Friday, 18 August 2017

A 630m Maritime Adventure

HAKUNA MATATA
It may not have been the YASME but the recent voyage of the HAKUNA MATATA had all of the radio fun that one might ask for during the mid-summer doldrums! (more later for those too young to recall the YASME)



Crewed by Mark (VA7MM) and YL May (VA7MAY), Toby (VE7CNF) and XYL Nancy, the 31' Benateu recently completed a 14-day circumnavigation of Georgia Strait's Gulf Islands. This is a yearly adventure that has been successfully completed for the past few summers and looks as though it may now be an annual tradition.

Normally, the crew kept up regular radio contact on HF as well as on VHF when possible but this year saw a major departure.

In previous summers, near the end of the voyage, the crew has always visited us here on Mayne Island for an afternoon of vittles and libation before heading for home. There is always a good amount of time spent recalling the past-year's radio activities, winter projects and reminiscence of the 'good old days'. Last year, just as the party was ending, I jokingly suggested that 'next year', it would be cool to work them from the boat on 630m.

Although there was no immediate commitment, I knew that the seed had been planted, and with three of the four crew being engineers, I suspected it might be hard for them to resist, and ... just before departure, the local bunch of 630m ops were put on alert to be watching for CF7MM/mm on 475 kHz CW as they would be attempting to work us from three different overnight anchorages during their summer voyage!

Evidently Toby had been working quietly during the winter to make this become a reality. Here are some pictures of the system along with Toby's (the system's builder) comments.

Variometer and matching transformer
I have attached photos of the CF7MM/MM 630m setup on Hakuna Matata. The lower black toolbox holds a variometer with selectable taps and a matching toroidal autotransformer with selectable taps. At the base of the antenna is another series loading coil.

Wire vertical and loading coil
The antenna wire is 14 ga 38 ft long with plastic Unadilla "END-sulators" at each end. Ground was the boats's cast steel keel and a couple of 30 ft wires near the gunnels. The rig is an IC-746 with my power-mixer transverter. Transmit power was about 20W TPO.

Toby (VE7CNF) working the pileups!
Tuning and matching was done with a resistive voltage divider setup, signal generator, and portable oscilloscope. Once the matching was figured out, I could re-tune the variometer to give a dip on the transverter's RF voltmeter and check that we had the same RF voltage as with a dummy load connected.

Tuneup
The antenna equivalent circuit is approximately 100 pF in series with 27 ohms. Coil losses were 23 ohms for about 50 ohms total load resistance, so the matching autotransformer was not used. The base loading coil is approximately 170 uH and the variometer is 950 uH, for 1120 uH total inductance.


QSOs were made at anchor from Boho Bay (49 29.808N 124 13.857W near Lasqueti Is), Silva Bay (49 09.047N 123 41.670W near Gabriola Is), and Winter Cove (48 48.621N 123 11.575W near Saturna Is).
 
The route, heading north from Vancouver
Stations worked on CW were VE7SL (Steve on Mayne Is, 12 to 48W TPO), VE7BDQ (John in Delta, 4 to 25W TPO), VE7VV (Roger in Victoria, 10W TPO), VE7CA (Markus in North Vancouver, 70W TPO), VA7JX (Jack in Campbell River, 100W TPO). Both VE7SL and VE7VV were also worked using LSB phone from Winter Cove.

Some of the contacts are shown below. Note the transceiver is not really on 160m ... it's just the i.f. for my 630m transverter!






I was impressed with the strength of ground wave signals given the low transmitter powers and EIRP's well below 5W. Received signals ranged from S1 to S9+10dB and copy was easy for all QSOs. QSO distances ranged from 10 to 142 km. We had low receive noise levels in all locations, with Silva Bay being a little noisier than the others due to many nearby boats and some shore power lines.

We tried disconnecting the gunnel ground wires and leaving only the keel, and found that the antenna capacitance and resistance did not change. When we disconnected the keel and left only the gunnel wires, the antenna capacitance dropped to about 87pF and antenna resistance dropped by a few ohms. It appears that the keel provided most of our ground coupling to sea water and it would have been a sufficient ground on its own.
It would have been interesting to compare signal reports with different ground arrangements. Next time...

More details of Toby's 630m transverter as well as a practical 630m antenna tune-up procedure can be found on his website here.

