Archive for the ‘work’ category

April 2016 trip to American Sa’moa

May 17th, 2016

I had originally planned to make a maintenance and upgrade visit to my instrumentation in American Samoa in February 2016.  There are lots of advantages to February:  It’s cold here in W3, the ARRL DX CW contest is in February, and the phenomenon I’m studying is most active during the equinoxes.  I scheduled a 7-day trip that ended with the weekend of ARRL DX so I had the opportunity work through the weekend or play some radio if work went better than expected.

My flight had been booked out of Washington National (DCA) airport at 5:15 am Monday morning, which is the best possible time of day at the worst possible airport.  A snowstorm of unknown magnitude was bearing down on the mid-Atlantic.  And, around 4:00 pm on Sunday afternoon, I fell asleep on the couch.  When I awoke 90 minutes later, it rapidly became clear that I had a nasty stomach flu.  As my condition deteriorated further, I finally decided I didn’t want to be fighting that for the next 24 hours on 767s on my way to a foreign place where I wasn’t sure what kind of medical facilities I could access.  I cancelled the trip and spent the next 24 hours in bed instead.

The trip was rescheduled for three weeks later in March and I managed to get this itinerary out of BWI, which is much more convenient.  I loaded up my gear and went to the airport at 4:00 am.  My upgrade had cleared so I didn’t pay excess on my overweight and extra Pelican cases.  Hurray for small victories!  We sat at the end of the runway on the tarmac doing the preflight checks and the cabin lights started flickering intermittently.  And we sat, and we sat. And, we returned to the gate and sat some more.  I nervously refreshed the ETA on my phone finally watching the arrival in PHX slip past the departure to HNL.  I deplaned.

The agents tried to convince me that I could “just take the flight to Honolulu tomorrow.”  With some effort, I communicated to them that the HNL-PPG (Sa’moa) leg of my journey only goes on Mondays and Fridays and that I would rather be stuck at home for a week rather than a week in Honolulu.  So, I cancelled the trip for a second time.  My bags went to PHX and were delivered to my house the next day.  I rescheduled the trip for late April with a night in Honolulu on the outbound leg to avoid this bit of bad luck happening twice.

Two days before I left, my local contact called me on the phone to tell me that Tropical Cyclone Amos was bearing down on the island.  Fortunately, the hurricane dumped some rain and brought some winds but passed to the north of island.  The April trip went off without a hitch, although it was scheduled for four days (Monday night – Friday night) instead of the original seven.  So, I was hustling to get my work done and find time for radio.

I was vaguely aware that KC0W is also in KH8, but given my historical bad luck with this particular visit, I didn’t reach out to him.  In fact, he’s the one that contacted me once I arrived.  We met for breakfast at the McDonald’s in Tafuna one morning and had a nice long ragchew about radio and travel.  Typical hams.  I decided to focus on bands (especially 160) that Tom wasn’t on given my limited time on the island.

Fortunately, I had access to this mobile phone tower, which I use for my wireless networking for instruments as well.  So, I climbed up to check on the network equipment and put a pulley on the tower so I could raise and lower ham antennas safely after-hours when no one was around.


The tower is on the top of Cape Matatula, which sticks out of the northeast corner of Tutuila island.  It’s the bit of land jutting out in the middle of the photo below.  If you open the full-size photo, you can see the tower just at the edge of a rather precipitous drop-off toward the rocky shore about 1/3 of the way from the right-hand side of the frame.  Needless to say, it’s a great QTH with 270 degrees of saltwater view as I’ve mentioned before.  At sunrise and sunset, the middle and higher bands are open to EU, JA, and NA/SA all at once.  The pileups are thrilling but very challenging.


Here’s the radio setup from this trip:  K2/100, KPA500, WKUSB, and TRLinux running under VirtualBox on my Mac.  This worked OK, but the WKUSB would drop out every few QSOs and needed to be completely rebooted which meant that I had to unplug the USB cable and restart TRLinux.  Obviously, this worked when I tested it at home but I was not stressing it like I was in the field.  I’m not sure whether it was an RF issue or software/hardware.  In any case, I will probably be installing another Windows VM like I’ve used previously.


I only ended up making about 400 QSOs on this trip, which is way down from the approximately 3000 QSOs I made over the past two trips.  The combination of aggressive work schedule, glitchy keying, and poor 160-meter conditions (too late in the season, but I made a few guys happy), made it hard to get excited about operating a lot.  Furthermore, my operating position was located in a room with an air compressor nearby that would kick on every few minutes.  Even with the excellent Etymotic MC5 earbuds, it was still loud.  Enough complaining!  There will be at least one more trip out there under my present project and if KC0W hasn’t worked everybody, I’ll be there to give you all new counters again.  I just uploaded the log to LoTW before I posted this blog entry.  I have not responded to any direct QSL cards yet.

Pictures from KH8 (second trip)

March 1st, 2015

I made another trip to American Sa’moa (KH8 for the radio amateurs in the audience) to deploy instrumentation.  It was a tight timeframe but the instruments seem to work and I managed to make a few ham radio contacts as well.

