AmateurRadio.com

The AWA Builders Group has been buzzing with activity over the past few days as many '29ers get prepared for the upcoming Bruce Kelley QSO Party. If you've been following the blog of late, you'll already know that the BK is the year's premier operating event to celebrate radio as it was in 1929....only self-excited oscillators are allowed (no crystals!) and only tubes that were first introduced in 1929 or earlier. Party activities commence this Saturday afternoon at 2300Z and run for 24 hours....same for the following weekend, only add 160m to the action.

You may hear plenty of activity in the nights leading up to the Party as various stations burn the cobwebs out of their handmade creations around 3550-3570 in the next few nights...you might give them a call if you hear them as most will be delighted to know that they're getting out of their backyard.

A few weeks ago, in the same spirit of preparation, I began work on a small amplifier for my Hull Hartley transmitter. Ever since entering the BK Party, I have been held hostage by the monster winds which always seem to show up here during early December. Self-excited oscillators connected to blowing antennas create an unusual-sounding signal...somewhat musical....up to about 30km, but after that, somewhat dreadful, as shifts in frequency between keying elements can be measured in tens of Hertz or more and make it difficult to copy a weak signal.

I put the amp together in the original 'ugly construction' style of the 20's, which I'll call 'ugly breadboard'. For the most part, period-appropriate components were used, as it was to be a 'proof-of-concept' project....to see if and how it would work and what changes might need to be implemented in a 'finished' version.

t

Amplifier stage followed by Hull Hartley exciter on far end.

The original circuit, shown below, was published in the February 1931 QST and penned by George Grammer (W1DF), the ARRL's Assistant Technical Editor. Since I already had the oscillator section, I built the amplifier only, making a few modifications.

Courtesy: http://www.arrl.org/

My changes involved removing the B+ from the exposed plate tank coil by putting C7 between the plate and the tank circuit, grounding the coil tap point and shunt-feeding the B+ directly to the plate. As well, the operating bias was changed from the original combination of grid-leak and external fixed-bias (always a pain) to grid-leak bias only. Since I planned to let the oscillator run and key only the amplifier stage, no external (extra) bias was needed. The original system of feeding drive via capacitive coupling from the oscillator tank circuit was maintained as was the 'plate neutralizing' system. With the plate tank no longer carrying B+, a wide-spaced variable capacitor was no longer required for C3. These changes are illustrated below:

Courtesy: http://www.arrl.org/

Testing went smoothly and with the help of a tuned RF-sniffing wavemeter (the actual one I built when I was a brand new15 years old ham!), the amplifier neutralized beautifully. It was unconditionally stable, in spite of the numerous clip leads surrounding the board connecting to the separate Hartley oscillator in a somewhat haywire fashion....it really was a mess. As one other '29 builder (KK7UV) so perfectly described his latest workbench project, it "looked like the transmitter was on life-support!"

Surprisingly little drive was required from the Hartley and it was run at just 200VDC. The amplifier efficiency was around 50% which could probably be improved upon with careful attention to biasing values, shorter leads and more efficient antenna coupling. On 80m, the only band that I wound a coil for, keying was clean and very nice (an advantage of being able to run the oscillator at low level). Without too much effort, 15 watts out was easily obtained...far too much for the BK Party.

Tapping down on the tank coil for 40m operation proved to be a different story as the note sounded like a buzz saw...very raspy and nasty. To really undertake a fair test, a dedicated 40m tank coil would have to be used as well as a  much 'cleaner build'.
The rat's nest of unwanted coupling of both RF and AC ripple was showing through on this higher frequency.

For multiband operating events, such as the BK, things have to be efficient enough to make band changing and tune-up procedures quick and simple and in its present haywire form, the amplifier would just not be 'contest-friendly'.

All in all it was a very valuable building exercise as a LOT was learned. I am now convinced that for a true MOPA (Master Oscillator Power Amplifier) combination to do what is needed will require an all-in-one style of construction....both oscillator and amplifier on the same board, with short leads and little chance for unwanted parasitic-coupling between stages. With separate coils for all bands and calibrated dials, tuning and changing bands would be very much easier than trying to couple two separate units together. I can see why the struggle to get the original '29ers away from their simple Hartley's and TNT's and over to MOPAS went on for several years.






