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Thursday 7 June 2012

NT7S Jason Milldrum Open Beacon QRSS Hell & DFCW

Yes there are C missing as this is the 30m version.

Picked up one of these at FDIM 2012 and put it together last night, took maybe 90 mins and I wasn't precious about it. The underside I have to clean the excess flux off yet.

Bit too big for an Altoid tin.

Top image is of the power and USB/uPC stage only... I had already stuffed all the resistors. The lower I soldered in the xtal and didn't bother with a socket. I always seem to wind the damned toroids back to front when lining up with a set of PCB holes. T1 he doesn't say how you should do it but I use a hint given to me a few years back and use a small hand drill and pre twist the bifilar winding in it, about 10 turns per inch, open the second image to see it clearer... T1 is the black toroid by the white BNC.

Blurb is:

"OpenBeacon is an open source crystal-controlled QRPp beacon transmitter which can output a variety of slow-speed modes, including QRSS, DFCW, and Sequential Multi-tone Hellschreiber. It is configured via USB port, so there are no jumpers to set and you can easily adjust all of the operating parameters via command line. Once configuration is complete, OpenBeacon may be removed from the PC and operate stand-alone.

OpenBeacon is considered a MEPT (manned experimental propagation transmitter), which means that you should never leave the control of it unattended.

  • Frequency: crystal controlled
    • Available bands: 30 meters
  • Modes: CW, QRSS, DFCW, Sequential Multi-tone Hellschreiber, Glyphcode, WSPR (experimental)
  • Power output: 300 mW nominal (at +13.7 VDC power supply)
  • Spectral purity: greatest harmonic <-45 dBc
  • Power supply: +5 VDC to +14 VDC
  • Current consumption: 50 mA at +5 VDC, 120 mA at +13.7 VDC
  • Control via USB on Windows, OS X, and Linux

From the project website is here and you can buy one online here

Once built I put the signal on scope etc and I measured about 310mW out when connected to a 7AH 12V SLA so for a QRSS beacon it is seriously QRO. I'll test it over the weekend and I think connected to the SLA with a solar trickle charger connected it would last for days/permanent.

I tested mine with Linux (CentOS, Mint and Ubuntu) and Windows 7 and no problems with any of them and to chnage the message/mode just means a few commands are all that is needed. I applaud the use of a standard USB B port not one of those mini B ports that seem to be the rage right now.

Not really sure the ISCP headers were needed but I guess if you want to reprogram the firmware you can. I think I'd have somehow added a power switch option to the PC so you can leave it plugged in.


Jason said...

Hey Dominic,

I've been following your blog for a few years now, but I didn't connect your face with your blog until this post! It was great to meet you and I'm glad that your OpenBeacon build went well. Hope to chat with you again at a future FDIM!

Jason Milldrum NT7S

M1KTA said...


I'll have this with me in 6W (Senegal) and C5 (Gambia).

Will see how it goes.