January 2017
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Burk Autopilot, DOS version

We have been doing work at a particular radio station for a few years now. Every time I go there, I look at this… thing:

Burk DOS Autopilot/CDL running on Windows 98

Burk DOS Autopilot/CDL running on Windows 98

It is a very old PC running Windows 98 and Burk Autopilot/CDL 4.6 for DOS.  The auto pilot program is running from a windows DOS prompt and seems to be working okay; my concern is about the age of the hardware and the potential for failure.  The Autopilot is what controls the AM station’s power levels, which vary from 1,000 watts daytime, to 4 watts night time.  We have all read about AM stations fined by the FCC for running daytime power levels at night.  Failure of the ancient autopilot computer could lead to exactly this scenario.

I attempted to purchase the newer, Windows XP version of Autopilot, only to be told “that item is not in this year’s budget.”  Apparently, it was not in the budget for following year, or the one after that.  Thus, when the hard drive on the old Windoze 98 machine began making a terrible grinding noise, I knew the end was near.  I made an attempt to run the Autopilot from a Windows XP DOS prompt, at which time I was informed: “The program cannot start or run due to incompatibility with 64 bit versions of windows…” GAK!  I kind of knew this already.

I began day dreaming about running a DOS virtual machine inside of a Ubuntu or Lubuntu operating system.  Then I found a DOS emulator program for Linux called “DOSemu” which looked like exactly what the doctor ordered.  Using the carcases of several old HP desktop computers, I came up with one working PC that had two organic serial ports.  This is actually not a bad unit, as it has a 1.6 GHz dual core processor and 2 GB RAM.  On this machine, I loaded the 32 bit version of Ubuntu 12.04 desktop.  Naturally, the original Autopilot/CDL 4.6 disks were nowhere to be found so I had to copy the directory off of the old computer.  It was also understood that this project was simply going to suck.  Therefore, the superannuated Windoze 98 machine had no network interface nor any USB ports.  My only option was to copy the files unto a 3 1/2 inch floppy disk.  Fortunately, I have a USB 3 1/2 floppy drive, which I was able to use to copy the files onto the new computer into the /home/ARC16 directory.

Downloading and setting up Dosemu was fairly straight forward.  There were a few configuration steps that needed to be completed before the Autopilot software would work and communicate with the ARC-16 remote control:

  • In the DOSemu configuration file, the hardware serial port needs to be configure to work with the DOS emulator.  This is located at /etc/dosemu/doseum.conf.  The default conf file has all of the serial ports commented out.  Remove the comment and change the serial port source:  $_com1 = “/dev/ttyS0” or $_com2 = “/dev/ttyS1”  The serial ports available can be determined by the following terminal command: dmesg | grep tty  The output should look something like this:

    paul@engineeringIII:~$ dmesg | grep tty
    [ 0.000000] console [tty0] enabled
    [ 37.531286] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
    [ 37.532138] 0000:04:00.3: ttyS1 at I/O 0x1020 (irq = 3) is a 16550A
    [16206.667112] usb 2-1.3: pl2303 converter now attached to ttyUSB0

    For USB to serial port converters, the serial port source may look something like this: $_com1 = “/dev/ttyUSB0”

  • The DOS emulator time can be synced to Linux time by: $_timemode = “linux” This is great because Linux can be synced to a NTP source, meaning Autopilot time will always be correct.
  • The logged on user that will be running the DOS emulator needs to be added to the “dialout” group.  This can be done by sudo adduser [user name] dialout.  This will allow the Autopilot software access to the comm port.
  • The DOS autoexec.bat file should be edited so that Burk autopilot loads automatically when DOSemu is started.  DOSemu automatically assigns the D drive to the Linux home directory.  Thus, simply adding:

    CD ARC16

    to the end of the autoexec.bat file will start the ARC16 program automatically when the DOSemu program is started.

  • DOSemu can then be added to the Ubuntu desktop startup.

The results:

DOS autopilot running on Linux machine

DOS autopilot running on Linux machine

Burk Autopilot/CDL (DOS version) running on a Linux (Ubuntu 12.04.4) machine.  The stupid thing will probably run forever now.

This computer is also used to program the satellite receivers, which are located at the transmitter site.  Thus, there are several manuals and program clocks stored in the documents folder.  I also installed the x11VNC server program, so that the computer desktop can be logged into remotely from the studio over the LAN link.

I noticed that the DOSemu program hits the processor fairly hard, with one core running about 45% most of the time.  That should be fine, as this machine is used very infrequently for other tasks.

Temperature Sensor for Burk Remote Control

As a part of the re-wiring of a transmitter site, I realized that the site needed a temperature sensor.  I believe it is important for any remote transmitter site to have a temperature sensor, too many things can go wrong at a transmitter site.

I recall one incident at WGNA-FM in Albany, NY were a ventilation fan failed on a hot summer day.  The Harris HT-10 transmitter stayed on the air while the temperature climbed through 160 degrees inside the building, finally shutting down when the solid state driver module failed.  This site had a temperature sensor and a live operator taking transmitter readings every three hours.  They faithfully logged the temperature increase in three hour increments but didn’t call anyone until the station went off.  When I arrived there, it was so hot inside the building the I couldn’t touch a metal surface.

For the present day project, I looked at the Burk BTU-4, which seemed a little pricey.  After doing a bit of quick research, I found the National Semiconductor LM34 a good alternative.  This unit puts out 10 mv/degree F, which can be directly calibrated to a metering input of a ACR-16 using the lin scale.   I checked the accuracy by using a piece of melting ice, it was right on.  The design and implementation is very simple:

LM34 temperature sensor

LM34 temperature sensor

The LM34 is available in TO-46 or TO-92 case.  I bypassed the V+ with a 0.01uf capacitor.  It should be mounted in a small box with the case of the LM34 mounted on a metal cover or heat sink.  The TO-46 version, the case is ground.  It can be run on any voltage from +5 to +30 VDC, I used +5 because I had a little wall wart with the right voltage.  The wire is any type of balanced audio wire like Belden 8459, etc.  The LM34 cost 4 dollars, the rest of the parts were laying around.  It took about 15 minutes to create.

The site is air conditioned, therefore I set the remote control to alarm if the temperature goes above 85 degrees F inside the building.


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