Magic Band And The DX Window


Late May and early June always sees 6m come to life ... sometimes slowly and sometimes with a 'bang'. Last year's good early start soon flickered-out into what was the poorest sporadic-e season that many could recall. This year's 'start' has almost been a no-show, with just a very few short openings to the south eastern states (Colorado, Utah) and one 'blink and you've missed it' opening to the Great Lakes.



Hopefully the 6m propagation gods are just having some fun with us and things will really spring to life shortly. Once we do get into some periods of good propagation, there are always new arrivals to the band, as most transceivers these days include the 6m band. Every season I hear of newcomers getting their knuckles wrapped for, probably unknowingly and in all innocence, operating inside the 'DX Window'.

If you're new to the band or perhaps not sure how the window should work, here's a short section taken from my Magicband web page, that explains the concept:

Don't Be A 'DX-Window' Lid! 

One of the quickest ways to get the 6m community saying nasty things about you behind your back is to mess-up in the DX Window. The DX Window (50.100 - 50.125 kHz) has long been established for one type of contact only, that being a legitimate DX QSO. 


The DX Window can only be of value if everyone follows these basic 'rules': 


If you are in the U.S.A. or Canada, DO NOT WORK ANY OTHER U.S.A. or CANADIAN STATIONS INSIDE THE WINDOW. The window is NOT for North America - North America contacts. 


Do not answer the "CQ" of U.S.A. or VE stations if you are in North America. This creates unnecessary QRM and chances are, they will not respond to your answer anyway. Calling or answering other North Americans in the DX-Window only reinforces bad operating habits, encouraging newcomers to do the same. If you want to work U.S.A. or CANADA, do it outside the DX Window! 


Work or call only stations outside of North America inside the DX Window. 


The only legitimate exception to these rules, that will not get you in the naughty-corner, is working a KL7, VE8, XE or some other such fairly rare North Americans. 


I hate to say it, but some of the worst offenders to the successful function of the DX Window are my fellow VE's, many of whom don't know or don't understand the simple concept of how it works. Now that you know, pass it on! 


Now, you may or may not agree with the concept of a DX window, so please don't shoot the messenger. What I do know however, is that if everyone does their best to adhere to the window's concept, it works well. Problems arise when those that should know better, and probably do, decide that for some reason, the concept doesn't apply to them or that it won't hurt, 'just this once'. Others, particularly newcomers, see it and think it's all OK and soon the window is full of domestic QSO's, effectively killing its usefulness.

As conditions slowly improve, hopefully we can work on six this summer. I usually hang out on CW, just below 50.100. As one long-time 6m diehard would often say to me, the newcomer over 40 years ago ... 'We'll see you, all of a sudden!"

Having fun on the "Magic Band"

In April I installed a second-hand HB9CV for 6m, primarily for use in the UKAC VHF contests but I hoped to use it during the upcoming sporadic 'E' season.


Still a relative newcomer to the hobby (only licensed at end of 2013) I had little experience of the 50MHz/6m band and have been mostly met with static whenever I did turn the dial to have a listen but happily that has changed in the last few weeks.

I knew that 6m can be an interesting, unpredictable almost unique band.  Being at the lower end of the VHF spectrum it exhibits the usual characteristics of VHF communication, mostly short range line-of-sight contacts since 50MHz is usually well beyond the maximum usable frequency (MUF) for normal 'F-layer' ionospheric propagation utilised by the lower bands. However solar activity and other factors can trigger other types of propagation, in fact the band can support just about every form of propagation possible and is the main reason why it has become known as the "Magic Band"

One interesting form of propagation is sporadic E, or popularly referred to as Es. Small clouds of unusually ionised atmospheric gas form in the lower E-layer of the ionosphere (located at altitudes of  90 to 160 km). These clouds 'bounce' the radio waves allowing long-distance communication at VHF frequencies, sometimes multiple hops are possible giving extreme DX. One advantage of sporadic E over other forms of propagation is that it allows low-power QRP communication. As its name suggests, sporadic E is not a normal occurrence but can happen at almost any time. It does display a seasonal pattern with activity peaking in the summertime most noticeable in mid-to-late June.

I had turned the antenna to the East and have been running WSPR on and off over the last month on 6m with no luck, just the odd spot from the UK. I was in the shack one Saturday evening and was tuning around on 6m and heard some Italian stations calling CQ on SSB. I tried my luck and answered (using 50W) and was amazed to be heard, working a couple of stations in quick succession then suddenly the opening closed mid contact with another station. I was hooked!

