October 01, 2017

QRP Labs U3B and an update on my U3S

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This is Hans Summers G0UPL:

Photo taken by PA7MDJ at HAM RADIO 2017 in Friedrichshafen

Hans is the designer and developer of amateur radio kits like the already legendary standalone Ultimate3S (U3S) 200 mW WSPR transmitter. The kits are sold through his company QRP Labs. Previously I've already written some blog posts about the U3S, of which I've built one myself, and of which I'm an extremely happy user! I met Hans at the QRP Labs booth at HAM RADIO 2017 in Friedrichshafen, and had the pleasure to have a chat with him. We all have our ham radio heroes, Hans is definitely one of mine.

This is the QRP Labs U3S:

U3S as built by PA7MDJ

And this is a prototype of the new QRP Labs U3B:

Photo taken by PA7MDJ at HAM RADIO 2017 in Friedrichshafen

The U3B basically is a miniature version of the U3S and was designed by Hans mainly to be used as a HF WSPR tracker payload for High Altitude Balloons. The U3B currently is still in its test phase, and the past few months about 9 test flights have been done. Most of the test flights were launched by well known WSPR balloonist Dave VE3KCL from Canada. I managed to catch the WSPR signals of two of the balloon test flights, the U3B-2 and the U3B-8.
The miniature size and the almost weightless SMD components make this a very lightweight payload ideal for single "party balloon" WSPR flights. The power of the U3B will be in the range of 10-20 mW, and the current draw will be extremely little. During the test flights, the current draw was so little that the tiny solar powered WSPR tracker remained awake and transmitting well into darkness where most other solar powered WSPR trackers would have already gone to sleep with a depleted battery quickly after sunset. The U3B "slept" for only a couple of hours. Although the power of 10mW might look very little, with the wire antenna of a WSPR balloon hanging in free air at about 10 km height it's sufficient to be picked up by the worldwide network of WSPR monitoring stations.

Eventually the U3B will be taken in production and will be sold through QRP Labs. Contrary to most other QRP Labs products, the U3B will not be sold as kit but as an already finished product, as the SMD components will be impossible to work on for the average kit builder. In Friedrichshafen Hans told me he was aiming at having the U3B ready for production in about three months. I think however that the popularity of the new QRP Labs QCX 5W CW transceiver kit might have slowed things down on the U3B development side, although test flights are still being launched; the U3B-9 is over the Atlantic Ocean as we speak.

I'm really looking forward to the U3B being taken in production and to experimenting with the tiny WSPR transmitter myself. My goal eventually is to launch a WSPR balloon myself, but I still have a lot to learn, about solar cells, insulated casings, helium, balloon pressure, the ideal launching weather, wind conditions, trajectory predictions, and probably many more things still unforeseen at this moment. It will be an interesting, but relatively long-haul project. Stay tuned!

Meanwhile my 200 mW U3S is still going strong, and since it started sending WSPR beacons for the first time in February, its signals have been picked up all over the world. Some places I want to mention are Reunion, Australia, Brazil and Vladivostok on 20m, and South Africa on 40m, all with an EFHW wire antenna. Do a search on U3S for more of my blog posts on this wonderful little transmitter.

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