Beacon in a Box A 10-Meter Auto Beacon By Jim Southwick, N7JS So the sunspot cycle's bottoming out and there won't be any OX on 70 meters ti1 2009, right? Wrong! There are always occasional openings on 10-meters, even at the bottom of the sunspot cycle, due to sporadic-E propagation.But how do you know about them? The answer, in a word: beacons.Here's how to build one...I've always been fascinated with HF beacons.Listening for them is a great way to find out if a particular band is propagating and from what direction.The 10-meter band especially interests me, because the FCC will allow a licensed operator to set up an unattended beacon.However, care should be exercised to check on your beacon regularly.The agreed upon segment is from 28.200-28.300 MHz.When the band is open, you generally can hear beacons throughout this range from all parts of the world using very little power and often a simple vertical or dipole antenna.Conversely, you can also transmit a beacon to all parts of the world with the same criteria..My goal with this project was to forgo dedicating an HF radio for the beacon and instead make a nice all-in-one unit that could fit in your hand and be portable, yet have the look of a nice little base-station unit.
I also wanted to keep the cost for everything under $100.This project features a control interface that will store the CW message and key the transmitter automatically at intervals you determine.I love bells and whistles.
Therefore, for the front of the beacon unit (photo A), I incorporated an RF meter and four switches, one to turn the system on and off, another to change between two different frequencies (in case one is busy or taken), a third to turn the monitor speaker on and off (who wants to hear that 24 hours a day?), and the fourth to turn on a light for illuminating the meter.I needed the last item to save power in case of portable use.Photo A- Front view of the beacon transmitter.A label machine gives everything a professional, finished look.(Photos by Leah Hogsten) On the back of the case (photo B) I have a power jack that can be used for a 12-volt power supply or auto-battery hookup, but the unit is also able to run 9-volt portable (complete with a 9-volt battery holder).
I also have a DB9 connector for connecting to a computer to easily program the beacon message and intervals.I also decided to use an SO239 for the antenna (rather than an RCA or BNC jack).At this frequency, we will be just fine with this much more convenient connector.This also allows you to connect a portable back of set antenna if you desire, for a complete all in one setup.
For portable use I simply purchased a back of set CB antenna from Radio Shack.The Miracle Whip antenna would also work nicely in this case.Well, with all the external hardware planned out, it was time to plan out the guts for this item
Namely a beacon interface and a transmitter.So let's begin! We'll start off with the beacon interface, called the Freakin' Beacon. Photo B- Rear view of the beacon transmitter.The 9-volt battery clip permits portable operation.
The DB-9 data port is for hooking up a computer to program your call sign and other options.This kit is available for $30 plus shipping from .The reason I went with this interface over others is the easy ability to program it from a DB9 connector, as well as the included LEO feature for the visual display I wanted.It is a very-high-quality interface that goes together easily and can be completed in just a few hours (see photo C)..If you are going to build a kit such as this, you need to spend a few dollars at the local Radio Shack or other parts store.You are going to need four toggle switches (2 OPOT and 2 SPST), 9-volt battery clip holder, OC input jack and plug, SO-239 chassis mount connector, OB9 computer cable and connector, a couple of chassis-mount LEDs (Note: The interface kit comes with the LEDs; however, they are circuit-board-mounted types and I wanted chassis-mount LEDs), wire clips, hookup wire, mini speaker, 9-volt battery connector, heat-shrink tubing, rubber feet for the case, and of course the metal case itself.Put the interface together very carefully, including using heat-shrink tubing around all connectors.It's all tested, all programmed with my call sign and a plead to QSL if you hear it - works perfectly, so one hurdle completed.Once the IC was installed, I did all the rest of the work on the controller board using an anti-static bag as a mat.It's a real bummer to walk around on the carpet admiring your work (beating on your chest) and then pick it up and zap it with an electrostatic charge.
Always make sure you are not carrying around thousands of volts in your body and then touching your circuit board as the first thing when you sit down (I've done it).Just find the closest ground (or person!), give it a zap, and then get back to work on your project.Photo C- Interior view of the "Freakin' Beacon" interface board, completed and installed.The electrical tape is to provide insulation for the transmitter board, which will be installed (upside down) above the interface circuitry.
At this point, I decided to do some metal work and put together a very compact case that would hold everything.
I went with the smallest case possible.You can get the small metal case I used from Radio Shack for a couple of bucks, but as noted below, I ran into space problems as I put everything together.If you'd rather have a bigger case than work with cramped spaces, you might want to go with something larger.Be sure to layout everything with a.pencil before drilling, taking into account that switches are much bigger than just the toggle part, etc.Remember, too, that the lip of the case also covers space.
If you don't have a Dremel@ tool, you shouldn't even be thinking about this project, especially when it comes time to do the cutouts for the meter and DB9 connector.It's
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