6 Meter Season: Diminishing Returns

I am reluctant to write this article. Although we are now 2 months past the peak of the summer sporadic E season the band is not quite dead. But I have to accept that we are about done and this is a good time to reflect on the season that was. E season wrap ups have become a regular feature of the blog; for example, here is last year's summary.

The 2022 season was a mixed bag. Propagation started slow on 6 meters, petered out right at the solstice peak, then July delivered a multitude of openings. The magic band likes to keep us guessing.

DXCC

On the DX front my DXCC count changed little. At the end of last year I had 111 worked and now the count is 120. Of the 9 new entities, a maximum of 7 can be attributed to sporadic E. The others were F-layer or TEP deep into South America to work CE and CX. The opening to the Pacific that netted E51WL and 3D2AG likely had a sporadic E component at this end of the path.

Considering that I logged 900 QSOs on 6 meters this season (over 700 of which are DX) that is one new country per 100 QSOs. The reach of sporadic E is limited and the further the path the lower the probability of an opening, especially at higher latitudes. Were there more activity from Africa the DX potential would be greater. Working DX on 6 meters is rarely easy, and if it was it would be less rewarding. I am not complaining, just relating the facts.

Operator duty cycle

One of the questions I am regularly asked about DXing on 6 meters is: when should I listen for which DX? Sporadic E is called sporadic for a reason, so I have to disappoint them. There are times of the day among a multitude of other indicators with an increased probability of DX over particular paths. Unfortunately for us, good and bad surprises are the norm.

There is no substitute for dedication and listening. At the very least, monitor DX spotting networks. During sporadic E season my rig is regularly monitoring 50.313 MHz even when the band is dead, just in case. I leave it on when I am out of the shack or away on other business so that I can review the sometimes long list of decoded FT8 messages.

The point is, you can't be sitting in front of the rig 24×7 for 4 months straight. Surprise openings are surprises (duh!) so you have to accept that you will miss some or many. When I miss openings I am able to learn likely propagation patterns by reviewing what I missed. That's the point of leaving the rig on when I can't be there.

There are times when I fully expect the band to open and I leave anyway. We all have responsibilities that brook no delay or rescheduling. During summer I also have non-ham interests that I attend to. Life is more than ham radio.

Here are many of the DXCC countries I missed working this year because I had to be away or I chose to be away: Z6, EY, ZL7, OA, V4, TR8, TT. There were also the inevitable almost new ones from partial contacts that could not be completed due to the rapid rise and fall of DX paths. One in particular that comes to mind is OD. 

Several others new ones were heard that did not hear me. That list is longer. Few hams have the quiet location that I have and it takes a lot of ERP and luck for be heard by them.

Rather than dwell of the disappointments, I prefer to focus on the future: the anticipation of next year's opportunities and the coming F-layer openings. I relish the challenges ahead.

Notable openings

There is an unfortunate habit for hams (just like regular folks) to brag. The presence of examples in this section is not intended that way, although I have to admit to being pleased with my successes. If this hobby doesn't give us pleasure, well, what's the point? With that in mind let's continue.

I already spoke of the fantastic Pacific opening that netted E51WL and 3D2AG early one evening so I'll simply link to that article. There you will also find a screenshot from a friend who copied ZL7DX. I was not present for that one and I don't know if I'd have copied the signal or made a QSO.

It is not always that way. My antenna system and low noise QTH often make the difference between my success and that of those nearby. I took the adjacent screenshot to prove to several friends that I was hearing Hawaii very well one evening in early June. Despite being within 100 km of me and with only slightly less effective antenna systems, they had no decodes of KH6HI or the other Hawaii stations I copied.

It's impossible to say whether the difference was propagation or our stations. Nevertheless, it is a fact that incremental improvements in transmission lines, power, antenna gain and antenna height are in your best interest. Small differences add up and will improve your success rate.

Last year I copied UN stations during a brief early morning opening. The amp was off and I failed to make a QSO. That isn't unusual for sporadic E.  I was therefore happily surprised when UN3G answered my CQ in early July. As you can see the signal reports are painfully low, but all that matters is that the QSO is good.

Much to my surprise there was more to come. On at least 3 further days in July we had openings to UN. In one case it lasted close to an hour. Now I have 6 contacts with Kazakhstan on 6 meters. Although the latter 5 are superfluous for DXCC, the joy of contacts over such a long path is never uninteresting. I almost don't mind that I missed EY8MM. There is always next year.

