Lightwave Scatter

Looking down the road at possible future 'clear-air scatter' or 'cloudbounce' lightwave tests with stations (VE7CNF and VA7MM) on the other side of Georgia Strait, I spent a few minutes breadboarding a more stable modulator for my lightwave system.


As it is at present, the modulator consists of a 556 tone generator, capable of either a steady tone for CW keying or a two-tone FSK 'beaconing' signal used to help the other station in aiming alignment.

For the slow QRSS CW narrow-bandwidth modes required for the scatter tests, I've always known that a tone which is much more stable and of precisely known frequency would be needed. The tone from the 556 does well as an aural CW keyed tone but would probably be all over the place when viewed in a very narrow-bandwidth and not nearly as stable as it sounds by ear.

The little modulator uses a 4500 KHz crystal (pulled from a old VCR several years ago) in a 4060 oscillator-divider. In this case, output from the chip is taken from either the 'divide-by-8192' pin 2, which outputs a precise frequency of 549 Hz or from the 'divide-by-4096' pin 1, which outputs a frequency of 1099Hz.

courtesy G3XBM: http://g3xbm-qrp.blogspot.ca/search/label/nlos

This tone is then used to drive an IRF 540 power MOSFET which controls current through the 1W Luxeon Deep Red LED in the transmitter. The 4060 modulator will be keyed via a QRSS software keying program that I have used for many years to key my LF transmitter.

The lightwave receiving station will look for the QRSS audio signal with an audio spectrum viewer such as Argo or Spectran. The ability to make automatic overnight screen captures will allow the receiving operator to get a good night's sleep while the system diligently watches for any traces of a signal.

An example of a strong signal capture showing a repeating "SL" identification is shown below, as it would appear in a perfect world. In this case (QRSS3), the short 'dots' are 3 seconds long while the 'dashes' are 9 seconds.

Huge signal gains (the ability to dig into the noise for signals) can be had by slowing things down and using narrower receiving bandwidths. Just going from a normal 12WPM speed CW (aural copy) to QRSS3 yields a gain of ~15db. At QRSS10 (10 second dots), an additional 5db is gained while slowing to QRSS60 (60 second dots), a whopping 28 db over 12WPM CW is gained!

Of course all of this extra 'hearing power' comes at a cost and in this case, the cost is 'time'. On an overnight of automated computer monitoring, time is not much of an issue ... it only becomes critical in 'QSO mode' when some QRSS QSOs can take several hours to complete. In any case, it will be interesting to see if any traces of lightwave signals will show up while bouncing around in the clouds.

The Georgia Strait scatter tests will not take place for some time but in the meantime, I hope to do some local tests here, from one side of my island to the other but will build a new portable receiver for these tests and leave my main system intact.

Sparking-Up On 2200m

I haven't been on 2200m (135.7 - 138.8 KHz) for some time ... my last transmissions on this band were almost three years ago. The recent acquisition of the 630m band has refocused a lot of my attention but Canadian activity has never been very high on the real 'top band'. Hopefully when the U.S. gets the 2200m band soon, activity will increase on both sides of the border.

An e-mail alert from Toby, VE7CNF, on the other side of Georgia Strait, indicated that everything was ready for a two-way test on 2200m and he was looking for his initial contact on the band. Having not been on the band for such a long time, some review of my 'tune-up' procedures were in order as well as the need to burn out the spider webs in my outdoor loading coil.

Since being on 2200m, I had modified my 2200m kilowatt transmitter so that it could also be used on the new 630m band. To change bands from 630m back to 2200m, I needed to swap the frequency-sensitive power divider back to 2200m as well as re-set the DDS frequency.

2200m Power Divider

Setting my DDS to the correct control frequency and keying the driver stage revealed no sign of a signal on 137.779 KHz. This was puzzling and several re-checks turned-up no reason for the problem ... it seemed as if there was no signal from the DDS into the transmitter. I set everything back to 630m, just to confirm that there wasn't a more serious problem but everything worked just fine. It was then that I realized my error.

