Sunday, 21 May 2017

MFJ-1026 Noise Canceller Tests At VA7MM


Mark, VA7MM, has been testing out his newly-acquired MFJ-1026 Noise Canceller and has provided several videos of the noise canceller in action.

Like so many other hams, Mark's suburban location has seen a gradually rising noise floor and the noise heard in this video is from an off-site location within his local neighbourhood, located about 400m away.

The noise canceller requires a separate 'noise antenna' in order to cancel any noise on the main receiving antenna and for all of the tests shown below, Mark's noise antenna was a Cushcraft R-7 vertical while using an Icom IC-7600 transceiver for listening.

Test 1 shows the noise canceller being used while listening to a broadcast station on 6.0 MHz:

Test 2 shows the canceller's effect on raw noise while viewing in Spectran:

Test 3 shows the canceller's effect on a 40m CW signal:

Test 4 shows the effect of just the IC-7600's noise blanker on the offending noise:

Mark's comments:

Living in the noise cloud one must resort to special measures to use affected portions of spectrum. I recently purchased an MFJ-1026 noise canceller and have been testing the unit and have attached videos demonstrating the unit’s performance. You will see examples of raw noise, SW broadcast and 40 m CW signals with the unit being switched in and out. Also for comparison is the noise blanker in the IC-7600 failing to eliminate the same noise. 
- the unit is able to eliminate noise in most instances when adjusted properly
- the noise sense antenna is critical and several different switchable noise sense antennas may be required for good performance
- setting up on AM mode with Spectran helps with fine adjustment
- it outperforms the radio’s noise blanker in all cases tested

With proper tuning and set up, it looks like the MFJ-1026 can make a worthwhile improvement in unwanted noise reduction.  Mark will also be testing and comparing a Timewave ANC-4 Noise Canceller with the MFJ and any videos received will be published here.

Monday, 15 May 2017

The G3XBM Experimental Blogs

G3XBM's 5W Earth-Mode Tx (courtesy: G3XBM)

My interest of late has been piqued by the ongoing VLF experimental work by several European amateurs.

Recalling that Roger, G3XBM, did some VLF experimenting a few years ago, I have been reviewing some of the excellent hands-on information gathered and published in his ham radio blog and to some of his other VLF pages.

It's not the first time that I have found project-inspiring reading within Roger's blogs. They really are a treasure-trove of useful information, construction notes and accumulated test data gathered from his methodical approach to so many interesting topics ... experimental amateur radio at its very best.

A few years ago I was immediately hooked by his experimental lightwave work, both line-of-sight and clear-air / cloudbounce scatter ... so much so that I also became involved in some lightwave work with other locals who were also inspired by Roger's information, culminating in our own West Coast Lightwave Adventure.

Roger's VLF experiments are also proving hard to resist, especially those of the earth-mode type and I may find myself falling victim to his detailed Sub 9kHz Amateur Radio pages and the Earth Mode pages in particular.

It seems that most amateur VLF work is being done in the vicinity of 8kHz since this part of the frequency spectrum is unassigned. I gather that one can conduct earth-mode tests in any portion of the VLF spectrum since no signal is being 'radiated' as is typically done via antennas. Further investigation remains to see if I need a 'developmental licence' to conduct some radiated (non-earth-mode) experiments in the 8kHz range as well.

Getting a VLF signal from here on Mayne Island across Georgia Strait via earth-mode or via conventional methods would make an interesting challenge and would certainly result in some new homebrewing opportunities.


Here on the island, I often hear audio associated with the container terminal and ship-loading operations near Tsawwassen, directly across the strait from here. I feel that this may be aided somewhat by the solid sandstone of the island being directly connected to the other side, so perhaps an earth-mode system utilizing the ocean as one-leg of a buried loop might be an interesting experiment to tackle ... or groundwave transmissions across the ocean via an antenna, to the other side, providing I could find someone to listen.

I see just two Canadian amateurs experimenting on VLF ... VO1NA (Joe) and VA3VVV (John) near Toronto. Any VE3's in the area who are interested in VLF may wish to contact John and exchange notes. He has a Facebook page showing his VLF setup. Interestingly, Joe's 30W VLF signal on 8.270 kHz has just crossed the Atlantic! Joe is documenting his VLF experiments here.

All of G3XBM's VLF blogs can be downloaded for reading or for printing via this link. Similarly, his lightwave experiments can all be found here ... both links will yield several pages of material if you click on the 'Older Posts' link at the bottom of each page.

The best way to follow these is chronologically which requires going all the way to the end of the final 'OlderPost' link and follow along with Roger as he gradually develops, evaluates and improves the gear that he needs to make progress. This is fascinating reading.

