ePOP / Cassiope launch is successful!

Congratulations today are in order for our Canadian colleagues and Elon Musk's company Space X. Space X conducted a successful launch of their Falcon 9 rocket for the first time from the west US coast out of a new facility at Vandenberg Air Force Base. Although much of the payload was devoted to technology demonstration packages, the space science community is thrilled to have on orbit the ePOP platform aboard the Cassiope satellite, another important orbiting platform for study of space weather and upper atmospheric variations.  Early reports are that the six-sided Cassiope satellite had a nominal separation and is healthy in orbit following its first ground station pass over Antarctica.

Led by principal investigator Professor Andrew Yau (University of Calgary), ePOP stands for Enhanced Polar Outflow Probe and is a significant milestone for the Canadian Space Agency.  The e-POP team is comprised of scientists and engineers from seven Canadian universities and three research organizations: the University of Calgary; York University; the Universities of Alberta; Athabasca; Saskatchewan; Western Ontario; and New Brunswick. The Communications Research Centre, located in Ottawa, as well as the Institute of Space and Astronautical Science of Japan and the U.S. Naval Research Laboratory are also partners in the project.

The instruments on ePOP will all help to continue investigations into the nature of heavy, cold ion outflow from the polar regions of Earth's ionosphere into the magnetosphere. These often oxygen ion rich flows come up from the ionosphere near noontime in a region known as the cusp, and represent a significant mass load for the coupled ionosphere-magnetosphere system. Understanding them is an important key to understanding the entire Earth geospace system's response to space weather variations, or changes in characteristics of the flow of the solar wind streaming outward continually from the sun's corona.  This is because heavy cold ion outflows significantly change the 'stiffness' of the magnetic field lines forming the magnetosphere surrounding earth, and therefore change resonant frequencies of a common wave mode coupling geospace.  The Alfven mode, named for Hannes Alfven, can be thought of as a longitudinal mode similar to plucking a string - except this time, instead of the string being one on say a musical instrument, the string is the magnetic field.  More heavy mass on that string changes the frequency when it's plucked, just like using heavier gauge strings lowers their resonant frequency.

For radio physics and geospace studies, ePOP has several important instruments:

• The Coherent Electromagnetic Radiation tomography experiment
(CER) will perform radio transmission from e-POP to ground for
radio propagation and ionospheric scintillation measurements.

• The Fast Auroral Imager (FAI) will measure the large-scale auroral
emissions in the 630-1100 nm wavelength range.

• The Global Position System (GPS) receiver-based Attitude, Position,
and profiling experiment (GAP) will be used for spacecraft position
and attitude determination and for ionospheric radio occultation
profiling measurements.

• The Imaging and Rapid-scanning ion Mass spectrometer (IRM) will
measure the composition and 3-dimensional velocity distributions of
ions in the ionosphere.

• The MaGnetic Field instrument (MGF) will investigate the localization
and characterization of field-aligned currents in the high-latitude
auroral zones and polar caps.

• The Neutral Mass and velocity Spectrometer (NMS) will measure
mass composition and velocity of neutral atmospheric species.

• The Radio Receiver Instrument (RRI) will measure wave electric fields
in the 10Hz - 18MHz range, at magnitudes from 1 μV/m to 1 V/m.
These measurements will provide information about the morphology
and dynamics of ionospheric density structures, auroral wave-particle
interactions, plasma nonlinear processes created by intense high
frequency waves, and the mechanism of coherent wave backscatter.

• The Suprathermal Electron Imager (SEI) will measure the electron
energy and pitch angle distribution over the energy range of 1 to
200 eV, with particular emphasis on photoelectrons in the 1 to 50 eV
range, which are believed to play an important role in the polar wind
outflow.

Cassiope has a polar, highly elliptical orbit (324 x 1500 km altitude).  At MIT Haystack, we expect to have many opportunities for science using in particular the CER beacon experiment with ground receivers during overflights.  These overflights will also allow us to make multipoint observations of subauroral ionospheric features through combining ePOP data with wide field ionospheric measurements using our megawatt class large aperture incoherent scatter radar system, HF backscatter radar measurements of convection using the SuperDARN array, and other orbiting satellites such as the DMSP platform.  