When modifying the transmitter, three years ago, I had also changed the transmitter's input frequency divider from a 'divide-by-four' to a 'divide-by-two' scheme. My original system on 137KHz started with a DDS frequency in the 5.48MHz range and then was divided by ten before being fed to the transmitter's input where the 548KHz signal was then divided by four. Using a higher DDS frequency allowed for greater frequency resolution at 2200m and allowed for very small frequency adjustments across the band. I would have kept the same system for 630m except that my 'divide-by-ten' chip was not very happy at 18MHz and refused to divide.The newer system now only allows me to move around the band in 4.5Hz steps. It's really not much of a problem as there is presently a minuscule amount of activity in Canada on 2200m, but as previously mentioned, this may change when U.S. amateurs gain access to the band.

Having sorted out my transmitter problems and confirming that all was well, the next task was to check antenna resonance and impedance matching as it would more than likely not be the same as I had left it. A low-power check using the 'scopematch' indicated that both resonance and impedance were not optimized. Tapping down on the loading coil by one-turn took care of resonance while adjusting the impedance tap in my matching transformer to its lowest value (see matching scheme below) resulted in a near perfect match on the scope.

I'm guessing that the resonance change was due to the recent heavy trimming of the 80' Balsam that supports one end of my 'inverted-L' and large three-wire flatop.

The tree's crown had previously been very dense and some of the branches were almost touching the flatop. The close proximity always made me worry about possible flashover at the antenna ends as voltages here would be several kilovolts. Removing much of the wet green tree branches directly beneath the flatop also likely contributed to the slight change in resonance.

Impedance Matching Transformer On TV Flyback Cores

The change in impedance to a lower value may have been due, in part, to the removal of the tree branches as well but more likely it was reflecting the change in my ground system. When I had last been on (in mid-winter), the ground was well saturated and the water table at normal heights. The present conditions are just the opposite as things are drier than they have ever been and the water table has certainly dropped substantially.

The sked with VE7CNF went smoothly and it was nice to see another new Canadian station taking an interest in the band, along with all of its challenges. Toby's 200W signal was a solid 559 here even with his small antenna system yet to be fully optimized. As well, he was bothered by heavy switching-power supply QRM from a nearby neighbour. Unfortunately, such noise sources seem to be increasing in numbers and are making operation on LF, already a big challenge, even more challenging. Toby has taken up the challenge with enthusiasm and has now had contacts on 2200m well as on 630m, adding to the ranks of active VE7's on LF and ... demonstrating yet again that amateurs can enjoy the LF bands with small 'backyard' antenna systems. Don't let living in the city be a reason to avoid our new LF bands.

Wouldn't it be great to see some activity from our neighbours in VE6 or VE5, both easily workable on both bands from the west coast... maybe you're up to the challenge!

Tuna Tin Fun

I was doing a little housekeeping in the shack this past week and ran across small piece of  anti-static foam with a transistor sticking out of it. It was the transistor from my Tuna Tin II final amplifier's stage ... the actual transistor that I had used to 'Work All States' on 7040KHz using my Tuna Tin back in 2000. Looking at it in my hand brought back a lot of wonderful memories from the fall of that year when I spent so much of my time looking for new states.

Like many others at the time, I was swept up in the second 'Tuna Tin revolution' when the NorCal QRP Club released a very inexpensive kit for the Tuna Tin II. It turned out to be the best $13 I had ever spent on ham radio bits as it brought me so much operating fun while making many new acquaintances in the process.

I recall the afternoon that I completed the kit ... attaching my antenna and calling 'CQ' on 7040 with a hand key plugged into the Tin. My afternoon call brought an immediate response from a station in Oregon who gave me a 579 report! Needless to say I was elated that it's ~360mw had done so well.

Over the next few days I worked a few more stations in the western states even stretching out to northern California and had pretty much decided that most of my QSO's with it would be fairly short range ... until the pre-dawn hours of August 6th when my hand-keyed 'CQ' was answered by NØTU (Steve), in Colorado! We had a nice solid ragchew until we ran out of darkness but the contact had given me re-newed optimism. If I could get a decent signal into Colorado, then perhaps I could actually work further afield ... maybe it was even possible to work all 50 states!

With that, I set myself a goal of trying to work them all. Although my 40m half-sloper was well matched and had proven to be a good performer in the 40m pileups, it only had four buried radials. The first thing I did was to bury another 30 radials around the base of the 48' tower, hoping to lower my ground losses as much as possible. With just one-third of a watt, there was no power to waste.

