A lot of ops ask, “Why do you insist on running WSPR2 when there are modes with better detection limits?” Still others ask how I could possibly run anything except CW on the hallowed maritime bands. You really can’t please most people most of the time but I will attempt to very briefly justify my operating practices here.
First and foremost, my preferred mode of operation is normal, aural CW. I enjoy QRQ (high speed) CW the best and appreciate the fact that there are competent CW ops on 630-meters that are not afraid to “air-it-out” when conditions permit.
But what about when I am not calling CQ or participating in CW QSO’s? I don’t care what band you are operating, there are a finite number of ops interested or willing to work you at any given time and soon enough the barrel runs dry. “Running a wheel” on CW is not a long term solution either because at reasonable CW speeds (15-18 wpm), the detection limit is in the –8 db to –10 db S/N levels and while we see these levels nightly to somewhere there are still better options for long term, long-haul beaconing on 630-meters. Everyone has different goals.
WSPR or the Weak Signal Propagation Reporter is best described as the Reverse Beacon Network using 4FSK rather than CW. Participating stations can transmit, receive or both and reception reports are uploaded to a database at www.wsprnet.org where the data is rendered visually showing which stations are hearing one another at any given time. By transmitting at a high repetition rate (50% is common which translates to 2 minutes on air and 2 minutes off air), it is possible to make determinations about band conditions by looking at the reported S/N. Data is also archived so trends in propagation can be studied. As we have seen over this winter, being able to run continuously elucidates a large number of unexpected openings, notably the daytime openings that extend to 1200 miles or better and not typically associated with ground wave. Furthermore, all of this information allows decisions to be made about the period of QSB or whether conditions can support CW or other digital QSO modes since operational thresholds are well established. WSPR can report down to –32 db or –33 db S/N.
I consider the WSPRnet website to be the key feature of WSPR and why I tend to use the mode a lot. That may seem shallow but please understand that as much as 630-meter operations are an exercise in high adventure and scientific conquest, there is also a huge marketing opportunity that brings people to the band. In fact many of the existing independent Part-5 experimental stations on the air today found their way to the band because of WSPR – It’s a gateway drug! Every year we see 20-30 new stations reporting on 630-meters and this number continues to go up as the number of transmitting stations increase. For those of us on the band, an increase in the number of reporting stations or those filing applications for their own grant is a win.
So while the QRSS modes clearly have a deeper detection limit and don’t require digital decoding, rather relying on visual interpretation of signals in a waterfall, it does require that an operator review archived screen shots for possible signals. WSPR has an existing and ever increasing number of receiving stations in place, integrated database, and the ability to execute queries, which is a significant advantage for what I do.