Information Related to Connecting the VLBA with Fiber Optics.

This page contains various bits of information I have gathered related to the possibility of connecting the VLBA antennas to a correlator with fiber optics in real time. The major concern is cost. There are two components to that cost. The first is the cost of the "last mile" connection to each site, which depends on a combination of distance and technology used. The second is the cost of access to sufficient bandwidth on the long distance lines. Most of the information below relates to the last mile. We still have very little concept of the long haul costs other than that, if we have to pay typical rates for Internet bandwidth, it is prohibitive.

This document was initially prepared in 2001. There were some updates later, with the last prior to 2012 being in 2005. It is receiving an update in Sept. 2012 based on site tech conversations with Eric Carlowe.

Distance to nearest
known fiber (km)
Summary of what we know.
St. Croix 17:45:24
3 - 5

2012: Fiber is terminated ~2.8 miles from the site.

2001: AT&T has a fiber backbone running the length of the island. We speculate that we might be able to attach at a casino 2-3 miles away. The local telephone company is not using this fiber. One of the site techs (Pete) used to work for AT&T.

Hancock 42:56:01

2012: I suspect that the previously noted fiber is still there, but the statement this time was that there is no fiber available.

2001: Mark Alfero talked to a phone company person in the field and was informed that the VLBA stations is 23,000 ft from the central office in Hancock and that there is fiber there. He is waiting for more info from the phone company engineers.

North Liberty 41:46:17

2012: Fiber is terminated at the site and current communications are via fiber.

2001: There is OC48 fiber under the driveway - within 1/4 mile. The local telephone cooperative would splice into there line there. They have all the equipment in place for an "ATM cloud".

Fort Davis 30:38:06
13 (or 3)

2012:The closest fiber is still the one going to McDonald.

2001:There is a Southwest Bell fiber to McDonald Observatory. The best place to connect might be Fort Davis. That is where the Southwest Bell office is that deals with McDonald. Distance to Fort Davis, according to INFOSYS is 8 miles. The McDonald fiber passes about 2 miles from our site so the connection could be closer if the fiber could be tapped.

Los Alamos 35:46:30

2012: There is fiber at the TA33 gate about 1 mile away. There may well still be access issues over that mile (see 2001), and previous attempts (EVLA) to develop access through Los Alamos have run into what sound like bureaucratic problems rather than technical ones. But they were not surmounted at the time.

2001: There could be problems getting to the tech area front gate because there are concerns about possible hazardous materials in the area. Once outside, there should be fiber nearby, but we don't know yet. We are asking for a quote for service from Qwest as part of the EVLA project.

Pie Town 34:18:04

2012: This site is connected for the USNO observations.

2001: Western New Mexico fiber to VLA is currently in use.
Old AT&T fiber crosses driveway and has stub, we think.

Kitt Peak 31:57:23

2012: The claim is that there is no fiber available, but that seems rather unlikely given the earlier situation. Also However note that the "VERTAS" below is likely to be VERITAS which eventually went to Mt. Hopkins. The Jan. 2012 Kitt Peak Tenant Newsletter 5 (find at indicates that there is a 1 Gig Ethernet and suggests that the technology may be in place for much higher rates. KPNO should probably be consulted.

2001: I talked to Steve Grandi of KPNO on 9sep2001. The Tohono O'odham Utility Authority has just pulled fiber to the top of Kitt Peak. It was strung on power poles up the mountain, then in conduit around the top. KPNO is leasing a DS3 line which will be on an OC192 connection being used by the utility. One small problem is that the West Ridge, where the VLBA antenna is located, is not connected to the peak by fiber. Last time a connection was investigated, the cost was $20-30k. The power poles that would be used may not be owned by the tribe. The copper cables are owned by KPNO.

2005: UPDATE: VERTAS, down by the lake, is having a fiber installed in early 2005 along the power and telephone lines that go through the picnic area. The contractor is leaving a drop for us in case we need it in the future. So fiber will be very close.

Owens Valley 37:13:54

2012: The fiber 3 miles away belongs to Verizon. We should update our knowledge of connections to OVRO and CARMA as those may have changed.

2001:I contacted Dave Woody at OVRO on 7sep2001. He says that there is fiber down the valley and that the nearest connection is in Big Pine, about 10 km away. There are power poles to close to OVRO, but all on-site lines are burried. The telephone line is burried to Big Pine on a shorter route than that taken by the poles. If we do decide to connect, we should contact Dave or Steve Scott because they would be interested in upgrading the connections to OVRO.

Brewster 48:07:52

2012: Fiber runs by the front gate to USEI (the old Comsat station). This is a good case where working through the phone company may not produce the optimum solution as they may not control the fiber to the satellite station (which now has many antennas).

2001: When fiber was laid to the Veristar antennas on the hill above our site, they left a point to connect at our site. The line is controlled by Veristar and we have been given a name to contact for information.

Mauna Kea 19:48:05

2012: This site is now connected for the USNO project. But we might need a bandwidth increase.

2001: There is fiber to the top of the mountain. We might need to attach at the top. We don't know the capacity.

GBT 38:25:59

2012: I'm not up to date yet.

2001: This is not a VLBA station, but should be connected in any real time scheme.

Some useful links

  FAQ on customer owned dark fiber. This document contains a great deal of useful information on customer owned dark fiber, including cost estimates. I have found that many sites either link to this, or have a local copy, so it seems to be an industry standard reference.

  Bandwidth Market is a site with a lot of summary information about many carriers. Warning, this is a .doc (Microsoft Word) document.

  MAPNET has a tool for plotting fiber the infrastructure of many companies. The resolution is a bit low, but the major lines are shown.

  LIGHTREADING Lots of misc information about fiber networks.

This page maintained by Craig Walker (