Wednesday, 29 August 2018

CLE 235 Results

BF-362 Seattle
 
 
 
 
 
As it turned out, summer lightning noise was the least of CLE 235's problems!
 
 
 
 
 
 
 
The weekend event saw its all too often 'solar hit' shortly after the start of the event, with Friday evening being the only night (in North America anyway) that had propagation. Saturday and Sunday nights were almost complete blackouts, with just one catch recorded on each night.
 
 
With the K-index soring to at least 7, there was really not much to be heard after Friday night save for a very robust appearance from RG-352 at the Rarotonga International Airport, just before dawn on Sunday morning. Thanks to Dan, VE7DES, listening from the club station at UBC, for the tip!Disturbed conditions often seem to enhance the Pacific path but other than Hawaii, this was the only other signal heard from the west. Sunday morning found DPY-365 in Washington state. Up until that time, its signal had been completely missing-in-action ... but it was loud at 0100 local. Perhaps it had been down for maintenance and not on the air until Sunday.
 
courtesy: NOAA

My log consisted of 30 stations, with all but two from Friday night before the storm. As usual, the receiver was a Perseus SDR and an 'Inverted-L', resonated at 300 kHz.
 
25 07:00  350     VTR   McGrath, ALS
25 12:00  350     SWU   Idaho Falls, ID, USA
25 08:00  350     RG   Oklahoma City, OK, USA
25 07:00  350     NY   Enderby, BC, CAN
25 07:00  351     YKQ   Waskaganish, QC, CAN
26 12:00  352     RG   Rarotonga IAP, CKS
25 07:00  353     ZXY   Whitehorse, YT, CAN
25 08:00  353     PG   Portage La Prairie, MB, CAN
25 13:00  353     LLD   Lanai Island, HWA
25 07:00  353     AL   Dixie, WA, USA
25 12:00  355     AUB   King Salmon, ALS
25 12:00  356     ZXE   Saskatoon, SK, CAN
25 08:00  356     ZF   Yellowknife, NT, CAN
25 08:00  356     PND   Portland, OR, USA
25 08:00  356     ON   Penticton, BC, CAN
25 12:00  356     MEF   Medford, OR, USA
25 09:00  358     SIT   Sitka, ALS
25 09:00  359     YQZ   Quesnel, BC, CAN
25 09:00  359     YAZ   Tofino, BC, CAN
25 07:00  361     HI   Holman, NT, CAN
25 07:00  361     E3   Wabasca, AB, CAN
25 07:00  362     YZS    Coral Harbour, NU, CAN
25 07:00  362     RPX   Roundup, MT, USA
25 07:00  362     BF   Seattle, WA, USA
25 08:00  362     6T   Foremost, AB, CAN
25 07:00  365     YGZ   Grise Fiord, NU, CAN
25 12:00  365     MA   Mayo, YT, CAN
27 08:00  365     DPY   Deer Park, WA, USA
25 07:00  365     AA   Harwood, MN, USA
25 12:00  368     ZP   Sandspit, BC, CAN
25 12:00  368     VX   Dafoe, SK, CAN

The results from ALL participants may be viewed here.

Monday, 20 August 2018

Hunting For NDBs In CLE 235

BF-362 courtesy: Steven M O'Kelley




This coming weekend will see another monthly CLE challenge. This time the hunting grounds will be 350.0 - 369.9 kHz.

 


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.

A really good challenge in this one is to hear BF-362, located in Seattle, Washington. I suspect that it's a 25-watter but is rarely logged outside of the Pacific Northwest region. If you are east of Montana and can hear it, your system is working well!

Listen for BF's  upper-sideband CW identifier (with your receiver in the CW mode) on 363.030 kHz while its lower-sideband can be heard on 360.943 kHz.

Although we are getting ever-closer to the fall DX season, lightning storms may yet be a problem, but at this time of the year we may get a lucky few quiet nights like this one in mid-June.

courtesy: http://thunderstorm.vaisala.com/explorer.html


If you are interested in building a system for the new (U.S.) 630m band, the CLE will give you the chance to test out your MF receiving capabilities and compare against what others in your area might be hearing.