Back in those days, I was still working and could only get to the Mayne Island QTH on weekends. With the Friday night ferry arriving at around 8PM, by the time the woodstove had been fired-up and dinner taken care of, I very often didn't get to the Tuna Tin until around 11PM. As it turned out, the late hour operation worked out well and it didn't take long for my state total to climb. The toughest states were the New England '1's and as I neared the end, I still needed several. In late November, 40m revealed its magic-side and an early-evening 'CQ' brought replies from three W1's, all at once, each one a new state. Finally, in early December, I worked Wyoming for state number fifty!

The fifty QSL's were duly gathered and  sent to the ARRL for an official "WAS" award. Although there was no special endorsement for the Tuna Tin, other than for 'QRP', there was a nice note about it in the 'ARRL Letter' as well as in QST:

First Tuna Tin 2 WAS claimed: When the Tuna Tin 2 low-power transmitter article appeared in QST in 1976, its author Doug DeMaw, W1CER (later W1FB), envisioned it as a weekend project that could be used for short-range contacts.
Now, a quarter of a century later, a Canadian amateur has claimed the first Tuna Tin 2 Worked All States Award! Steve McDonald, VE7SL, got caught up in "Tuna Tin 2 Mania" and bought one of the popular TT2 kits. After working about 30 states with the little rig, WAS suddenly seemed plausible. McDonald realized his dream several months later when he turned in his cards for WAS. All contacts for the award had been completed while he was running about 400 mW from a Tuna Tin 2. As far as the ARRL awards folks know, this marked the first time WAS was achieved with a Tuna Tin 2--although there is no special endorsement for having done so. "Doug DeMaw knew in his heart that the rig would be useful and popular, but I don't think he ever envisioned that this little transmitter would still be working its QRP magic over 25 years after it first appeared in the pages of QST," said ARRL Lab Supervisor Ed Hare, W1RFI--himself a QRP and TT2 aficionado who has promoted the Tuna Tin 2 Revival and was McDonald's Connecticut contact for WAS. Congratulations to VE7SL on a tremendous operating accomplishment.--Ed Hare, W1RFI

Holding the battle-scarred 2N2222 in the palm of my hand reminded me of just how much excitement can be had with just a few simple parts and the magic of radio.

CLE197 Results

It seems that our medium-frequency NDB CLE's (Co-ordinated Listening Event) go hand-in-hand with solar disturbances and wacky geomagnetic conditions. If you want to know when the next big geomagnetic upset will be, just check the date of the next CLE!


Along with a half dozen M-flares and auroral-producing 'K' indexes of 5-6, most of North America was blanketed with severe thunderstorm activity, always typical of this time of the year. In spite of the poor conditions, several signals did manage to find their way into my log. Sunday night provided the best conditions, with far less thunderstorm activity and a slight improvement in propagation. Saturday night's lightning map looked like this:

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

courtesy: http://www.noaa.gov/

Loggings in RED where made on Friday night, GREEN on Saturday night and BLUE on Sunday night.

All stations were heard on the Perseus SDR while using my LF 'inverted-L' resonated at 300KHz.

 LOG:

