Way back in 1991 an article appeared in Radio-Electronics magazine about a spectrum analyzer in the form of a plug-in card for an IBM PC. The card was available as a kit from DKD Instruments. It really caught my fancy so I ordered one and built it. It worked great, providing two bands, 0.1 to 100 MHz and 50 to 810 MHz. Graphical software running in the PC displayed the output. For the price the unit can't be beat.

Unfortunately time has a way of making good technology obsolete. DOS went the way of the Dodo years ago, and my last PC with an ISA slot is now gone. Should I toss the card in the trash?

I remembered that the card included a PC parallel port interface, so it could operate outside of the PC, with a suitable power supply, although I had never considered using it that way. My PC still includes a parallel port (or you can get a USB/parallel adapter), so in 2007 I got to thinking about getting the card working again. I made up a parallel port cable and hooked up a power supply. I booted DOS on my PC and ran the 810B software. Using the setup program I configured the interface to the printer port, and the unit actually worked!

Booting DOS is not a nice or convenient way to use a test instrument. Windows DOS box compatibility does not extend to programs doing direct I/O to a hardware device like the printer port. There had to be a better way to bring all this together.

Then I remembered I had download Microsoft Virtual PC 2004 some time ago but could not run it because of a requirement for XP Pro, and I was running XP Home at the time. Since I am now running XP Pro, I decided to see if I could run DOS as a guest OS, compatible with the 810B software. I discovered that Virtual PC 2007 was now available, so I downloaded it from Microsoft. It installed easily and I created a virtual OS called DOS. I also created a 4MB virtual hard drive. I was able to install the DOS and the 810B software, and after enabling access to the printer port, it all actually worked! Here is a screen shot of the software running (click on it for a larger view):

Now all I have to do is start up Virtual PC 2007 and fire up the DOS guest and run the 810B program.

DKD still retains some useful information on the 810B here. It was helpful to me an I appreciate it.

Here is my 810B in its "new" case. The power supply and audio amplifier is at the back, and the squelch board is on the right wall.

Back to VE3LNY's Home Page