POSITION - NAVTEX STATION DISTANCE FOR IDENTIFICATION
(2024)
Once ships sailed around the world without Navtex on board!
What is the problem?
There are more Navtex stations that have the same identification character. For example the Navtex stations in Den Helder (Holland) and also Haifa (Israel) have both the "P" as identification character. If we want to know which station it is, we can use a GID or Graphical Identificator. Contains the message information about the North Sea then we know that it is Den Helder (Holland). If the message contains information about the Mediterranean Sea then it is Haifa (Israel). But often there is no GID. However, almost always there is a position mentioned in the message!
My simple idea was to measure the distance from such a position to the stations with the same ID character. And then you can assume that the nearest station with that ID character to that position is the right Navtex station. It is just a HTML script or a web page with Javascript code for the calculations. Click on the link below to try it!
Link to navtexwhere.htm
How does it work?
It is a simple tool to find the name and location of a Navtex transmitter based on the ID character of a message and if available, a position in the message.
Fill in the ID character of a message and the position in the message and press "CALCULATE" and a list of stations is displayed sorted by distance from that position. You do only have to fill in the integer parts of the position, that is accurate enough. So not 53.2406 and 6.2955 but only 53 and 6! If you try this position, you will see that Den Helder (Holland) is the nearest Navtex station and that should be the one!
Nice tool for "NAVTEXsnoop"!
My Navtex decoding software "NAVTEXsnoop" does not have an integrated data base. This is a nice tool to find information about the received Navtex stations.
Because there are some more options. If you set your own location as the position, the distance of a list of Navtex station is calculated to your own location. And you can also do an extra selection for Navtex Area or Country Code. If you set a "*" as ID and a country code, then all the Navtex stations in that country are shown.
And if you only fill in the ID character of a message, then a list of stations is displayed sorted by distance from your own location when you press "CALCULATE".
If you press the button "TX-NOW" the Navtex stations are displayed that have the current transmit schedule time peroid of 10 minutes. Every 10 minutes the list is updated.
GID's and UID's
The data base shows GID's and UID's. What is that?
GID is a Graphical Identifier word. If this word is in the message then together with the ID character the station is identified.
UID is a special word. When the message contains this word, the station is already identified with an incorrect ID character in the message header or even without message header!
The data base maintained by Cormac EI4HQ of the Navtex DX group!
How to make such a website?
That is impossible without the data base maintained by Cormac EI4HQ of the Navtex DX group! But the format is not usable for this website. I made a simple Python program to convert it in a usable format for the HTML script. Just execute that simple Python program and the data base that needs to have the name "YAND_STATIONS.txt" is converted to a file with the name "JSdatabase.txt". All that remains is to insert the text of that file between the lines of the HTML script "navtexdxpos.htm" with a text editor like GEANY:
// ===== INSERT THE DATABASE HERE! =====
and
// ===== END DATA BASE =====
And you can also modify in the first lines of the HTML script "navtexdxpos.htm" the default position to your own location and the data base version!
var mylat = 38.853;
var mylon = -0.159;
const dbversion = "Version 2.5 of the YAND_STATIONS data base maintained by Cormac EI4HQ of the Navtex DX group";
Open the HTML file with your webbrowser to run it, that is all!
The HTML script can be edited with a text editor like GEANY.
SOFTWARE
Before using this program, you have to install Python. That is very simple. But read first something about Python by clicking the following link:
WHAT IS PYTHON AND HOW DO YOU INSTALL PYTHON
As the source code of Python is written in ASCII, it is very simple to modify the program to you own requirements. Think for example about the size of the screen, the colors etc.
Required Python version:
Required external modules (site-packages for the correct Python version!):
Link to download the ZIP file with HTML script, Python software and picture with Navtex areas
Index PA2OHH