You can buy an inexpensive hockey puck GPS receiver for about $30. It comes with a short cord and USB plug. It appears to the computer as a COM port and delivers the GPS data as an RS-232 bitstream. At this price point, you don’t get the 1 pulse-per-second output, but you do get reasonably accurate lat/long coordinates and GPS time to a fraction of a second.

I know of several uses for these receivers. One is to pair the GPS receiver with a software program called NMEATime from VisualGPS. NMEATime runs in the background and keeps the PC’s clock synchronized to GPS time. This is very handy for running FT-8, or for operating in a contest where you want contacts to be recorded in the log at the right time. NMEATime version 2 is shareware, with a free trial download and a $20 fee for continued use. It is well worth the money. If you are on a budget, an earlier version of the program is free, and also works quite well.

The second killer app for a cheap GPS receiver is Winlink Express. Winlink can be configured to “read” the data stream from a GPS and automatically enter your geographic coordinates into forms that have location fields. This is very helpful if you use the PC in the field. Winlink also has a tool that allows you to send a service message to the Common Message Server (CMS) containing your current GPS coordinates and a brief text message. Your position is shown on a map at the Winlink website a few seconds later, and there are various tracking features available for advanced users. Winlink also automatically forwards the message to aprs.fi, so you can use Winlink to drop “bread crumbs” on the APRS map even if your radio isn’t equipped with APRS.

If you have a GPS receiver, you tell Winlink Express which COM port and baud rate to use, and the software takes the lat/long coordinates directly from the GPS. If you don’t have a GPS receiver connected (or can’t “see” the sky from your operating position), you can enter the lat/long into Winlink Express manually to drop a bread crumb. Look for this feature in the Winlink Express menu under Settings .. GPS / Position Reports.

A third use is with contest logging programs such as N1MM Logger +. At Field Day, we use a a laptop computer running N1MM to log our contacts. The laptops are connected in a local area network. One laptop is designated as the master. It has an attached GPS receiver that N1MM uses to set the time and date, not only on the master computer, but all other laptops running N1MM. This ensures that all contacts are logged during the contest with accurate date and time stamps.

The GPS receiver I have used for several years is GlobalSat Model BU-353-S4. It is widely available, and there are many similar units available on Amazon, eBay, and other fine retailers. I make no claim that this model is the best or least expensive option out there. I only know that it works with all my ham radio apps. It even works in my basement as long as I have the receiver near a window or wood wall.

At some point, I purchased a second BU-353 for use with a go-kit laptop. To my surprise, it didn’t work when I initially plugged it in. I initially thought it was defective, but it turns out that the BU-353 and similar devices use a supercapacitor to back up the device configuration. If left unpowered for a long period of time, the configuration data may be lost and the device will revert to factory defaults. If this occurs, your software app may lose communications with the device. Even if your GPS unit works right out of the box, it is probably best to run through a setup procedure to make sure its configuration is optimal. Click here for details.

Recently, I found another GPS receiver that appears to have better performance than the BU-353. Unlike the BU-353, it has the capability to receive data from GNSS and GLONASS satellites (among others). I purchased mine from AliExpress for $25. Information on how to configure it is in this document.

Normally, a serial port device can be used with only one PC app at a time. But we want to make the serial stream from the GPS receiver available to both NMEATime and Winlink Express simultaneously. Fortunately, you can download and install a free utility called com0com that splits the incoming serial stream into multiple virtual serial ports. You can then assign one of these virtual serial ports to each app that requires GPS data. Instructions on how to accomplish that can be found in this document.

–KN3U