Sunday 30 April 2017

The May 'Bug Roundup'

Vibroplex "Blue Racer"

Ever since earning my ticket as a teenager back in '63, almost all of my on-air activity has been focused on CW ... I've always loved it.

For my first year on-the-air, I used a nice brass hand key purchased locally for just a few dollars but once I had mastered that and I was just unable to send any faster with it, I purchased a Vibroplex 'Original', for, if memory serves me correct, around $40. I used it exclusively until building a homebrew memory keyer in the mid-70's and the Vibroplex saw little service for several years.

The Vibroplex 'Original'
Back when I first got on the air there were very few amateurs using keyers. Most used bugs and the remainder used the brass hand pumps. It was very easy to tune across the band and identify any of the locals just by the sound of their fist ... like snowflakes, no two were the same. The same went for most stations that were very active. DX or otherwise, one could usually tell who it was long before the callsigns were heard.
So much has changed now with the almost exclusive use of electronic keyers and everyone pretty much sounds the same, which is rather a pity I think.

Once my interest in building vintage-style vacuum-tube transmitters evolved, my interest in bugs was reactivated and over the years I have purchased a few more.

I'll do anything I can to promote and encourage the use of CW and especially hand-generated CW. That's why I was excited to read a recent e-mail from W6SFM, posted to several lists that I read, announcing the Bug Roundup!
The Samuel F. Morse Amateur Radio Club, a Sacramento, California based CW enthusiast club wanted a special time to bring bug operators together on the air. In the same spirit as ARRL's Straight Key Night, participants are encouraged to make simple, conversational, “chewing-the-fat”, "Rag Chew" QSOs using their bug type key. This is an opportunity to exercise, share and exhibit your personalized fist. This is NOT a contest. Simply Call "CQ BR" so folks know you are a Bug Roundup Participant. Grab that bug, clean those contacts, and let’er fly! Let’s hear that “Banana Boat / Lake Erie Swing" or that commercial KPH/WCC quality fist.

Reserve the day! Saturday May 20th - Sunday May 21st, 2017
7:00 AM to 7:00 AM Pacific Time (LOCAL)
1400 UTC through 1400 UTC

For more information, to register your station and key for participation, and to help assist in spotting, potentially increasing QSOs, an On-line chat window link can be found near the bottom of Bug Roundup home page located at We hope to hear you all on the air!

It looks like a fun event and might make another good reason to fire-up your old boatanchors on CW once again. It looks like you can keep track of activity and possibly set up skeds via their chat-window page during the BR.

In any event, my biggest decision will be to choose which bug to use as I have five at last count. I think I'll be brave and try the Blue Racer but will probably have to dampen it down a bit as they are really quite fast.

Thursday 27 April 2017

LF / MF Antenna Planning

courtesy: Chuck Roblin

For U.S. amateurs, the 2200 and 630m bands will soon be a reality and I have no doubt that there will be an accompanying surge in interest among large numbers of homebrewers and low band diehards.

It should be an exciting time as new stations gradually start to populate the band from coast to coast.

High on the 'to do' list will be the planning and building (or modifying) of a suitable antenna system for the band(s) of choice. For most, this will be new territory, but the reality is that there has been a long tradition of operation in the LF and MF bands in the U.S. for many years ... all under the Part 15 'Lowfer' and 'Medfer' service.

Although activity in this category has fallen off over the years due to the availability of the much less-restrictive Part 5 experimental licences, there is still a great legacy of literature and information left behind that is every bit as useful today as it was back in the golden years of Lowfer operations.

Here is one such document from Stephen McGreevy's Natural ELF-VLF Radio website that many newcomers to these bands may find very helpful as it covers a wide variety of LF antenna-related basics in a down-to-earth manner.

An even more detailed treatise on virtually all aspects of LF and MF antenna topics is that found on Rik, ON7YD's website. His antenna pages can be found here. Although originally developed for the 2200m band, the principles are equally applicable to 630m as well.

Hopefully both of these sources will help you decide how to get a working antenna system up and running on the new bands. And as always, much help is available via the Internet on the Lowfer Reflector, the RSGB LF reflector or on the 600MRG Reflector.