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

Here are the full details for this weekend's co-ordinated listening event.
It is open to everyone including CLE new-comers:

Days: Friday 24 August - Monday 27 August
Times: Start and end at midday, your LOCAL time
Range: 350.0 - 369.9 kHz


This range is a busy one, usually giving us a high number of NDBs heard.

We last concentrated on these frequencies during CLE219 in May 2017.

Wherever you are, please join us and log the NDBs that you can positively
identify that are listed in this busy frequency range (it includes 350.0 kHz
but not 370 kHz) plus any UNIDs that you come across there.

Send your CLE log to the List, preferably as a plain text email
(not in an attachment) with "CLE235 - FINAL Logs" at the start of its
subject line.

Please show on EVERY LINE of your log:


# The date ( e.g. 2018-08-24  or just the day no. 24 ) and UTC
(the day changes at 00:00 UTC).
# kHz (the beacon's nominal published frequency, if you know it)
# The Call Ident.

Show those main items FIRST on each line, before other optional details
such as Location, Distance, Offsets, Cycle time, etc.


If you send any incomplete logs to the List during the event, please also
send your 'FINAL', complete one.


Please always make your log interesting to everyone by showing your
own location and brief details of the receiver and aerial(s), etc., that
you were using.

We will send the usual 'Any More Logs?' email so that you can check that your log has been found OK.



You can check on all CLE-related information from the CLE Page


http://www.ndblist.info/cle.htm


It includes a link to seeklists for the Event from the Rxx Database.

Good listening
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 the 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). 

-------------------------------------------------------------------

These listening events serve several purposes. They:
  • determine, worldwide, which beacons are actually in service and on-the-air so the online database can be kept up-to-date
  • determine, worldwide, which beacons are out-of-service or have gone silent since the last CLE covering this range
  • will indicate the state of propagation conditions at the various participant locations
  • will give you an indication of how well your LF/MF receiving system is working
  • give participants a fun yet challenging activity to keep their listening skills honed
Final details can be found at the NDB List website, and worldwide results, for every participant, will be posted there a few days after the event.

The Yahoo ndblist Group has been moved to Groups.io and The NDB List Group will now be found there! The very active group is a great place to learn more about the 'Art of NDB DXing' or to meet other listeners in your region. There is a lot of good information available there and new members are always very welcome. As well, you can follow the results of other CLE participants from night to night as propagation is always an active topic of discussion.


You need not be an NDB List member to participate in the CLEs and all reports, no matter how small, are of much value to the organizers. 

Remember - 'First-time' logs are always VERY welcome!

Reports may be sent to the NDB List Group or e-mailed to CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above. If you are a member of the group, all final results will also be e-mailed and posted there.


Please ... give the CLE a try ... then let us know what NDB's can be heard from your location! Your report can then be added to the worldwide database to help keep it up-to-date.

                               Have fun and good hunting!

Sunday, 12 August 2018

Recent Noise Mystery Solved

 
You may recall a recent blog regarding my installation of a new pair of inverted-V dipoles, fed from a common coaxial feedline at around 85'. Both antennas 'hear' very well and everything was peachy until I recently put the inverted-V's on my Perseus SDR.



I had been particularly interested in using the new high antennas for my general shortwave listening on 40m and below but what I observed was immediately troubling when listening on the 5 - 6MHz, 49m band. After much head-scratching about what I had noticed, I posted the following 'help' message to the Perseus reflector as well as to the Perseus SDR Facebook site:

Perhaps others can help explain something odd that I have just noticed with my Perseus while comparing antennas.

I was comparing signal levels and noise between a 40m half sloper and a very high dual 40/80m pair of inverted-V dipoles fed from a common feedline. Both the sloper and the dipoles are fed with 50 ohm cable and all three antennas are well matched at the low end of the band(s).

