kb8u
02-01-2009, 11:34 AM
I have just finished a computer program and web page that I thought this group might be interested in:
http://kb8u.ham-radio-op.net/TV
It repeatedly scans for DTV stations and tries to find the call sign from the program when the tuner locks on a channel. If successful, it plots the relative signal strength and signal/noise. If the call sign can be found on fcc.gov, it retrieves the location and other data and displays it on a map, color coded by strength. If a station drops out, it will change the color to black and it will stay on the map for 48 hours. When zoomed out, only the strongest station in a city is displayed to avoid map clutter. The map updates every 5 minutes.
The tuner is a Silicondust HDHomeRun. The antenna is currently a Tennadyne T32 LPDA up about 45 feet that I point in different directions from time to time. The computer program is written in Perl; it in turn repeatedly runs a free program available from Silicondust to scan for DTV signals. Signal strength graphs are plotted with an open source package called Cricket. The OS and web server are also open source, Ubuntu Linux and Apache. I found some example javascript code on the internet for the map that I modified.
If anybody would like to run their own copy of this on their web page, please contact me. I'll open-source it if there's enough interest. <mycallsign>_vhf@hotmail.com (replace <mycallsign> with my ham radio call sign and don't forget the underscore.)
Wish list:
1. All stations would transmit their call sign in the program. :banghead:WPXD Ann Arbor, for example does not so it is ignored. Serves them right.
2. Display distance and bearing.
3. Look up and map Canadian and Mexican DTV (any location info available?).
4. Sort stations by RF channel number instead of strength and RF channel number.
5. don't run hdhomerun_config, use API instead.
6. MORE DX!
Bugs :duh::
1. The map starts at the same location and zoom level each time, so E-skip may not show right now. I plan on fixing that.
2. FCC data is NAD27(?), Google is WGS84 so the icons may be off a few dozen feet. Just look for the tower if you need more accuracy....
3. Internet Explorer may cut off the call sign label in the list of stations on the right. I'll probably fix that (time to learn CSS). Try the latest Firefox.
4. Very old browsers may not refresh the screen every 5 minutes. Try the latest Firefox.
5. FCC look ups only check permanently licensed stations. WILX in Lansing, for example, is using a Special Temporary Authorization (until they move back to channel 10?) so it isn't on the map. If Congress delays the switch to all-DTV then I may fix that.
6. Previous to today, some of the graphed data is bogus. Some bugs were fixed, but if the perl program crashes or the tuner flakes out, the last values will be used there on out. It's all pretty solid so I'm not going to fix that.
http://kb8u.ham-radio-op.net/TV
It repeatedly scans for DTV stations and tries to find the call sign from the program when the tuner locks on a channel. If successful, it plots the relative signal strength and signal/noise. If the call sign can be found on fcc.gov, it retrieves the location and other data and displays it on a map, color coded by strength. If a station drops out, it will change the color to black and it will stay on the map for 48 hours. When zoomed out, only the strongest station in a city is displayed to avoid map clutter. The map updates every 5 minutes.
The tuner is a Silicondust HDHomeRun. The antenna is currently a Tennadyne T32 LPDA up about 45 feet that I point in different directions from time to time. The computer program is written in Perl; it in turn repeatedly runs a free program available from Silicondust to scan for DTV signals. Signal strength graphs are plotted with an open source package called Cricket. The OS and web server are also open source, Ubuntu Linux and Apache. I found some example javascript code on the internet for the map that I modified.
If anybody would like to run their own copy of this on their web page, please contact me. I'll open-source it if there's enough interest. <mycallsign>_vhf@hotmail.com (replace <mycallsign> with my ham radio call sign and don't forget the underscore.)
Wish list:
1. All stations would transmit their call sign in the program. :banghead:WPXD Ann Arbor, for example does not so it is ignored. Serves them right.
2. Display distance and bearing.
3. Look up and map Canadian and Mexican DTV (any location info available?).
4. Sort stations by RF channel number instead of strength and RF channel number.
5. don't run hdhomerun_config, use API instead.
6. MORE DX!
Bugs :duh::
1. The map starts at the same location and zoom level each time, so E-skip may not show right now. I plan on fixing that.
2. FCC data is NAD27(?), Google is WGS84 so the icons may be off a few dozen feet. Just look for the tower if you need more accuracy....
3. Internet Explorer may cut off the call sign label in the list of stations on the right. I'll probably fix that (time to learn CSS). Try the latest Firefox.
4. Very old browsers may not refresh the screen every 5 minutes. Try the latest Firefox.
5. FCC look ups only check permanently licensed stations. WILX in Lansing, for example, is using a Special Temporary Authorization (until they move back to channel 10?) so it isn't on the map. If Congress delays the switch to all-DTV then I may fix that.
6. Previous to today, some of the graphed data is bogus. Some bugs were fixed, but if the perl program crashes or the tuner flakes out, the last values will be used there on out. It's all pretty solid so I'm not going to fix that.