But be suitably warned ... you may readily fall victim to his experimental work as well and suddenly find yourself with another exciting project!

Wednesday, 10 May 2017

May's 'Red Ryder' EME Ops

There still seems to be a number of 'big guns' showing up each month, that I have not heard or worked before as well as several 2-Yagi 'little pistols' that I am able to work under very good lunar path conditions. I suspect that having just 1-Yagi puts me in the $2.95 'Red Ryder' category!

With the QSL's from last month's surprisingly good EME conditions just starting to arrive, May's moonbounce operation continued to produce good results.

Whether this is because of better than normal lunar path conditions or just a result of my neighbour's tree-pruning, remains to be seen.

The few days of operating in early May were, as usual, planned to take advantage of the Moon's closest approach as well as the Moon's most northerly declinations. The latter condition puts moonrises directly out in front of the house and looking across Georgia Strait's many miles of saltwater. The extra theoretical 'sea-gain' appears to be a reality under these conditions and allows my 9el Yagi to garner another 6db on both transmit and receive paths, making it perform more like a '4-Yagi' array.

Eight stations were worked this time around, with six of them being new 'initials', bringing my EME total from 95 to 101. Several of these stations were speaker-audible, at CW levels.

          NTØV #96
          IK7EZN #97
          EA2AGZ #98
          F6HVK #99
          G4CDN #100
          DK5LA #101

IK7EZN's cross polarized 4 x 13 array    

EA2AGZ's 4 x 16 array

DK5LA's cross polarized 8 x 16 array ...very loud!

For now, any earlier thoughts of building a 4CX250 300 watt amplifier have been put on hold, while I continue to slowly work my way through what seems a never-ending list of workable stations.

Friday, 5 May 2017

LF / MF News From Monitor Sensors

A note from Roger, VK4YB of Monitor Sensors, reports some interesting news.

You might recall that his company manufactures a very versatile and well-engineered 630m transverter which was used at both ends of our two 630m JT9 contacts last year during the fall equinox propagation peak between North America and down-under.

Roger now reports that Monitor Sensors will be producing a new 2200m transverter, with all of the bells and whistles found on the 630m unit which has proven to be a real workhorse.

Monitor Sensors 2200m Transverter

The Monitor Sensors TVTR2 2200m Transverter enables any Amateur Radio Station, equipped with a conventional HF transceiver, immediate, all mode, access to the new 135.7-137.8 kHz, 2200m band.
The receiver design incorporates a 7pole Chebyshev filter, 3kHz wide roofing filter and a 5 pole Chebyshev filter in cascade before the double balanced, commutating mixer, fed by an ultra stable, temperature compensated, extremely low phase noise, MEMS local oscillator. The mixer is followed by a Chebychev band pass filter into an ultra linear, low noise, current feedback, IF amplifier. The receiver noise floor, in a 500Hz bandwidth, is -125 dBm and yet the onset of compression is not reached until +11dBm. A front end 20dB attenuator can be switched in for even higher signal handling. Overall receiver gain is set to +6dB, or -14dBm with attenuator in.

The transmitter input circuit incorporates a 0-14 dB switched step attenuator to prevent over driving. The same mixer and local oscillator are used on the transmit side. The PA uses 6 rugged lateral FETs in class AB push-pull to easily achieve the 50 watts rated output. Lateral FETs are inherently linear and thermally stable. The transmitter can be run at full power, indefinitely, into a dead short or open circuit without any danger of damaging the FETs. Transmit-receive switching is automatic with user selectable VOX delay. Alternatively the PTT line may be used.

The transverter employs extensive and accurate metering. Power input and output, SWR, Frequency, Attenuation in use, Temperature, Supply Voltage, Current and Resistance are displayed.
Transmission is inhibited if carrier frequencies outside the 135.7-137.8 kHz band are detected. A tuning screen may be selected which displays SWR in digital and graphical form for easy antenna adjustment. The menu system is self explanatory and users report no manual is needed, although one is supplied. A USB socket is provided for future code upgrades (free of charge) from the Monitor Sensors web site.

The transverter has been designed for the best possible protection against accidental mishaps. It will survive reverse polarity supply and the injection of 100 watts of HF into any of its ports whether in transmit or receive mode. If supply current exceeds 25 Amps, the supply is cut in 3 microseconds. This electronic breaker can be reset by simply switching off and on again. The transmitter will shut down in the unlikely event that the internal heat sink reaches 90°C. The cooling fan is under the proportional control of the microcomputer and begins operation above 35°C. Any unusual operation will cause the screen to turn red and an appropriate warning will be displayed.

