Live RF data on an interactive
Internet map

[Live RF Feed via VU2NCT on 144.800 MHz]

This page demonstrates the ham radio capability in penetrating the Internet to serve useful purposes. This is a live APRS data feed page. APRS stands for Automatic Position Reporting System. But this is not to be mistaken just as a mere automatic vehicle tracking system. It is real-time two way digital radio communication where many of the vital information are exchanged almost automatically. Non-hams can monitor ham radio APRS digital communication using this page.

To just get a feel of how APRS activity is going on at other parts of the world here are a few links:

| AE5PL | | WA4DSY | | SV1CNS  | | HB9PVI |

Radio & Beyond!

On the New Delhi map displayed below, we can see hams doing APRS communication [If they wish they may talk or otherwise exchange APRS digital data using their radios]. If they transmit APRS digital data on 144.800 MHz [which is VU2NCT APRS frequency], an APRS ready radio [Kenwood TH D7 AG] hooked to the Internet at VU2NCT can pick up the radio signal and in-turn feed the data to the Internet. During this demo, in a simulated exercise, the mobile station VU2MUE-9 [In most probability this may be during a demonstration. So if you don't see VU2MUE-9 on the map please feel free to contact him] appears on the map from RF originated data. There may be position reporting from Non-RF originated stations also. The station WB4TLP appearing with a WX icon is a ham weather station feeding weather data to Internet and these data are also available on the map for utility.

How to use the map?

Wait for the map to fully load [121 kb]

[2] If a message like 'allow the Signed Java Applet to run' appears. Do that by clicking 'YES' or 'OK'. Because doing so is safe.

[3] Click on the map to activate the JAVA controls.

[4] Initially when we see the map, we may not see VU2NCT icon (our club call-sign). This means that the automatic position beacon from VU2NCT is not yet sent. Have patience till the beacon is sent. There are different beacon rates used by different stations depending on speed and necessity. The icon may also not come on the map if VU2NCT does not position report.

[5] When VU2MUE-9 [This is SSID of VU2MUE representing a mobile ham station] appears on the map, 'CLICK' it. A small text line below the map tells the position information of the mobile station. It not only tells the position information but also tells other information like Speed of the vehicle, direction of travel [course], AMSL [Altitude, i.e. Above Mean Sea Level] etc. If a text message is sent, the message can also be read.

[6] To read messages. Press the 'M' key. Pressing M key writes the messages to the 'Java Console'.

Where to find the Java console?

The JAVA CONSOLE can be opened from Internet Explorer Browser's TOOLS > SUN JAVA CONSOLE

Problem opening the map?

If your browser is not JAVA enabled, the map would not load. Download JAVA 2.0 Runtime environment. If you get an 'Error opening Data' message in the browser status bar, it may be due to a LAN proxy connection.


VHF & UHF Satellite Cross Yagis with AZ-El Rotors at VU2NCT club station

VU2NCT club station at Vigyan Prasar

APRS Ready setup at VU2NCT

New Delhi APRS Demo page
|What is APRS?|APRS benefits|  |Why javAPRS?|  |Map use instructions|
|Map Commands| |hams get UI-VIEW| |APRS Presentations & Lectures|
|APRS Resource Collection|| Monitor Text Messages |

APRS is the Registered Trademark of Bob Bruninga WB4APR US Naval Academy

Why javAPRS?

Peter Loveall's [AE5PL] javAPRS [javAPRS 2.7b24 2006 Pete Loveall AE5PL] enables demonstration of ham to non-ham communication [Non-hams can only monitor APRS ham activities using their Internet Browsers]. It's utility during an emergency situation is self-explanatory.
Dr. Steve Dimse (K4HG) first introduced the APRS interface to the Internet in 1999. This enabled the display of APRS maps on Internet Browsers and thus RF originated APRS information from mobile ham stations can now become accessible to the non-hams too. 

During the demo, VU2MUE [SSID VU2MUE-9 Secondary Station IDentification for land mobiles]  feeds the real-time RF [Radio Frequency] data via a KENWOOD radio interfaced to a computer at VU2NCT and that data reaches you via the Internet showing his positions & messages on a map. [a mobile station can in fact be tracked if the Internet map is monitored dedicatedly]. VU2NCT logs on to Rin Fukuda's (JG1VGX) Tier 2 T2JAPAN APRS server using Late Roger Barker's (G4IDE) UI-VIEW and then the data is internationally distributed from T2JAPAN tier 2 server. Mobile ham stations can remotely text message or send e-mail via the VU2NCT IGate even without a direct Internet connectivity. RF originated text message or e-mail can be read using this page.

Click the image for high resolution UI-VIEW screen shot

UI-VIEW by Roger Barker, G4IDE

Roger Barker's [G4IDE] UI-VIEW is a popular Windows based APRS application used by hams [radio amateurs licensed by the government] all over the world. UI-VIEW requires a validation from APRS server administrators. Being hams we always appreciate others also to become hams so that they can also use a beautiful software like UI-VIEW and enjoy the benefits of APRS Technology. There are many APRS applications now available for free.