Congratulations to all involved, and we're looking forward to a long and successful mission.  You can follow the status of the mission at SpaceFlight Now's page, and more Cassiope information is at the project home page.

LOFAR, EISCAT, SKA... and KAIRA of course!

Today's photograph was from the recent science seminar. Here, Prof. Markku Lehtinen explains the major projects and the vital link between them.

The graphic on the slide was one from the early days of the web log. Still as relevant as ever!  :-)

Installing the field equipment

This past week, a team from KAIRA/SGO, LTU and EISCAT have been installing a digital beamforming system on the Kiruna Demonstrator Array. Today, we feature some of the photographs from the installation of the field equipment.

Tomi brings out more USRP subracks. (Photo: D. McKay-Bukowski)

Johan installing the LTU receiver system. (Photo: D. McKay-Bukowski)

Lars-Göran runs the cables back into the main building. (Photo: D. McKay-Bukowski)

It's Retro Friday at MIT Haystack Observatory.. by Necessity

Hello from MIT Haystack in the northeast US.  Here, as with any production quality geospace observatory, sometimes we have to reach deep and use whatever tools are available to get the job done.  Today, this took the form of a scramble all-hands hardware debugging session on a legacy Sun disk server powering user space
files for the Atmospheric Sciences Group.  The server's external RAID storage array abruptly turned off due to a bad uninterruptible power supply after it exhausted its batteries.  Unfortunately, its pitiful beeping noise (if there was any) was drowned out by whirring fans in the network closet.

Since no modern computing hardware has real 9 pin serial ports any more, and since the Sun server was designed to run headless with serial only console access, we ended up making use of some .. legacy .. equipment lying around.  The 486DX 33 MHz laptop (8 MB memory) used to be a debug platform for an embedded antenna controller on our 46 meter UHF steerable antenna, talking in that role to a system running embedded DOS 1.0.  The 486DX saw new brief life since it had a working, real serial port.  Somehow, I managed to remember where the Terminal program was on its spiffy, working Windows 3.11 installation.  As you can see, unfortunately the keyboard had a non-functioning "Enter" key (rather critical) so we had to steal a PS/2 external keyboard from somewhere.   See the annotated photo for other qualities of our situation.

The real world intrudes on scientific thoughts.

2 hours later (and several kibbitzers involved too), we had a working system again!  This is actually a good analogy for what goes on regularly at any large facility - lots of improvising with equipment of various vintages, sometimes ancient.  All those things that you forgot might be useful again someday.  However, in this case I'm not hoping for a repeat!

Thanks to Juha Vierinen for the photo at a crucial moment, when things were finally looking a bit better after some despair.

Passive radar with $16 dual coherent channel rtlsdr dongle receiver

My previous post describes the $16 dual channel rtl_sdr dongle hack. In the last few days I've done some more testing and it turns out I can use the system for passive radar! I didn't expect this, because the receiver only has 8 bits and passive radar requires a lot of dynamic range.

Airplanes and occasional specular meteor echoes. 

I hooked up the two channels into yagi antennas that we have used with Echotek and USRP receivers for passive radar. One of the antennas was measuring the transmit waveform, and the other was measuring the echoes. I ran a measurement, and to my great surprise, it worked just fine.

I did tweak the signal levels a bit in order to ensure that I optimally use the dynamic range. I also had the bandwidth set to 2.4 MHz, giving me about 4.5 bits extra dynamic range after filtering the signal to 100 kHz in single precision floating point.

Two log periodic antennas used to passive radar with the dual coherent RTLSDR R820T dongle.

This really does give us a glimpse of the future where high end digital receivers will cost $10 per channel. The low end ones are already in that price range. Think of all the potential science that can be done!

$16 dual-channel coherent digital receiver

I have been playing around with the cool RTL dongles (more on rtl-sdr dongles on superkuh's web page or rtl-sdr.com) that you can buy on e-bay for about US$8 (including shipping). These are very capable 8-bit digital receivers that have up to 2.4 MHz bandwidth and can tune anywhere between 24 MHz and 1850 MHz.

