collaborations each day, there was little time/energy to actually operate.  Getting to Peru was uneventful—we took an American Airlines codeshare flight on LAN Airlines via Miama to Lima and got there early in the morning.  Unlike their neighbors to the south, Peruvian Customs is by far the most curious I’ve encountered while carrying radio gear—just a minor headache but Sarah was a bit concerned when they took me away for additional questioning.  I carry modest gear—a Yaesu FT-840, Astron SS-30 (this should be replaced with something smaller, but it’s what I have), WKUSB, Palm Mini-Paddle, the K8GU portable antenna system, and various cables to connect it all up.  After clearing Customs, we boarded a bus to Paracas, where the meeting would be held…

Paracas, which is about four hours’ drive south of Lima, was the site of a major earthquake several years prior and is still in recovery.  The hotel that hosted the conference and a few nearby hotels had all been rebuilt from the ground up since the earthquake.  The city is on a small bay that is protected from the Pacific.  It’s very beautiful—desert sands that go right down to the bay.  After a few days at the meeting, I managed to get the antenna set up.

One of the things that surprised me was an excellent JA opening on 20 meters just after sunrise before I went to breakfast and then the meeting.  I am pretty sure it was a direct-path opening because the signals did not sound like long path and the long path crosses the southern auroral oval, whereas the direct path does not.  (Auroral absorption, by the way, is one reason that the long path can be more effective than the short path.)  Any time I called CQ as OA5/K8GU, I was greeted with a roaring pileup.  Not bad for an antenna propped up on my veranda.  Verticals on the beach rule, and this one wasn’t even really on the beach.

At the request of a friend, I made a special effort to operate on 12-meter CW in the afternoon.  The portable antenna would not tune up on 12 meters with the wire radials I had laid out.  In a moment of desperation, I assembled some extra pieces of my portable antenna to produce a tuned radial that I clip-leaded to the ground lug as depicted in the photo above.  It worked right away and I was quite popular there as well.

A comment about computers—my standard work-issued computer is a MacBook Pro, which although perfect for my work, is essentially useless for amateur radio.  I know this will generate a torrent of discussion, but if you are accustomed to real contest/DXpedition logging software available for DOS and Windows, you know that the stuff for the Mac doesn’t cut the mustard.  I have logged DX operations on paper (CE/K8GU), or in the case of the OX/K8GU operation, brought along a second computer.  However, in a long-delayed flash of insight, I bought and installed VMware Fusion on the Mac in February.  It runs Windows XP and TR4W with the WKUSB just brilliantly and with no special configuration.  Aside from having to press Fn+F1 to CQ, this was an epic win.  KB9UWU tells me that there’s an option in VMware to eliminate this nuisance as well.

After the meeting in Paracas, we returned to Lima, where we celebrated the 50th anniversary of the Jicamarca Radio Observatory.  The cornerstone of the Jicamarca facility is a 49.92-MHz radar that feeds an 18,720-element phased array, pictured above.  Jicamarca is one of the most powerful radio transmitters in the world, capable of 4.5 MW output, and is used for a variety of atmospheric, ionospheric, and space science experiments.  Like Arecibo, it was originally designed to perform incoherent scatter measurements of the ionospheric electron density profile.

Lots of fire in that wire!  Have you ever seen a coaxial cable that’s rated for over a megawatt at 50 MHz?  This is the feedpoint of the phased array.  There are a few tuned stubs in there, too.

Here’s one of the four 1.5-MW transmitter cavities.  A maximum of three are used together.  When configured for three transmitters, the driver stage puts out 7 kW!  Needless to say, everything is custom made on site.  The transmitting tetrodes (8973s, if I recall correctly) are refurbished by the manufacturer as needed.

After Jicamarca, we went to Cusco, which is south and east of Paracas, and much more lush than the deserts around Lima and Paracas.

We spent a lot of time being tourists in Cusco and vicinity and I had some difficulty with my computer so I only made a handful of OA7/K8GU QSOs from Cusco on 17 meters.  It is quite remarkable how much better the bands were from the coast.  As someone who has operated from W3, W8, W9 and W0, I can attest to that difference as well.  I missed my morning JA run…

A final thought—we drove through a lot of towns and communities in OA4, OA5, and OA7, on this trip.  Nearly every town, no matter how small, had at least one building with an HF fan dipole on the roof.  HF is alive and well in a mountainous country like Peru!

QSL information:  If you worked OA5/K8GU or OA7/K8GU, the best way to get a confirmation is through ARRL’s Logbook of the World.  I have been responding to direct cards (to my FCC address) with a one-day turn-around lately.

