AmateurRadio.com

courtesy: KC8RP FT8 Info

We are now half-way through this summer’s Sporadic-E season, normally the magic band’s best time of the year. The only exception to this being the winter months of those solar cycles that are robust enough to raise the F2 MUF up as far as 50MHz ... something that occurred for only two or three days during the peak of Solar Cycle 24.

Unfortunately, it really looks as if the old reliable bread and butter modes on 6m, CW and SSB, are fast going the way of the dodo bird, as very few signals on either of these modes have been heard here this summer. As speculated last year at this time, it seems as though the weak signal (WSJT) FT8 mode now reigns supreme on the band, which has come as a great disappointment to myself and many other diehard CW ops.

At the start of this year’s season I reluctantly decided to pay more attention to this mode and see if it could put any  new DXCC entities into my 6m log ... if so, it would be time well-spent.

For the past several years, my main 6m interest has focused on European or South / Central American openings, which are usually unpredictable and short-lived. As usual, most of the season’s openings have been domestic, with signals from the central and south-eastern states being the ones most often heard. Usually, signals during these openings are strong and fairly reliable and lend themselves to easy two-way work on either CW or SSB. For the vast majority of summer time openings, FT8 is not needed, as signals are not weak.

For some reason, the popularity of this weak-signal mode on 6m continues to grow in popularity even though signals are so strong! Where this mode really shines is on the short-lived long haul openings to EU or on similar long paths from the PNW, of which there have been very few this season.

With everyone crowded into a narrow passband of ~ 2kHz, it doesn’t take much to mess things up for your neighbours if you don’t think carefully about how your operating can affect other users of that small sliver of space.

One of the most common examples of poor operating skills that I see is the seemingly endless CQ. This is much easier to do on FT8 than with conventional modes, as the software used can do this automatically for you, every 15 seconds ... while you fiddle with something else in the shack. I’ve seen some nearby stations call CQ continuously for over 60 minutes at a time, with no replies. What this does is make it difficult for other nearby users to actually hear / decode any weak signals on the band that are being covered by the loud CQing station(s) during this entire span of time. Strong local signals can wreak considerable havoc with weak-signal mode software as it's just not designed to happily handle strong signals and do a good job of decoding weak ones at the same time! Please think about this if you are one of those long CQers ... you are not the only one trying to use the band.

Another observation has to do with 'sequencing'. FT8 users must decide if they will transmit on the ‘even’ or on the ‘odd’ 15-second sequence. If you, and all of your neighbours are loud with each other, then it makes sense that everyone is better off operating on the same sequence. This way, all locals are transmitting at the same time which means they are all listening at the same time as well ... nobody causes QRM for one another if everyone uses the same sequence.

This comes off the rails very easily when just one or two strong neighbours choose to transmit during the receive sequence being used by everyone else.

There has been a long-standing precedent for sequencing, established and utilized by meteor-scatter operators for several decades. It calls for stations on the eastern-most end of a path (Europeans for example) to transmit on ‘evens’ ... the ‘0-15’ and ‘30-45’ second segment of each minute. Stations on the western-end of the path (NA) transmit on the ‘odds’ ... ‘15-30’ and ‘45-60’ second portion of each minute. When looking towards JA later in the day, everything reverses for NA stations, as they now become the eastern-end of the path.

Some operators seem to get totally confused by this or don’t check to see what sequence is being used locally before starting to operate ... while some don’t really seem to care.

I’m not complaining about what a given amateur chooses to do but simply describing some of the roadblocks to better use of FT8 and why it is not necessarily very well-suited for 90% of the typical propagation seen on 6m Es.

Many of the newer stations often seem to be using poor or makeshift antenna systems on 6m and are often not able to hear stations responding to their CQs, which may be strong enough locally to disrupt reception for those that are able to hear weaker signals.

