Saturday, 22 October 2016

New - VE7SL Twitter Page

Research indicates that new brain cells are grown whenever you learn a new process or study new material. If that's the case, I've a head-full of new cells this week after deciding to set-up a Twitter account for the first time.

Setting up the account and trying to learn the ins and outs of tweets, hash tags, re-tweets, who sees what and who doesn't ... all without trying to mess things up too badly, has been fun. Although I haven't figured everything out with confidence, I'm far enough along to get going ... I think!

The link to my Twitter account is here and I will add a specific link on my blog page, at the top of the right hand sidebar.

Although I try to keep my blog's subject material related to my amateur radio interests and activities, I envision a broader range of subject commentary for Twitter ... not limited to just 'radio' but also some of my other interests and daily observations. As well, I can use it to announce my beaconing schedule and to report any interesting contacts or propagation conditions of note. Although I live on a small island, there is a lot to do here that keeps me busy ... I have many interests and activities, way too many for the number of hours in the day it seems, and some of these will be 'tweet' topic material.

In the meantime, I will begin the hunt for other Twitter users with similar interests who I would like to add to my 'follow' list and hopefully begin to build my own list of 'followers' over the months ahead. Although I can make no guarantees, I'll be trying not to end up in the naughty-corner by doing something dumb ... any and all input / advice gladly accepted!

Monday, 17 October 2016

Wishing Upon A Star

My love for radio began at an early age when I first started to tune the shortwave bands at age eleven. Little did I know then, that I was listening near the peak of the strongest solar cycle in recorded history, monster Cycle 19.

I thought that what I was hearing was normal for shortwave and that it would always be this way ... and it was, for a number of years.

As the solar cycle slowly declined, I began to take a deeper interest in propagation and its relationship with the Sun. After obtaining my licence and getting on the air, the reality set in with the arrival of a rather dismal Cycle 20. Following the vagaries of propagation became almost a hobby in itself, trying to correlate what I was observing with what the Sun was doing and even getting comfortable with predicting what might happen next.

It was particularly exciting during the stronger Cycles (21-23), to watch the dramatic effect of solar radiation on the F layer during the peak winter years of these cycles. With a major interest in 50MHz, watching the solar flux became a daily ritual, along with the fascinating daily rise of the F2 MUF as the Sun peaked over the horizon.

On normal mornings, around sunrise, the MUF would typically start close to 28MHz and slowly begin to rise over the next few hours. Often it would slow and settle-in between 38 and 42MHz, stay there for most of the day and then slowly recede as darkness approached.

I found myself looking forward to and wishing for more solar flares, along with the solar flux boost that inevitably followed.

On these mornings, the MUF would often be at 35MHz or higher, right at sunrise ... and begin climbing. Some days it would shoot-up like a rocket and in a matter of minutes would be at 50MHz or above, bringing thundering signals from the east coast not long after dawn. On other mornings it would climb much more slowly, receding and then advancing again, surging higher and then lower, as it teased its way towards the magicband. It was as if the ionosphere was a living breathing entity, as the solar radiation danced a slow tango with the critical frequency of the moment. Often it would stop at around 48 or 49MHz, stay there for several hours and then collapse ... no 6m excitement that day.

A nice bonus of watching this live interaction between the Sun and our ionosphere, was listening to the communications in the range between 28MHz and 50MHz as I followed the rising MUF. This was, and still is to a lesser extent, utilized on FM by paramedics, fire and police services throughout the U.S. It was not uncommon to hear mobile units enroute to an emergency, with sirens blazing in the background. Southern drawls usually meant that any 6m openings would begin in the southern states or the Caribbean, while Boston or New York accents, would herald an opening to New England or the possibility of trans-Atlantic openings to Africa or Europe. I became even more familiar with the daily interaction of the solar wind and how it affected radio ... and found it fascinating.

But just as the Sun affects propagation so positively, I was recently soberly reminded of how 'unfriendly' it can be ... as it has been in the past and will be again in the future. An article in this month's 'Astronomy', by Bob Berman, discussed threats to global welfare and in particular, a modern day repeat of the Carrington Event of 1859.