I recently came up with a trivial hack to build a receiver with multiple coherent channels using the RTL dongles. I do this basically by unsoldering the quartz clock on the slave units and cable the clock from the master RTL dongle to the input of the buffer amplifier (Xtal_in) in the slave units (I've attached some pictures).

I originally drove the master crystal with both dongles, which also worked. However, Ian Buckley pointed out to me that a more typical way of doing this is feeding the signal into Xtal_In (in the pictures below). So I tried that too, and it also worked. I'm still not sure what the optimal setup is, as there is no schema for the dongle, but both methods I've tried so far have worked in practice.

This is how you make a dual coherent channel digital receiver with $16.  The clock drive probably won't be enough for many of these, but this can be fixed with a buffer or some other active splitter. 

The oscillator is wired using a piece of 75 Ohm antenna coax that came with the dongle. It's like they designed the dongle for  multi-channel coherent applications. 

This has some implications for low cost geophysical instruments. It will be possible to use this receiver for the 150/400 MHz beacon satellite receiver, as this only requires that the receivers have clocks that are locked with each other. Interferometry and passive radar are other application examples. With more than two locked channels, applications such as imaging start to become possible.

I've made some relative phase noise measurements, and the systems don't have detectable sample drift over two hours, and their relative phase is also pretty stable.

Spectrum at 1 Hz sample rate of the relative z_1/z_2 phase signal going into two receivers. 

IQ plot of the z_1/z_2 relative phase signal over ~6000 seconds at 1 Hz sample rate. 

And oh, by the way, I found this nice usb hub, which I'm going to use to hopefully get a 7 channel coherent rtl system.

Hub with the right usb port orientation for rtl dongles. 

Stay tuned for more results. I already have some pretty nice passive radar results using the system, which I'll be posting in a few days.

Update: Apparently three dongles will also run fine from one master clock. I know the clock isn't split correctly, but adding any components would increase the total cost and the whole point of this exercise is to determine what the lower bound is for software defined radios.

Three channel coherent RTLSDR receiver. 

Receiver/USRP installation on the Kiruna Demonstrator Array

This week a team from KAIRA/SGO and LTU, together with our colleagues from EISCAT, are working to install a digital beamforming system on the Kiruna Demonstrator Array. During the next week, we'll be featuring a few photographs from this busy time.

The Kiruna Demonstrator Array (Photo: D. McKay-Bukowski)

Current configuration, 6x4 dual-polarisation directional antennas. (Photo: D. McKay-Bukowski)

Lars-Göran digging out the duct entry points. Our previous experience from KAIRA
was absolutely invaluable for this part of the work. (Photo: D. McKay-Bukowski)

Laying the new (bright yellow!) ducting for the network cables. (Photo: D. McKay-Bukowski)

Passive Radar Update

This week, I spent a few more days trying to understand the errors related with strong radar targets in the analysis of weak targets in passive radar. As a consequence of this, I wrote a linear least squares estimator to remove this contribution more effectively (and consistently). I also optimized my code a bit, and got a massive speed-up. Now the signal processing and plotting all runs in real time.

This video shows a lot of aeroplanes around the New England area detected using a simple passive radar setup, consisting of: one USRP and two yagi antennas, a quad core Linux PC. Every now and then an occasional specular meteor echo is observed too. Because this is FM radio, the waveform is not always optimal for inverting the echoes, which results in a blow up of the solutions when the waveform is narrow band (eg., somebody talking, or silence). This is not a problem with digital modulation schemes, which will be explored next. I updated my code. I came up with a way to efficiently estimate ground clutter and transmitter self-noise using a linear least squares matrix equation, which works better than the previous attempt. I also made some optimizations that allow me to run this in real-time using a normal PC. Next up: imaging using the midas-mini cube.

Thanks for SGO100

A message from the director of SGO, Esa Turunen...

SGO is now 100 years old and the new century is here. Warm thanks to everyone supporting the arrangements, our guests gave positive feedback of the experience. The Open House event had 230 visitors, Science Day for schools 180 pupils, the Studia Generalia -lecture by Esko Valtaoja was attended by more than 200 listeners and similarly 200 persons found their way to the main ceremony at the Sports Hall ...

