Because of a large number of questions about the web controlled radio, here's some additional information in the form of a "FAQ" type file.
The web controlled radio provides near real time audio from a computer controlled shortwave receiver. This is a RECEIVE ONLY application. For information on a full transceiver version of the software visit http://www.ralabs.com/remote/.
It works like this:
The main web site uses a full time 112K ISDN connection to the Internet via Dreamscape internet services in Syracuse, NY. The
main web server uses Microsoft Windows NT and Website version 1.1f to provide the web
pages. It also runs a copy of the RealNetwork Basic
Server software to provide the near real time audio. The main web server system is a
Pentium 166 with 96 MB of RAM and about 4 GB of drive space.
Two Pentium 166 systems located in the ham shack are the radio controllers and audio digitizer systems. They run Windows 95/98 with Website 1.1f, RealNetwork's Encoder software for the audio and custom written CGI software to provide the web to radio interface. The computers have 64 MB of RAM and about 2 GB of drive space for the web server software. the control software, the support files and logs.
The software is written in Visual Basic 6.0. It sends the frequency entry page then a confirmation page when you enter a frequency and mode. The frequency and mode you select is converted to the proper format for the radio and sent to the radio using the serial port on each computer.
The radios, antenna and location:
The antenna is a 120 ft long wire at the 20 foot level. A RF Systems DA-4 signal distribution amp is used to feed the radios. A Ten-Tec RX-320 and the Icom IC-R75 are presently on-line. The site is located near Canastota, NY (about 25 miles east of Syracuse, NY).
1) The whole thing connects to the Internet using a full time 112k ISDN line. As a result there are limits on the number of users connecting to the system at once. The connection supports up to 7 audio/video connections before things deteriorate too much.
2) Currently there is no control on frequency changes. You could change the frequency then another user could change the frequency a few seconds later. Limits on who uses the system and how often might come in a future software version.
3) The audio stream does not change immediately after a frequency change. This is because the RealAudio player buffers a few seconds of audio to smooth out network congestion problems. It can take up to 15 seconds or so for the audio to change. THIS IS NORMAL.
4) This is not a full time effort. The radios and PCs are part of a ham station. If the "hamshack" server doesn't respond then the radio and the computer are being used in the ham station configuration or the system is in maintainence mode.
"My RealAudio software gives an error message when I try to connect" - A few folks have written that they are having problems accessing the audio. If you don't have the latest version of the RealPlayer software then click on the link to visit the Real Network web site to get it. Older versions may have problems either connecting or playing the audio stream.
"I can change frequency Ok but I don't get any sound." - Did you remember to click on the link to start the RealPlayer connection?
"I can get the radio to change frequency and hear the sound but it's all broken up." - The link to the Internet is only a 112K ISDN link. It can handle about 7 audio/video streams at once leaving some extra space for the web traffic for the control page. More than this causes "network congestion" problems for the RealPlayer software. Since faster ways of connecting to the Internet are considerably more expensive, it's unlikely that the connection will improve in the forseeable future. You may also be having problems with the Internet bandwidth between my servers and your computer.
"a way to tell if anyone is curently using the radio?" - Not at this time. There are no utilities that tell me if someone is connected to one of the audio streams. If one becomes available and I can add a line or two to the program code I'll give it a try.
"a graphical interface for the radio?" - Probably but at the expense of the number of audio streams the system can handle. As I've pointed out already, the bandwidth available is limited. If I added a graphic interface the graphics files alone could amount to 25-50K each time you changed frequency. This would mean less available bandwidth to send audio. I have to balance useability against the "pretty factor". A graphics interface would be nice but it hardly adds to the useability of the system when faced with limited bandwidth. Maybe if I win the NY Lottery and finally get that T1 line I've been dreaming of for so long.....
I'm considering making a version of this software available "ready to run". Here's a description of what you may need to use a "commercial" version of the software. Please email me at the armoldr@ralabs.com if you're interested.
Here's what I use to make the web controlled radio work:
This software handles the serving the audio streams, encoding the audio and playing it
back.
RealNetworks
RealNetworks Basic Server (for Win Nt or 95)
RealNetworks Encoder (works under Win Nt/95)
RealNetworks RealPlayer software (Win Nt/95)
This software handles the web pages on both the primary web server and the hamshack web
server.
Website 1.1F (or any other web server that does standard CGI under Windows 95/98/NT)
A book called Building Your Own Website was available from O'Reilly and Associates. It contained a CD with Website
1.1F (or newer). Microsoft's IIS under Windows NT4 should also be able to support this
software.
I suggest that you use a Pentium 233 or better should you undertake this task on a single computer. It is possible to run things on a single PC but since I had multiple systems available I decided to split up the load. Get at least 128 MB of memory if you intend to try this on a single PC. I also recommend Windows NT 4.0 over Windows 95/98 for this application on a single system.
Source code for the application is NOT AVAILABLE. Versions of the control software for specific radios WILL be available however. Keep watching the main web radio page for information.
That about wraps it up for now. Please feel free to send suggestions or trouble reports to the address below.
Back to the Web Controlled Radio Page.
Questions? Go ahead and send email to Bob Arnold N2JEU at arnoldr@ralabs.com
Visit the Random Access Labs web pages for additional
information on electronics, SWL'ing, amateur radio, robotics and much more.