Learning to SOTA - Painfully!

As there is so much gloom in the news these days here is my attempt to cheer folk up.

I recently completed making a 20m QCX+ from QRP Labs. I didn’t think it was transmitting at first as there was no voltage at the dummy load. I also couldn’t see any signs of a signal using a USB SDR connected to my PC. So it was dead then?

No, the cheap SDR can’t detect 14MHz signals even when only a short distance from the transmitter. Adding an upconverter between the antenna and the SDR sorted this problem as it brought the HF signal into the range the SDR could recognize. And a signal to recognize there was! The lack of voltage at the dummy load was down to me measuring from the wrong place. When I did it correctly I found 13.8 volts.

That was yesterday’s breakthrough, today’s efforts were to try and send a signal a little further than the distance across my bench.

I had learned of something called the Reverse Beacon Network recently and decided to give this a try. The QCX+ has memory slots you can load with a message and the radio will transmit this with a quick button push. Given my stuttering attempts to learn Morse this feature was perfect for me.

So I entered TEST DE M7WIV M7WIV M7WIV, strung up the antenna and pressed send after finding a quiet frequency.

No response, I tried again then after a few more minutes of futile beeping I spotted the QCX+ was in Practice mode and though it might have been beeping in the headphones not a single mW was reaching the antenna!

Take two: Switching off Practice mode I tried again and within a few minutes I started being “spotted” on the RBN map. Things got better a little later when the sun crept over the Atlantic and I had a few spots from North America. Not bad I thought for about 4W or less from an end fed wire strung across my garden and with no earth connection as I haven’t created one yet.

I was eager to see how things might look from a hill so this afternoon I walked up to the summit of Pen Beacon on the southern edge of Dartmoor. It isn’t a SOTA summit but the ground falls away quite sharply to the west so I was expecting to reach further than I had this morning, perhaps even the west coast of the US?

At the summit, a 45 minute walk from the car, I started unpacking but a sinking feeling I had forgotten something began to grow. I had almost everything but what I didn’t have because it was left behind was the co-ax to connect the radio to the balun. Oops!

On the positive side my dog enjoyed the walk.

But a valuable lesson was learned - create a SOTA packing list.

Sadly, the weather forecast is poor for the next few, days but when it improves I will try again. And while I’m waiting for the rain to stop I’ll have a go at making the 30m QCX Mini which arrived this week. :slight_smile:


Welcome to the club!

You are not the first and won’t be the last to forget some small but essential, part when going to a summit. We’ve all done it!

I was interested to hear that your USB SDR couldn’t hear 14MHz without an up-convertor. If that’s an RTL-SDR, I thought the software was changed to make HF usage possible - albeit with not as much gain as on VHF/UHF but usable. You might want to check if there’s a software update, but if you have an up-convertor now, that’s a better solution in any case.

Well done on using pre-programmed CW messages and the RBN to test you equipment out.

73 Ed.


Happens to us all John. Well, most of us. Or maybe just a select handful of us.

I am currently on The Cloud G/SP-015. I fancied a bit of 30m. Set up the antenna then found I’d left the paddle in the car - bit of a problem that on a no-phone band!

Thankfully, I had the tablet with me and it had some charge left in it. And so FT8 it is!

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A list is a great idea. It’s also almost foolproof if you have everything that you need for SOTA fit into one bag or case. I have a small soft case for my KX2 and everything I need to transmit is always in that case. The current exceptions are the antenna mast and external battery. In oder to head out for a SOTA expedition I only need to remember three things.


I too keep a list of stuff. And I can get all my SOTA stuff in two boxes. If they are packed to almost full then I know I’ve got everything. Yes, I can see a flaw in the box idea but its also where I keep that stuff too!

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Hi John,

Good work with the QCX+. I have an 80m kit waiting to be assembled but have not even opened the package yet.

If the memory TEST function is programmable, I would change it to VVV de M7WIV. The reason is that VVV is the symbol/code for “testing”. And TEST is a shortening of CQ CONTEST, so if you send that message on a band with an active contest, you might get 50 replies! You may be delighted that your short TEST was so effective, but it may not be what you intended!

The RBN is what drives the automatic spotting system RBNHOLE, which matches RBN spots with SOTA Alerts and if all conditions are met, posts a spot on sotawatch indicating your callsign and frequency.

73 Andrew VK1DA/VK2UH


I’ll have a go with the VVV prefix - and look at the SOTA link too. Thank you. :slight_smile:

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