Listening to a 6 MHz signal from China National Radio around 10 am today, the signal was around S7-8 on the Perseus, using the 40m sloper. Listening to the same signal, at the same time, on the Yaesu FT-1000mp, with the high inverted-V, it was slightly better, maybe by 5-6 db and overall lower noise. I then put the inverted-V onto the Perseus and there was not even a trace of the signal! I made this check with several signals and always with the same result.

Now I suspect that the SWR of the 7MHz inverted-V when used at 6MHz, is very high and the load presented to the Perseus antenna input is likely highly reactive and far from 50 ohms but that doesn't seem to bother the FT-1000.

I then ran the inverted-V through my antenna tuner so that it effectively produced a 50 ohm non-reactive input load for the Perseus and did the tests again...with the same results. Swapping antennas for the 40m sloper once again produced the same signal levels in both the Perseus and the FT-1000.

So what is going on here and why does the Perseus balk at the 7 MHz inverted-V while listening on 6 MHz? Is there something in the Perseus front-end analog filtering system that is overly sensitive even though the reactance was tuned out via the tuner? Is it the 80m V on the same feedline as the 40m V that is causing some still unwanted reactance that is not tuned out with the tuner?

Any ideas what is happening here as it looks like I will not be able to use the inverted-V antennas on the Perseus for general SWL out-of-band listening for some, as yet unknown, reason.



As you can see, I was completely mystified by what I was hearing, or rather not hearing, and as it turned out, completely off the mark.

I received a few replies offering some possible reasons for what I was seeing but none of them proved helpful in solving my dilemma ... until Roelof Bakker (PA├śRDT) weighed-in! Roelof suggested that I look at the antenna's performance while running Perseus's built-in 'HFSpan' function.

HFSpan is a stand-alone 0-40MHz spectrum analyzer, that comes with the Perseus software. Although I was aware of it, I have only used it sparingly. I next did some screen captures with all three antennas, one at a time, and sent them to Roelof.

His analysis did not take long as he immediately identified my problem ... a very high noise floor when using the mysteriously-performing inverted-V. Roelof suggested some common mode choking to eliminate the problem.

Already having an isolating transformer in hand from a previous experiment, I inserted it directly at the Perseus antenna input and looked at the noise floor again, around 40m. The transformer was wound on a small FT87-J core with a 3 turn primary directly opposite a 3 turn secondary. I was astounded to see the background noise floor drop from -85dbm to a very quiet -110dbm!

Evidently there was a lot of noise being picked-up on the inverted-V's feedline shield. Not hearing any of this noise on the FT-1000 indicated that the noise was probably associated with the Perseus power supply, the laptop or the laptop's power supply. This immediately explained why I wasn't hearing anything with this antenna when used with the Perseus.

Roelof then suggested that a 2 turn / 2 turn transformer, offering less inter-winding capacitive coupling, might provide even more isolation ... and he was right again. A further ~4dbm lowering of the ambient noise was measured.


It may not be pretty but it produced an astounding improvement!

Further comparisons between the FT-1000 and the Perseus revealed that the FT-1000 was still producing a slightly better SNR than the Perseus, when using the inverted-V so evidently there was still some noise affecting the signal. I had a few very large #43 ferrite toroids and decided to wrap a few turns (5) of the RG8-X feedline around the toroid to see if there would be any improvement.

Once again, using HFSpan, I compared the noise floor both with and without the #43 choke and saw a further 6-7 dbm improvement! Going back to comparing SNRs between the FT-1000 and the Perseus, I now saw no difference between how I was hearing on both receivers, when using the troublesome inverted-V ... eureka!

Here are the 'before' and 'after' screen shots using HFSpan, the Perseus built-in spectrum analyzer. Both screen shots were taken at the same time (mid-afternoon) and show the results of the noise mitigation work.

0-10MHz sweep - with noise problems
Same sweep, noise eliminated, signals now unmasked

As of yet, I have not determined the actual noise source. I suspected it may have been coming from the Perseus power supply or from the laptop supply but that was not the case. Perhaps it is coming from the laptop's processor via the USB cable which I will also choke and see if HFSpan reveals anything further

This problem was a great learning experience for me, in more ways than one and I am most grateful to Roelof for his detective work and experience with noise issues and for taking the time to respond to my initial inquiry. Hopefully you may find something here that can help you as well.