So once again I am at the mercy of the wind-gods and hoping for two back-to-back Saturdays of quiet BK-friendly air...in early December...on the west coast...by the ocean...yeh, right!

Courtesy: http://www.noaa.gov/

With the solar flux index remaining relatively high over the past week, the F2 MUF has been spending most of the day in the mid 40MHz region. For 6m operators, it's always a good sign to see the MUF climb this high as it only takes a nudge to keep it climbing, hopefully to reach that magical 50MHz level.



The region between 10m and 6m is chalk-full of commercial two-way FM activity, particularly from 39MHz on up. With the skip zone running east-west, oftentimes the distinctive Boston accent or the unmistakable Bronx chatter can be heard...police, taxis, fire departments...sometimes even with sirens blazing away in the background. Other times, things will be further south, with accents favoring easily-recognized southern drawls.

Early this morning at 0641Z, a small M1.8 flare added some extra fuel to the F2 fire, resulting in an unusually early-morning rise in the MUF.

Courtesy: http://www.solarham.net/xray2.htm

By 0900 local time, it was hovering around 46-47MHz when I started to hear the 22-watt W4CLM beacon near Atlanta, Georgia. Warming-up the transmitter and calling a few CQ's on 50.098, I was soon answered by Bob, N3LL, in EL86 on the west coast of Florida ....a nice single-hop (2600mile) F2 QSO. Another CQ brought KJ4E in EL98, to the northeast of Bob.

Courtesy: https://maps.google.com/

Now normally, at this time of the morning, the F2 MUF would continue to slowly climb....usually peaking-out somewhere between 1030-1230 local time, so things were looking hopeful. During our exchange, N3LL peaked at 599 as the MUF continued to surge between 46 and 50MHz, struggling to maintain its ever weakening-grip on the magicband.

From here, things went south fast and for some reason, the normally slow climb halted as the MUF quickly retreated to the low 40MHz regions...it was all over.

The end of the opening can be clearly seen in the geomagnetic activity recorded at the Kiruna Magnetometer (Sweden). The circled area indicates the period of high MUF:


 ...but what started the sudden spike in the MUF today...was it the earlier flare or the suddenly south-going 'Bz' component of the Interplanetary Magnetic Field as seen about an hour earlier?

Courtesy: http://www.solarham.net/solarwind.htm

Such are the things that 6m junkies find fascinating, as this portion of the spectrum is always full of surprises and curiosities. Even as it slowly decays, poorly-performing Cycle 24 can't resist the opportunity to keep us guessing once again.

I wonder what surprises tomorrow will bring?

Probably the most-often discussed ham radio topic is that of 'antennas' and with LFers it is no different.

When it comes to antennas used for receiving,
you might be surprised to learn that even small, simple antennas, can be very effective on 630m. Small loops are easy to build and work well as they are often quieter than wire antennas and with preampflication, will usually yield a better signal-to-noise ratio.


The shielded Burhan's loop described here, is a good performer on 630m and below, while a tuned wire loop can be just as effective if resonated to 630m.

Easily built active antennas are also popular and once situated in a quiet spot in your backyard, can work extremely well, considering their size and simplicity. The PAØRDT active antenna is popular worldwide and offers good performance, if properly placed, as shown in this LF bandscan from Japan.


Several of the stations that I recently worked on crossband, from 630m to HF, were using their normal HF dipoles to listen on 630m. Often times a non-resonant antenna, such as an 80m dipole, can give reasonably quiet performance and is worth trying should you just want to listen. Others have used HF dipoles with the feedline shorted and fed as a top-loaded vertical (T), and resonated to 630m against a small radial ground. Try what you presently have and you may be surprised at what you can hear.

Transmitting antennas need not be large to enjoy 630m propagation. For most backyards, an inverted 'L' antenna would probably be the easiest to configure.