TVTR2 Specifications

RF frequency range 135.7 to 137.8 kHz
IF frequency range 1805.7 to 1807.8 kHz (others available in the 160m band)
Transmission modes CW, SSB, WSPR, and all other data modes
Output Power 50 Watts Continuous, 100% duty cycle @13.8V supply
Input and Output Impedance 50 Ohms
Supply voltage 13.8 VDC @ 15 Amps nominal, 10-16 VDC operational
Rx noise floor -125 dBm (500 Hz bandwidth)
Rx 3dB compression point +15 dBm (Rx attenuator out)
Rx IF rejection better than 75dB
Rx conversion gain +6dB nominal
Roofing filter in-band ripple +/- 0.5dB
Tx 3rd order IMD -33 dB below PEP, typical at 50W output
Tx 5th order IMD -45dB below PEP, typical at 50W output
Tx harmonics and spurii All better than -50dB
Tx conversion gain +10dB nominal
Power input connector 2 * Anderson Power Poles (one Power cable supplied)
RF connectors 3 * SO239 (one PL259 to PL259 cable supplied)
PTT connectors 2 * RCA (one RCA to RCA cable supplied)
USB connector Micro B USB, (matching cable supplied)
Dimensions 12½ * 4¼ * 3 inches, 320 * 120 * 76 mm
Weight 3.4 lbs, 1.6 kg

In addition to the transverters, Monitor Sensors will also be manufacturing solid state amplifiers for both the 2200m and 630m bands with power levels at around the 450W output level. Like the transverters, these will be 'linear' devices as well. It is possible that a duo-band amplifier will also eventually be produced.

It will be interesting to see if any other new gear becomes commercially available from other manufacturers once the LF / MF ham bands are introduced in the U.S.A. , something that is expected to happen fairly soon.

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.

Thursday, 30 March 2017

LF and MF Now Very Close For U.S. Amateurs!

For U.S. amateurs anxiously awaiting implementation of the new 630m and 2200m bands, the wait seems to be almost over!

Good news came down late yesterday in the form of the FCC's "Report and Order" (ET Docket No. 15-99) which lays out the proposed rules and regulations that, barring any further changes, will likely become standard operating procedures once these two bands become finalized.

Highlights of the FCC's document are as follows:

1. Recognition that both Utilities (UTC) and amateurs can co-exist within these parts of the spectrum:

... co existence between PLC systems and amateur radio operations in these bands is possible, and the service rules we adopt in this Order will foster this co existence.

2. Amateurs operating within these bands must be no closer than 1 km from transmission lines that are actively carrying PLC (control) signals:

As proposed, we will permit amateur stations to operate in the 135.7-137.8 kHz and 472-479 kHz bands when separated by a specified distance from electric power transmission lines with PLC systems that use the same bands.   To support the operations of both the amateur service and PLC systems in these bands, we adopt a minimum horizontal separation distance of one kilometer between the transmission line and the amateur station when operating in these bands.

We find that a one kilometer separation distance reasonably ensures that PLC systems and amateur radio stations are unlikely to experience interference.  In addition, establishing a zone where amateur use is not authorized will simplify and streamline the process for determining whether an amateur station can transmit in these bands when in proximity to transmission lines upon which PLC systems operate.

3. Amateurs must "make notification" to local UTC authorities before commencing operation on either of these two bands:

We will require amateur operators to notify UTC of the location of their proposed station prior to commencing operations, to confirm that the station is not located within the one kilometer separation distance. 

The notification requirement will entail notifying UTC of the operator’s call sign and coordinates of the proposed station’s location for confirmation that the location is outside the one kilometer separation distance, or the relevant PLC system is not transmitting on the requested bands.  UTC, which maintains a database of PLC systems must respond to the notification within 30 days if it objects.  If UTC raises no objection, amateur radio operators may commence operations on the band identified in their notification.  The Wireless Telecommunications Bureau will issue a public notice providing the details for filing notifications with UTC.

A simple notification to UTC with a 30-day waiting period does not appear to be burdensome.  Amateur operations can commence as soon as that period expires.  ARRL claims that UTC should provide access to the PLC database to them or directly to amateurs to assist them in determining whether their notified operations are within the one-kilometer separation distance from transmission lines with PLC systems operating on these bands.  ARRL fails to make a persuasive case why it would be a better organization to make those determinations rather than UTC.  Further, since UTC has control of the PLC database which can be updated, we find no reason to mandate its release to another party especially considering the sensitive nature of information it contains.