I have deliberately made a point of never calling CQ on FT8. From decades of CW DXing I have come to understand that it’s much easier to work DX, on any band, by spending your time listening ... and then calling when the time is right. It’s no different with FT8, yet I see CQs that go on forever. Some will argue that if nobody called CQ, then there would be nobody to hear, which is of course valid ... the reality is, most amateurs cannot resist calling CQ, especially DX stations who enjoy working a pileup. There seems to be no shortage of CQers and those seeking DX should take advantage of that fact.

One loud station was seen yesterday calling another for over 90 minutes-straight. Perhaps he had wandered away from his shack and had forgotten to ‘Halt Tx’ before leaving! FT8 users need to understand how to use their software efficiently.

As for PNW to EU propagation this summer, it has been almost non-existent although I have worked CT1HZE in Portugal and JW7QIA in Svalbard ... by listening ... listening ... and calling briefly, both on FT8. In both cases, signals were brief but strong enough for CW! During the short-lived appearance of the JW7, two NA stations were noted calling ‘CQ JW’ the entire time. Perhaps if they had spent this wasted time more wisely by listening, they would have worked JW.

I’m happy to report that Svalbard was a new DXCC entity for me on 6m, #88, and the first 'new one' in a few years.

It seems that when used sensibly, FT8 is a useful application to have in your DX toolbox ... but for most daily summer Es operation, it’s just not needed. CW or SSB is well up to the task most of the time, even for small stations. Where FT8 shines is on the very brief, often unstable, long haul (EU-NA or JA-NA) paths and then, only if your neighbours don’t do things that will get them into the naughty-corner!

Now, let’s see what the second half of the season has in store for the magic band .... maybe the best is yet to come.

When I completed my ‘Jones 6L6 Push-Pull Oscillator’ project in the spring, I made a start on a new ‘spring-summer radio project’ which was to be based on some 1937 RK-39 tubes that had been gathering dust here for many years.

With an unusually sunny and warm spring, I soon found that my radio-bench time was being hi-jacked with a lot of outside yard work and getting all of next winter’s firewood split and stacked away before the really hot weather arrived.

I found myself working on the project in tiny bites, sometimes not making any progress at all during the passage of a week. Headway was also tempered by the fact that I’ll often deliberate for several days over the placement of a single component or the selection of one component over another. I find this slow pace and decision ‘pondering’ during the design phase of any project to be most enjoyable as it gets my old brain working more than normal, on things that really interest me.

I’m happy to report that my latest project is now complete and fully operational and ready for operation!

As usual, I have written and published a web page fully describing the project and some of the background details of the building process.

My ‘Building A ‘37-Style ‘RK-39’ Crystal Power-Oscillator' page can be found here.

Hopefully we can have a CW QSO with it in the near future!

This blog first appeared in February 2016 but is just as relevant today as it was then!


 I admit it. I have an extraordinarily kind next door neighbour!

Ever since erecting a new, much bigger LF antenna several years ago, she has allowed me to run its large, three-wire 100' tophat, directly over the top of her house to a tree on the far edge of her property. As well, she removed her only light dimmer, knowing that it was creating a LOT of nasty RF 'hash' throughout the LF / MF spectrum, seriously degrading my LF reception. To hear the RF noise-signature of a typical light dimmer, listen here, on the ARRL's helpful page of 'household' RFI recordings ... that's just how it sounded here as well!

She recently did a major renovation, which included a new multi-light dining-room fixture and expressed to me a desire to be able to dim it ... oh-oh, I was definitely not looking forward to this.

I did a little web-research and soon learned that some of the most RF-quiet dimmers were being produced by Lutron. One model in particular, claimed to pay special attention to RF noise-filtering and that was the "Centurion", whose smallest model is a 600 watt-capable unit, with a large finned heatsink front plate ... model #C-600P-WH.

I decided to order one from the only dealer I could find in Vancouver that seemed to carry this line of dimmers. The cost was just a little over $40 Canadian (sells for about $25 in the U.S.A.) ... cheap enough if it would do the job!