Over the past few weeks I have caught a few more openings and have managed to work (in no particular order) Latvia, Croatia, Lithuania, Slovenia, Czech Republic, Slovakia, Serbia, Italy, Germany, Switzerland, Poland, France, Spain, Austria, Canary Islands and Finland - using a combination of voice on SSB and the JT65 digital mode.

Using JT65 has been particularly interesting since it allows me to 'remote operate' from work otherwise I would miss most of the 'Es'. Being able to monitor the waterfall and see the signals gaining and falling in strength during the minute long transmission is particularly fascinating.

Using the PSKReporter website I can see the location of all the stations I could hear and was being heard by. This map shows activity over the couple of hours on the 26 May using just JT65.


I have joined the UK Six Meter Group (UKSMG) to find out more about this "magic band" and their website is full of lots of information and resources along with the magazine Six News for subscribers.


Having fun on the "Magic Band"

In April I installed a second-hand HB9CV for 6m, primarily for use in the UKAC VHF contests but I hoped to use it during the upcoming sporadic 'E' season.


Still a relative newcomer to the hobby (only licensed at end of 2013) I had little experience of the 50MHz/6m band and have been mostly met with static whenever I did turn the dial to have a listen but happily that has changed in the last few weeks.

I knew that 6m can be an interesting, unpredictable almost unique band.  Being at the lower end of the VHF spectrum it exhibits the usual characteristics of VHF communication, mostly short range line-of-sight contacts since 50MHz is usually well beyond the maximum usable frequency (MUF) for normal 'F-layer' ionospheric propagation utilised by the lower bands. However solar activity and other factors can trigger other types of propagation, in fact the band can support just about every form of propagation possible and is the main reason why it has become known as the "Magic Band"

One interesting form of propagation is sporadic E, or popularly referred to as Es. Small clouds of unusually ionised atmospheric gas form in the lower E-layer of the ionosphere (located at altitudes of  90 to 160 km). These clouds 'bounce' the radio waves allowing long-distance communication at VHF frequencies, sometimes multiple hops are possible giving extreme DX. One advantage of sporadic E over other forms of propagation is that it allows low-power QRP communication. As its name suggests, sporadic E is not a normal occurrence but can happen at almost any time. It does display a seasonal pattern with activity peaking in the summertime most noticeable in mid-to-late June.

I had turned the antenna to the East and have been running WSPR on and off over the last month on 6m with no luck, just the odd spot from the UK. I was in the shack one Saturday evening and was tuning around on 6m and heard some Italian stations calling CQ on SSB. I tried my luck and answered (using 50W) and was amazed to be heard, working a couple of stations in quick succession then suddenly the opening closed mid contact with another station. I was hooked!

Over the past few weeks I have caught a few more openings and have managed to work (in no particular order) Latvia, Croatia, Lithuania, Slovenia, Czech Republic, Slovakia, Serbia, Italy, Germany, Switzerland, Poland, France, Spain, Austria, Canary Islands and Finland - using a combination of voice on SSB and the JT65 digital mode.

Using JT65 has been particularly interesting since it allows me to 'remote operate' from work otherwise I would miss most of the 'Es'. Being able to monitor the waterfall and see the signals gaining and falling in strength during the minute long transmission is particularly fascinating.

Using the PSKReporter website I can see the location of all the stations I could hear and was being heard by. This map shows activity over the couple of hours on the 26 May using just JT65.


I have joined the UK Six Meter Group (UKSMG) to find out more about this "magic band" and their website is full of lots of information and resources along with the magazine Six News for subscribers.


6m/70cm antenna updates at the QTH

I have made some changes to my antenna set up. A local amateur was selling a second 13-element 70cm yagi and a 6m HB9CV antenna at a low price so decided to acquire them.


The 70cm yagi was to replace the small 7-element one which I pressed into service as a hand held antenna for potentially finding my HAB payloads last year.

To be honest I wasn't really after a 6m antenna due to the size and visual impact. I have a 6m 'wooden' moxon I made back in 2014 but it is heavy, ugly and unstable so had been collecting cobwebs in the garage. I decided with the prospect of 'Sporadic E' season around the corner I would be foolish not to put it up.