Pictures from KH8/K8GU

October 8th, 2014

I don’t really have time to do a full write-up, but I made a “quick” trip to American Samoa over the weekend to plan a future scientific instrument installation and managed to get on the air for a few hours.  Here are some snapshots from my phone.

A Summer Trip to Greenland

August 3rd, 2013


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).

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!


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

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.

W3APL/B 903-MHz beacon

May 7th, 2013

Late last Summer, it came to my attention that the 903-MHz W3APL beacon had gone off-line.  The failure was intermittent and seemed to resolve itself after power was reset.  Several efforts to troubleshoot it were undertaken by myself and others, including running it at high duty into a dummy load over a period of days.  I was unable to get the problem to manifest itself on my bench.

A synthesized source (Analog Devices demo board) was offered by a friend of the Club, however it did not produce the desired output (or any output at all).  It’s not clear whether this was the fault of the synthesizer or the user (me).  The notional plan was to replace the beacon, which consists of a 75-MHz crystal oscillator followed by 12x of multiplication and a small RF power module, with the synthesizer and a new RF power module.  The project languished, as they often do in my hands.  But, two weeks ago I picked up the task again and made some real headway.

Really, the failure had to be one of a couple of things:  1.  Intermittent connection exacerbated by thermal cycling.  2. Oscillator “unlock” due to component aging and thermal cycling. I reasoned that as long as we could eliminate #1, the multiplier chain and amplifier should be fine.  The behavior seemed to point toward #2 or perhaps a combination of #1 and #2.  I came across a forlorn Programmed Test Sources PTS-040 that I had rescued from another group’s surplus heap to put in my lab.  I hadn’t used it in the two years that it was in my possession, so it seemed logical to provide it to the Club on a long-term loan.  The problem was that it didn’t go up to 75-MHz.  So, I cooked up a little multiplier chain.  My “good” HP spectrum analyzer is on-loan to a paying program so I had to make do with the FFT function on the fastest Tektronix portable scope I had in the lab.

My initial effort at the multiplier chain was to build a 2N3904 amplifier that swung way into saturation producing a signal rich in harmonics.  I went straight away for the 903-MHz signal but I couldn’t get a good enough lumped-element filter to eliminate the adjacent harmonics.  So, I tried for the 75-MHz injection.  This demanded a buffer amplifier so I lazily reached for the MMIC drawer in and retrieved one of the plentiful MAR-8s.  Plenty of gain…and, as I would find out in a moment…conditionally stable!  To exercise the eloquent euphemism of Ben, N3UM, the MMIC “burst into song” at about 63 MHz.

Back to the drawing board.  I knew that I had something that would work, so I redesigned the deadbug layout on an SMD protoboard (the kind with all the pads in a grid).  I replaced the discrete 2N3904 and MAR-8 MMIC amps with SGA-4586Z MMICs (which are a little too nice for this service, but I have a ton of them).  Viola!


It’s the little board on the far wall of the diecast box with the SMA connector on the left and two toroids.  37-MHz RF comes in from the PTS-040 through the BNC jack in the wall.  It’s multiplied up to 75 MHz on the new board and piped down to the remaining 12x multiplication and amplification stages before going to the little brick PA in the lower left (not visible).

So far, it sounds good.  I was able to monitor it with my W1GHZ transverter strapped to the IC-290A in my car and using a WA5VJB cheap Yagi tossed in the back seat.  I lost the signal about 5 miles away with that setup, which is really pretty decent all things considered at that frequency, etc, etc.  Nominally, the frequency should be 903.054 MHz.  I found it at about 903.048 MHz on the lash-up.  Brian, ND3F (aka N3IQ/R) reported that he found it at 903.046 MHz with KA3EJJ’s setup.  If you’re in the vicinity of FM19ne and are setup on 902/903, we’d appreciate a report.  The big thing is the long-term stability.  So, we’ll continue to monitor it.

Now…to get back to that 930 on my bench…


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.

Good Design

March 8th, 2011

Good design by Javad, just like the arrow hidden between the ‘E’ and ‘x’ in FedEx.

Wallops Island SuperDARN

February 21st, 2011

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


November 19th, 2010

Today we have a little bit of fun ham-related tinkering from work.  This is two different frequencies transmitted from the same site.

There are lots of neat details in a ray-trace:  skip focusing, Pedersen rays, mode-splitting, …  One thing that’s fun about writing your own models is that you can modify (intentionally or not) the model physics to do unphysical things…

The second run shows X and O modes for a single frequency and a failed attempt at modeling an MF signal into an E-F region duct.  (The ducting, by the way, has nothing to do with my actual work.  I was simulating it for ham purposes, although it helped me uncover a problem.)  The signals do get to the duct, but they bend the wrong way.  This has been fixed in the code, but it serves to remind that modelers have complete control.  The background ionosphere is relatively unphysical in this one as well…

The raytrace code used above is small, simple, and written in MATLAB.  I doubt that it will ever be released publicly, but if so I will note it here on the blog.