WSPR success with new kit

Conclusion first:

Start of build to 1st spot – 50 minutes.

As luck would have it, the second station to spot me was Jay W5OLF himself from 800 miles away – the maker of the kit!


The build was simple, logically-ordered and straightforward.

Stuffing the parts took 30 minutes, then wound one 29-turn toroid and soldered it in place…then attached a dummy load and 13.8V power supply, hit the board-mounted pushbutton and watched the needle of the WM-2 wattmeter swing over.

Tweaked the cap for exactly 2 watts out and then used a multimeter to set Pin 1 of the VCXO chip to 1.65 volts. This put me in the WSPR freq range without needing a freq counter, though I could have just used the main rig for this adjustment.

At the next even minute (actually 2 seconds before it) I hit the button again and, after a two second delay, a transmission began, this time into my dipole. Power out stayed at 2 watts for the entire 1min 50sec transmission after which I saw myself spotted by KC9GWK.

Awesome possum.

WSPR w/o main rig, computer, sound card interface and interconnecting cables. Not to sound like an ad (I have no connection with W5OLF other than having bought this kit – and being spotted by him) but this little kit does exactly what I wanted to do, as easily as I wanted to do it.





  7 comments for “WSPR success with new kit

  1. July 23, 2011 at 3:06 pm

    Very interesting John. Was looking for this. Wish to continue WSPR but without a computer and on a battery and solar power. This kit seems to be a good choice. Could you tell me what solution is the best to key this little TX? I think you needd something with a GPS or so. Since WSPR needs a very accurate timing. 73, Bas

    • July 23, 2011 at 3:16 pm

      Bas, here in the shack I’m just using my computer’s clock to tell me when to push the button. Afield I’d use my always-accurate atomic (Casio) watch. Yeah, I’m a geek.

      For automatic transmissions, the manual mentions a “repeating interval event timer” at that can be wired to a connection on the WSPR board for keying.

  2. July 23, 2011 at 6:55 pm

    Good evening John great to see you posted the results and seems very easy to assemble and setup. I did go to the Ebay and was confused to see the bidding and not just purchase setup happening. Other than adding the mod to key the unit at the proper time intervals one would have to keep timing the process.

    • July 23, 2011 at 7:02 pm

      I think that eBay, for a variety of reasons, is not the best way to offer number of kits you may have available but I also don’t know the scope of availability.

      The kit is fun though and I’m impressed by the ingenuity behind it. As for the push-button timing, I don’t consider that an issue. I look at my watch, wait for :58 seconds and push the button. I don’t need to do it continuously – only as often as propogation is likely to change. Whatever inconvenience one may find in pushing a button is more than made up for by the simplicity of now operating this mode.

  3. July 24, 2011 at 7:24 am

    Well, I’ve “pressed the button” maybe half a dozen times now and this tiny little circuit board has squirted its signal across two oceans. Last night, the Netherlands and Germany and this morning into Japan and Australia, mate.

    Jay emailed me this morning to let me know that my yesterday’s method of hitting the button at the :58 second mark is actually wrong – that I should push it at the even-minute :00 second mark & that the 2-second delay is a normal part of the WSPR transmission that begins at :00.

    I’ll be collating the info of these two posts into a page in a few days so that everything is in one place.

  4. July 24, 2011 at 12:59 pm

    Looks very interesting John and I think that Jay will find quite a sizable market of people who want to WSPR but don’t want to tie up a rig, computer and the interconnection hardware.

    The only thing that gives me slight pause is the price. $50 seems a little on the high side to me but then, I don’t think there’s anything else on the market like it right now.

    Thanks for the post – I think Jay has produced something that quite a few people have been wanting!

    • July 24, 2011 at 1:09 pm

      I’ve had the same thought, Dave to be honest with you. But I think of it not in terms of what it consists of but of what it provides: convenience. I don’t have to tweak with audio in levels to my K3 and audio out from my sound card, etc to operate WSPR…and then revert back to operate my default mode of CW. That’s worth at least a 20-spot to me, which is why I ordered the kit in the first place.

      I know others may not see it the same as me and they have the other option. As I’ll mention soon in a review, WSPR, to me, is a tool – this kit is the enabler.

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