Whet the Appetite: 6 Meters

Winter is a great time to sit indoors with a coffee mug in hand. I'll pound a keyboard or do anything that doesn't involve going outdoors. Mind you, I love winter and I take every opportunity to put on my snowshoes or partake in other outdoor activities. It's just that most of the time it is easy, too easy, to sit inside where it's warm and cozy and admire the winter scene through a frosty window. 

February 27 was one of those days. There was an ongoing geomagnetic storm so, instead of paying attention to poor conditions on HF, I pointed the 6 meter yagi south and monitored the FT8 watering hole at 50.313 MHz while I went about my day. Geomagnetic disturbances are often responsible for enhanced north-south propagation. In combination with a high solar flux, the K-index of 7 and lots of DX spots for north-south propagation between Europe and Africa, it made perfect sense to pay close attention to what might develop.

When I looked over my shoulder at the WSJT-X display in the middle of the afternoon I was rewarded with a screen full of signals. They had popped up quite suddenly so it was quite a surprise. It was particularly surprising because it was not the kind of activity I was expecting. There was far more than the usual South American activity.

Off the side of the yagi I copied station across the US Midwest and California. Many of them were calling stations in the Pacific Ocean region. These included ZL, VK, FK, KH6 and 3D2. I swung the antenna to 240° to see what would show up. What I saw had me punching the amplifier's on switch and impatiently waiting 3 minutes for the tetrode to warm up.

There were many strong California stations and a few from Mexico. From here, they are in a direct great circle path to New Zealand. About 5 minutes later I copied the very first ZL station of this solar cycle. So I called, and called and called and called.

It was quite a thrill despite failing to connect. Two ZL stations were heard (ZL1AKW and ZL1RS), along with several very loud Hawaiians. I saved the decode file for searching afterward since there were so many signals that it was impossible to scan everything in real time. It's quite easy to imagine things that aren't really there. I later confirmed that no other Pacific DX was decoded at my station.

Calling CQ netted several W6 stations but nothing else. PSK Reporter showed no reception reports beyond KH6. Exciting as the opening was, I had struck out. The opening continued for about 30 minutes, with ZL heard for about half that time. Their signals were never strong, peaking at -11 db. The opening ended as suddenly as it began. I continued to monitor for the next several hours to no avail.

Expect to see more of these openings in the coming months. As the SFI rises, even when it is not enough to support F2 propagation on its own, enhancement from TEP, sporadic E and auroral E will create surprising DX openings. Don't let it catch you by surprise! If you want the DX, you will have to pay attention. The Pacific opening when I worked E5 and 3D2 last summer was an early preview of improving east-west propagation at higher latitudes.

I confess that I get tired of being asked what days and times to expect the DX to come rolling in. It is rarely that simple: there is no fixed schedule. You must monitor, listen and monitor some more. Don't count on a friend letting you know, except to brag afterward about the new countries they worked. 

I can offer a few hints to those unfamiliar with 6 meter propagation. Sitting on the edge of what the ionosphere can do, it takes only a small deviation from normal or a peak in ordinary phenomena to deliver extraordinary DX opportunities. Let's look first at the opening mentioned above. In addition to the geomagnetic conditions, there was a fortuitous daily arrangement.

Here we see the geometry of the terminator at the exact time the ZL stations were heard: 2030Z. Notice that it is noon almost exactly at the longitude mid-point between me and New Zealand. Due to our respective north and south latitudes, ZL is about the same time past their sunrise as VE3 is before our sunset. This is important since solar insolation, and therefore EUV intensity, is at a maximum in the tropics which signals between us must traverse. With sufficient propagation at temperate latitudes we can connect via the tropics. This may have been a combination of auroral E and TEP.

It is just such fortuitous occurrences that tip a dead band towards fireworks. This is not the only recent incidence of tropical assistance to propagation, and it's one I've mentioned in my 6 meter article in past years. Now let's look back several days to an opening in the opposite direction.

February 21 brought an unexpected opening. I worked about 10 stations in Europe, from England to Italy, and EA8. Particularly exciting was hearing ZS6TK calling Europeans. By the time my amp warmed up he was gone. I called CQ with the yagi pointing east. PSK Reporter shows that I was heard at ZS6WN. Unfortunately, a QSO with South Africa was not in the cards that day.