4. Power limits will be expressed in EIRP as well as maximum PEP:

Amateur stations may operate in the 135.7-137.8 kHz band with a maximum radiated power of one watt EIRP ... that amateur stations operating in the 135.7-137.8 kHz band should be subject only to the general Part 97 limit of 1.5 kW peak envelope power (PEP).

We also adopt the power limits proposed in the WRC-12 NPRM for amateur stations operating in the 472-479 kHz band.   For such stations, the maximum radiated power will be five watts EIRP, except for stations located in the portion of Alaska that is within 800 kilometers of the Russian Federation, where the EIRP will be limited to one watt.  We also limit the transmitter power for amateur radio operations in the 472 479 kHz band to 500 watts PEP; provided, however, that the resulting radiated power does not exceed five watts EIRP.   In other words, it may be necessary to reduce transmitter power below 500 watts PEP to avoid exceeding the five watts EIRP limit.

5. Antenna height will be limited:

... we will require that the antennas used to transmit in these bands not exceed 60 meters in height above ground level (AGL), as ARRL proposed.

6. Regarding transmission modes, no bandwidths have been specified in order to encourage experimentation:

Consistent with our proposal in the WRC-12 NPRM,  and with the existing rules in Section 97.305 for the frequency bands below 30 MHz, we authorize amateur stations to transmit the following emission types throughout the new amateur bands: CW (international Morse code telegraphy), RTTY (narrow-band direct-printing telegraphy), data, phone, and image emissions.   These emission types provide amateur operators with maximum flexibility, and we find that additional restrictions would needlessly hinder experimentation.

7. Experimental stations appear to 'still be in business' but are encouraged to transition to the 'amateur' service:

Finally, we decline to permit previously licensed experimental stations – some of which have been authorized with significantly more radiated power than the adopted EIRP limits for these new amateur service bands – to communicate with amateur stations operating in these bands.  Amateur operations in these bands currently authorized under experimental licenses should transition their operations in accordance with the adopted rules and not circumvent such rules by use of experimental licenses.

My understanding of the R&O document is that participating parties may still file a 'Petition For Reconsideration' notification within 30 days of the R&O's publication in the Federal Register. Once these (if any) are dealt with, there are no other roadblocks preventing immediate implementation.

The document contains additional details not discussed here and makes fascinating reading for amateurs that might be looking forward to the new allocations.

This is the news that many U.S. amateurs have been waiting many years to hear! It is also good news for Canadian's operating on these bands to know that they may soon see a large increase in activity south of the border. Let's hope things continue to transpire favorably and that we will finally see the new bands become a reality.

Get those soldering irons out guys and gals!

Saturday, 25 March 2017

The Everlasting Ameco AC-1

courtesy: WB1GFH's AC-1 site

I continue to be amazed at the high prices being paid on E-Bay for original Ameco AC-1 transmitters but perhaps I shouldn't ... they've been doing this for several years now.

Few radios that I can think of have elevated themselves to the cult status enjoyed by the AC-1, but the 3-tube Knight Ocean Hopper regen also comes to mind. Both radios typically reach $100- $200 on auction, with some going for much more. There were plenty of AC-1's sold and built over the years so it's not as if they're rare.

They seem to pop up frequently on E-Bay and the auctions are usually very spirited. I see a nice looking one at present, with 23 bids so far and now at $150! I guess the timing is just about right, with a large supply of now-retired ex-50's Novices who once owned an AC-1, looking to turn back the clock and recreate their early radio experience.

As transmitters go, they don't come much simpler, but the well-designed and smartly marketed radio made it extremely popular among the vast numbers of newly-licenced teenaged Novices who likely didn't have much spare change ... the first ones hit the market in the late 50's, right in time for the strongest solar cycle on record, selling for $14.95 in kit form. AC-1's continued to be sold into the early 70's with the price rising to around $25 ... a nice long run for most ham gear. I may be wrong but I don't think they were ever available in anything other than kit form.

 Here is what the kit looked like upon arrival ... this one still NIB in 2012!

It's not difficult to imagine the level of excitement that this would have stirred up with a young Novice, eager to get on the air.

There is also a large builder's interest in making AC-1 'clones' along with a dedicated Yahoo Group for additional support. Several years go I decided to scratch-build my own clone and found that I had everything needed except for the gray hammertone spray paint. Although most AC-1's used black chicken head knobs, some early models used maroon knobs so I decided to go with a red slide switch and red chicken head knobs on my reproduction. The important decal was available at the time from the Yahoo group but I see them now being sold by Radio Daze, for those that may want to try their hand at building a clone themselves.

