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


EVN Station Report, November 2005


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


 Status

1.3cm continues to be available LCP+RCP, as does 0.7cm.  (0.7cm is
still in receiver laboratory pending some wiring. If 0.7cm proposals
demand for it, it can be made available.)

13/3.6cm standard S/X (_not_ wideband X with the third IF3)
geo-RCP-only receiver is available.  It is owned by Finnish Geodetic
Institute (FGI) and using it for astronomy requires arrangements, thus
prospective PIs need to contact Mh directly.  (Best chances to get the
RX would be if EVN demand is time-wise close to a geodetic experiment
Mh takes part, check geo schedule at
http://ivscc.gsfc.nasa.gov/program/index.html, get the "Plain Text"
Master file and search for 'Mh'.)

The single-headstack VLBA recorder (the upper tracks of which had been
failing for years, no reason/explanation ever found for this) has been
detached from the rack and put into storage, so no tape recordings at
Mh anymore.

The Mark5A unit bought by the Finnish Geodetic Institute is being used
in all experiments. It has developed a strange behaviour, some disk
packs wor only in slot B. If they are inserted in slot A some of the
disks are not recognised and the Mark5 program locks so that the disk
pack cannot be powered down. Only a complete reboot helps. The test
programs provided with the Mark5 do not help, since they lock too.

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.

A repair kit has been designed for the gigabit counter in the VLBA
BBC.  It has not been tested yet, but it only replaces the GaAs
counter with the same device in a different package.

 eVLBI

Several eVLBI speed records have been achieved during the last year
using reliable UDP protocols. In October 2004 a 640 Mbit/s
disk-to-disk was achieved from the Otaniemi campus to JIVE. In
December 2004 a 400 Mbit/s speed was achieved from Kashima, Japan to
JIVE. Also a realtime version of the Tsunami protocol has been
developed at Metsähovi. The protocol is capable of transferring
realtime data error-free between two microcomputers.A nice feature is
that both microcomputers can make backup copies of the data on disks
while transferring the realtime data.

 Fiber connection

Metsähovi has ordered a dark fiber connection to the Funet hub,
bypassing the HUT network. Delivery time is 2-3 months. Since the
connection is dark fiber, Metsähoi can install 10 Gbit/s equipment
that is increasingly competitive in price.  

 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 geoVLBI 2010 plan seems to be based on this
technology. For details see www.seti.org and
astron.berkeley.edu/ral/ata/memos/

 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.