All-in-all, I think the 630m operation was a great success and very likely the first-ever 630m marine mobile operation on that band, as I don't recall this happening anywhere else over the years. It was also a great way to pay homage to the band's original maritime heritage where its quality groundwave and skywave capabilities were used to advantage for so many decades safeguarding mariners worldwide.



Maritime mobile operation on the amateur bands has some great history behind it, including the yacht YASME. In the mid-50's, Danny Weil was the first ever amateur to undertake DX'pedition style operations via sailboat, as he visited numerous rare islands in the Caribbean and South Pacific.

Danny on the YASME - courtesy: www.gm3itn.co.uk
Original YASME QSL -  courtesy: http://hamgallery.com/

His exploits were regularly published in CQ magazine at the time and always made for exciting reading as Danny would eventually wreck three YASMES over the years! His adventures laid the groundwork for future island-hopping DX operations such as those undertaken by Gus Browning (W4BPD), Don Miller (W9WNV) and all that followed ... I'm sure they would all have enjoyed working the HAKUNA MATATA as well!

Monday, 14 August 2017

The VK3BVW Winter DX Survey

courtesy: VK3BVW


Every once in awhile I get the yen to tune through the international SW broadcast bands as my interest in good old, basic SWL'ing, is rekindled.

These bands are certainly quieter compared to when I first discovered the magic of radio and started DXing at age eleven using a lovely old all band cathedral-style GE set up in my attic-high radio shack ... no longer just a boring attic bedroom, but one with walls plastered with QSLs from all over the world.




It was an amazing experience and one that obviously has left a lasting impression. There were hundreds and hundreds of stations on SW, throughout all of the HF bands but the highest I could tune was 19mc. on the old General Electric beauty ... who knows what was missed up higher as this was the peak of Cycle 19 and HF was on fire!

As the huge decline in international SW broadcasting over the past few years continues, I'm always pleasantly surprised to see that there are still a lot of nice DX targets to hunt for.

I was particularly excited to read Rob's (VK3BVW) just released blogspot, describing his fall listening project from down-under. Being the DX season down in Australia, Rob decided to do daily bandscans of the low HF international SW bands (4.8 - 10MHz) to see what popped-up from day to day, which was actually afternoon to afternoon, since his listening was done between noon and 4PM local time. The project may be viewed here along with a nice introductory video ... in all, a huge effort by Rob with a lot of helpful details to go along with the logs.

While there be sure to visit the rest of Rob's SW blog ... there's a lot of good stuff here to get your SWL juices flowing!

His survey results are very encouraging for those of us that may have thought that there is just not much to be heard when it comes to international SW broadcasting. As Rob points out, even though these logs reflect what was heard in Australia, most, if not all should be hearable in North America as well, even more so as we approach the DX season in North America.

So pull up your chair sometime after dark, grab a cup of your favorite beverage, and take a relaxing tune through the SW bands with Rob's list in hand ... see what you can find, and perhaps rekindle that early fascination in SW radio outside of the ham bands that may have hooked you many years ago. You may also find this broadcast frequency database helpful should you run across something unknown.

Monday, 7 August 2017

YADD

Maritime Traffic - courtesy: www.marinetraffic.com/
When the HF maritime CW bands were shut down in the late 90's, one of my favorite pastimes also ended ... listening for and logging the various coastal stations as well as listening for the ships themselves.

Until very recently, I had believed that there were no longer any HF maritime operations left, other than various Coast Guard weather announcements and an emergency watch on certain USB frequencies.

Over the past week I have discovered that HF maritime activity is still alive and well, through the worldwide Digital Selective Calling (DSC) system, which has been around in one form or another since the early 90's as part of the Global Maritime Distress and Safety System (GMDSS) ... I guess I was just asleep at the switch, having not been aware of the HF DSC activity!

Although it's not CW, there's still ample opportunity to hear and follow global shipping traffic as vessels of all types contact coastal land stations or call each other. One requirement that keeps the DSC frequencies busy is the requirement for vessels to test their systems at least once per week, providing many opportunities to log various coastal stations or add a new ship to your logbook. Ships can be heard calling coastals for a routine signal test, setting up an SSB phone QSO on a specified frequency or just calling another ship for a test or a phone sked. As well, DSC can be used to send a distress message alert in times of emergency.