A Winter Trip to Greenland

February 3rd, 2012

Last year, I managed to scrape together some equipment funds at work to buy a small spectrograph system for studying atmospheric light emissions (airglow and aurora).  A co-worker secured the funds and contacts for us to install it at an observatory in Greenland.  Because we need to make the measurements at night, and because the instrument was delivered in early December, we made immediate plans to go to Greenland as soon as possible.  (Sarah is certainly laughing at this point because the plans were actually far from immediate and we bought our passage just over one week before departure.)

Greenland is only a short (4- to 6-hour) flight from the NE U.S., however the only route that operates in winter (and indeed the only commercial route) is on Air Greenland via Copenhagen, which operates four round-trip flights per week in winter.  This turned getting there into a two-day affair of perverse travel arrangements totaling over 12,000 air miles to go about 4200 miles round-trip on the great circle.  I met my co-worker, a United Airlines devotee (myself an American Airlines devotee), in Copenhagen and we flew to Kangerlussuaq (Sondrestrom) on Air Greenland.

One of the things that strikes you about Greenland as you approach Kangerlussuaq is how otherworldly and remote it is.  Kangerlussuaq is the site of the former U.S. Sondrestrom Air Force Base, and one of two runways (the other is at Thule) on the island large enough to accommodate aircraft capable of flying to Greenland from abroad (this is a mild, although amusing exaggeration).  Air Greenland has its hub there, shuttling passengers off to towns around Greenland on twin-engine turboprops like the Dash-8.  It is, as our host explained, “…not your typical Greenland town.  It is far inland at the end of the fjord and not on the coast.  The only reason it exists is because of the airport.”  Fuel and supplies are all brought in from outside.  Like most current and former U.S. military installations worldwide, it is reliant on diesel fuel for its on-going existence.  It’s sobering to be someplace that is totally unsustainable, although one might argue similarly of many U.S. cities, but I digress.

Kangerlussuaq is also near “the dog line,” north of which sled dogs are very common.  Here is one of the two road hazard signs we saw while driving around…dogsled crossing:

The instrument set up easily the first afternoon and we were able to collect some data with it that night.  As we were setting the instrument up, we heard reports of an Earth-directed CME from the Sun and hoped for aurora over the next few days. We were not disappointed…

The second night, I stood “aurora watch” in the cold while my warm-blooded co-worker processed the previous night’s data.  Soon, I saw some faint cloudy white sheets way down on the horizon and I ran back in to alert him and retrieve the camera tripod.  This photograph was taken facing toward the east southeast.

And, the 3.5-MW peak L-band incoherent scatter radar was running.  The dish is blurred because it is moving.

And, here is a shot of my fan dipole strung up on the DK9SQ mast.

Speaking of radio, I did manage to make a few QSOs as OX/K8GU on 17 meters, but not as many as I would have liked.  The combination of high absorption in the auroral oval (mostly to our south during our stay), little sunlight, a poor low-angle shot (required to avoid the auroral zone) to North America, short openings, and the fact that we were well-occupied with work for the four days we were there conspired to keep my contact count low.  QSOs will go into LoTW soon—the certificate was issued yesterday.  I have not yet designed a card, but there will be a special card.  Thanks to those who did contact me.

7-bit Barker Code and Matched Filter

January 8th, 2012

Teaching Evan the basics of radar signal processing with this baby-block 7-bit Barker code and its matched filter.

Wallops Island SuperDARN

February 21st, 2011

A few photographs from work on the Wallops Island SuperDARN radar last week…

Locality Bias

January 3rd, 2011

Slate Labs has an “interactive tool” to look at food deserts in the U.S. by county—places where a healthy variety of food is unavailable.  They define a metric of desertification by counting the number of people who do not have access (not sure how this is defined) to a car AND live farther than one mile from a supermarket (not sure how this is defined, either).  So, I went looking at some places I’ve lived.

My home county is Holmes County, Ohio.  If you look at the map, it’s the one that’s an island of dark brown in the middle of Ohio.  27.91 percent of Holmes County is a food desert by this metric!  Blame it on the Amish.  Because the county is rural, there are few grocery stores.  And, because the Amish do not have access to their own cars, they count a large portion of this population.  Other counties with large Amish populations (relative to the non-Amish population) also stand out clearly.

It also appears that the map is distorted by population density, with sparsely populated areas being more prone to classification as food deserts.  Is this fair?  Is there anything that can be reasonably done about these areas even if they are food deserts?  I don’t at all disagree that this is an important, significant problem, but it seems that there might have been a better metric.  Perhaps it’s the most accessible metric with the available data?

Although this map may be revealing in many ways, it also distorts the reality a bit.  For me, it’s a reminder to not consume “news infographics” too casually.  I haven’t read all of the comments on the Slate piece and probably won’t.  So, forgive me if someone has already noted some of the above.  As a final note, most of the people who write for Slate are relatively ignorant of what happens in the part of the country between the Coast Ranges and the Appalachians.  So, as one commenter wrote, it’s a “typical urbanite view” of food.