When the unit came in, I picked it up on my next ferry trip to the city and upon my return, installed it the following afternoon. Before doing the installation, I fired-up the receiving system, tuned to 300kHz, and with the baby monitor set up beside the speaker, took the portable monitor with me.

After installing the new dimmer, I turned on the baby monitor, held my breath ... and turned on the light fixture. Wow ... not a trace of hash could be heard! Adjusting the dimmer from high to low produced no difference in the noise level. I later did a more thorough bandscan and could find no evidence of RFI, on any frequency. The only RFI that I could detect was when placing my Sony ICF-2010 close to the actual dimmer. I was unable to detect any noise further than 6" away from the lights or the dimmer!

So it seems that this model can be highly recommended, for your own home or if you have a next door neighbour 'light-dimmer problem'.

The magic band has always had a strong pull on me, ever since being put under its spell in the late 60s. I quickly learned that the surest way to guarantee a band opening was to leave the house for a few hours. Invariably when returning, the other local 6m addicts would gleefully describe everything that you had ‘just missed’. The 6m gods were rarely forgiving and this unfailing behaviour became part of the band's mystique.



This odd love-hate relationship continues to this day but with the FT8 mode being used almost exclusively now on 6m, it’s your computer that now snickers at you for any untimely excursions from the shack ... showing you, in any delightful color scheme that you choose, all of the DX that you 'just missed' once again!

It happened to me again yesterday, while out in the yard stacking next winter's firewood.

It was just a short excursion, as the eastern stations were working Europeans and all of the VE4 beacons were very loud back here on the coast. The possibilities of a link to the European path kept my excursion to only 10 minutes but sure enough, there it was on my WSJT-X list of decodes .... several CQs from CT7ANG in Portugal! My laptop could barely stop giggling. This would have been the first PNW-EU QSO of the summer had I been maintaining vigilance.l!

163315 -14 0.1 738 ~ CQ CT7ANG IM67
I continued to stack firewood and to watch the band more closely, knowing that every once in awhile, for entertainment purposes, the prop gods will toss out a bone or two, just to keep you on the hook.

A later check indicated that CT1HZE’s CQs had been decoded just a few moments earlier ... there was renewed hope!


185100 -2 0.2 2134 ~ CQ NA CT1HZE IM57

Joe’s strong FT8 CQ popped-up again a few minutes later and he came right back to my initial call. Although that was it for the day, the 2019 PNW-EU path had begun!

courtesy: PSK Reporter

I’m still somewhat ambivalent about FT8 and its ‘coldness’ when it comes to person-to-person interaction, but since most of the DX action on 6m is now digital, it’s either embrace it or miss out. At the moment, I’m at least prepared to hug it and see how it behaves. If it puts more Europeans and new DXCCs into my magic band log, then that’s a worthwhile investment.

Unlike way too many others, I’m not prepared to let my computer endlessly CQ for hours at a time. In a crowded local environment, with big strong signals being the norm, this method of operating is simply disrespectful to other amateurs as this mostly useless CQing will usually make reception of any weaker signals impossible.

FT8 is a weak-signal mode and the interfaces used do not handle extremely strong local signals very well. I would urge others to think about this poor operating practice and adopt what has always proved to be the best tactic for catching DX ... listen, listen, listen. The same tactic works just as well on FT8 as it does on CW.

Back to stacking firewood but having tossed me a bone yesterday, I’m sure the prop gods will be out to get even for awhile!

This coming weekend will see another monthly CLE challenge. This time the hunting grounds will be split:    260.0 - 269.9 kHz and 440-1740kHz.

 

For those unfamiliar with this monthly activity, a 'CLE' is a 'Co-ordinated Listening Event', as NDB DXers around the world focus their listening time on one small slice of the NDB spectrum.

If you've been meaning to participate in  CLE, then maybe this weekend is a fine time to try! Lately, we've had a lot of first time submissions so you won't be alone!