After downloading UI-VIEW, hams in Asia region can contact Art Takashi, JA1OGS for APRS Server validation. Art Takashi, JA1OGS is the official Registrar of APRS for Region-3 Asian countries.

Why this map?

The map below demonstrates the utility of an Interactive Internet map. This APRS map is accessible to hams as well as non hams too. Text messages originated from RF stations can be monitored by non-hams. This has utility in ham radio emergency communication [press 'M' and the read message at JAVA Console]

APRS benefits

  • Accurate position information about mobile & fixed stations on an Internet map.
  • Direction finding for precise beaming.
  • Tracking a mobile station [useful during emergency operation/tactical situation when prompt receipt of information about positions and progress of mobile stations is of utmost necessity for efficient coordination]
  • Line-of-Sight Distance and bearing of stations from base station available just at the click of a button.
  • Monitoring of 'radio to radio digital text messages' on an Internet browser. Non-ham family members of a ham can track him/her and read messages. During emergencies, if the Internet does not fail, this would help non-hams to monitor emergency messages.
  • Monitoring of real-time weather information originated from ham radio weather stations [Real-time Weather information like Wind Speed, Wind Direction, Temperature, Barometric Pressure, Humidity, Rainfall etc. are available on this map with just the click of a button.
  • Plotting of real-time objects on the map. For example an accident site, crash site, intimation about a traffic jam for route planning, fire site or information about a ham radio event etc.
  • Allows important information to be exchanged without human intervention. This is important during a tactical or emergency situation, when we need to concentrate in other important jobs (for example 'Search & Rescue').
  • Reduces voice traffic by avoiding repetitive conversations and thus economical use the radio bandwidth. [e.g. What is your name/call-sign? [QRA/QRZ?]/Where are you? [ QTH? ]/Tell me your location so that I can turn my Yagi beam Antenna towards you/What is your e-mail?/Where are you going?/Are you busy?[ QRL?]/What is the height of your antenna/building?/How far you are from me?/In which direction you are now moving?/At what speed you are traveling?/what is the wind direction and wind speed?/What is the Temperature?/Is there any rainfall today?/What is the barometric pressure at your place......

100% Radio & Beyond.....

Stan Horzepa

Stan Horzepa, WA1LOU

APRS is 100% ham radio. javAPRS is 100% ham radio and beyond! It is '100% Ham Radio + Internet'. Who says it is not radio at all? Discard the 'Internet', APRS was there and would be. Advent of Internet eliminated the requirement of shared channel long distance Radio Frequency paths' and enhanced it by providing the high speed long distance backbones. Father of APRS Bob Bruninga [WB4APR] remarks in the foreword of ARRL book [APRS Moving Hams on Radio and the Internet - A Guide to the Automatic Position Reporting System] written by Stan Horzepa, WA1LOU: "The availability of almost infinite bandwidth for "free" on the Internet, fiber or backbones has made a paradigm shift that most ham operators have not awakened to yet..."


[ Read the instructions below the map to use various controls]

VU2MUE-9 [ Mobile Station Example ] APPEARS ON THE MAP BELOW!
Please use the drop down menu to select the Maps
[ Select Gurgaon Area Maps on December 1, 2006 during
Disaster Communication Mock Drill Exercise

Sorry, your browser doesn't do Java!

Clicking on a station shows its information
[distance and bearing from base station] in the status bar.

VU2NCT Area Map Courtesy: Google Earth
New Delhi Map courtesy: Maps of India
Gurgaon Mock Drill Area Maps Courtesy: Eicher City Map


The above box displays Ham Radio Digital Communications heard by this page

javAPRS Commands (Case Insensitive) for the above map


zooms up (wider view)


zooms down (narrower view)


lists stations heard to the Java console


lists only weather station reports to the Java console


lists beacons to the Java console


lists ID reports to the Java console


lists last 25 messages to the Java console


centers map on clicked location


zooms in on clicked location

Arrow keys

scrolls map

Tips to map position adjustment

It may not require to 'zoom in' the map [ ALT + CLICK the point/station you want to 'Zoom In' ] if too many stations don't clutter in a small area. In case if you 'Zoom In' too much and want to restore the map back to its normal size and position [without refreshing the page, because 'refreshing' removes all the stations till they position report the next time ], use the 'Page Up' or 'Page Down' keys' and may be combinations of Left/Right/Up/Down Arrow keys.

Once you get a significant portion of the map visible, CTRL + CLICK at the centre of the map. On the New Delhi map, this is the 'green area marked as NEHRU PLACE'. The map should be placed in its normal position within the applet area.

Feel free to contact VU2NCT for a demo at

VU2NCT Amateur Radio Club Station
Vigyan Prasar, Department of Science & Technology, Govt. of India
A-50, Phase II, Sector 62
Noida, U.P. 201307