Esa Turunen addresses the gathering. (Photo: D. McKay-Bukowski)

We had a final kakkukahvit (= cake & coffee) event with our friends from FMI at Polaria on Monday and we will organize a similar coffee break in Oulu at the first convenient opportunity.

KAIRA operational status label

Over the last few months, we've had some occasional technical problems with KAIRA. That's all fixed now and the station is back online and observing again. However, the outages did highlight the fact that we could use some improved monitoring and also that this monitoring needs to be more visible.

So, as a result of this we've put a new monitoring tool in place which generates a display icon. This will be used in various places on our system for the benefit of staff, but we've also decided to put it on the web log too. Apart from being useful to our observers and the support staff, it may also be of interest to the general public and anyone else who might be interested in KAIRA's operational status.

When working well, the status icon will be pretty bland, with just some text indicating that it is operational and what the time of the last check was. It will look something like this:

Checks are made once a minute, so you should see it change if you were to reload the web page.

However, if something is not quite right, the background will change to a pretty eye-catching colour and the text will indicate the likely cause of the fault (or at least a pointer for the support team as to where they could start looking to work out what is wrong). Some examples include:

In summary, the status label will help improve uptime and let us catch and fix problems quickly. But it will also be a useful widget for users of the system too.

The Sodankylä Geophysical Observatory 16 channel USRP N210 based digital receiver

Tomi Teppo, Derek McKay-Bukowski, and I have been working on the 16-channel USRP N210 system that I put together before I left _. In anticipation of using this with a phased array antenna array in Kiruna, the setup needed to be modified in a way that all USRPs communicate via a switch, as the field site only has one fibre optic cable going into the building. A few days ago, we completed the setup and verified that we can do get 16 channels through a switch. This was not possible just a little while ago, so the firmware has definitely improved. Before all the channels were directly connected to the computer. Hurray! 

This system will have many cool uses with eg., riometry, or HF radar imaging.

16 channel USRP N210 setup. 

USRP racks. 

8 USRPs going one switch, which has one 1 Gbit line going to the computer. I don't know what the upper switch is for though (maybe testing). 

All the equipment. Everything is still a bit tangled. 

Two computers.  More computers can be added if we need more bandwidth or computational capacity.

New Ionospheric tomography receiver in Svalbard

Our expert on ionospheric tomography, Johannes Norberg, just came back from his trip to Svalbard where he installed yet another 150/400 MHz beacon satellite ionospheric tomography receiver. The first light was observed on 12.9. and after trying testing RFI levels on several locations, the antenna was installed on top of the Kjell Henriksen Observatory building. The tomography receiver is the sixth new receiver that is part of the TomoScand ionospheric tomography chain operated jointly by the Finnish Meteorological Institute and the Sodankylä Geophysical Observatory.

Jussi tells me that the weather was beautiful during his stay, and the install went smoothly without any problems whatsoever. Way to go Jussi, just like in Strömsö (the install went like it was a scripted TV program).

The beautiful view from the Kjell Henriksen Observatory in Svalbard, overlooking the EISCAT Svalbard radar and the Longyearbyen valley. 

The receiver on the of the building. Installing a receiver here is tricky due to snow and ice drifts, strong winds, and polar bears. 

The receivers were nicely installed into a rack. 

A phase curve measured with the Svalbard receiver. 

SGO 100 -- The last half century

The sixties and early seventies were a period of intense expansion. In 1962 and 1964, new buildings were constructed for the ionospheric station. Riometers were installed at SGO in 1963 to study the lower ionosphere. In 1968 a new administrational centre, with accommodation, library and archive storage was constructed. In 1971, the Pittiövaara site was also extensively developed.

Although primarily a geophysical observatory, the astrophysical sciences were also well attended. A radio astronomy receiver was built for the IGY to measure scintillation of the radio star Cas A (a task that KAIRA still undertakes today) and in 1972 a zenith telescope was constructed to make precision measurements of the polar variations... a measurement set that continued for some 20 years until replaced by recent satellite-based methods.