If you have a tower, the vertical portion of the 'L' could be hung from a support arm off of the tower, with the horizontal portion as long and as high as possible. If you have some trees to hang wires from, a center-fed 'T' antenna would also be effective.

Top-loaded 'T' Antennas. Courtesy: http://en.wikipedia.org/wiki/T-Antenna

In both of these examples, try and get as much 'vertical' as possible and then work on the top-hat portion. Top-hats with multiple wires will also increase antenna efficiency. An interesting paper by VK2DX, explains the process that he used to build and match a simple inverted 'L'.

Courtesy: VK2DX

As well, JUMA publishes an informative application note on building an 'L' for 630m.

If you don't have room for one of these types of antennas, effective results can also be had with short top-loaded radiators as used at many NDB installations. Try to go as high as you can and make the top-hat as large as possible.


Any of the transmitting antennas described above will require sufficient series inductance (base loading usually) to bring them to resonance as well as some form of variometer to fine-tune exactly. As well, they all require some form of ground system to radiate.

Since most backyards will never be large enough for an efficient ground system on 160m, let alone on 630m, just do the best that you can. You might be surprised at the results achieved with just a simple system of a few buried radials but the more you can lay down, the better. Radials can be effectively hidden beneath the grass with a few days of effort. Some have noted an increase in antenna current when ground rods were driven in at the far end of the radials.

Courtesy: http://www.auroralchorus.com/

This well-written series of articles describing simple antenna systems for the 1750m band is chalk-full of neat ideas and practical information...all applicable to the 630m band.


For an even more in-depth look at practical LF and MF antennas, the ON7YD site is hard to beat...again, all applicable to 630m.

Canada's new 630m band is a wonderful opportunity to build and experiment with all aspects of your station and it's crying out for activity!

It's still not too late to be the first station on 630m from most parts of Canada and the VE7's are waiting to work you!

10' x 20' LF Loop

As is usually the case, conditions deteriorated rapidly as the CLE weekend approached. Conditions varied throughout North America as those listening from the south-eastern regions of the U.S. reported much better propagation than those further to the northwest. Friday night appeared to be the best of the lot but all three nights were very much less than stellar.

The three-night event produced a total of 39 NDBs, with a couple of surprises.






DD UTC    kHz     Call       mi   Location
----------------------------------------------------------

22 05:00  370     YBV        1169 Berens River Apt, MB, CAN
22 06:59  370     OUN        1611 UoOk Westheimer Apt, OK, USA
22 05:00  371     YK         211  Yakima, WA, USA
23 09:00  371     PUR        1629 Marshall, MO, USA
22 05:00  371     ITU        558  Great Falls, MT, USA
22 05:00  371     GW         1946 Kuujjuarapik, QC, CAN
22 05:00  372     ZPA        824  Prince Albert, SK, CAN
22 05:00  372     YCO        1340 Coppermine, NU, CAN
22 05:12  372     FPN        675  Petersburg, ALS
22 07:00  373     TF         1191 Pueblo Mem Apt, CO, USA
22 05:00  373     MF         444  Table Rock, OR, USA
22 05:00  374     LV         776  Livermore, CA, USA
22 05:00  374     EX         190  Kelowna, BC, CAN
23 09:00  374     EE         1319 Forada, MN, USA
22 05:00  374     BOD        942  Bowman, ND, USA
24 09:59  375     PSN        1854 Palestine, TX, USA
22 05:00  375     FS         896  Fort Simpson, NT, CAN
22 10:59  375     DW         1629 Owasso, OK, USA
22 07:00  375     CP         900  Casper, WY, USA
22 05:00  375     BD         803  Moose Jaw, SK, CAN
22 07:00  376     ZIN        3326 Matthew Town, BAH
22 07:00  376     YAG        1345 Fort Frances, ON, CAN
22 13:59  376     PVQ        1690 Deadhorse, ALS
22 06:59  377     EHA        1350 Elkhart, KS, USA
23 06:59  378     ZFA        1000 Faro Municipal Apt, YT, CAN
22 05:00  378     OT         381  North Bend, OR, USA
22 10:59  379     ZEG        526  Edmonton Intl, AB, CAN
22 05:00  379     YBE        945  Uranium City, SK, CAN
23 12:59  379     IWW        1360 Kenai, ALS
22 09:00  380     OEL        1297 Oakley, KS, USA
22 05:00  380     GC         899  Gillette, WY, USA
22 05:00  382     YPW        86   Powell River, BC, CAN
22 05:00  382     YE         686  Fort Nelson, BC, CAN
22 12:59  382     JNR        1731 Unalakleet, ALS
22 12:00  382     GRN        1522 Guerro Negro, MEX
22 05:00  382     AW         75   Marysville, WA, USA
22 06:59  383     PI         658  Pocatello, ID, USA
22 05:20  383     CNP        1146 Chappell, NE, USA
22 05:00  384     3F         792  Ile-a-la-crosse, SK, CAN
-----------------------------------------------------------------

