Friday, 7 December 2018

630m ... The New 'Magic Band'?



The 'magic band' has always been associated with 50 MHz and its amazing propagation ... usually unpredictable and often without logical explanation. This past summer saw an explosion of digital FT8 activity on 6m which has, for me (and for others I suspect), eliminated almost all of the enjoyment I have found every year on this band.


With so much of the previous CW and phone activity now gone to FT8, the 'feel' of the band is just not what it once was. What I find puzzling is that so many have embraced this weak signal mode yet most of the two-way QSOs seem to be made between stations that can easily hear each other ... often at the very strong levels produced by 6m sporadic-E!

With FT8's inability to chat about antennas, rigs, propagation, locations or simply to exchange names, for me the magic has gone. Being able to hear signals build, fade up and down, or to experience the sudden arrival of bone-crushing signals from the east coast where none had existed moments earlier, is all part of what attracted me to 6m decades ago. I spent only a few hours on the band last summer, working a number of JA stations on FT8. No particular sense of satisfaction was garnered ... working a JA opening on CW is just way more exciting!

For many, the arrival of FT8 to the magic band has opened a whole new world and from seeing so many unfamiliar call signs on 6m this summer, it seems that FT8 has brought a lot of newcomers to the band. Unlike the JAs' worked every summer on CW, almost all of the FT8 JAs' sent their QSL immediately, with almost all excitingly indicating "1st VE" ... so this has to be a good thing! I suspect, that unless the level of conventional-mode activity returns to previous levels on 6m (highly unlikely), my interest in 50MHz will slowly wane or vanish altogether ... but thankfully, there's still magic to be found elsewhere on the ham bands!

As solar Cycle 24 draws down into its final months, the deep lows that were experienced at the end of Cycle 23 are starting to develop once again. For the past few weeks, propagation below the broadcast band has been the best it has been since the previous solar quieting.

Being just below the bottom edge of the broadcast band, 630m (472-479 kHz) has seen some of the benefits of the recent round of stagnant geomagnetic activity.

While some transcontinental QSOs are regularly being made on CW, most contacts are being completed using the weak signal JT9 QSO mode. Contacts can often be completed just as the sun begins to set and staying up into the wee hours to catch east coast DX is not a requirement. Over the past few weeks my 'states worked' total has climbed to 30 and with a couple of holdouts, the QSLs have been steadily arriving.

My 630m states worked, shown in red. Map courtesy: https://mapchart.net/

Last month's arrivals, in spite of the Canada Post delivery disruptions, are shown below.




The recent great propagation on 630m is well-demonstrated by last Saturday night's activity. For the previous two evenings, my JT9 CQ's (as well as QSOs) were being decoded for hours at a time by Rolf, LA2XPA in Norway. He was also hearing Larry, W7IUV, located a few hundred miles to my southwest, on the other side of the Cascade mountains in Washington state. Both of our signals would fade and trade places in Norway but often reaching audible CW levels! The problem was that neither myself or Larry could see any of Rolf's replies to us ... disappointing to us and frustrating for Rolf.

After an hour of trying, I asked Rolf (via the ON4KST LF chat page) what he was using for a receive antenna. It turned out that his secret weapon was a 1000' beverage pointed this way ... no wonder he was hearing so well. Larry, who was using a shorter, easterly pointing BOG (Beverage On Ground) for 630m receive, commented that he also had a 1000' beverage pointed toward Europe but it was optimized for 160m and doubted that it would work on 630. Just to make sure, he plugged it into a second receiver and soon indicated that he 'might' have seen a weak JT9 trace on the waterfall, close to Rolf's frequency.

One minute later Larry's comment was just "wow!" and the following minute he explained what had occurred. It seems that the 'possible weak trace' had suddenly skyrocketed to a -16db signal ... right at the edge of audibility! Larry and Rolf quickly exchanged signal reports and "RRs" as the first Europe-West Coast 630m QSO went into the history books ... 'wow' indeed!

Rolf reported that at his end, Larry's already good signal suddenly shot up to -5db, an easily copied CW level, before fading away for the night. Larry was pretty shocked at how quickly this strong short enhancement had occurred and we all hoped that the oft observed 'spotlight' propagation seen on 630 would move further west to VE7 ... but for now, it was not to be.

Earlier in the evening I had commented to Larry about some previous quirky 630m propagation and had suggested to him that it was probably just due to "the magic of radio" ... to which he politely dismissed with "sorry no magic, just hard work and dumb luck". Looks like he was right on both accounts, but after Saturday's excitement I think he may now believe in a little magic as well!

Saturday, 1 December 2018

Manhattan Style

After blogging for over four years now, I've covered a lot of topics that have piqued my interest in the ham radio world. I'm going to (once in awhile) select some previous blogs for reposting since they are every bit as valid as they were a few years ago and many new readers will have never found them without going way back! This one is from June, 2014.

                                            
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I haven't yet decided to rebuild the little 630m CW transmitter using Manhattan style or the newer Muppet style being promoted by Chuck, K7QO.
K7QO Muppet Style
The Muppet style seems to be PCB without holes, with parts being mounted on the copper pads directly. Like Manhattan or Ugly construction, changing components is very convenient. I pretty much split final construction methods between Manhattan style or dedicated PCB.

I recently ran low on the pads used for Manhattan and made another pile of various sizes. For those interested in using this style, it's pretty quick and easy to manufacture a good stock of your own pads using a simple hand punch.


These punches are widely available on e-Bay or possibly at your local hardware outlet or craft store. They come with various sized dies but I have only found myself using two sizes, 5/32 and 3/16. The punches have a small point at the center which I filed off so not to create a dimple in the punched pad.





It's also advisable to scuff sand the bottom of the PCB strip as well as to shine up the copper side with some light steel wool before punching any pads. They will eventually be glued to the circuit's PCB copper surface using a small dab of CA ("super glue") glue and the slight scuffing beforehand will ensure that the pads stay put. My usual technique is to place a tiny dab of glue with a toothpick at the spot where the pad will go. I then pick up the pad using an X-acto knife, spearing the pad's copper side and then pressing it down on the glue spot. CA cures quickly once it is oxygen-starved so pressing down on the pad for a few seconds is usually all that is needed. Any time I have run into trouble it was because I used too much glue....just a small dab is needed.


VE7SL Lowfer Tx
There are many good tutorials on Manhattan-style construction to be found on the internet as well as some super examples of what can be accomplished using this method as a "final" version technique.
For me, one of Manhattan's strongest selling points is that even though final part values may have been fleshed out during a rough build, parts can still easily be changed, added or even removed without a lot of fuss....unlike a PCB....but Muppet does look interesting!