The opening was not limited to South Africa and Europe. Stations further to the east in W1 had a far more substantial opening. They were hearing and working stations in the Middle East (9K, 4X), Africa (3C, 7X) and in the western Indian Ocean (3B9, FR). I could only watch and envy their good fortune. Indeed, it turns out that great circle path to the northeast, which from here is the one for all of these stations and the Europeans that I worked, was not favourable. All signals peaked to the east, not the northeast.

This is an instance of skew path that is not unusual when the MUF is marginal. Ionization, as mentioned earlier, is higher in the tropics. Signals were scattering from the more intense ionization area south of the great circle path. The same phenomenon is common on 10 meters soon after sunrise when European signals peak while beaming east. As the day progresses and illumination of the usual path continues, signals shift to the direct northeast path.

I was unlucky that day other than the European opening. There will be more opportunities in the days and months ahead.

Closer to home, the aurora produced by the recent geomagnetic storm supported a modest amount of VHF propagation. On the evening of February 26, I worked stations in W1, W8 and VE, and I copied beacons as far afield as VE4 and VY0. W0 stations were heard. I worked little since I didn't bother with the amp and aurora signals are typically quite weak. 

Aurora propagation is interesting but it isn't DX. That's why I couldn't be bothered to warm up the amp. Going back several cycles to 1989/90, I had a blast working aurora on 6 meters and 2 meters. With sunspots come flares and CME (coronal mass ejection), and the probability of intense aurora extending to lower latitudes. 

If that's your fancy, expect instances of this kind of 6 meter propagation to increase over the next 2 years. These days I am mainly interested in auroral-E propagation for Arctic circle DX such as KL7 and Scandinavia, and as a bridge to F-layer propagation in sunlit areas on the northern hemisphere. Non-DX propagation on 6 meters rarely excites me as it once did.

During the February 27 opening to the Pacific there was an excellent opening to South America. I had to forego it to focus on the Pacific. North-south propagation is more common so it made sense to seize the opportunity of rarer DX. That said, it would have been nice to work them, including one South American country that I have yet to work on 6 meter FT8: OA.

This was not the first time I've had an opening to the South Pacific this solar cycle and it won't be the last. Worldwide DX propagation on 6 meters will only get better through at least 2024 and probably 2025. Forecasts of solar activity are full of uncertainties, yet we're far enough along to say that the current cycle will be at least equal to the last one. I was not really active on 6 meters in that cycle and it was before the advent of digital modes for terrestrial VHF operation.

Cycle 25 is likely to be the best yet for 6 meter DXers. This is despite a cycle maximum unlikely to rival past cycles. Consider:

• Activity level on 6 meters is greater than ever. Every HF rig, and now many amplifiers, feature 6 meters. Pretty well every HF operator has a 6 meter rig.
• No matter how you feel about it, digital modes have caused a surge of activity. Many hams, for reasons of having no CW ability or are restricted to small antennas, find VHF digital modes to be an ideal outlet for their enthusiasm.
• Most hams are old. They are retirees with more time on their hands. Unlike when I was young, the bands are populated during weekdays. I missed many great 6 meter openings in decades past when I was busy at work.
• The cash rich baby boomers are launching more DXpeditions than ever. These range from suitcase style operations from Caribbean vacation locales to rare islands and countries around the world. Many of them are active on 6 meters.

2023 promises to be a year to remember for 6 meter DX enthusiasts such as myself. While the MUF may not hit 50 MHz as often as we'd like, the tie-in with sporadic E and TEP, combined with the far higher activity, will generate opportunities like no previous solar cycle. With 120 DXCC entities on 6 meters, I have reached the point of diminishing returns without the aid of F2 propagation. I expect a significant jump in my DXCC count this year.

Have I whet your appetite? Have you been thinking of becoming active on 6 meters, but have yet to make the leap? Get ready. When the equinox arrives in a few weeks the DX openings will become more frequent. As April turns to May, sporadic E will arrive. In combination with improving F2 propagation it could get wild. I'll be there, and I hope to see you there as well.