The HB9CV wasn't in the best of conditions but seemed complete albeit it was purchased dismantled. The elements were a little weathered so I set about cleaning them up with a light rubbing down with some wire wool and a rag with a drop of WD40. On closer inspection the tube that made up the front element had some noticeable bending and on removing the plastic mounting to investigate I spotted a crack in the tube wall by the hole for the mounting bolt.

While it hadn't totally separated it would only be a matter of time before it did fail as it was flexing, the plastic mount was the only thing holding it together. I found a suitable piece of alloy tube from a scrap antenna which was a perfect fit inside the broken element. I cut a suitable length and pushed it up inside the element to the appropriate position and then simply drilled through and bolted either side of the central hole to stabilise and strengthen it (can be seen in image below)


The next issue I had to address was the feed point, it came with about six inches of RG58 coax projecting from it where it had simply been cut for removal by the previous owner. I prised off the cover cap to find it full of water, the reason being a hole in the back and it being stored outside I believe.


Thankfully the trimming capacitor seemed okay, while it was wet it wasn't corroded. It was all dried out and the hole plugged with silicon and I set about re-assembling the antenna which was a little fiddly to get the phasing line to sit properly but once done it was a simple matter of adjusting the capacitor to get the VSWR to a minimum in the SSB section of the 6m band. I mounted on the rotator pole just below the X50 collinear.


I used it last month in the 6m UKAC and while my operating not exactly earth shattering I was happy with its performance using just 10W in the low power section just "search and pouncing" for a little over an hour.
.

The 70cm Yagi was straight forward as was already assembled, I just had to make a slight tweak to the gamma-matching bar as the VSWR was unexpectedly high around 2:1 in the SSB segment of the band, it seemed to have been tuned for the FM portion of the band. I managed just an hour "search and pouncing" in Aprils 70cm UKAC, I started late and while signal reports both ways were a marked improvement I found the extra directionality and off beam rejection something I will have to get used not helped by a temperamental rotator. 

6m/70cm antenna updates at the QTH

I have made some changes to my antenna set up. A local amateur was selling a second 13-element 70cm yagi and a 6m HB9CV antenna at a low price so decided to acquire them.


The 70cm yagi was to replace the small 7-element one which I pressed into service as a hand held antenna for potentially finding my HAB payloads last year.

To be honest I wasn't really after a 6m antenna due to the size and visual impact. I have a 6m 'wooden' moxon I made back in 2014 but it is heavy, ugly and unstable so had been collecting cobwebs in the garage. I decided with the prospect of 'Sporadic E' season around the corner I would be foolish not to put it up.

The HB9CV wasn't in the best of conditions but seemed complete albeit it was purchased dismantled. The elements were a little weathered so I set about cleaning them up with a light rubbing down with some wire wool and a rag with a drop of WD40. On closer inspection the tube that made up the front element had some noticeable bending and on removing the plastic mounting to investigate I spotted a crack in the tube wall by the hole for the mounting bolt.

While it hadn't totally separated it would only be a matter of time before it did fail as it was flexing, the plastic mount was the only thing holding it together. I found a suitable piece of alloy tube from a scrap antenna which was a perfect fit inside the broken element. I cut a suitable length and pushed it up inside the element to the appropriate position and then simply drilled through and bolted either side of the central hole to stabilise and strengthen it (can be seen in image below)


The next issue I had to address was the feed point, it came with about six inches of RG58 coax projecting from it where it had simply been cut for removal by the previous owner. I prised off the cover cap to find it full of water, the reason being a hole in the back and it being stored outside I believe.


Thankfully the trimming capacitor seemed okay, while it was wet it wasn't corroded. It was all dried out and the hole plugged with silicon and I set about re-assembling the antenna which was a little fiddly to get the phasing line to sit properly but once done it was a simple matter of adjusting the capacitor to get the VSWR to a minimum in the SSB section of the 6m band. I mounted on the rotator pole just below the X50 collinear.


I used it last month in the 6m UKAC and while my operating not exactly earth shattering I was happy with its performance using just 10W in the low power section just "search and pouncing" for a little over an hour.
.

The 70cm Yagi was straight forward as was already assembled, I just had to make a slight tweak to the gamma-matching bar as the VSWR was unexpectedly high around 2:1 in the SSB segment of the band, it seemed to have been tuned for the FM portion of the band. I managed just an hour "search and pouncing" in Aprils 70cm UKAC, I started late and while signal reports both ways were a marked improvement I found the extra directionality and off beam rejection something I will have to get used not helped by a temperamental rotator. 