DD UTC    kHz     Call       mi    Location

--------------------------------------------------------------------------- 
22 06:00 240 BVS   48      Burlington, WA, USA
22 10:00 241 YLL   648    Lloydminster Municipal Apt, AB, CAN
22 12:30 242 ZT    223      Port Hardy, BC, CAN
22 10:00 242 XC   342     Cranbrook, BC, CAN
22 10:00 244 TH   1166     Thompson, MB, CAN
23 07:00 245 YZE 1890    Gore Bay, ON, CAN
22 12:00 245 HNS   865    Haines, ALS
24 09:00 245 FS   1311    ROKKY - Sioux Falls, SD, USA
22 10:00 245 CRR    821     Circle Town County Apt, MT, USA
24 05:00 245 CB   1528    Cambridge Bay, NU, CAN
23 12:00 245 AVQ    1298    Marana Regional Apt, AZ, USA
22 09:00 246 ZXJ   517   Y'Taylor' Fort St. John, BC, CAN
22 09:00 248 ZZP   486     Dead Tree - Queen Charlotte Is, BC, CAN
22 09:00 248 QL   471    Lethbridge, AB, CAN
22 09:00 248 QH    811   Watson Lake, YT, CAN
22 09:00 250 FO   1002    Flin Flon Municipal Apt, MB, CAN
22 12:30 250 2J   220    Grand Forks Municipal Apt, BC, CAN
22 09:00 251 YCD   32    Nanaimo, BC, CAN
22 09:00 251 PWD    850    Plentywood, MT, USA
22 12:30 251 OSE   1708    Oscarville - Bethel Apt, ALS
23 11:30 251 AM   1445     PANDE - Amarillo, TX, USA
24 08:00 253 GB    1324    'Garno' Marshall, MN, USA
22 09:00 254 ZYC   441    Calgary, AB, CAN
22 09:00 254 SM   891    Fort Smith, AB, CAN
24 11:30 256 TQK   1322    Scott City Municipal Apt, KS, USA
22 12:30 256 LSO    188    Kelso - Rocky Point - Kelso, WA, USA
22 12:00 256 EB   537    Namao - CFB Edmonton, AB, CAN
22 09:00 257 XE   757     Saskatoon, SK, CAN
24 09:00 257 SAZ    1329    Staples, MN, USA
22 09:00 257 LW    192    Kelowna - Wood Lake, BC, CAN
22 09:00 258 ZSJ   1324    Sandy Lake Apt, ON, CAN
23 08:00 420 FQ    1422   MONTZ - East Chain, MN, USA
24 09:00 428 POH   1433    Pocahontas Municipal Apt, IA, USA
22 12:00 429 BTS   1571    Wood River - Dillingham, ALS
24 09:00 434 SLB   1410    Storm Lake Municipal Apt, IA, USA
------------------------------------------------------------------------------------

Thankfully, by this time next month and into October, quieter nights and better propagation will prevail ... fall often produces the best propagation of the year and has always been my favorite time of the year, outdoors and at the dials.

Another VE3KCL Balloon Adventure

courtesy: http://qrp-labs.com/ and https://www.google.ca/maps/

Dave, VE3KCL launched his latest balloon, 'S-4', on Friday, August 21st. He timed the launching very well as it was immediately swept-up by high-speed winds and, unlike earlier attempts, shot up to the north and out over the North Atlantic very quickly.

Like earlier flights, 'S-4' also uses a special U3 firmware version on an Arduino Nano board, with a QRP Labs Synthesiser, along with two hydrogen-filled party balloons with HF antennas hung between them. You can read all about Dave's previous flights here and keep up on the balloon's track here.

The balloon is transmitting data regularly on the following schedule:

0:00 CW ID, and 22wpm CW on 30m, 20m and 17m bands
0:01 JT9 on 10,140,450: "#CS#AT" (callsign, altitude)
0:02 JT9 on 10,140,450: "#LT#A0" (latitude, temperature on analogue A0)
0:03 JT9 on 10,140,450: "#LN#A3" (longitude, battery on analogue A3)
0:04 JT9 on 10,140,450: "#M6#GS" (6-char Maidenhead locator, groundspeed)
0:05 JT9 on 14,078,450: "#CS_#M6" (callsign, 6-char Maidenhead locator)
0:06 WSPR on 10,140,250 (standard WSPR transmission)
0:08 WSPR on 10,140,250 with special data telemetry encoding
0:10 22wpm CW on 15m, 10m and 6m bands
0:11 Calibration
0:12 Repeat...

Frequencies to listen on are:

Minute Mode Tag Frequency (Notes)
00:00 CWID. 10.140450 (GPS off)
00:12 CW 05 10.139150
00:27 CW 05 14.100550
00:42 CW 05 18.109150
01:00 JT9 00 10.140450
02:00 JT9 03 10.140450
03:00 JT9 04 10.140450
04:00 JT9 01 10.140450
05:00 JT9 02 14.078450
06:00 WSPR. 10.140250 (normal WSPR)
08:00 WSPR. 10.140250 (encoded WSPR)
09:50 CW 05 21.150150 (GPS on)
10:05 CW 05 28.205150
10:20 CW 05 50.070150
10:35 QRSS. 10.140450 (continuous 'space')
10:55 calibration
12:00 restart the sequence

Let's wish Dave luck and hope that this one makes a successful circumnavigation. It would be the first by a Canadian amateur I believe.