Messages are sent in an error-correcting FSK mode, similar to the Navtex system, using the same speed and shift of 100 baud /170Hz. There are a few programs that can be used to decode the DSC messages but one of the best and most popular is the freely available "YADD", by Dirk Claessens .

YADD stands for "Yet Another DSC Decoder" and is an offshoot of Dirk's equally popular and effective "YAND", a free Navtex decoder.

YADD and several other software decoders can be downloaded from the NDB List Info site ... the best source of hands-on information for topics involving NDBs, Navtex, DGPS, DSC DXing and more.

After downloading and installing YADD and setting audio levels correctly, YADD began decoding signals with ease.


The spectrum display at the top of YADD's screen shows the audio passband coming from the receiver. With the receiver in the CW mode, DSC signals will appear on the frequency that your receiver's BFO offset frequency is set for. I prefer an offset of 400Hz so the spectrum display shows the signal at 400Hz, with the tuning cursor centered on a signal. A narrow CW filter should also be selected but no narrower than 170Hz.

Each vessel using the system, as well as the coastal land stations, have a unique 9-digit MMSI number (Maritime Mobile Service Identity). Once the software detects the MMSI numbers being used, it can then display the vessel's name (or the coastal's location and distance) so you know who you are listening to ... it's all very slick!

After initially running my receiver for a few minutes on the 12MHz DSC channel, I decided to look up the location of the first two ships I had heard, using one of the Internet's marine traffic sites.

I was surprised to find that my first catch was a large tanker under way in Kola Bay, having just departed Murmansk, in the Russian Arctic. Vessel number two was also under way along the east coast of South Korea.

The YADD screen above is showing the large bulk carrier 'SALANDI' (3FEB9) calling Rio de Janeiro Radio (PWZ) today on 16804.5KHz.

Courtesy: Henk Guddee
 A quick position check shows the SALANDI at anchor awaiting docking in Santos, southwest of Rio.



I soon discovered an active group of DSC DXers in Yahoo Group's DSC List, which I quickly joined and started asking a lot of questions. The 'Files' section also contains the latest list of ship MMSI numbers so that your YADD look-up text file can be kept up-to-date.

One of the group members, GM4SLV, has set up a wonderful website called YaDDNet devoted to collecting and posting listener's decoded loggings in realtime. One of YADD's features is the ability to automatically upload decoded signals, similar to PSK Reporter. It's an easy 30-second job to configure YADD to upload your spots to the net. His site also contains the latest MMSI look-up file used by YADD which is updated in real time from the latest log postings ... presently at 34,566 vessels!

Clicking on any of the uploaded ship names displayed in the real time YaDDNet log, automatically takes you to an online vessel-tracking site which usually has a picture of the ship along with all of its information, including its present position.

If you set up YADD to do some listening, I'd strongly urge you to also set it up so that your decoded spots are uploaded to the YaDDNet page in real time. Configuring this capability is very simple. Your latest logs will also keep the MMSI database up-to-date for all YADD users.

If, like me, you have missed the maritime CW activity on HF, you may find monitoring DSC traffic of interest ... both ships and coastals. I may even try QSLing some of the coastals again, many of which will still issue a traditional card QSL, upholding a long standing shortwave radio tradition ... but grab them while you can!

From my collection. Heard 4349KHz CW Aug '96

Monday, 31 July 2017

July's EME Window

With QSLs still arriving from previous 2m EME action, I was looking extra forward to late July's very short window.

When last month's activity was interrupted by my 140W brick amplifier catching fire, I was anxious to see if my repairs and homebrew RFC would still allow me to play on the moon. With July's best-positioned moonrises being too close to the sun (which was also rising at the same time), I was only able to spend a short time over two days before the moon travelled too far to the south and into my neighbour's trees.






Luckily I was rewarded with what seemed like very good lunar conditions, enabling me to easily work six different stations ... three of them being all-time new ones and boosting my EME initials total to 112.