This particular frequency range (370-384.9kHz) is a tough one for me, since my local pest signal, 'AP' is on 378kHz, smack in the middle of the listening range. 'AP's antenna is just .4 miles (2100') from my antenna and its signal is about 60db over S9.... Very loud!

AP to me...Courtesy: https://www.google.ca/maps/

The new 10' x 20' rotatable loop continues to work well. When pointed towards the east, it offers significant nulling of AP's signal and when carefully aligned to the deepest null-point, reduces the signal by almost 30db...but still leaves a very strong signal.

Using this 'deep null' position, I was (somewhat surprisingly) able to log another Canadian NDB (ZFA  Mayo Airprt, Yukon Territory) on the same frequency as AP. The ident-tone modulation frequencies are separated by 10Hz (408Hz vs 418Hz) which was enough to allow the very narrow ~3Hz Perseus filtering, combined with two notch filters, to reveal the 'ZFA' identifier between the 'AP' identifier. Listen for the weak 'ZFA' ident after the loud keying artifacts of 'AP', when they are transmitting just a steady tone.



The other surprise was the logging of 'PVQ' in Deadhorse, Alaska, way up on the extreme northern slope oil fields.

Courtesy: https://www.google.ca/maps/

My last reception of this beacon was in March and conditions usually have to be very quiet, geomagnetically, to hear it at all. The coronal-hole streaming of this past weekend, putting the damper on LF propagation, makes this path very unlikely and surprising! See if you can hear the weak 'PVQ' identifier during its short appearance early on Saturday morning:


CLE organizer, Brian Keyte (G3SIA), reports 51 participants worldwide and over 2100 reception reports. All reports have been added to the RNA/REU beacon database.

As well, Brian will be publishing all results on the NDB Information page shortly.

All-in-all CLE188 was another enjoyable event....hopefully conditions will be better by this time next month and if you did not participate, maybe you will give it a try next time!

Using the transverter approach offers the advantage of providing a higher-stability signal generated by the main station's transceiver oscillator system. Most of the digital modes require a higher stability than would be needed for straight CW.

If your main interest is normal speed CW, then a digital VFO, such as the one devised by GW3UEP, would do the job.

If you are content operating on 475.0 kHz, then an inexpensive 7.6MHz crystal, in a divided-down oscillator will work well, and with good enough stability for some QRSS work as my earlier "GW3UEP Transmitter In QRSS Mode" report indicated.


The other option for frequency generation is a DDS.

N3ZI DDS

For several years now, I have used an inexpensive N3ZI DDS to drive my 2200m transmitter and, more recently, my 630m system. The N3ZI DDS is an affordable option should you decide on a non-transverter style of transmitter.

For those wanting something a bit more robust, W1VD describes a very nice high-power transmitter. His website is packed with useful circuits and ideas for both 2200m and 630m.

W1VD Dual-Band Kilowatt : http://www.w1vd.com/

W7IUV also describes, in great detail, his method of generating high-power on 630m. There is much to be learned from his document describing the design and operation of his unique 'linear-mode' transmitter.