Monday 24 April 2017

CLE 218 Results

This past weekend's CLE event was, as is so often the case, perfectly timed with the arrival of poor propagation in most parts of the world. This time around, it was particularly bad.

The 'Co-ordinated Listening Event' might more aptly be called the 'Cursed Listening Event' as once again the same large coronal hole (shown above) that has been present for several solar rotations seems to be more disruptive than ever. The subsequent higher than normal solar wind speeds causing widespread auroral conditions and elevated K indices have pretty much made a mess of MF and HF radio for the past several days.


NDB-band recordings made with the Perseus SDR for the three-night event turned up very little activity other than a few strange hot-spots. Both 'OIN' in Kansas and 'CC' in California were strong on all three nights! Nothing from eastern Canada was heard and one of Alaska's strongest signals, 'ELF', was barely detected. Only the following few stations were logged:

23 08:00 341.0    ELF  Cold Bay, ALS
22 06:00 338.0    ZU   Whitecourt, AB, CAN
22 06:00 343.0    YZH  Slave Lake, AB, CAN
22 04:00 344.0    YC   Calgary, AB, CAN
22 12:00 338.0    RYN  Tucson, AZ, USA
22 04:00 344.0    XX   Abbotsford, BC, CAN
22 12:00 335.0    CC   Concord, CA, USA
22 10:00 344.0    FCH  Fresno, CA, USA
22 08:00 341.0    OIN  Oberlin, KS, USA
22 04:00 344.0    BKU  Baker, MT, USA
24 08:00 335.0    BK   Brookings, SD, USA
22 04:00 347.0    PA   Prince Albert, SK, CAN
22 08:00 338.0    K    Port Angeles, WA, USA
22 04:00 348.0    MNC  Shelton, WA, USA
22 05:00 341.0    DB   Burwash, YT, CAN

I suspect the this same coronal hole will be with us for several more rotations ... perhaps it's time fool Ol' Sol and stagger our CLE's 28-day cycle so it doesn't continue go sync-up with poor band conditions but somehow I think that Murphy might not be so easily duped!

Wednesday 19 April 2017

Hunting For NDBs In CLE218

'XX-344' - Abbotsford, BC

This coming weekend will see another CLE challenge. This time the hunting grounds will be:  335.0 - 349.9 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 Abbotsford  NDB, 'XX', on 344 kHz. 'XX' is located about 40 miles east of  Vancouver International (YVR) and a few miles SW of the Abbotsford Airport, YVR's alternate for those foggy winter nights. 'XX' is a 500-watter and is well heard, having been logged from the east coast to Hawaii and is a good propagation indicator for listeners in eastern North America. Look for 'XX' on 344.404 kHz with your receiver in the CW mode.

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

For example, 'AA' in Fargo, MN, 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':

Hello all

Our 218th Co-ordinated Listening Event is less than a week away.
Just a normal CLE using a busy range of frequencies which usually attracts a lot of interest.
First-timers' CLE logs will also be very welcome, as always.

Days: Friday 21 April - Monday 24 April
Times: Start and end at midday, your LOCAL time
Range: 335.0 - 349.9 kHz

Please join us wherever you are - just log the NDBs you can identify
having their nominal frequencies in the range (it includes 335 kHz
but not 350 kHz) and any UNIDs that you come across there too.

We last concentrated on these frequencies for CLE200 in Nov. 2015
when 55 of us joined in.

From: Brian Keyte G3SIA ndbcle'at'
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). 

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!

Saturday 15 April 2017

The JK BevFlex-4 Antenna

This past week, comments regarding an interesting new low-noise directionally-switched receive antenna popped-up on both the Topband reflector and the IRCA (BCB DXers) reflector.

The new JK BevFlex-4 is reported to work very well without requiring a lot of real estate for deployment. The antenna was designed by Geoff Mendenhall, W8GNM, and Ned Mountain, WC4X.

There are several things that make this package a little different. The antenna can be configured in four basic forms: CLASSIC BEVERAGE, BEVERAGE ON GROUND (BOG) / BEVERAGE IN SOD (BIS), INVERTED EWE, or as a FLAG. What is quite different however is its flexible feedpoint allowing the antenna to be fed at any point along its length when used in the BOG or BEVERAGE configuration. The antenna is completely passive and requires no preamplification although, in some configurations, it is suggested for use above 7MHz.