I2FAK Franco / 16x19 el array
RK3FG Anatoly / 4x15 el array
G4SWX John / 4x16 el array
F4DJK Paul / 4x11 el array / #110
F5AQX Andre / 4x11 el array / #111
DL9DBJ Hartmut / 4x10 el array / #112


In addition, DL1VPL told me that he was able to copy me with his single 12el Yagi during the QSO with I2FAK! Needless to say, a contact between two single Yagi stations would be truly remarkable. I've only been able to copy a single Yagi station once over the years.

F4DJK's 4x11 el array

F5AQX's 4x11 el array

DJ9DBJ's 4x10 el array

I was gratified to see that letting the smoke out of my little amplifier last month apparently caused no permanent damage and the repair seems to be holding up ... but I'll leave the bottom off for now just in case it gets any more crazy ideas.

Wednesday, 26 July 2017

Hunting For NDBs In CLE 221

YBV - 370kHz  (VE3GOP)



This coming weekend will see another CLE challenge. This time the hunting grounds will be:  370.0 - 384.9 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 nice challenge in this one is to hear the Berens River (Manitoba)  NDB, 'YBV', on 370 kHz. 'YBV' is a 25-watter and is well heard, having been logged from coast-to-coast as well as in Europe. Look for 'YBV's CW identifier, repeated every 10.4 seconds, on 370.373 kHz with your receiver in the CW mode.

YBV's 25W TX Rack (VE3GOP)
Summertime CLEs can often be challenging, not because of poor propagation but more likely, summer lightning storms ... hopefully it will be quiet for your location.

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' in Fargo 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 usual 'heads-up':

Hi all,

Please join us in our 221st coordinated Listening Event which starts
this Friday. All are very welcome. 

CLEs are not contests - if you enjoy taking part you will be a winner!
54 of us sent logs for CLE204 back in February 2016 when we
listened on these same frequencies.
It will certainly be tougher for most of us at this time of year.

Days: Friday 28 July - Monday 31 July
Times: Start and end at midday, your LOCAL TIME
Range: 370 - 384.9 kHz

Just log all the NDBs that you can identify with their nominal (listed)
frequencies in the range (it includes 370 kHz, but not 385 kHz)
plus any UNIDs that you come across there.

Please send your CLE log to the List in a plain text email if possible
(not in an attachment) with 'CLE221' at the start of its title.
Show on each log line:

# The date (e.g. 2017-07-29, etc., or just 29) and UTC.
(the date changes at 00:00 UTC)
# kHz (the nominal published frequency, if known)
# The Call Ident.

Show those main items FIRST - other optional details such as Location
and Distance go LATER in the same line.
If you send interim logs, please also send a 'Final' (complete) log.

As always, tell us your own location and brief details of the equipment
that you were using during the weekend.

I'll send the usual 'Any More Logs?' email at about 17:00 UTC on
Tuesday - you can check from it that your log has been found OK.
All logs must arrive on the list by 08:00 UTC on Wednesday 2nd
August at the very latest.
Joachim has again offered to make the combined results which he
hopes to complete on that day.

To help your listening, seeklists and maps for your part of the World
are available via the CLE page http://www.ndblist.info/cle.htm

Good listening - enjoy the CLE
Brian
----------------------------------------------------------
From: Brian Keyte G3SIA ndbcle'at'gmail.com
Location: Surrey, SE England (CLE coordinator)
----------------------------------------------------------

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. If you are a member of the ndblist Group, results will also be e-mailed and posted there.

The very active Yahoo ndblist 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.

If you are contemplating getting started on 630m, listening for NDBs  is an excellent way to test out your receive capabilities as there are several NDBs located near this part of the spectrum.

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

'First-time' logs are always VERY welcome!

Reports may be sent to the ndblist or e-mailed to either myself or CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above.

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.

Good hunting!

Friday, 21 July 2017

Canada Post / QSLs / Magicband Transformations



Several weeks ago I mused about my interest in earth-mode VLF experiments, following the inspirational exploits of G3XBM in his earth-mode work a few years ago.





His low powered system utilizing a 5W audio IC and simple circuitry produced surprisingly interesting results over several kilometers.

With possible future experimenting in mind, I found a nice low-powered IC audio amplifier kit from China on e-Bay, capable of producing about 18W at 12V ... more with higher voltage and proper heat-sinking.