In 1975, Finland joined the European Incoherent Scatter Radar Association (EISCAT), along with several other countries. This resulted in a new building and a 32m parabolic antenna being constructed at SGO. Initially operating at UHF frequencies for radar reception and the HI neutral hydrogen line for interplanetary scintillation measurements, it has recently been upgraded to operate at the lower VHF frequencies.

The 32m EISCAT antenna at SGO.

In 1997, SGO merged with the University of Oulu, and is now a major research unit of the university. In 1998, University's observatory merged with SGO.

And, of course, SGO is responsible for KAIRA. Constructed during 2011-2012, KAIRA is one of the flagship projects of SGO, but one that is built on a long tradition of careful, methodical and patient measurements... 100 years of extremely valuable scientific achievement and a crucial set of data about the natural world.


References

Kataja, "A Short History of the Sodankylä Geophysical Observatory", Geophysica, 35(1-2),3-13, 1999.

McKay-Bukowski, "KAIRA: The Kilpisjärvi Atmospheric Imaging Receiver Array", submitted, 2013.

SGO 100 -- An observatory is formed

This month, we are celebrating the 100th anniversary of Sodanklyä Geophysical Observatory (SGO). As part of the celebration of this prestigious occasion, we are looking back at the history of the facility and what a tumultuous past it has had. Yesterday we considered the very early days leading up to the formation of the permanent observatory. Today, we continue the story.


On inception, SGO became the first permanent magnetic observatory in the Arctic. It operated successfully despite the outbreak of the First World War. Only during the Finnish War of Indepence in 1918 was there any interruption to the measurements, but even then, only for a few months.

In 1927, auroral phtography was started at the SGO site and the station participated in the Second Polar Year (1932-1933). This was an important time for the observatory with new international collaborations being forged. New measurements were being developed to detect rapid variation of magnetic fields and the so-called earth-currents. In addition, SGO was an important meteorological station as well as a geophysical observatory.

The main building of SGO from 1913-1944.

SGO continued routine observations during the Winter War of 1939-1940 and when the hostilities resumed in 1941. During the Winter/Continuation War, SGO stayed in full operation. However, with the outbreak of the Lapland War (1944-1945), the observatory had to be evacuated and this took place on 15 September 1944. The evacuation was rushed on only the personnel and the most important archives could be saved.

During mid October 1944, the observatory was overrun and destroyed.

At the conclusion of the Lapland War, the Finnish Academy of Science and Letters was quick to return and in mid-1945, the first weather observations resumed with magnetic recordings commencing on New Year's day of 1946. Rebuilding and improvement continued throughout this time, leading up to the Third Polar Year (1957-1958). This event (later renamed as the International Geophysical Year) was a major scientific achievement for the world, and SGO played and important part. In addition to routine observations, it heralded the installation of a new ionospheric sounding station and, at around the same time, the first seismosgraphy measurements commenced at the site.


Reference

Kataja, E., A Short History of the Sodankylä Geophysical Observatory,
Geophysica, 35(1-2),3-13, 1999.

SGO 100 -- the early days

This month, we are celebrating the 100th anniversary of Sodankylä Geophysical Observatory (SGO). As part of the celebration of this prestigious occasion, we take a look back at the history of the facility and what a tumultuous past it has had.

The first geophysical observations at Sodankylä actually pre-date the 1913 founding of the observatory. In fact, the first observations from the region date back to the First Polar Year (1882-1883). The Finnish Society of Sciences and Letters participated in the Polar year work, by setting up a small meteorological station as the village of Sodankylä. This station included geomagnetic observations ad well and continuous magnetic observations were conducted from 21 August 1882 to 31 August 1883. One last set of measurements was made in August 1884.

Observatory buildings at Sodankylä for the First Polar Year, 1882-1883.

Since then several proposals had been made to carry out magnetic surveys, but it was the Finnish Academy of Science and Letters made the necessary breakthrough. The Academy was founded in 1908 and one of their first tasks was to establish a detailed plan for a permanent station for the purposes of astronomical and geodetic measurements. A large area of land near Sodankylä was acquired and in late 1913 the Sodankylä Geophysical Observatory (SGO) commenced operations under the directorship of Dr J. Keränen.