As well, if you're trying to learn CW, copying NDBs is perfect practice as the identifier speed is generally slow and the letters are repeated again every few seconds!

A nice challenge in this one is to hear VR - 266 kHz. 'VR' is the outer marker for the '26s' at Vancouver International (CYVR) and is located in Richmond, BC.

'VR' runs 50W into a closed triangular loop but is well-heard throughout North America having been reported as far as North Carolina to the east and Hawaii to the west.. Listen for its upper-sideband CW identifier (with your receiver in the CW mode) on 266.404 kHz.

At this time of the season, summer lightning storms may provide additional listening challenges but maybe we will get lucky. Propagation can often be as good as mid-winter if the lightning cooperates.

When tuning for NDBs, put your receiver in the CW mode and listen for the NDB's CW identifier, repeated every few seconds. Listen for U.S. NDB identifiers approximately 1 kHz higher or lower than the published transmitted frequency since these beacons are modulated with a 1020 Hz tone approximately.

For example, 'AA' near Fargo, ND, transmits on 365 kHz and its upper sideband CW identifier is tuned at 366.025 kHz while its lower sideband CW ident can be tuned at 363.946 kHz. Its USB tone is actually 1025 Hz while its LSB tone is 1054 Hz.

Often, one sideband will be much stronger than the other so if you don't hear the first one, try listening on the other sideband.

Canadian NDBs normally have an USB tone only, usually very close to 400 Hz. They also have a long dash (keydown) following the CW identifier.

All NDBs heard in North America will be listed in the RNA database (updated daily) while those heard in Europe may be found in the REU database. Beacons heard outside of these regions will be found in the RWW database.

From CLE organizer Brian Keyte, G3SIA, comes the details:


Hello all,

Our end-of-May Coordinated Listening Event will soon be here.
It will be a hunt for normal NDBs in two contrasting frequency ranges.
As always, first-time CLE logs will be extra welcome.

    Days:    Friday 24 May - Monday 27 May
    Times:   Start and end at midday, your local time
    Targets: Normal NDBs  (not NAVTEX or *amateur beacons)
    QRG:     260.0 -   269.9 kHz
     plus:     440.0 -  1740.0 kHz

These are interesting frequencies for most of us, with some quiet
wide-open spaces.  We last used them for CLE228 in January 2018.

Most of us should be able to hear some NDBs in both ranges, though
Europe only has a handful in the '260s'.  From 440 kHz onwards, North
America has a few, mostly around 510-530 kHz, but listeners in Eastern
Europe have a BONANZA – probably over 400 active NDBs in Russia
(RUS + RSE) alone, though for most of us in Western Europe many of
them are hiding among Europe's Medium Wave Broadcast Stations.

*(There used to be amateur beacons using CW on frequencies mainly
around 474 - 478 kHz.  Over the years they have been moving to use
other frequencies and modes. Last time we only heard three and only
in Europe.  So we’ll no longer be listening for Amateur signals in this
CLE's frequency range)

Please send your CLE log to NDB List, if possible as a plain text email
and not in an attachment, with 'CLE244 FINAL' at the start of its title.

Show on EVERY line of your log:
  #   The Date  e.g. '2019-05-25', etc.  (or just '26')
  #   UTC  (the day changes at 00:00 UTC).
  #   kHz  - the beacon's nominal published frequency if you know it.
  #   The Call Ident.

Those main items can be in any order within themselves, but BEFORE any
other optional details (Location, Distance, etc.) later in the same line.

As always, give details in your log of your own location and the receiver,
aerial(s), etc. that you were using.
If you send any interim logs, be sure to send a FINAL (complete) one.

You can find anything else to help you, including CLE seeklists for your
part of the World, from the CLE page, http://www.ndblist.info/cle.htm

Please look out for extra information in the Final Details in a few days
with advice about log-making, etc.

