A Geomagnetic Monitoring Station may be added to the Observatory for monitoring changes in the earth's magnetic field and to supplement and build upon the Observatory's existing Aurora monitoring using AllSky Camera and new NorthCam Camera.

There were seem to be two potential routes :

1. Build a cheap system using a single fluxgate magnetometer, with ardunio and other self built circuitry
   
2. Buy and install a SAM-III system with from Reeve.com including build option and 2 or 3 sensors.

Issues / Decisions

• System
  • Self Build System
  • SAM III System
    
• Number of sensors :
  • 1  :  Y
  • 2  :  X & Y
  • 3 :   X, Y & Z
    
• Location :
  • In the flower bed next to fence at bottom of garden. 
       Pro : Most obvious location
       Con: Lack of room for digging, disturbance to shrubs, difficulty in burying cable
  • Neighbouring Field
       Pro:   Maximise distance from car / lawn mower disturbance
       Con:  Don't own the ground, possibility that field is ploughed by farmer
  • In the lawn
      Pro :   Easiest option for digging
      Con :  Some disturbance to lawn (temporary),  magnetic disturbance when mowing the lawn
    
• Hole:  
  Drilling a 1m deep hole will be a difficult task due to the nature the hard subsoil and the underlying boulder clay deposit.
  
  • Ideal depth
  • minimum acceptable depth (in case of difficulty digging hole)
  • hole diameter
  • digging method
  • Manual auger and open openers
  • petrol driven auger, 1 person or 2 person
  • room to dig hole is critical
    
• Cable run
  • Path 1 : Along Fence Line  (harder to lay, unless attached to fence
  • Path 2 : Below the lawn   (easier to lay ?)
  • Conduit:  Conduit it needed for protection,   need to take 3 CAT6 cables
     
• Base Station Location & Connection
  • AllSky/Weather Computing Bay
      Pro:    doesn't interfer with live observatory session
      Con :  longer cable run,  computer resource less available (competes with Weather Station, AllSky Camera, NorthCam Camera)
• Observatory Computing Bay
    Pro : shorter cable run,   lower computer usage (apart from during live sessions), more room ?
    Con : COM1 to COM6 may already be used.
• Enclosure Size :   165 mm x 125 mm x 76 mm
• Installation Target
  • Mar 2025
  • Apr 2025

 Provisional Decisions (2024-12-27)
- System : SAM III
- Number of sensors : 3 (x,y,z)
- Location :  In the lawn
- Hole :   1m deep
- Cable Run :  Below the lawn
- Base Station :  Observatory Computing Bay
- Installation Target:   April 2025

 

SAM-III Provisional Cost Breakdown
SAM-III Kit with (3) magnetometer sensors		SK3-3	$ 341.00
Enclosure, Rectangular, gray polycarbonate, machined & drilled		BEN-1	$  74.50
USB-Serial adapter, USB 2.0		USB-1	$  16.40
12 V Power Adapter, regulated 12vdc, 10w		ACU-1210	$  65.00
Build Option, Construct and test the SAM-III PCBs		BLD-1	$100.00
International Shipping (say $80)		INS-1	$  80.00
		Total	$666.90
GBP (incl tax 25%)			£665.00
100m Cat6 Cable  (provides up to 33m cable run)			£  50
Piping  (say £40)			£  40

Order Inquiry (2024-12-29)

An initial order enquiry was sent to OrderInfo@reeve.com on 2024-12-29.

Update 2025-01-18

- SAM III ordererd & paid. System will ship out around 2025-03-03 for delivery in mid/late March.
- Cat6 ethernet cable (60m) purchased & received
- Flexible Conduit piping purchased & received
- Potential magnetic interference source (large coil of stock fencing adjacent to fence line) relocated to a distant position.

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