Whenever buying from China, I look for a dealer with the highest feedback rating and always compare their complaints versus the number of orders shipped. There always seems to be a few that are 99.9 - 100%, which, for me, has always assured that they are probably not selling junk. Anything lower than 98% can often be a red flag.

The kit was just $1.50 and with free-shipping, what's to lose?

A few weeks after I had placed my order, the nightly TV news had a spot regarding the problem that these "free shipping" packets were creating for Canada Post and their customers. It seems that in the past few months, as more and more "free" shipments were arriving from the far east, Canada Post had not been able to keep up with the processing. The news spot showed row upon row of shipping containers parked at the back of Vancouver International's (YVR) postal processing plant, with all of them filled with thousands of small "free" packets waiting to be processed!

It seems that each packet needs to be scanned by the border security folks (CBSA) for illegal material before it can be processed by Canada Post and the back-up was building at a tremendous rate. There appears to be little if any profit for Canada Post with these smaller untracked packages and they are given the lowest priority-rating possible.


In order to speed up the process, both CBSA and Canada Post facilities would need to expand their operational capabilities at the airport and I suspect there is no serious will to do this until pressured politically by angry customers.

All parcels from China that are mailed to Canada stop at Vancouver's YVR before going further. The mammoth recent increase in online "free-shipping", in spite of the normally estimated 3-4 week delivery time, has proven too attractive for customers and our domestic system has failed to meet the new load demands.

With this new information in mind, my e-Bay purchase would prove to be an interesting test of the system and of the TV news spot's accuracy. Normally, I would have expected my tiny parcel to arrive in about 30 days, but mine would be one that eventually ended up in the airport parking lot.

The kit finally arrived this week, with a delivery time of 89 days! Many online sellers will offer an inexpensive option to pay for faster shipping, something that will still take a couple of weeks but much better than three months. If you are given this inexpensive shipping option I would highly recommend that you choose it, and if not, ask for an alternative to "free shipping". Unless something changes soon, delays will continue to increase.

I also wonder, and perhaps you can comment below, are U.S. customers seeing the same long delays as we here in Canada are experiencing when the "free shipping" option is chosen?

#########################


QSLs in my mailbox always excite me ... especially like yesterday's, arriving in a thin light-brown envelope decorated with colorful stamps.





I'm 100% certain this is because of receiving similar-appearing envelopes containing QSL cards during my formative years from age eleven onward and how much enjoyment the cards from shortwave stations all over the world brought me at this young age. For me, there is no replacement for a paper QSL, but sadly, this long-standing tradition is slowly slipping away due to the high cost of mailing even a normal-size envelope.

Earlier this summer I had a nice run of JA's on 6m Es but this time, instead of CW, they were on JT65A. Yesterday's card was for one of the digital contacts.


Signals were weak, at -23 db ... far too weak to be heard on CW but easily readable during the 60 second deep-listen period mandated by the JT65A mode. With so many stations now listening higher in the band for JT-mode signals, there has been very little activity on CW and now, with the introduction of yet another new digital mode, FT8, even the digital activity is split into sections, with neither mode being compatible.

I have held off installing the newer WSJT-X version containing the FT8 fifteen-second transmission mode until all of the bugs are ironed out ... the software will likely be tweaked a few more times yet before it reaches the polished final version we see for JT65 and others. 

FT8 has been designed for weaker 6m Es openings that are often too short in duration for the longer time periods needed by JT65's sixty-second sequences. FT8 contacts can be completed quickly, before short-lived signals can drop out, but the shorter sequences come at the cost of reduced sensitivity ... probably a worthwhile tradeoff.

Conventional mode activity on 6m has suffered tremendously with the introduction of these new modes and it seems that if you want to work weak signal DX (and not all do), sadly it may be digital or nothing at all if the trends continue.

If all of the DX moves from CW to digital, for me, much of the magic will disappear as well. Letting the computer do all of the thinking is not nearly as satisfying or enjoyable as using my brain and CW skills to put a new rare one in the log. Six meters continues to evolve and I'm not overly excited by the direction it seems to be going.

Saturday, 15 July 2017

WWV's New Antenna On 25MHz - QSA?

New Turnstile Antenna / WWV - 25MHz


Last week's ARRL announcement regarding WWV's new circular polarized Turnstile antenna tests on their 25MHz transmitter quickly garnered my interest.