We take it for granted now, but that was in a different age, when winters were brutal and the station, located some 1000 km from the capital city, was a remote outpost indeed.


References

Nevanlinna, H., "Geomagnetic Observations at Sodankylä during the First International Polar Year (1882-1883)", Geophysica, 35(1-2), 15-22, 1999

Kataja, E., "A Short History of the Sodankylä Geophysical Observatory",
Geophysica, 35(1-2),3-13, 1999.

Report from ERIS 2013

Last week, the European Radio Interferometry School (ERIS2013) was held in the Netherlands. Our report is from Sari Lasanen (U. Oulu) who attended the event. Sari writes:

It's been a great week at ERIS 2013, the European radio interferometry summer school. This year, the school was hosted by ASTRON/JIVE at Dwingeloo in beautiful Netherlands. Being a mathematician, it wasn't just once or twice that I was asked why to attend a radio interferometry school.

Why indeed?

From the historical viewpoint we inverse problems researcher are greatly indebted to astronomy for the first examples of high impact discoveries from indirect and noisy data. After all, the least squares fitting was developed by C. F. Gauss in order to recover the orbits of heavenly bodies (like the asteroid Ceres) from inaccurate and overdetermined data. And just think about how the planet Neptune was discovered? Indirect data! Catching up with the modern tools of radio interferometry has been tremendously useful and fun. Not only have I learned what is going on in calibration and imaging but also what the big question in today's astronomy actually are. Surely you have heard about dark matter but what about re-ionisation? If not, google it at once. That's where lot of today's radio astronomy is happening.

ERIS2013 Group Photograph (ASTRON/JIVE)

Thanks, Sari, for the great report and for sending the meeting photograph, taken at the Westerbork Synthesis Array. As can be seen, the school was very well attended!

Link:  http://www.astron.nl/eris2013/

KAIRA plasma parameter fit

Ilkka Virtanen and Niklas Siipola have been analysing some of the KAIRA data that was recorded during the previous Finnish EISCAT campaign. The following plots show bi-static incoherent scatter plasma parameter profile plots obtained using KAIRA. The results are in good agreement with the Tromsø measurements, and also show for the first time that a simultaneous bi-static plasma parameter profile can be obtained using a phased array incoherent scatter radar receiver. This is still work in progress, but this is yet another step in the direction of KAIRA performing routine incoherent scatter plasma parameter measurements.

The PI of the experiment was Anita Aikio and the purpose of the experiment was to 1) obtain the first tri-static EISCAT VHF measurements, and 2) to leverage the multi beam capability of KAIRA to obtain a profile of wind velocity vectors (due to the lack of a third station, only two components of the velocity vector can be obtained).

Plasma parameters obtained using KAIRA.

Plasma parameters obtained using EISCAT VHF.

KAIRA 3D film shown at SGO Open Day

Today, as part of the Observatory's 100 year anniversary, there is an open day at Tähtelä. One of the features of the day, will be a chance to see the KAIRA film in 3D in the conference room at SGO.

The open day runs from 10:00 - 16:00 (Finnish time) on Saturday 14 September 2013.

Sodankylä Geophysical Observatory Open Day

Just a reminder...

... for those in the Sodankylä area, there will be a public open day tomorrow 14th September 2013 from 10:00 until 16:00 at the SGO site at Tähtelä. This will be a great opportunity to see the institute, the EISCAT facility, and lots more!

The open day is part of the celebrations this month of the 100th anniversary of the observatory.

Details:

http://blog.eiscat3d.org/2013/09/visit-sodankyla-eiscat-site.html
http://www.oulu.fi/sgoenglish/node/18448

Ireland's Bid for a New Radio Observatory

Today we are featuring the new promotional video produced by the I-LOFAR consortium. I-LOFAR is the Irish LOFAR telescope bid, which the KAIRA team have been assisting. If they can raise the remaining funding (of which they already have a substantial start), they will be able to implement LOFAR station in central Ireland. This will be crucial, not just for their own national astronomy programme, but also for extending the longest baselines of the LOFAR network, adding to it sensitivity, and fostering vitally needed collaborative programmes between the existing European Community and Irish universities and industry.