SLOWLY declining solar activity

The slide down from a solar maximum is (usually) slower than the climb from the minimum to the maximum. Very gradually, the sun is going “off the boil” and solar activity is slowly falling away. With each year for several years to come things will get progressively harder on the higher bands. Some are predicting the next maximum may be a “damp squib”, so enjoy the conditions while they last. It is quite possible that 10m will never be as good again in the lifetimes of many of us. Certainly 10m is already not as good as a year ago. Although Es is good at any part of the cycle in late spring and summer, F2 DX is best around the peak of solar activity. In the past 6m has supported worldwide DX at times, but I think those days are sadly over.

See http://www.solen.info/solar/ .

6m SSSP JA’s

JA7DYN's Station

Six meters delivered a mid-afternoon surprise yesterday, with a brief opening between the west coast and Japan. It was one of those openings that would have been missed entirely, a few years ago.



At around 2300Z, JE1BMJ (Han), announced via the ON4KST 50MHz chat page that he would be CQ'ing towards North America on 50.090KHz. I was working at the bench with the receiver running in the background and took a moment to turn my 4el yagi towards Japan and put the receiver on frequency. Nothing was heard for several minutes when, as if a switch had been thrown, the frequency became alive with CW sending "... DX K". About 20 seconds later it started again, a CQ DX from JE1BMJ. It is amazing how often the band or a path will appear to suddenly open, in this case, at just the tail end of Kas's CQ ... not a whisper of anything before the very tail end. As I listened, his signal built from the initial 559 to 579 at which point I called and we exchanged signal reports.

I moved down the band and called CQ DX and was immediately called by several loud JA stations. Over the course of the short opening (just 15 minutes from start to finish), I worked the following stations in Japan:

                                       JE1BMJ
                                      JA1VOK
                                      JR2HCB
                                     JF1UMK
                                     JAØRUG
                                     JM1IGJ
                                     JG1TSG
                                     JHØKHR
                                    JF1IRW
                                    JA7DYN
                                   JK1EXO


As mentioned earlier, this was an opening that would probably have been missed a few years ago, for several reasons. One factor is the growing use of the Internet to spot activity or stations that are actually on-the-air in real time. Another reason is the very short window of opportunity. Without stations looking, thanks to Han's QRV announcement, it is probable that nobody would have been pointing towards Japan at that time of the day ... but, more likely, the biggest reason is the exploitation of the SSSP path between NA and Asia that has become somewhat of a regular occurrence over the past several summers.

SSSP or Short-path Summer Solstice Propagation is the mechanism uncovered by JE1BMJ in 1999. In that year he discovered that his signals could be heard almost daily in many parts of Europe by transmitting on a regular evening schedule. He then turned his attention to North America, in the morning, and found much the same thing. Han continues to this day on a regular schedule each day and more often than not, works several stations in North America ... from both coasts and everything in between. He has even worked into Central America on SSSP.

SSSP is a summertime-only event in the northern hemisphere and relies on the scattered ice crystals found in the Polar Mesospheric Summer Echo region (PMSE), located about 88km above the ground, very near the same height as the E-layer.

courtesy: JE1BMJ

Signals travel through the polar region and never touch the ground until the far end of the path is reached. In all probability, this is the same mechanism that west coast stations are able to work transpolar-Es into Europe during the summer. The season is short-lived (June/July) and openings can have weak rapidly fading signals or, as in yesterday's case, strong steady signals during the course of the opening. Openings can last from just a few minutes to several hours. Thanks to the Internet and real-time chat, most of these openings are no longer being missed.
Stations being worked via SSSP seem to be, for the most part, running high-power and / or large antenna systems. It is rare to work many of the 100 watt stations, although under good conditions, it does happen.

JR2HCB's 6m Yagi Stack
For the major portion of my 45 years of activity on 6m, working Europe in the summer was never even dreamt of. Late-night openings to Japan, were however, fairly regular and could be counted upon at least once or twice per summer. Both of these paths are now a regular occurrence, with the path to JA being more common than the path to Europe. As Han speculates in his paper, it may have something to do with the growing warmer temperatures in the polar regions due to greenhouse warming effects. If this is the case, perhaps we will see even more of these types of openings in the future.

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