Their 25MHz signal used to be heard world-wide on F2 until it was dropped in 1977, but somewhat surprisingly, was resurrected in 2014.

I recall hearing its 2nd harmonic on sporadic-E very routinely on 50.000MHz when I first became active on 6m back in the late 60's. Back then it was also not uncommon to hear the 3rd and 4th harmonics of ship CW stations operating on 12 and 16MHz, at the very low end of 6m and just below the band edge on 49MHz.

6m Prop Indicator From The 70's!
They were often heard calling or working maritime land stations in Hawaii or Japan and the reception of these signals meant that the band was open out to the Pacific somewhere ... but of course there was no way of knowing just how far out they were and there were never any amateur signals to be heard.

Having not listened for WWV's 25MHz signal for several decades, I set up yesterday to see if it could be heard here in mid-summer. Using my Perseus SDR and my LF/MF inverted-L, self-resonant in the middle of the broadcast-band (gosh knows what the pattern looks like up on 25MHz!), I started monitoring just after lunch. I could detect their carrier which was very weak but steady, probably arriving on ionospheric scatter via the e-layer.

A few hours later I re-checked after hearing a few Colorado signals on 6m Es and sure enough, there they were with a fairly robust signal. It too, was no doubt arriving via sporadic-E as it was again today during another widespread Es opening from the PNW to as far south as Puerto Rico.

Here is a recording of the 25MHz signal made this morning with my Perseus SDR along with a comparison recording of their 20MHz signal, made about 30 seconds later.


There is not a lot of difference between the two and both run similar powers ... 2.5kW on 20MHz and 2kW on 25MHz. The 20MHz system uses a half-wave vertical on a 7.5m tower while the 25MHz outlet uses the crossed-dipole circular polarized Turnstile shown at the top of the blog.

Reception reports of their 25MHz signal are being sought and can be e-mailed to WWV at this address.

Tuesday, 11 July 2017

RFI - More Vigilance Coming?


A posting yesterday in the Yahoo MW DXer's Group pointed to a new article at RadioWorld.com, re the new urgency within the broadcast field to address the growing noise floor.


The article "Noise Inquiry Spurs Recommendations" discusses the fallout from last year's FCC Technical Advisory Council's (TAC) Inquiry ET-16-191, seeking public comments on the rapid increase in "man-made RF noise issues".

As radio amateurs have known for decades already, there is a huge problem when it comes to spectrum noise levels. They were even complaining about this way back in 1932's Short Wave Craft ... "The reasons for this extraordinary amount of noise which we have to contend with at the present time are manifold." If only they knew how quiet it really was!

Now that noise is beginning to have severe affects on profit margins when it comes to AM, FM, TV and Wi-Fi connected devices, it seems that there may now be a larger appetite for some resolution.

"Other industries using RF wireless technologies report growing noise trouble as well. A recent IEEE Spectrum article was subtitled “Electronic Noise Is Drowning Out the Internet of Things.” Designers of IoT devices are not getting the range they expect due to unexpectedly high background noise, it reported."

Comments to the enquiry pointed out the usual offenders, all well-known to hams, such as noisy powerlines, switching power supplies, noisy motors etc and emphasized the fact that none of these offenders should cause interference if properly designed.

The TAC Working Group recommended some steps that it thought the FCC should take with the key one being an FCC Notice of Proposed Rulemaking to "resolve unanswered questions and take corrective action".

According to a recent meeting between The Association of Federal Communications Consulting Engineers and FCC officials, it was pointed out that:
  • there had been no official RF noise studies done in over 40 years. 
  • some manufacturers are deliberately cheating to skirt emission requirements.
  • those in charge of enforcement (FCC) need to be more diligent. 
Much can be said for the same conditions here in Canada where our ISED has failed to properly safeguard spectrum noise pollution.
Other somewhat "telling" recommendations were also put forward and can be viewed in the Radioworld article here.

If you're one of the hundreds (thousands?) struggling with a new mystery noise source, perhaps you can identify the noise signature from one of these two sites:

http://www.arrl.org/sounds-of-rfi

http://www.rfiservices.com/sound.htm

It is reported that the new FCC Chairman seemed receptive to the concerns presented but so far there has been no official action. Hopefully he will soon tackle this with the same gusto shown for chasing down illegal broadcasters. With recent FCC cutbacks and proposed budget slashing from Washington, one wonders if this problem will be given the attention that it needs before it is truly too late to reverse.

