A recent reflector posting tended to confirm a rather intriguing trend that I have also been noticing over the past few years.
The poster lamented the fact that he often found very few or even no CW / SSB signals on the HF bands while at the same time seeing lots of activity throughout the digital portion of the bands.
It does seem like there is far less CW and phone activity on the HF bands now, than there was a few years ago and there is no question that digital activity has soared. Whether it's RTTY, PSK31, JT65, WSPR, JT9 or others, these digital signals are always prominent and, band plan or not, are slowly migrating further in the band as activity increases ... but is this the reason for the decline of traditional modes?
The digital weak-signal modes make these extremely popular for a number of reasons. Nowadays, many amateurs are living in antenna-restricted communities and are forced to develop smaller, lower and less effective stealthy antenna systems if they wish to get on the air and make contacts. Most of these modes perform well with minimal amounts of power and are capable of hearing well into the noise ... and unless you live out in the country, with well-separated neighbours, we all know that noise is increasing at horrific levels almost everywhere. These two factors alone might well explain much of the growth in digital activity.
Licencing requirements have also been slowly evolving and today, getting a ticket is much easier than it was several decades ago ... and in many cases, without the requirements of knowing anything about CW. Every month, North Americans see a large number of new amateurs, many with no code skills and possibly not much interest in acquiring them. From my own local observations, most of these new amateurs usually head straight to FM on the VHF/UHF bands and have little knowledge of or interest in HF radio. These factors must also play into the demise of activity on the traditional HF modes as well.
We also shouldn't overlook the influence that Old Sol is having on our HF bands as well. Solar Cycle 24 (begun in 2008) has been one of the poorest on record and continues to generate month after month of terribly poor HF propagation. As a young SWL who listened in Cycle 19, (the largest on record), I can vouch for the relationship between HF activity and good propagation. Those were amazing days, when 20 and 15m would stay open all night long ... even 10m would often still be open with F2 propagation at midnight towards VK and ZL! Everyday, month after month, the bands were simply bulging with activity, from end to end ... high solar flux numbers bring high activity numbers and we are now experiencing the downside effects of what happens when the sun dreadfully underperforms. The only exception to band-bulging activity today seems to be limited to major contest weekends only. Where these people go the rest of the time is a mystery.
There are surely other reasons as well for the gradual decline of traditional-mode HF activity, including the fact that the general ham population is getting older. Large numbers of stations are simply 'going away' as interest or opportunity declines and as more of the aging traditional-mode ops go 'SK'. I know of several hams that have just given-up because of insurmountable increases in their local noise floors. Our new and usually younger hams, have largely grown up in the 'digital age' and for those that do find themselves exploring the HF bands without CW skills, might logically settle into the digital modes first.
Things are changing quickly, of that there is no doubt. Last summer, on 50MHz, I noticed a large increase in the number of dedicated CW operators moving to JT65 and JT9 during openings and this summer has already seen another huge migration from one mode to the other.
Although this year's Sporadic-E season is just getting started, I have already heard many more countries on JT65 than I have on the traditional modes (Japan, Philippines, China, Formosa, Alaska, Venezuela, Cuba, Brazil). Yesterday I listened to a PY calling CQ on CW for some length, with no takers, while it seemed most of the usual west coast ops were watching the digital band. I fear that many good QSO possibilities will be lost as more stations switch to the much slower digital modes ... on 6m, many of the openings last for a very short time making CW or SSB the quickest way to complete a contact. The other problem I notice this summer is that there are several JT sub-modes and it is often difficult or impossible to figure out which mode is being used let alone having the time to switch to the other mode before signals are gone ... perhaps a case of having too much of a 'good thing'? Hopefully one mode will emerge as the '6m standard' so all are on the same page.
What will be the long-term outcome of these changes remains to be seen but I suspect we'll see more and more of our HF CW and SSB spectrum space gradually shrinking to make room for more digital activity, likely to become the dominant modes eventually.
As a life-time, almost exclusive CW operator since age 15, I find this somewhat disheartening but must admit that over the past few years, I have found my own level of weak-signal digital activity increasing by leaps and bounds. These are powerful, capable modes and offer amateurs new and exciting challenges from VLF to nanowaves. Are they as exciting as my much-loved CW? Ask me in a couple of years!