This was a double mega-flare and CME, taking only 19 hours to reach earth, compared to the normal 3-day trip. It was the strongest impact on earth ever recorded and one that will be repeated ... and is almost, statistically 'overdue', unless we dodged it in 2012 when a storm of similar magnitude missed the earth.

In Berman's words:

"What would a Carrington-level event do today, with our ubiquitous power lines, transformers, and more than a thousand operational satellites? In 2008, the U.S. government convened a panel of experts, who concluded that such a storm would completely destroy our electric grid. It would require two to 10 years to repair and cost about $2 trillion. We'd be knocked back to the stone age.
That panel panel called Carrington a "low frequency/high consequence" event - the kind humans typically ignore until it happens."

We quickly release how dependent on the hydro system we have become, when our power goes out for a few hours or even a day or two, following a severe weather event. Such an event is certainly 'inconvenient' but soon forgotten when the power returns. Going without power, and its trickle-down effects on our depended-upon infrastructures for several months or longer, would not be just 'inconvenient'. It would be a life-altering.

The Carrington event happened during Cycle 10, on the upward climb to the peak of an average-sized cycle. Solar scientists, for the most part, now predict a general decrease in solar activity over the next few cycles ... a spotless sun may become more the norm. Perhaps it is a good thing that the likelihood of a mega-flare event will be reduced but it seems that a repeat, at some point, is inevitable.

Maybe I'd better stop wishing for flares.

Thursday, 13 October 2016

630m VK's Light-Up North America

It seems that all of my blogspots of late have focused on 630m propagation ... but what has been happening down there recently has been both amazing and somewhat unexpected. With the growing number of active stations listening and transmitting, the band's propagation capabilities and mysteries are quickly revealing themselves.

Last night was a great example but perhaps the WSPRnet prop map illustrates this best.

The amount of North American activity grows each day, especially now that the DX season has arrived. At one point last night, KB5NJD reports over 100 stations either transmitting or reporting via the WSPRnet activity page! With thunderstorm activity gradually shrinking, reception should only get better over the next few months.

Particularly striking was the long haul propagation from VK to North America, with northernmost VK4YB leading the pack. His 90 watt signal made it all the way to VE3IQB, near Ottawa as well as to NO3M, in Pennsylvania! To provide further hope to those that have little room for big receiving antennas, VE3IQB uses a typical small active e-probe antenna, 20' above ground!

This spotlight propagation to the select regions of the east coast is further mystified by the level of geomagnetic activity overnight, with the K index reaching level 5 and higher!

Interestingly, all of this was right over my head, with not a single peep heard here from Roger. Stations across Georgia Strait, VE7BDQ, VE7CNF and VA7MM all reported hearing Roger as well as being heard by him. For the latter two, yesterday and today represent their initial decodes to down under.

I'm theorizing that Roger's signal was arriving today at much lower angles than normal, evidenced by its far-reaching east coast reception and the fact that it couldn't get over my 600' local obstruction to the west. I've always believed that it takes higher angled signal arrival for me to hear Roger and today's events seem to support this.

Exactly what would cause this to be the case, I'll leave to the experts but I imagine that the sudden surge in geomagnetic activity played a significant role in today's very different propagation paths.

Roger was not the only VK lighting-up the map today. A much more detailed account of all the action can be found on the KB5NJD's daily 630m report here ... all very inspirational and hopefully enough to spur even more new activity on the MF band.

Why not give a listen and see what you can hear?

Tuesday, 11 October 2016

VE3 - VE7 630m QSO

The 630m band continues to provide interesting challenges for Canadian amateurs ... be they antenna, equipment or propagation related.

Sunday night produced another flurry of excitement on the new band, further demonstrating its potential for small stations operating from the suburbs.

On Sunday evening, VE3CIQ in Carleton Place, Ontario (southwest of Ottawa), and I, completed a two-way JT9 contact, following a short exchange of the required information (and more) just after midnight, Ontario time.