Good luck, Ireland! And have a nice weekend all!

Desktop CW radar

Karim Kuyeng and Rob Sorbello from Penn State just sent me these pictures from the CW radar that we setup in July. It is a variation of the cantenna radar developed by Gregory Charvat, although this is using a USRP N200 and a SBX daughterboard. Instead of using cantennas, we used horn antennas.

The idea is very similar to police traffic radars. Radiate a continuous wave and measure the frequency of the radar echo.

Meeting at Kirkkonummi

A joint workshop was held between Sodankylä Geophysical Observatory (SGO) and the Finnish Geodetic Institute (FGI) at Kirkkonummi. The purpose was to consider together how EISCAT, KAIRA and EISCAT_3D will make better orbit determinations for Space Rocks, meteoroids, temporarily captured objects, space debris and small asteroids. The pizza boxes of course allow working during lunch break, too!

Joint FGI/SGO working meeting. (Photo: E. Turunen)

3 mW ionogram

I've been playing with my low cost, low power, low footprint ionosonde. I'm still missing some parts for the system, but I thought I'd give it a try. Here is an ionogram using 3 mW of power fed into a badly mismatched antenna.

Hopefully very soon in the near future, I will have the prototype ready, and I can convince somebody to fund a large network of these things. 

Millstone Hill Digital Acquisition System Mini (MIDAS-Mini)

Today I cabled up the new MIDAS-Mini system that Frank Lind and I are putting together at MIT Haystack. This is a suitcase sized shock mounted rack that contains four USRP N200 devices, an octoclock (gps stabilized oscillator and a 1 PPS + 10 MHz clock splitter), and a 1 U server computer.  The computer is fast enough to simultaneously record four 25 MHz wide bands of data, which will be very useful. The box is small and rugged enough to be transported on an airplane.

We currently have two such racks, and there are plans to build more at a later point. With multiple boxes it is possible to get even more channels, and it is possible to chain the clock together to act as  4Nx4N MIMO systems.

Yeah, the cabling sucks. I just wanted to get my testing and calibration routines running. This will be cleaned up.

More cabling mess. 

One from the archive...

Recently, I was trawling through the archives looking at some of the early construction photographs. As I flipped through endless images of frames and tiles I came across this gem. I know it is an old photograph, and from completely the wrong time of year, but we never featured it on the web log and it would be a shame to let it stay hidden.

This shot is from after the first winter with the full High-Band Antenna (HBA) array. You can tell it is an early photograph as only the plastic mesh is on the sides of the HBA framesets, rather than the current version which is additionally reinforces with reused timber slats.

First winter for the full KAIRA HBA array. 2013-02-01 12:08 UTC. Photo: M. Postila.

Have a nice weekend!

A meeting of old friends

Well, it has been a while, but it was lovely to see "my" blue Land Rover again! Okay, okay... it's not really mine, but I used it every day during the construction of LOFAR station UK608 and grew rather fond of it.

"My" blue Land Rover. (Photo: D. McKay-Bukowski)

ASTRON at Chilbolton

Today I was at the Rawlings Array (the LOFAR station at Chilbolton, UK) to meet with the ASTRON engineers who specialise in radio-frequency and digital signal processing. It was an extremely productive day, which included some design work, software training and some work on the array itself looking at how to replace fron-end RF-boards in the HBA tiles.

ASTRON arrives at the Chilbolton Observatory. (Photo: D. McKay-Bukowski)

Opening up an HBA tile for some RF-maintenance demonstrations. (Photo: D. McKay-Bukowski)

Weather forecasts

It is certainly useful to keep an eye on the weather and for us checking on the situation at Kilpisjärvi is no exception. In Finland, the weather service is handled by the Finnish Meteorological Institute (FMI). They provide an excellent online web service, with local statistics and forecasting for the region... in English, Finnish and Swedish. An easy search function allows you to find the region or place you are looking for in Finland quickly and easily.

Oh, and here is the direct link to Kilpisjärvi...

http://en.ilmatieteenlaitos.fi/weather/enontekiö/kilpisjärvi