May 3, 2007

Digipup: A Linux live CD for amateur radio

Author: Joe Barr

Puppy Linux is a lightweight live Linux distribution that you can boot and run from a CD, USB stick, or DVD. One of its features is the ability to create specialized "pups" -- new versions of Puppy Linux geared toward a specific purpose. Digipup is one such example, with a focus on amateur radio. I spun it up, and found Digipup to be a great way to check out amateur radio utilities for Linux.

My test machine was an Acer AST-180 with a dual-core Athlon 4000 and a gigabyte of DRAM. When booting, I was offered a choice of video servers: X.org or the smaller, less advanced, but more nimble, xvesa. X.org simplified my choice by refusing to load, so I chose xvesa instead. It performed well; I was surprised at the speed of the GUI. Slow speed is the curse of all live versions of Linux, but Digipup almost made me forget that I was booting from a CD.

Digipup contains three of Dave Freese's (W1HKJ) most popular free software offerings for amateur radio: Fldigi, which does a great job on digital sound card modes like PSK, RTTY, MFSK, and others; Fl_logbook, a small, fast, efficient logging program to record your contacts; and Geoid, which computes the bearing and distance between sites using either latitude and longitude or Maidenhead grid locators.

Freese also makes these programs available as "pet" files, which is the packaging scheme used by Puppy Linux, so if you already have a Puppy live CD, you can simply download the pets and then remaster the ISO using his instructions.

Fldigi

Fldigi allows you to connect your computer to your transceiver and use its sound card to send and receive digital signals like PSK31, RTTY, MFSK, Olivia, CW, and others. For a complete rundown on this program, see the review we did a few months ago.

You'll need to configure Fldigi completely, from font to sound card to operator demographics. Probably the most important configuration item will be sound, but if you don't pick a valid font, you won't see anything you send or receive. To get your sound level set correctly, click on Menu -> Multimedia -> Zmixer and you will be able to use the Tune function in Fldigi while adjusting the volume for peak sound without any ALC deflection.

As with the newer versions of Fldigi, you have your choice of communicating with your rig using either the traditional Hamlib interface or Fldigi's own RigCAT. For some reason, I had to revert to Hamlib in order to get communications between the rig and the computer working, though I normally use RigCAT.

Fl_logbook

Click to enlarge

Fl_logbook is a fast, lightweight, no-frills logger. You can use it manually, or it can work in conjunction with the Save button on Fldigi, which will populate the data fields on a new contact record with the data shown in its top panel, allowing you to add a contact to your log with just a single click of a button.

Fl_logbook also allows you to import, export, or merge log files in ADIF, MultiPSK (LO), MultiPSK (TXT), or its own .lgb format. I exported the records from XLog in ADIF format in order to import them into Fl_logbook.

Geoid

The third application, Geoid, is a simple calculator that computes the distance between stations and shows the bearing from one to another. The bearing is helpful when you are working a rare DX call and you're not sure toward which direction to point your antenna. As you can see from this screen shot, which shows all three apps at once, one station I contacted while using Digipup is located along a bearing 19 degrees from true north from me, and is approximately 1,630 kilometers away.

Conclusion

With Digipup, you can verify compatibility with your amateur radio rig, your logs, and your inner nature without going to the trouble of installing a Linux distribution to do so. Just plop Digipup in your CD drive, boot the system, and there you are.

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