Antenna Bearing Tool Help

[Nov 2019]

 

Antenna Bearing Tool [ABT] is an alternative to a magnetic compass for antenna installers to determine the required compass bearing. ABT uses known landmarks as a reference bearing and the “offset” is calculated.

ABT has two modes:

1. Cellular mode for “Base station Transmitter Sites”. [BTS]

2. Point to Point mode for microwave systems. 

The land mark in either case must be visible and identifiable.

NOTE: [BTS = Cell Phone Tower]

 

There are a many reasons for using this method in preference to using a compass:

1.     Antenna bearings are usually referenced to True North and it is a common mistake to apply the correction for a magnetic bearing in the wrong direction, therefore doubling the offset.

2.     In many cases steel work or electric power sources affect the compass.

 

BTS MODE:

The principle of use is simple:

1.     The Icon for the BTS   is located on the map at the transmitting site. 

2.     The Icon for the Land Mark  is located on the map at the land mark.

3.     The desired antenna bearing [degrees true] is entered via the pop-up keyboard. [Tap the text to activate the keyboard entry]

4.     The two lines on the map show the line to the land mark [RED] and the desired antenna bearing.

You can then point the Red line towards the land mark and aim the antenna along the Green line.  Alternatively the Offset can be read from the screen and a protractor/theodolite used in place of the phone.

 

BTS Icon Location:

The BTS Icon can be located on the map in four ways:

1.     Touch/hold/drag the icon to position

2.     Enter the Latitude and Longitude to the display via the keyboard.  [Tap the text to activate the keyboard entry]

3.     Tap the “BTS Here” button.  The icon will move to your current location if you have GPS lock.

4.     Tap the “Site List”  button and the green Site List will be displayed, covering the map.  The map info panel [Blue] remains visible.

Select a site by tapping on the record, name and co-ordinates are shown on the green title bar.  Tap the “BTS/A-END” button, the icon will move to that location.

The map info panel will update Site Name in the Blue title bar.  The Longitude and Latitude displays will also be updated.

 

Land Mark Icon Location:

The Land Mark Icon can be located on the map in three ways:

1.     Touch/hold/drag the icon to position

2.     Enter the Latitude and Longitude to the display via the keyboard.  [Tap the text to activate the keyboard entry]

3.     Tap the “Site List”  button and the green Site List will be displayed, covering the map.  The map info panel [Blue] remains visible.

Select a site by tapping on the record the name is then shown on the green title bar.  Tap the “LandMark” button, the icon will move to that location.

The map info panel will update the Longitude and Latitude.  Site Name in the Blue title bar does not change.

 

Map Control

1.     The map centre can be moved by dragging, zoom is controlled by two finger pinch.

2.     Click the “Map Type” button.  The map will toggle between Road Map and Satellite views.

3.     Click the “Auto Zoom” button.  The map will move and centre to show the icons.

 

Save

The “Save” button will save a screenshot as a Portable Networks Graphic [png] file.  The user enters a file name without the .png extension

 

Files

The “Files” button allows the user to view and delete saved files.

 

POINT to POINT MODE:

Point to Point mode operates in basically the same way as Cellular mode except that there are three icons: “A” end, “B” end and Landmark.

The offset is calculated from the “A” end to “B” end bearing line.  Path distance and “A” to “B” bearing are also calculated.

Path distance can be displayed in either kilometre or miles.  The units [Km/Mls] can be toggled by clicking on “PATH DIST”.

 

SITE LIST:

The following describes the Site List functions:

 

“Site List” button in the Blue section will show the Site List.  Initially the Site List has a number of entries; these are fictitious sites for demonstration purposes only. 

Delete these after you have entered at least one location of your own.

 

“Store” button takes the Site Name from the title bar of the Blue panel and the Longitude and Latitude of the BTS/A-END and stores this as a new entry in the database.  This new entry is immediately displayed in the site list in alphabetical order.

[NOTE: The selection of BTS or A-END data depends whether the App is in BTS mode or End to End mode.]

 

“BTS/A-END” button moves the BTS/A-END icon on the map to the site entry selected in the Site List.  To select a site from the list tap the entry and the Site Name will be displayed on the Green title bar.

When the “BTS/A-END” button is tapped the BTS/A-END icon moves to the selected location on the map.

 

“LandMark” button moves the Land Mark icon to the selected location on the map.

 

“Del” button removes the selected entry from the database and the site list. 

Before deletion the Site Name, Longitude and Latitude details are transferred to the map information [Blue], if the deletion was an error, tapping the “Store” button will restore the entry to the database.

 

“Imp” button is used to import a site list, this import will overwrite the existing data and existing records will be lost.

The user must first copy a CSV file of list into the ABT folder on the phone. 

The CSV file would normally be generated from a spread sheet or database and must be named “impsitelist.csv”. 

The CSV file must be based on three columns,  Site Name,Longitude,Latitude.  Headers are optional and will not affect the import.

 

“Imp+” button is similar to the “Imp”  button but does not overwrite the existing data.  The imported list is appended to the existing data; if there are duplicates they are deleted.

A record is only seen as a duplicate if ALL data matches.  EG If there are two records with the name, “London”, but with different Latitudes they will not be seen as duplicates.

 

“Exp” button is used to export the current Site List as a CSV file to the ABT folder.  This file is named expsitelist.csv and has no headers.

 

“?” button displays a quick info file: exit by using the phones back button.

 

SEARCH FUNCTION: Tap on the Green Title Bar and edit the Site Name.  As the text changes the site list will scroll to the closest match, the more of the name typed the closer the match. 

End the search using the keyboard return key.

 

SUNDIAL:

The Sun Dial function is a “Last Resort” option when operating in an environment with no identifiable land marks. [Deserts, snowfields]

This function is turned on/off with the Sun Dial button at the bottom left corner of the map.  A sun symbol, a shadow line are displayed and the map is rotated.  With the device in the horizontal, the sun symbol is pointed towards the sun [as a land mark] and the antenna bearing line is aligned correctly.

Alignment with the sun can be eased by placing a small object [inverted golf tee, pencil stub, etc.] to act as a gnomon.

NOTE1: This method ceases to be valid at less than 24degrees from the equator; this function will not work at these latitudes.

NOTE2: This method may be useful if orienteering through mountains in iron ore country.

 

MECCA:

The MECCA function uses the Point to Point mode to show the direction of Mecca from the user’s current location.  The Mecca button is initially not shown.  The button is activated from the Settings menu.

When activated the Mecca button is located at the bottom right corner of the map.  A click on the button will centre the map on the current location, the green line points toward Mecca.  A second click on the Mecca button restores the previous screen.

 

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