Wednesday, 1 August 2018

Barn Door CLE Regen Results


This past weekend's 'Barn Door' CLE' saw a lot of participation, in spite of the mid-summer doldrums and the universal nasty lightning noise.


After reading CLE-organizer Brian Keyte's interesting posting to the ndblist, describing his homebrew single transistor regenerative receiver, I was inspired enough to dig out the soldering iron and build one for myself.

The circuit widely described as a '1AD regen' was originally designed several years ago by crystal-radio guru Mike Tuggle out in Hawaii. Mike is widely known for his exquisitely designed "Lyonodyne" DX crystal radio, which inspired an entire decade of intense DX crystal radio building activity back in the late 90's.

Mike Tuggle's 'Lyonodyne' DX Crystal Radio

His  '1 Active Device' medium-wave regen consists of a handful of simple components and a MOSFET that is up to the task. His design was, and still is, being duplicated by many throughout the NDB DX listening community.


Mike's original 1AD regen

Mike recently sent me the circuit diagram that he eventually settled with, showing two possible ways of extracting audio with the widely popular Bogen T725 output transformer.



My own version used Mike's output scheme on the right and the RF circuitry in Roelof Bakker and Steve Ratzlaff's modified version, shown below. I had to increase the tickler (feedback) winding from 4 turns to 11 turns in order to get any regeneration. With 11 turns, my regeneration kicked-in at about three-quarters from the end of the regen control. At some point in time, while testing, some of the leads from my Bogen T725 output transformer momentarily brushed against each other, smoking my FET. Upon replacing it with another BF966, the receiver was much hotter, with regeneration kicking-in very close to the start of the pot. I'm not sure if the first FET was already damaged or that there is enough variation from FET to FET (of the same type) to make some have more gain than others. Accidentally blowing up the FET proved beneficial in the end!



Although most users employ sensitive sound powered headphones with their regens, including myself, some use modern phones with an extra stage of audio, such as an LM386.

Although not nearly as pretty as Mike's regen, my own 1AD was built in an afternoon, just for the recent Barn Door CLE.


My own MW 1AD regen

I later added a calibrated dial plate, breaking the segment from 200kHz to 550kHz into two separate bands, with calibration ~ +/- 1kHz so that I pretty much new where I was tuning at all times. This allowed me to target specific beacons and wait for them to fade up.

When first published, Mike suggested the BF966 MOSFET seemed to work well and I purchased five of them with the intention of someday building a 1AD for the NDB band. The purchase came in handy, as today, the BF966 is no longer available. Apparently the similar, and still available BF998 works well (from tests done by Steve Ratzlaff) but is now in an SMD package at just 18 cents! No doubt there are dozens of MOSFETS that will do the job and at these prices, experimenting with various devices would be a very worthwhile project.

When operating, the regen proved to be surprisingly sensitive, and by using my 10' x 20' loop, I was able to put my local pest (AP-378 kHz and 1/2 mile away) into a deep null so that its huge signal was no longer blocking the top half of the NDB band. The null allowed me to hear beacons within a few kHz of the blowtorch signal as shown below:


------------------------------------------
DD UTC    kHz     Call        Location
------------------------------------------
28 05:15  200     YJ     Victoria, BC, CAN
28 05:15  203     YBL    Campbell River, BC, CAN
28 05:21  214     LU     Abbotsford, BC, CAN
28 11:10  218     PR     Prince Rupert, BC, CAN
28 11:07  221     QU     Grande Prairie, AB, CAN
28 05:30  223     YKA    Kamloops, BC, CAN
28 05:36  227     CG     Castlegar, BC, CAN
28 05:38  230     YD     Smithers, BC, CAN
28 11:04  233     ALJ    Hinchinbrook Island, ALS
28 05:42  236     YZA    Ashcroft, BC, CAN
30 10:06  239     OJ     High Level, AB, CAN
28 05:42  240     BVS    Burlington, WA, USA
30 10:04  241     YLL    Llyodminster, AB, CAN
28 05:44  242     ZT     Port Hardy, BC, CAN
29 11:27  242     XC     Cranbrook, BC, CAN
29 11:26  246     ZXJ    Fort St. John, BC, CAN
30 10:21  248     QH     Watson Lake, YT, CAN
28 05:43  251     YCD    Nanaimo, BC, CAN
29 11:20  254     ZYC    Calgary, AB, CAN
30 09:56  254     SM     Fort Smith, AB, CAN
28 05:50  257     LW     Kelowna, BC, CAN
30 09:54  257     XE     Saskatoon, SK, CAN
28 10:55  260     YSQ    Atlin, BC, CAN
28 05:50  266     VR     Vancouver, BC, CAN
30 09:50  269     ZW     Teslin, YT, CAN
28 05:51  272     XS     Prince George, BC, CAN
28 10:47  283     DUT    Dutch Harbor, ALS
28 06:06  284     FHR    Friday Harbor, WA, USA
30 09:35  284     QD     The Pas, MB, CAN
28 10:39  287     PE     Peace River, AB, CAN
28 06:07  290     YYF    Penticton, BC, CAN
28 06:07  293     MB     Sidney, BC, CAN
28 10:39  295     8C     Fairview, AB, CAN
28 10:39  299     TV     Turner Valley, AB, CAN
28 06:11  312     UNT    Naramata, BC, CAN
28 06:14  325     YJQ    Bella Bella, BC, CAN
28 06:16  326     DC     Princeton, BC, CAN
29 11:08  326     XJ     Fort St. John, BC, CAN
28 06:16  332     WC     White Rock, BC, CAN
28 06:18  338     K      Port Angeles, WA, USA
29 11:06  338     ZU     Whitecourt, AB, CAN
29 11:05  341     DB     Burwash, YT, CAN
28 06:19  344     XX     Abbotsford, BC, CAN
30 09:08  348     MNC    Shelton, WA, USA
28 06:20  350     NY     Enderby, BC, CAN
28 10:25  356     ON     Penticton, BC, CAN
30 09:03  356     ZF     Yellowknife, NT, CAN
28 06:20  359     YQZ    Quesnel, BC, CAN
28 10:20  362     RPX    Roundup, MT, USA
28 10:17  362     BF     Seattle, WA, USA
28 06:22  368     ZP     Sandspit, BC, CAN
29 10:17  368     SX     Cranbrook, BC, CAN
29 10:31  374     EX     Rutland, BC, CAN
29 10:31  375     FS     Fort Simpson, NT, CAN
28 06:20  378     AP     Active Pass, BC, CAN
28 06:26  382     YPW    Powell River, BC, CAN
29 10:37  382     YE     Fort Nelson, BC, CAN
28 06:23  385     WL     Williams Lake, BC, CAN
29 10:39  388     MM     Fort Mc Murray, AB, CAN
28 06:41  389     YWB    Kelowna, BC, CAN
29 10:42  394     DQ     Dawson Creek, BC, CAN
29 10:44  397     ZSS    Yellowhead, SK, CAN
29 10:48  398     YOD    Cold Lake, AB, CAN
28 06:28  400     QQ     Comox, BC, CAN
28 06:28  404     MOG    Montegue, CA, USA
29 10:49  405     2K     Camrose, AB, CAN
29 10:16  406     YLJ    Meadow Lake, SK, CAN
28 06:29  408     MW     Moses Lake, WA, USA
29 10:53  414     8M     Elk Point, AB, CAN
28 20:00  515     CL     Cresent Beach, WA, USA

I ended up with 70 stations logged, including a couple of Alaskans, in spite of the horrendous lightning noise on all three nights. Doing another 'Barn Door CLE' in the middle of the quiet DX season would be much more exciting and several 1AD users have indicated an appetite for such an event. If you put something together please let me know as having an army of 1AD's ready to go would be a great incentive to schedule another Barn Door weekend!