The Etherkit OpenBeacon – A Very Versatile Programmable MEPT

etherkit’s OpenBeacon is the first kit to be offered by proprietor Jason NT7S and I think it’s a good one for him to open up with.  Sure, it’s not the first QRSS transmitter kit on the market but unless I’m missing something (and I don’t believe that I am) it is the most versatile one offered to date. Here is a list of all the modes that it can transmit:

• Dual Frequency CW with 3, 6, 10 or 120 second dits (3 second DFCW is the most commonly used QRSS mode on the HF amateur bands and is the default mode programmed into OpenBeacon)
• QRSS CW with 3, 6, 10 or 120 second dits
• Regular CW (you choose the speed)
• Sequential Multi-Tone Hellschreiber
• WSPR – billed as an experimental mode, but I’ve used it with success
• Glyphcode – a mode that uses Hellschreiber to generate dots and dashes
• A special calibration mode that is useful for setting the center-frequency and bandwidth of your transmitted signal

There are no jumpers for mode-switching. It’s all done with the software client that is available for Windows, Linux and Mac OS X. This software control opens the door for anyone who wishes to come up with their own code to control OpenBeacon (and hopefully share it with other users in the etherkit OpenBeacon forum.)

First things first. Here’s what you get:

In this shot, I took the rather good-looking PCB out of it’s wrapping so you can see it a bit better:

Construction is straightforward. If you’re new to kit assembly and the art of soldering, it may take a little longer to figure out. The usual guidelines apply – identify all the parts, and don’t solder anything into the board until you’re sure that it’s the right part, and you’re soldering it in with the correct orientation. There are useful checks included at several points during the build and after the first stage has been completed, you get to connect the board to a USB cable and see your computer recognize the OpenBeacon. If you’re running Windows, you’ll need to install a driver before this can be accomplished, but it’s reassuring to have the project recognized by your computer at such an early stage of construction.

Here’s the finished board:

And another view of the completed board:

Apologies – I forgot to include a rule in the pictures to give you an idea of the size of the board, so for the record, it measures 70mm x 90mm.

One thing I really like about OpenBeacon is the on-board connectors. Once you’ve finished assembling it, you can plug in a USB cable and an antenna, program it with your call-sign and you’re on the air. If you want to run higher RF output power than the approximately 40mW max you get from USB power, then you can plug in DC power to the on-board DC power connector and get about 300mW from a 13.8V supply. These kinds of QRSS transmitters are often not installed in conventional enclosures anyway, so it’s really good to be able to begin experimenting with OpenBeacon straight off the bat.

This is a bit gratuitous, but here’s a really close-up view of part of the board:

If you don’t already have a QRSS viewer, Argo is the easiest to set up and get going with.  OpenBeacon is already set to transmit in QRSS3 as the default mode, but you will need to program it with your callsign by downloading the client for your particular operating system and following the directions on the etherkit site. If you have problems with any of this, Jason NT7S, or one of the etherkit forum members should be able to help you out.

Of course, the first thing you want to do with a transmitter like this is to see what your QRSS signal looks like on your own viewer:

The very next thing was to see what my callsign looked like in Multi-Tone Sequential Hellschreiber:

You’ll notice that the vertical scale on my Argo screen captures is calibrated with the frequency.  To achieve this, you’ll need to accurately calibrate your receiver so that you can set it to 10139 KHz. In my case, I know that after it has been running for a while, my K2 receives at about 10Hz lower than the dial frequency, so to receive on 10139 KHz I set my K2 to 10139.01. The next step is to enter an offset of 10139000 in the calibration menu and you’re all set. The QRSS band normally runs from 10140 to 10140.1, so a carrier in the center of the QRSS band will produce a tone of 1050 Hz in the speaker of your receiver.

One thing that’s very important to remember if you run into any difficulties during assembly –

Incidentally, before anyone suggests that I was illegally radiating a signal without proper identification, the above screen capture was taken as a result of outputting 5mW from the OpenBeacon into a 50 ohm dummy load – not too much radiating was taking place.

