Metsähovi Radio Observatory, Finland (vlbi@hut.fi)


EVN Station Report, March 2006


Ari Mujunen (Ari.Mujunen@hut.fi)
Jouko Ritakari (Jouko.Ritakari@hut.fi)




 eVLBI

Metsähovi is continuing eVLBI efforts in the EXPReS program.  One of
the first goals is to arrange a 512 Mbit/s or 1Gbit/s eVLBI real-time
demonstration using the five-year-old PCEVN equipment.  We feel that
this goal is achievable.


 Fiber connection

A 42-kilometer dark fiber has been installed from Metsähovi to the
Finnish University Network (Funet) hub in Otaniemi and Funet has
agreed to provide a 10 Gbit/s connection.  Metsähovi is ordering 10
Gbit/s equipment, the process is on hold until Funet gives information
about the make of the equipment in Otaniemi.
 

 New developments

The Metsähovi team has made a brief study of the technologies used by
the SETI institute in the Allen Telescope Array. This technology uses
common and inexpensive components designed for cellular phone
basestations and gives essentially the same (or better) functionality
as the old BBCs. The (geodetic) VLBI2010 report seems to endorse this
technology.  For details see www.seti.org and
astron.berkeley.edu/ral/ata/memos/


 Status

The Mark5A unit bought by the Finnish Geodetic Institute is being used
in all experiments. It was broken in October 2005, some disk packs
worked only in slot B. If they were inserted in slot A some of the
disks were not recognised and the Mark5 program locked so that the
disk pack could not be powered down. Only a complete reboot
helped. The test programs provided with the Mark5 did not help, since
they locked too.

The Mark5A unit was sent to Conduant for warranty repairs on
10-Jan-2006 and now (15-Mar-2006) it finally returned.  (It spent
18-Jan..06-Mar-2006 at Conduant.)  The reason for the strange
behaviour is not known, nor what was actually repaired/changed.

All the 14 BBCs can achieve lock at their geodetic standard
frequencies but BBC09--14 have all sorts of other troubles.  For
astronomy it is best to favor 8 BBC modes.

Six of the GaAs counters in the BBC oscillators/synthesizers have
broken during the last ten years. Now they have been (mostly) repaired
with with repair kits provided by Paul Burgess and Salvador Sanchez.


 Manpower

At the moment MRO has two effectively part-time persons working in
VLBI: Ari Mujunen, whose main occupation is laboratory engineer and
Jouko Ritakari, who is working part-time at MRO. People from Finnish
Geodetic Institute are helping in the geo sessions.