Thursday, 6 July 2017

June Moonbounce Heats Up

Last week's favorable northern declination of the Moon allowed me two days of activity, once my moonrises had lagged far enough behind the early sunrises.

With fixed elevation and not having the ability to track the moon as it rises, I can only operate for about two hours before the moon gets too high. The highest elevation that I am able to work seems to stop near 20 degrees.

With QSLs from earlier sessions still arriving, I noted last week's activity was down somewhat from the previous month ... summertime activities usually take priority over EME for most moonbouncers.








During my two mornings of moon time I worked five stations which included two new DXCC countries, bringing my 2m DXCC total to 30. Stations worked at the end of June were:

                    ON4AOI #106 (new country)
                    OH3AWW #107 (new country)
                    I2RV second QSO
                    DK9WI #108
                    IK6CAK #109

ON4AOI - 4 X 14V / 14H array
OH3AWW - 4 X 9el array
IK6CAK - 9H / 6V 8el LFA array more
Interestingly, all of the stations answered one of my CQs, with one CQ having three different callers at one time ... pretty exciting and something that I don't think has occurred here before! But that wasn't the only excitement of the week.

In the middle of a CQ following my QSO with IK6CAK, I heard a faint 'crack' sound from my amplifier, an aging RF Concepts 2-135, followed by the unmistakable whiff of a 'too hot' electronic component ... every ham is familiar with this always unwelcome odor and it usually spells trouble.



During the next CQ, I saw a trace of smoke coming out of the amp's back corner vent holes, at which point I reluctantly shut things down in the middle of some superb EME conditions.

After tearing into the amplifier, the only thing that looked stressed was a small inductor (L14 below), part of the output filtering / impedance matching circuitry.


It looked a little darker and somewhat stressed and as I gave it a poke with a screwdriver blade, it immediately disintegrated into what you see below.


It was a small (1.2uH) encapsulated RFC which appeared to be wire-wound on a core material that I did not recognize and likely suitable for VHF. I surmised that after several years of 100% duty-cycle JT65 operation, the inductor had been over-stressed to the point of failure ... helping to filter all of those nasty high frequency harmonics can't be an easy job!

After a search of my RFC collection (see below), salvaged mostly from junked TVs, monitors, VCRs and other electronic cast-offs temporarily 'borrowed' for stripping from our local recycle center here on Mayne Island, I settled on a 1.2uH choke that I hoped would be a suitable replacement. It had just a few turns so I assumed it was wound on some sort of powdered iron or ferrite form. Whether or not it would behave at 144MHz was another question.


After reassembling the amplifier the following morning, I keyed up at full power during the EME window but halfway through my initial CQ I saw smoke and then flames coming from the inside of the case ... yikes! Shutting down immediately killed the fire and after tearing into the amp yet again, I saw that this time, the output coupling capacitor (C51) had completely destroyed itself.


The new inductor (L14) appeared a little heated, but I assumed it was only smoke-damaged from the nearby flameout of the capacitor. I replaced C51, an 820pF silver mica, with a higher rated one of the same value and, once again, gave it the smoke test ... literally.

After a few seconds, a whiff of smoke appeared from the back of the amp, followed by the SWR trip-out kicking in and shutting the amp down.

This time it appeared that the inductor was definitely complicit in the destruction of the capacitor as it was charred and black. I surmised that whatever core material the little inductor was wound upon, definitely was not suitable at 144MHz and had caused the little inductor to either change value or to saturate ... whatever it was doing had created a highly reactive condition in the output circuit, changing the output load impedance and sending the SWR sky-high.

This time I replaced the inductor with a homebrew one, wound on a plain phenolic former, hoping to avoid any ferro-magnetic / frequency compatibility issues. After reassembling the amplifier, it seemed to be happy once again and ran nicely for several 60 second JT65B sequences at full power with no smoke or component heating!

By this time I had run out of favorable EME windows as my moonrises were now too far to the south to keep me away from the neighbour's trees ... I'll just have to be patient and wait until the end of the month for the next definitive test. Let's hope there's no more smoke.