San Bruno Mountain (Building 7)

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Revision as of 15:16, 16 January 2023 by Kn6plv (talk | contribs) (→‎Plans)
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San Bruno Ham Tower

Site located on San Bruno Mountain, next to Building 7, near the KTSF transmitter (map)(photos)

Site Details

Tower

The tower has a 4° slope on the main lower beams. The base of the tower is approximately 23 feet wide. The first horizontal beam is 8 feet from the ground. The second beam is 7 feet above the first. The supporting angled beams, running from the group, are at an angle of 37° from vertical. The ham shack is located on the south side of the tower with a slight peeked roof. The top of the roof peek is 6 feet from the second beam. The edge of the roof is approximately level with the first beam.

The beams themselves are 3.5in horizontally, 3in vertically, and 0.25in thick with a rounded edge. The double beam which forms the second horizontal beam is 1.25in thick.

Mounting

All equipment must be mounded on galvanized supports which are themselves attached to the tower using beam clamps. All current mounting brackets should be considered unusable. Mounts using "stacked" struts are no longer allowed.

Cabling

Cabling must be run with beam camps and stainless steel zip ties and cannot be directly attached to the tower. Cables run into the shack via rubber cable glands (not the plastic tube!). Cable loops are discouraged, as is excessive cable in the shack.

Power

The site provide main power (without backup) as well as 24vdc, 12vdc and -24vdc (breakers not provided) with battery backup. No solar or generator.

Configuration

Currently the site has an Mikrotik hAP, a Ubiquiti NSM5, a Ubiquiti Rocket M5 + 120 degree sector antenna, a Ubiquiti UISP Router, and a Ubiquiti AirFiber dish pointing at Fish Ranch. All device are power either directly, or via the router, from the house 24vdc supply.

Devices
Device IP Notes
USIP Router DHCP
airFiber 5XHD DHCP to Fish Ranch, Management VLAN 100
UISP LTU Rocket DHCP to San Carlos, Management VLAN 100
VLANs
VLAN Description
1 AREDN WAN
2 AREDN DtD
13 Fish Ranch XLINK
15 San Carlos XLINK
100 AREDN LAN
911 Emergency local management
KN6PLV-SANBRUNO-ROUTER (UISP Router)
Port Description VLANs PoE Notes
1 KN6PLV-SANBRUNO-HAP 2, 13, 15, (100) Off hAP provides DHCP address to non-AREDN devices
2 KN6PLV-SANBRUNO-RM5-2 2 24v Nodes are not given LAN or WAN access
3 W2GMD-SANBRUNO-RM5 2 24v
4 (aredn) 2 24v
5 (aredn) 2 24v
6 (aredn) 2 24v
7 DISH-TO-FISHRANCH 2, 13, 100 24v (4-wire)
8 DISH-TO-SANCARLOS 15, 100 24v (4-wire)
9 Local management (911) - SFP, 192.168.91.1
KN6PLV-SANBRUNO-HAP
Port Description VLANs Notes
1 (1) WAN
2 2, 13, 15, (U) Custom config provide LAN + DtD on ports 2-5
3 2, 13, 15, (U)
4 2, 13, 15, (U)
5 KN6PLV-SANBRUNO-ROUTER 2, 13, 15, (U) Provides DHCP addresses to LAN devices

Notes

Part of the Bay Area Backbone connecting to Fish Ranch.

New Mounts

New mounts have been design using a 2" galvanized pipe attached to galvanized struts using pipe clamps. The struts are in turn attached to the tower using beam camps. The design can be found here.

Plans

  • Run a wifi scan at the proposed antenna mount point to see how noisy it is
  • Reposition airFiber link to Fish Ranch for optimal signal strength (to be honest, this seems pretty good already)
  • Switch out the current hAP Lite for a new hAP AC2

Nodes

On axis view from antenna

DISH-TO-FISHRANCH

Radio: airFiber 5XHD

Frequency: 5.99 GHz (Unlicensed use - FCC note)

Bandwidth: 50 MHz

Antenna: Ubiquiti RD-5G30-LW 30 dBi

Location: 37.68678, -122.43527

Altitude: 400m

Bearing: 56° toward Oakland

ToSanCarlos.jpg

DISH-TO-SANCARLOS

Radio: UISP LTU Rocket

Frequency: 5.935 GHz (Unlicensed use - FCC note)

Bandwidth: 50 MHz

Antenna: Ubiquiti RD-5G30-LW 30 dBi

Location: 37.68678, -122.43527

Altitude: 400m

Bearing: 149° toward San Carlos

Read Only Access: mesh / Back-Bone

SanBrunoMtnHAP.jpg

KN6PLV-SANBRUNO-HAP

Radio: Mikrotik hAP

Antenna: Built-in (unused)

Location: Inside the HAM Shack

Altitude: 385m

Bearing: N/A

On axis view from antenna

W2GMD-SANBRUNO-RM5

Radio: Ubiquiti Rocket M5

Antenna: 120 degree sector

Location: 37.68674, -122.43525

Altitude: 387m

Bearing: 159° toward Millbrae

On axis view from antenna

KN6PLV-SANBRUNO-RM5-2

Radio: Ubiquiti Rocket M5

Antenna: 90 degree sector

Location: 37.68673, -122.43532

Altitude: 392m

Bearing: 236° toward Colma

Coordination

The San Bruno Mountain HAM site is own and managed by Matthew Kaufman as part of the WB6ECE Repeater Group. Coordination of changes to the site (e.g. new radios) is managed on the mailing list Sbruno_shack. Unfortunately this is an invite only group with no public archives.

Commercial Neighbors

The local WISP in this area is Etheric although they use a different tower. They license (WQTV709) spectrum from 11.2 GHz to 11.7 GHz.

Contacts

  • Tim Wilkinson - KN6PLV - tim@sfwem.net
  • Steve Ligtelyn - KC6SVW - steve@tcomeng.com
  • Matthew Kaufman - KA6SQG - matthew@eeph.com