Full details can be found at the JK Antennas website, as well as the manual and a FAQ page.

The FAQ sheet indicates that it will perform from LW through to 10m but the most dramatic improvement in reception from users has been noted on the lower bands. It sounds like it might make an interesting antenna for NDB DXing as well.

In the BOG form, the antenna can lay right on the ground or be buried (BIS) just below the surface using RG-6 for the actual antenna element. Other configurations allow much smaller, stealth-sized wire to be employed.

An interesting YouTube video of the antenna in action as well as an in-depth description may be viewed here:

Here is one comment from an east coast topbander:

I also bought one this year....deployed it as an EWE, as that’s all the room
I have, small lot in a order to work them you need to
hear them, and once I put that up, I could hear !!! first put up as EU/VK-ZL
and worked several in the DX contest, but when the african dxpedetions were on, moved it to due east/west., and worked all of them, S01, etc.....front to back is remarkable on 160, it works ok on 80, (mine was 10ft high and 38 ft long) but really rocks on 160 !!!!, and really cuts down the line noise/static I normally hear on my transmit Inv L.

Perhaps this may be your answer for a small effective receive antenna for LW and above but even if not, their website description makes for interesting reading.

Sunday 9 April 2017

April Moonbounce

My Moonrise

This week I had several days of unobstructed ocean moonrises as the Moon peaked on its monthly northern declination track. Thanks to the recent topping of my next door neighbour's large Douglas Fir, and removal of low-hanging branches, I am now able to track moonrises a little further to the south than before and can add two more EME days that were previously blocked by the large tree. All operations are on 2m JT65B mode, using a 9el Yagi and 140W output.

When I started (April 1) conditions looked as if they should be good, with lunar perigee (Moon's closest approach), degradation (background skynoise) and declination all looking favorable, but I was in for a surprise.

The rising yellow plot indicates the Earth-Moon distance growing further apart (increasing path losses) while the red plot indicates fluctuation in daily skynoise (temperature) near the moon. The blue plot indicates declination track from north to south ... for me, the higher the better.

Listening on the first two days (April 1-2) produced a few weak signals from the larger stations only and nothing from the more common '4-Yagi' stations and, no QSO's ... something was amiss. I can only attribute this to some real-time solar flaring during this two-day period and the resultant short term geomagnetic agitation the flares produced ... but almost as if the 'switch' had been flipped, the third day proved to be much different.

On day three, five new 'initials' were worked including one new state (New York) and two new DXCC countries! Truly surprising was that two of the stations worked were using just two Yagis, with both stations answering one of my 'CQ's.

Good conditions continued for the next few days, bringing my initials count from #87 to # 95, with the following stations all going into the log, turning a disappointing start into one of the best lunar sessions I have encountered:

HA6NQ, LZ2FO (two 13 el Yagis), EB5EEO, K2ZJ (two 14 el Yagis), DK5YA, S52LM, F8DO, PA5Y, SV6KRW, UA3PTW, OK1UGA.

April's operation brought  my 2m DXCC count to 29 and states worked total to 27.

SV6KRW's 4 x 8el Array

EB5EEO's 4 x 32el Cross-polarized Array (16V / 16H)

DK5YA's 4 x 22 Cross-polarized Array (11V / 11H)
As mentioned in my last EME report, I keep wondering when I will run out of stations that are able to hear my small station, forcing me to build a bigger amplifier for a few more precious db, but with the ability to occasionally work some 2-Yagi stations, the list of potential targets has increased dramatically ... perhaps the large Fir tree was a bigger attenuator than I had thought.

Wednesday 5 April 2017

The Artwork Of DK1IS

Recent discussion on the RSGB LF Group reflector about high-powered LF / MF amplifiers brought an interesting response from Tom, DK1IS, and his unique solution.

It's no secret that a Class D / E amplifier using switching MOSFETs is a popular and reasonably inexpensive method of generating some serious RF on the LF and MF bands. Equally well-known is their propensity to gobble-up FETs should the amplifiers encounter much reactance in their output load. Most builders include some form of protection for sudden over-current or unwanted SWR excursions which will shut down the amplifier before any FETs can self-destruct. Those that don't usually end up replacing FETs.