The AC-1 uses the inexpensive 6V6 elevated from AF to RF duty, in a crystal-friendly Colpitts crystal oscillator. The only departure from the norm is the output circuit. Most inexpensive one-tubers end up with a link-coupled output but the AC-1 uses the more versatile pi-network ... something that no doubt added to its production costs but produced a transmitter able to load a wider range of antenna impedances while providing superior harmonic attenuation, both important in a beginner's rig.

My clone puts out 8 watts on 80m and 7 watts on 40m. Although never intended, doubling to 20m sees a large drop in efficiency, with output power dropping to 2 watts. Swapping to a 6L6 yields an extra couple of watts. Not enough to be noticed at the other end except when doubling or tripling.

I haven't had my clone on the air for a few years and think it's time to spark it up once again for some summertime fun on 40m CW. It would be great to work another clone or even a real AC-1 if you have one, but any contacts will be exciting if you would like to try.

I'll be hanging around 7118 kHz or down near 7040 and ... I won't be loud!

Another Blast Coming


Speaking of 'everlasting', wimpy Solar Cycle 24 has been showing more energy in its death throws than it ever seemed to show during its peak.

It continues to blast earth with a never-ending series of coronal hole streams leading to periods of high signal absorption (particularly on the lower frequencies) and widespread auroras.

The present rip in the Sun's surface is the same one that caused major disruptions during the last solar rotation. Geomagnetic storming and propagation disruptions are forecast to begin around the 28th, with a proviso ... these ones could be even worse than last time as the wind's polarity at present is favorable to greater coupling with the Earth's magnetosphere, sending the Earth's Bz southward (negative) into auroral producing, prop-killing conditions.

Sometimes, though not normally, these events can produce periods of enhanced low frequency propagation, especially during the hours just before the event's commencement ... the best thing to do is just continue to operate normally and not assume the worst. I've been guilty of this in the past and being caught off guard, have missed some better than usual LF propagation.

 I'll keep my fingers crossed over the next few days and think positive ... Bz-wise!

Monday, 20 March 2017

The Don Miller Enigma

A mention in the KE9V weekly 'CALLING CQ' e-mail letter brought back more memories of my teen DX years. The article pointed to a YouTube interview of legendary DXer Dr. Don Miller, W9WNV, conducted by another DX legend, Martti Laine, OH2BH. The fascinating interview was conducted in December 2016 and is broken into five parts.

For those old enough to remember, Don spent a few years in the late 60's providing DXers with one rare country after another ... dozens of them. He was a superb operator and the originator of the now ubiquitous "5NN" shortened signal report, after trying unsuccessfully with "FNN". He was also one of the very first to operate 'split', requiring stations to call up or down instead of the then prevalent one frequency pileup! Don was really instrumental in shaping much of what we see today as 'standard ops' when it comes to DX'pedition operations. To hear Don handle a pileup was something else. Often when the pile became very large, he would listen to the calling crowd for a couple of minutes and then respond with a list of calls and signal reports ... nothing like the individual exchanges we see today.

My little DX-20 and VF-1 were only able to work Don at one of his stops ... YJ8WW on 40m CW. He was all about giving the little guy, those running modest stations, an opportunity to work some rare countries.

courtesy: F6BLK
All was not roses however. Don ran into several problems with the ARRL regarding some of his 'supposed' locations. Several of his operations were disqualified for lack of proper documentation, sworn affidavits from his DX companion that they weren't actually where they claimed to be and by his own admission. As well, there were certain stations at the top of the honor roll that, for whatever reason, Don was just 'unable to hear'. This infuriated many of the top DXers of the day as well as officiators of the DXCC program, still in its infancy. Don claims his selective deafness was because some of these amateurs were 'DX hogs', working him several times on the same band, a practice he discouraged. Others claim that it was because these top DXers did not contribute monetarily to his expeditions. I suspect the truth lies somewhere in between. With big egos and honor roll status involved, a lot of bad blood was spilled in the DX community at the time ... bitter memories to this day still, for some.

As bad as things had become for Don, it got much worse, when in 1980, rightly or wrongly, he was convicted of conspiring to have his estranged wife killed and was sentenced to 25 years to life.

Don Miller is one of those 'larger than life' personalities whose presentations at DX clubs and conventions would bring the large crowds to their feet with his DX stories and expedition accomplishments.

The YouTube interviews show a somewhat contrite, remorseful man, compared to the one we met in the 60's but there's still a hint of that young mischief-maker and a twinkle in his 80 year old eyes as he teases of putting another rare one on-the-air, one last time.

courtesy: OH2BH
Don is now AE6IY and if you hear or work him, love him or hate him, be aware that you are talking to one of amateur radio's living icons.

[See also: "The Don Miller Story As Told By Hugh Cassidy, WA6AUD]