WSPR vs. PSK Reporter
September 22, 2010 2 Comments
In the last few days I’ve started experimenting with WSPR, a mode for radio beaconing. You run a program (called WSPR) that sends a beacon transmission once in a while and listen’s to other people’s beacons the rest of the time. The program uploads its reception reports to a web site, wsprnet.org, so you can see who received your beacon signal at at what signal-to-noise ratio.
WSPR is basically an unattended operation. Once the program is running, there is really nothing for you to do. You can check who spotted you and who you spotted, but that’s watching, not doing.
It’s interesting to compare WSPR to PSK reporter, the website that collects and presents PSK31 reception reports.
The main difference is that WSPR is more symmetric. You can both transmit and spot other people’s transmissions. This tells you how well your receiving system works and how well your transmitting system works (it also tell you, of course, whether there is propagation in the path, which it the main objective of WSPR). PSK Reporter is less symmetric. You can leave your receiver on overnight and see in the morning who you received, but you are not supposed to beacon all night to see who can receive your signal and when. What you spot in PSK reporter is not beacons, but actual communication between two stations (or at least, stations attempting to communicate with someone).
The flip side of this is that WSPR is more boring to most people. There is not much to do but monitor what’s happening. PSK31, on the other hand, is an actual activity (unless you are just passively reporting). You have to tune to a signal, see who’s calling, respond to their call, see if they heard you or not, and so on. Even though many people use keyboard macros for the actual communication, there’s still something for the operator to do. I guess many people find this satisfying.
The result of PSK31 being less boring is that more people appear to do it than WSPR. I don’t have actual statistics, but my PSK reporting nights resulted in spotting more stations in many more countries than WSPR spotting nights. More stations and more countries make spotting more exciting, at least to me.
So that’s the main tradeoff. In WSPR you can transmit and see who receives you without human intervention, whereas in PSK31 if you want to see who receives you then you must contact people. On the other hand, there’s more activity in PSK31 than in WSPR.
The other main difference is that WSPR is much more reliable. PSK reporter works by finding a patten that matches “de <callsign> <callsign>” in the text of the transmission. The only error detection mechanism is the exact repetition of the callsign. PSK31 does not have any other error detection or correction built in, so corrupt received text is very common. The probability of having the exactly the same error in both occurrences of the callsign is not huge, but it’s not close to zero at all. My reports (using DM780) on PSK reporter include quite a few bogus reports. (To be fair, PSK31 was designed for human-to-human chatting, with error detection and correction to be done by the human operators, whereas WSPR was designed for computer-to-computer communication.)
An update: WSPR is not perfect either. I supposedly received callsign 2V2YFX with locator in the ocean near Antarctica. I was the only station to receive it. So WSPR’s error detection is not that strong either, unfortunately.
The web interfaces to both systems are both fantastic, but there are big differences here too. In PSK reporter, the map interface is excellent. You can filter by either transmitter or receiver, or country, band, or mode (PSK reporter collects spots of several modes, not just PSK). The mapped results are color coded by band and are visually compact; they normally show just a marker, not the callsign. If you click on a marker you get more information. The WSPR web site also has a map interface, but it’s not as good. You can filter by callsign, but it will show reports where the call sign is either the transmitter or the receiver; you can’t select only one direction. The results are shows with arcs connecting the receiver and transmitter, which really clutters the map, and with callsigns, which again clutter the map. The arcs have some color and width coding, but I could not figure out what the coding it.
The markers in PSK reporter are decorated so that a very compact visual marker carries quite a bit of information. You can distinguish stations that were spotted recently and stations that have accounts on eQSL.cc or on LOTW (this increases the confidence that the callsign is correct). I wish that the map also marked stations that are dubious; they should not be too hard to classify. Basically, if there are many reporters, than lone reports are probably bogus, because typically many reporters will spot each stations. Obviously single-reporter spots are not always bogus, but as long as they are still shown on the map (with a decoration suggesting they might be bogus), we don’t lose any information.
Both web sites also show database results in a tabular way. Here the WSPR web site is better, with much more control over the queries, good displays that refresh automatically (the maps in both web sites refresh automatically), and with all the historical data available for download in database format.
I am very pleased with both systems. PSK reporter allowed me to collect many reception reports over several nights, including reception of stations in some very far and fairly exotic places. WSPR also allows me to see where my signal is reaching without making macro-style contact (which I don’t like). I am happy to see that my Softrock, 16W homebrewed amplifier, and homebrewed loop antenna reach all the way to Japan, Australia, Canada, and the US. So far running the Softrock barefoot at 1W only reached Europe, but I’m sure it can reach further with patience.