Despite the frequency of openings and large ham population, there are countries in Europe I have yet to work. Some have only occasional activity or their station conditions are poor. Two that I added were ER and ZA. The Italian station in Albania was periodically heard by me and my friends but never strong enough or in for long enough to allow for a QSO. 

During one excellent opening he was quite strong on 50.323 MHz and, as you can see, the new one was rapidly logged. It's always fun to convert a purple CQ to green. Signals improved and the friends I notified were also able to add ZA to their 6 meter DXCC total. The buddy system works.

I finally managed to work HL this year, and 4 of them for good measure. The bearing as you travel the short distance from JA6 to HL to BY shifts alarmingly north due to the long path length. That's what makes them so difficult from this part of the world.

The final South Korean station I worked occurred unexpectedly late in the evening (July 7, UTC). It took several tries with a kilowatt to finally be heard. Unexpected DX is always a pleasure. After our QSO he began calling CQ NA, probably similarly surprised by the opening to eastern NA.

Among my misses this year was China. As already mentioned, China is difficult due to the northern bearing of about 345° to 0° for the densely populated eastern half of the country. Compare that to 330° to 335° bearing range for Japan, which is a far easier path. Indeed, I worked dozens of new Japanese stations this year over several openings.

As you can see from the screenshot, I certainly tried to work China! BA4SI appears to be in the Shanghai region, which is about the least northerly path from here. Perhaps like many others they have a QRN problem. I heard them and other Chinese stations on at least 3 evenings in July. None responded to my calls. Other than BA4SI none of them were in for more than 3 consecutive FT8 intervals, which is barely sufficient for an QSO. I'll try again next year.

A notable opening that almost but didn't quite reach me was VK4. That's an extraordinary long path! It is a little north of west for us to those stations located in eastern VK4. That is about as far to the south the great circle path goes from here to anywhere in Australia, and that makes it about the easiest.

Many stations not far to the west and south of us were successful working the several VK4 stations that participated in the opening. I and my friends had not a single decode. Some things were never meant to be. This one may have to wait for an F-layer opening.

Pros and cons of increased activity

When the band is open it's busy, very busy. An increasing number of hams are discovering 6 meters and they are active. This is fantastic but it does add to the QRM and QRN. 

The increase is not only local so there are more DX stations to work and more countries to be worked. Cutting through the QRM to do so is unfortunately necessary. I prefer it this way compared to a quiet band with fewer stations to work. The intercontinental window at 50.323 MHz is less busy yet relatively few stations QSY.

Some of the QRM is due to improperly adjusted transmitters and amplifiers. Although we use the SSB mode on our equipment, digital is not phone. On SSB we "own" the full 2.7 kHz of spectrum we occupy, which is necessary to contain enough of the human voice to enable legibility. It is therefore not an inconvenience to others that we use non-linear techniques such as clipping and compression to increase average power. The distortion due to non-linear processing improves communications when judiciously applied.

Try this on digital modes and bedlam ensues. The 3 kHz window typically employed for FT8 requires that each occupant strictly limits their signals to the approximate 50 Hz audio bandwidth required. To do so requires audio linearity and RF linearity. 

Unfortunately our rigs often make this difficult since the non-linear features used for SSB must be manually disabled when switching to digital. Many hams forget or don't realize its importance. I know and yet I occasionally make mistakes. With a constant probability for each operator to make a "mistake", the probability of QRM due to these mistakes increases in proportion to activity. Then there are the anonymous "policemen" who add to the QRM with directed custom messages to harass the guilty parties. 

Expect problems to continue until we have a new generation of equipment that incorporates improved digital features and abandon use of the SSB mode. Hopefully that will also reduce distortion, audible computer sounds and background noise from live mics. For example, in the FTdx5000 that I use the mic is always live despite using the rear audio jacks to connect the PC. I have to remember to unplug the mic when switching to FT8. It's easy to forget.

Another notable behaviour is the increasing presence of robots. For those not familiar with digital robots, they are typically made from forks of the open source WSJT-X software. Robots are in violations of the open source license. It is not easy to get them taken down and there are numerous applications proliferating in the wild. I won't provide specific examples but the curious will not find them difficult to locate on the internet.

Robots will automatically CQ or call CQ'ers, work stations and log the QSOs. Some do not discriminate, calling everyone they hear, often progressing up and down the FT8 window in a easily identified pattern. Others are more particular about their behaviour and use filters to limit who they call. 