Noting the increased east-west favorability over the past few nights, Phil and I decided to give it a shot and were delighted to cover the 2200 mile / 3500km path while Murphy was sleeping and not messing with propagation.

Rather than randomly beacon on JT9, we both set 'calling each other' messages. Although this continued for some time, the QSO only took 12 minutes to complete once I started to decode Phil's signal out west. He had been decoding me and sending signal reports for a long time before his signal eventually peaked up here for the evening. I suspect that we could have continued the contact for the remainder of the night as his signal was getting stronger and stronger as we worked.

Screen shot of QSO from VE3CIQ's end
Following our QSO, Phil sent me some information about his station. His transmitter consists of a Yaesu FT-817 driving an XKA transverter which in turn drives his homebuilt class-E amplifier. The amp consists of three switching FETs in parallel, operating at 24V and produces about 175W out.

VE3CIQ - 630m Station

VE3CIQ - Homebrew 630m Class-E Transmitter
Phil's antenna is an 'inverted-L' style ... 45' up to the top of a Pine tree and then a very very long sloping top hat wire, folded back on itself three times, in a zig-zag pattern. This use of linear-loading allows him to squeeze a near full 1/4 wave antenna into his suburban lot as well as to reduce the size of his loading coil inductance. His ground system consists of ~3,000' of buried radials. By all accounts, it seems to perform very well as his WSPR beacon was recently heard in Hawaii!

VE3CIQ - 630m Linear-loaded Antenna

Phil's station stands as yet another fine example of those living in the suburbs without a lot of room for antennas yet still able to successfully operate and explore our new 630m band. With a little ham-radio creativity, it's surprising how well a small station can perform, especially when the propagation co-operates.

Following our contact, I moved back to the WSPR section of the band and continued beaconing overnight.

Apparently Phil and I picked a good evening to run a sked as the overnight WSPR map shows it to have been the best night of the new DX season so far, with forty-four individual stations reporting my signal via the WSPRnet website.

Interest and activity on 630m continues to grow nightly, now that the DX season has arrived and the reality of a 630m ham band for U.S. amateurs grows ever closer.

Saturday, 8 October 2016

The GØMRF Class-D 630m Transmitter


Dave, GØRMF, long time LF proponent and ardent home-brewer has recently posted construction details of his new 630m transmitter.

It is a readily reproducible design that may be of interest to those looking for a transmitter capable of developing full ERP power output.

From Dave's description:

This amplifier is based on the ‘300W Class D Transmitter for 136kHz’ published by the RSGB in Radio Communication and reproduced in the LF Experimenters Handbook by Peter Dodd G3LDO.
This circuit, updated and modified for 630m, uses 2 MOSFETs in push pull driven by square-waves from a CMOS D-type flip flop. The power can be varied from around 25 to 300W by increasing the supply voltage over a 12 to 32V range. Circuits are included to protect against excessive supply current and high reflected RF power.
The amplifier is suitable for any non-linear mode. Examples include CW, QRSS, WSPR, JT-9, JT-65 and FSK.
The circuit has been built on a dedicated double-sided PCB measuring 164 x 120mm. For ease of construction 90% of the components are leaded but it has been necessary to use a few surface mount devices as the normal DIP versions of some ICs are increasingly difficult to find.

In many respects, this circuit is similar to my own homebrew transmitter which can be used on both 630 and 2200m. Although Dave has built his circuit on double-sided PCB, the project would be equally at home on one-sided board or even constructed 'Manhattan' style, the method I chose. This latter style lends itself to easy component swapping to optimize circuit performance.

VE7SL 2200m / 630m Manhattan-style Transmitter
If you are interested in the PCB approach, Dave has made the PCB available, with the needed surface mount IC's pre-soldered to the board. In addition, he has the toroids and resistors available for purchase here.

In addition, Dave's website contains several interesting circuits that might be of interest to those getting started on 630m.