73
   Brian
---------------------------------------------------------------------
From:      Brian Keyte G3SIA           ndbcle’at’gmail.com
Location:  Surrey,  SE England          (CLE coordinator)
--------------------------------------------------------------------- 


(Reminder:  You could use any one remote receiver for your loggings,
stating its location and owner - with their permission if required.
A remote listener may NOT also use another receiver, whether local
or remote, to obtain further loggings for the same CLE).

courtesy: Roger, G3XBM

For the past few years several amateurs in Europe and along the east coast of North America have been experimenting on the ‘dreamers band’, 8.7 - 9.1 kHz.








Some rather surprising distances have been covered on these frequencies in spite of the dreadfully poor efficiencies realized with backyard antenna systems.

Previous 'earth-mode' backyard experiments on VLF by Roger, G3XBM, are well documented on his website along with details on his simple homebrew gear used to send signals across town using the earth. Following Roger's steady progression via his previous blog spots makes for fascinating reading ... there is some really great stuff here making it difficult to not jump in and take the plunge yourself.

This experimental field presents the ideal opportunity for a couple (or several) local amateurs to work together at exchanging signals on these low frequencies with simple home built equipment.

A major contributor to the present state of the ‘VLF / ULF amateur art’ is Stefan, DK7FC and a posting this week to the old RSGB's (blacksheep) LF reflector makes some of his earlier work pale by comparison as he announced the reception of his 270Hz signal (the 1110km band!) at a distance of  177 km!

Just a note from a recent experiment at 270.1 Hz.

On Sunday morning, 2019-05-12_10:34,+150m, I've done a carrier transmission on my ground loop antenna again. I did not expect more than, hopefully, a detectable spectrum peak in 57.6 km distance, i.e. at my tree site. The tree receiver site was listening and recording data using vlf-rx tools.
One E field antenna and two orthogonal loops were listening. The loops have been improved recently! They consist out of a single circular turn of 1.2 m diameter using 10mm diameter copper tube (about 25 mm^2). It is a closed loop, non-resonated, with an impedance matching transformer. This transformer previously had 1:100 turns. Now it (they) has 2:240 turns, i.e. two turns primary (out of 14mm^2, AWG6). This improved the sensitivity below 2 kHz significantly ( abt. 4...5 dB).
Furthermore the TX antenna length and angle has been improved, resulting in about +3 dB more signal strength on the RX site!

In a previous experiment at 270.1 Hz, some month ago, there was no result at all, not the weakest trace, despite excessive tweaking of all parameters. So the question was, will the improvements result in a detectable signal now?

Several things went wrong in that experiment. I forgot a bag containing important equipment such as the power supply for the netbook that generates the carrier signal. Also the output power was not as high as planned, just about 380 W, giving 2.2 A antenna current (I measured 64.7 V at 1 A DC). Anyway i managed to improvise so the experiment was started, but with some hours of delay which meant i higher QRN background level. Then, on the WLAN link to the tree, there were several interruptions of the stream (i'll move to 5 GHz very soon!). I even got some QRM from my battery charger for some short time periods (forgot to disable the charger remotely). So there were several factors that could have been improved or avoided. And the middle of May is not the ideal time anyway.

Well, 270.1 Hz, that's the 1110 km band! The far field begins at 177 km distance, i.e. i am clearly in the near field here. Thus, from a 'magnetic' TX antenna, we would expect that the signal is mainly detectable on the H field, i.e. the loop antennas.
The first interesting results is that this expectation is actually confirmed. There is nothing detectable on the E field but the carrier S/N in the H fields is close to 10 dB in the first run. Mixing the H fields and tweaking the filters rises the carrier S/N to 10.7 dB, see attachment.

So far not really an undoubtedly detection but it is a candidate for optimism! With a few less problems during the experiment there is a chance for 14 dB SNR. Also, there is quite much sideband QRM around 300 Hz which makes 270 Hz a bit harder to work on.

73, Stefan