Most robot software users appear to have no evil intent. They may simply enjoy the novelty of the technology. Others like the idea of logging lots of stations while they at work or doing other things. A few do it to demonstrate (mostly to themselves) that digital modes are not "real" amateur radio. I will not work robots that I can recognize as robots. Persistent bad actors are particularly obvious and they have a well-earned poor reputation. 

Most on the band don't care or are even aware that they are working robots. It was inevitable that robot operators would migrate from HF to 6 meters along with everyone else.

Propagation lessons

It's impossible to be passionate about DXing on 6 meters without developing a keen appreciation of the underlying propagation science. Despite the vastly improved understanding of the mechanisms underlying sporadic E, TEP, scattering and other propagation modes, predictability remains elusive. 

We do far better with the weather since measurements that feed computer models are easier and more extensive. There are also strong economic incentives to improve predictions. Radio propagation lacks the economic incentive in the 21st century and there is no good way to install measurement instruments at multiple points in the outer reaches of the atmosphere. Remote observations are a poor substitute. 

Predictability will therefore remain a challenge. Those seeking certainty will continue to be disappointed with the poor predictability of openings on 6 meters.

Despite the challenges, the increased level of 6 meter activity, prevalence of digital modes and the broad use of internet tools are giving us a better understanding of sporadic E propagation. Although prediction is poor, we can do a lot better than in past decades. Here is a short list of what has become apparent to me (and others):

• Weak and brief sporadic E propagation over both short and long paths are more frequent than has been previously believed. Single decodes of distant stations on a "dead" band are fairly common. The proliferation of big stations continuously transmitting CQs makes this possible; beacons are too weak and require effort to individually monitor. I also will periodically rattle off CQs on a dead band, and in combination with PSK Reporter I see flags of my transmissions being decoded in unexpected places more than I would have once believed possible.
• Overnight DX openings during sporadic E season are more common than expected. I have taken to leaving WSJT-X running overnight many times this year, with the yagi pointed north into the perpetual Arctic daylight. The log of decoded messages that I review in the morning contains notable surprises. I have also been surprised by how often I will get a flag in western NA during our mornings, well before their sunrise, while I'm beaming to Europe or west Asia.
• Brief long distance openings to eastern Europe and Asia are common in the hour or two after sunrise. These are easy to miss since I am not an early riser and sunrise in the weeks surrounding the solstice is 5:15 AM.
• Conditions that result in an opening today don't immediately dissipate. There is an increased probability of a similar opening, perhaps weaker or stronger, the next day. I have noticed this on almost every path: east Asia, central Asia, east/west/south Europe, NA west coast, and South America. The same may be true of the Pacific, but with sparse activity it is difficult to know.
  

While scientifically interesting, some of the above phenomena do not translate into QSOs. The openings are too transitory and digital modes too slow to take good advantage. But they are there, and that's good to know. We may develop technological aids to turn those opportunities into results in the future. Being a ham involves progressing the art and not twiddling the VFO knob as we had to do in days of yore.

Looking ahead

We can expect a return of north-south propagation as we approach the fall equinox in late September. That can happen with modest solar activity if other factors are favourable. There are a few more South Americans that I would like an opportunity to work. Beyond that, we'll need a higher solar flux. 

When the solar flux rises above 150 the propagation, as seen from here, will spread east and west across the tropics and to the southern hemisphere. Going by my experience from the 1989/90 solar maximum, openings to South America will expand to include southern Africa and equatorial Africa. It is almost certainly present to the eastern part of the South Pacific, but there is almost no one there. The sparsity of land and hams is at fault.

Eventually, but probably not this year, we'll see east-west propagation within the northern hemisphere. The solar flux would have to hold above 180 for that to happen, and it would have to happen during the fall and spring for best results. Deeper into winter the northerly paths are less likely to open since solar insolation at high latitudes is weak. Winter sporadic E will occur but it is poor for DX at my location.

Despite the title of this article, I am hopeful that 2023 will be a good year for 6 meter DXing. We can count on a higher solar flux, increased activity and the return of sporadic E. More paths will open and more of us will be there to take advantage. With the diminishing returns of sporadic E propagation at my DXCC level, those additional propagation modes are needed to eke out more than a handful of new countries each year. 

Although the 1989/90 solar maximum was exceptionally good, I could not get past 70 countries because so few countries had access to 6 meters. It was frustrating to have great propagation to Europe and only be able to work a handful of countries. The majority had no access to the band. Those barriers are almost entirely down so if the present solar cycle is a good one there will be no shortage of DX to work, including with small stations. We have a lot to look forward to.

For the present my attention has shifted back to HF and preparing my station for the fall and winter contest season. I still have much to do.