W7IUV 630m TX: http://www.w7iuv.com

Another practical way of generating moderate power, certainly enough to meet the Canadian 5W EIRP limit, is to combine two or more 100W transmitters, such as the GW3UEP transmitter. It is reasonably simple and inexpensive to combine several modules with the use of a homebrew power combiner, as previously described.

Homebrew 630m two-Port Power Combiner / VE7SL

Of course, none of this would be of any use without thinking about suitable 630m antennas...ones that will fit in your backyard!

If you're thinking about getting something going for our new 630m band, the following web resources may be of help to you.

There are a couple of 630m transmitters available on the commercial market that I know of.



JUMA , in Finland, offers the TX500, an extremely well engineered 60W Class D CW transmitter in kit form.

JUMA TX500 Transmitter: http://www.jumaradio.com/juma-tx500/

From Australia, VK3XDK offers the LF/HF TransverterV2, a linear mode transmitter. Available in prebuilt form only, the transmitter claims 12W output when supplied with 13.8VDC. Various IF's are available. The transmitter uses SMT construction and is well-documented on the VK3XDK website.

VK3XDK Linear Transverter: http://www.vk3xdk.net46.net/

From the U.S.A., WA3ETD offers a Class D transverter (non-linear) in either prebuilt or kit form.
At 13.2VDC, an output of 19-22W is claimed from the single FET final amplifier. Full details can be viewed here.

MF Solutions Transverter: http://njdtechnologies.net/

For the homebrewer, the new band presents many possibilities. Two of the most popular designs are the G3XBM 472kHz transverter and the GW3UEP Class-E CW transmitter.

Roger's (G3XBM) has been widely reproduced in the UK and makes a nice way to get on the band on CW or with WSPR. Although the final amplifier is non-linear, with a little experimentation, it could be put into a linear mode for PSK or the JT modes. Perhaps that is what M1GEO did, as his video shows the transverter being used on SSB.

M1GEO's Homebrew Version of the G3XBM Xvrtr

The other fine design is that of GW3UEP (Rog) and has been widely reproduced with good results. My own experience with this design was described here in an earlier blog. Here is EIØCF's version of Rog's design.

Source: http://www.gw3uep.ukfsn.org/25W_QTX/QTX.htm

Courtesy: http://americanradiohistory.com/

And...once again it's time for the monthly Co-ordinted Listening Event (CLE) for NDB hunters....the 188th event. These always interesting and popular affairs take place over three nights, with this one starting on Friday, November 21st at local noon and running until Monday, November 24th, local noon.








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

This time, it's a normal event, focusing on a small (~ 15kHz) section of the NDB band. Here are the details from event organizer, Brian Keyte (G3SIA):


Hi all,

The CLE Survey results are so interesting I almost forgot to send this!
Please join us in our 188th Co-ordinated Listening Event which starts
this Friday. All are very welcome - 'Regulars' and 'First-Timers' alike.
CLEs are not contests - if you enjoy taking part you are a winner!

Days: Friday 21st - Monday 24th November
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 CLE188 at the start of its title.
Show on each log line:

# The date (e.g. 2014-11-21, etc., or just 21) and UTC.
(the date changes at 00:00 UTC)
# kHz (the nominal published frequency, if known)
# The Call Ident.

Please 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 18:00 UTC on
Tuesday - you can check from it that your log has been found OK.All logs must arrive on the list by 09:00 UTC on Wednesday 26th
at the very latest.
I hope the combined results will be completed on that day.

To help your listening, seeklists 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 co-ordinator)
----------------------------------------------------------

(If you wish you could use any one remote receiver for your loggings,
stating the location and owner - with their permission if required.
A remote listener may NOT also use another receiver, local or remote,
to make further loggings for the same CLE).

Final details can be found at the NDB List website, and worldwide results, for every participant, will be posted there a few days after the event.

The 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.

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. 

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

Please...don't be shy and do 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.