Many thanks to Conrad (N2YCH) who shares the following field report:
QRPppppp….WSPR
By: Conrad Trautmann (N2YCH)
WSPR, or Weak Signal Propagation Reporter, is a digital mode you can select within WSJT-X. You can use the data that’s generated by the WSPR network to check your own antenna’s performance for transmitting and receiving and also to see what paths are open by band at a particular time of day from your QTH. Recently, I’ve been using WSPR to improve my own antenna systems and to help reduce local noise sources.
Originally developed by Joe Taylor, K1JT, an approximately two minute QRP transmission contains the originating station’s call sign, the maidenhead grid locator and the transmit power level being used. Stations typically use 250mw up to 5watts when they send these signals. WSJT-X allows you to select how often you want to send this transmission and what bands to transmit on. There’s an embedded schedule in WSJT-X that allows “band-hopping” for stations using a multiband antenna to transmit on different bands. When not transmitting, it listens for and decodes other stations transmitting and can post “spots” of those stations to the WSPR network database.
Here on QRPer.com, Thomas, K4SWL posted in this field report what the various flavors of QRP power levels are…
- QRP: 5 watts to 1 watt (for some contest 10 watts = SSB QRP)
- QRPp: Less than 1 watt to 100 mw
- QRPpp: Less than 100mw
Did you know that there are more than 3,000 WSPR HF beacons running on all of the amateur bands all over the world at QRP power or less? Many are running 250mw or less. If you open up WSJT-X and select the WSPR mode, you’ll see that the pull down for power levels give you these options:
- 37dbm = 5w
- 33dbm = 2w
- 30dbm = 1w
- 27dbm = 500mw
- 23dbm = 200mw
- 20dbm = 100mw
- 17dbm = 50mw
- 13dbm = 20mw
- 10dbm = 10mw
- 7dbm = 5mw
- 3dbm = 2mw
- 0dbm = 1mw
You could transmit your own beacon if you choose to using WSJT-X. You can also receive many of the 3,000+ beacons that are on the air right now if you wanted.
Why, you ask?
Let me tell you about the WSPR journey I’ve taken over the past few months and how what I’ve learned has benefitted me, my station and my antennas. Here’s how extreme QRPpp signals can help all of us.
I’m an avid digital operator, and I’ve tested many of the digital modes that WSJT-X, FLDigi, VarAC and others have to offer.
WSPR (Weak Signal Propagation Reporter) is a program embedded as a mode in WSJT-X and you can set it to transmit at the various power levels I listed above and band hop to different bands if your antenna can support those frequencies. When it’s not transmitting, it will receive and post the beacons it hears to the WSPRnet.org web site. For anyone familiar with pskreporter.info, WSPRnet.org is similar in that it provides maps of where and when “spots” are received and the relative signal strength the signals were when received by station, the mode and frequency.
After setting my station to transmit and receive on WSPR and looking at my spots on WSPRnet.org that were reported by receiving stations over the previous day, it was a thrill to see my 250mw signal making it out all over the world. Amazing actually, that such a small amount of power could travel that far. 250mw to Antarctica? That’s pretty good.
I bought a QRP-Labs QCX transceiver and the external companion GPS clock, which supports running WSPR transmission stand alone, without tying up a computer. Then I learned about the Sotabeams WSPRLite Antenna Tester (a 250mw WSPR transmitter) and the various WSPR transmitters offered by ZachTek which can also run without needing a computer.
My goal was to have WSPR beacons transmitting on as many bands as possible. Combining them into a single, multiband antenna posed its own problems, which is a topic for another article. However, all of these solutions just transmitted. I was hoping to also be able to receive and post spots as well.
Then, QRP-Labs (shout out to Hans Summers) came out with the QDX and then the QMX, both of which connect to a PC and are controlled by WSJT-X to do the band hopping transmitting and receiving. Like FT8, WSPR does depend on timing to work best, so using an external GPS clock for the QCX or connecting a QDX or QMX to a computer that can get it’s time from the internet can help keep the transmission cycles in sync with the receiver sites for best reception results.
This is cool stuff, but still, what’s the point? That’s when a friend I made in the WSPR community, Tom, WA2TP pointed out how to use all of these beacons to improve my station’s receiving capabilities. I have a good HF receiver and a dipole antenna and a hexbeam on a rotor and I figured I was good to go. I was making contacts without any problems. Tom told me this: “It’s all about the noise.”
He recommended using a wideband SDR called a Kiwi that can view the entire HF spectrum from 0 -30MHz on a waterfall at one time. My ICOM IC-7610 can connect to a PC and work with HDSDR software which has a waterfall, but it will only show you the spectrum of the particular band you’re on, not the entire HF spectrum at once. The Kiwi shows the entire spectrum from 0 to 30 MHz and when set up just right, you can see noise in there…a lot of noise, emanating from all sorts of things.
If you’re trying to receive a 250mw WSPR beacon signal transmitting from Australia, the noise from the after-market, wall-wart switching power supply connected to your cell phone charger a few feet away from your antenna could be way noisier and will blank that VK beacon right out. Your antenna and ability to hear distant signals is only as good as how low or quiet the local QRM is that we all have to deal with.
So began my hunt for noise, with a lot of guidance from folks with experience at it. Continue reading Beyond the Beacon: Conrad Discovers the Unexpected Benefits of WSPR