I did run OpenBeacon for one night in QRSS3 mode but wasn’t able to find my signal on any grabbers.  It was only one night and I was, after all, running just 5mW RF output (sucker for punishment here). I’ll be trying it again soon, but at the time I was keen to forge ahead and try the WSPR experimental mode.  I did briefly have a go at figuring out Glyphcode but either the instructions in the Client Software Useage Guide on the etherkit site weren’t clear, or I was being a bit thick.  It could well have been the latter. I’ve no doubt that Glyphcode isn’t hard to program but at the time, was more immediately interested in playing around with WSPR on OpenBeacon, so I hoofed it on forward to that section of the online guide.

To transmit a WSPR signal with OpenBeacon, you first have to load the buffer with the appropriate code. I downloaded wsprcode.exe and placed it in the root directory of my PC.  This is a description of what I did on my PC running Windows. Your mileage will vary if you are running any other OS. In DOS at the command prompt I typed wsprcode “AA7EE CM87 7”  You’ll need to do the same with your callsign, 4-digit locator and power level (in dBM). wsprcode will output the data symbols, sync symbols and channel symbols for your particular data – all you need is the last set of characters – the channel symbols.  Cut and paste this data into a simple text editor (I used notepad on my PC) and edit it to erase all spaces between characters as well as any carriage returns so that all you are left with are 162 characters in a continuous string with no spaces (or anything else) between them.

The next step is to program the buffer of your OpenBeacon with the WSPR code. Using the OpenBeacon client software, the command for this is openbeacon wsprbuffer “flangesprocket” where flangesprocket represents the string of 162 channel symbol characters.

All that remains is to place OpenBeacon in wspr mode, adjust the transmission bandwidth to 10Hz, and the frequency to put you in the wspr band, and manually trigger OpenBeacon (either with S1 or through the client software) at the beginning of an even-numbered minute. OpenBeacon will transmit your wspr signal for the required 1 min 50 seconds.

Here are the unique spots representing 2 evenings of operation:

Date	Call	Frequency	SNR	Drift	Grid	dBm	W	by	loc	km	mi
2012-05-28 02:36	AA7EE	10.140138	-17	0	CM87ut	+7	0.005	K7LG	DM04se	530	329
2012-05-28 02:20	AA7EE	10.140102	-23	0	CM87ut	+7	0.005	VE6PDQ/1	DO33fl	1867	1160
2012-05-27 05:24	AA7EE	10.140108	-22	-1	CM87ut	+7	0.005	K7MSC	CN76wv	1021	634
2012-05-26 07:20	AA7EE	10.140125	-19	0	CM87ut	+17	0.050	W7WKR	CN98pi	1179	733
2012-05-26 07:10	AA7EE	10.140144	-16	0	CM87ut	+17	0.050	W5OLF	DM78hb	1482	921
2012-05-26 06:20	AA7EE	10.140138	-22	0	CM87ut	+17	0.050	K7UEB	DN06tb	973	605
2012-05-26 05:34	AA7EE	10.140129	-26	0	CM87ut	+17	0.050	VE6PDQ	DO34ir	2000	1243
2012-05-26 04:36	AA7EE	10.140108	-8	0	CM87ut	+17	0.050	KC6KGE	DM05gd	390	242
2012-05-26 00:08	AA7EE	10.140114	-16	0	CM87ut	+17	0.050	N6RY	DM13id	688	428

Not a lot of unique spots, but I was only running 5mW.  The first spots were reported as being 50mW, but this was my mistake – I was actually running just 5mW and corrected the wspr code as soon as I discovered my error. I decided to stick with an output power of +7dBM as that is the power I feed my diode ring mixers, and it just slightly blows me away that my signals were decoded by VE6PDQ over 1200 miles from me with the same power that my local oscillators put out. Quite amazing. I have no doubt that I’ll achieve even better DX if I keep at it.  As I have developed an affinity for level 7 diode ring mixers, running a power output of +7dBM from the OpenBeacon seems very fitting.

Now, as etherkit is an open source amateur radio company, I’m hoping that someone will write a routine to automatically trigger OpenBeacon when in WSPR mode. It definitely seems to work quite well in that mode.

This is where I stand with my OpenBeacon so far, and I think it’s the most versatile MEPT available in kit form. It boasts many different modes and speeds (as well as WSPR) and to change between them you don’t have to fuss around with wire jumpers. It’s all done in software, like many other things in OpenBeacon. This ability to control it in software, along with the wide variety of modes, and the open-source nature of etherkit make it, in my opinion, the ideal MEPT for a lot of users.

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