I would venture to guess that over 90% of the transmitters now being employed on LF or MF are using switching MOSFETs in a Class D / E design but there are some amateurs using vacuum tubes to do their heavy-lifting ... and with good results.

DK1IS's beautiful homebrew amplifier is shown below. Tom provided the following description:

Hi Wolf and group,

nice to hear that someone else is thinking about this approach! I´m
content with my homemade tube PA for LF and MF which has provided
reliable service since nearly 4 years now. Only some thoughts about this
concept - I hope not to bore all those hams who are happy with their
semiconductor PAs:

Years ago I had a MOSFET PA for LF, Class B push-pull with 250 W RF. It
worked well at constant conditions, but when I had to retune the antenna
due to larger QSY or made antenna experiments there always was the
danger of blowing up these nervous semiconductors. After 4 or 5 times
changing the MOSFETS I decided to build a new PA - with tubes! Looking a
little bit anachronistic this PA is absolutely good-natured. Designed for
broadband service on LF and MF it makes no problems when changing the
antenna coarse tuning from one band to the other even when the fine
tuning isn't done yet. With my former MOSFET-PA this would have been

I wanted to have a linear PA - this usually means class B. You have to
decide between narrow band and broad band (like an audio-amp) design.
For narrow band you can use a single-ended PA but you have to add a
resonance circuit. For broad band you should use a push-pull PA and have
to build a suitable output transformer. I opted for broad band design
because it is usable for LF and MF without changes at the PA. With this
design and sin-driving I reach a total harmonic distortion of about 5 %
at 700 W RF on a pure resistive dummy load. With the usual narrow,
narrow band antennas on LF and MF you don´t need additional filters!

Concerning the tubes: If you take the common TX tubes with plate
voltages of several kV all output circuits have rather high impedances,
that means large coils for the resonance circuits resp. large
transformer windings and very high voltages - potentially a construction
problem. This led me to the choice of 2x 4x PL519 in push-pull, a rugged
colour TV line output tube with low plate voltage and high plate
current. In this way I came down to a plate-to-plate resistance of about
1 kOhm at 600 V DC plate voltage, where you easily can build a ferrite
broad band output transformer down to 50 Ohms. A disadvantage of this
concept is that you have to give individual bias to each tube, that
means for the first start-up you have to align 8 potentiometers
carefully to nearly equal cathode currents for all the tubes. But
according to my experience this alignment remains stable over a long
time. I have inserted 1-Ohm-resistors in each cathode line and have
brought the voltage drops to 8 cinch connectors, where I can monitor the
DC component (with external filtering) as well as the real time current.
With 4 tubes in parallel per branch of course you have to take care for
self oscillations. The extensive use of bypass capacitors, ferrite beads
and parasitic chokes in the plate lines is mandatory as well as good
grounding concepts are. The tubes don´t pull control grid current (this
would even be true in class C!) but you need 3 or 4 W RF input power due
to all the ohmic loads at the tube´s control grids caused by the
individual bias paths. On the other hand this certainly helps to avoid
oscillations. You can see some pictures of this PA at

By the way: why not to try these tubes at class D? With DC plate
voltages of perhaps 1200 V you should get a nice QRO-PA ...

Wolf, you are right: building such a PA from scratch is a time consuming
enterprise. I didn´t count the working hours but according to my lab log
the whole project took about 9 months - an adequate time for a new baby!
It was a great experience anyway.

Good luck and 73,
Tom, DK1IS

2x 4x PL519 Push-Pull  

TX, power supply, RX, exciter
As 'day one' for U.S. amateurs gaining their new LF / MF bands draws closer, many are seriously thinking about building or modifying rigs to get on the air. I'm sure the use of switching MOSFET amplifiers will still reign supreme when it comes to decision-making time but with some feeling more comfortable with tube technology, especially when used for power amplifiers, I suspect we will see some interesting tube transmitters being employed as well. I'm sure that some will even seek to modify older tube rigs, knowing that a pair of 6146's can muster enough power to have plenty of fun on the new band as well.

DK1IS has provided an inspiring example of what can be done using vacuum tubes ... they certainly should not be discounted as a viable method of generating your hard-earned LF / MF ERP.