Thursday, January 29, 2009
The other piece of the puzzle is antenna modelling software. For a long time now I've wanted to be able to design and analyze antennas on the computer. After trying the demo version of EZNEC by W7EL I was instantly hooked. $89 and a quick web download later I had the full version. The learning curve wasn't too bad and after some heavy reading both of the online manual and the antenna modelling sections of the Antenna Book and Low-Band DXing I think I've got a pretty good idea of how to do things and, more importantly, what the limitations of the underlying NEC2 software are. With EZNEC you can actually SEE the magic. Antenna patterns are displayed in 3D. You can see the RF currents flowing in individual conductors. You can sweep the antenna with a virtual antenna analyzer to calculate feedpoint impedance and design matching networks. The best part is that you don't have to learn the theory to begin understanding how stuff actually works. For example, I was playing around with a multi-element wire antenna. I've seen antennas before that had multiple driven elements connected in series by a section of ladder line so I just tried it. By adjusting the length of the virtual ladder line I could instanly tell what sort of effect it had. I was quickly able to optimize the length to produce the highest gain with a reasonable antenna pattern. Which works best, a director or a reflector? It only takes a minute to evaluate both and decide which has the advantage. How will the antenna perform in the real world? I was looking for a DXpedition antenna that would be able to slope down from a single 30 foot high support. Several of the first designs I tried had good pattern and gain when they were straight and level but tanked when I brought one end close to the ground. An other design worked better but had an unrealistic feedpoint impedance. Every trick I tried to fix the feedpoint would distort the pattern. A guy could mess around FOREVER with real wires and never find the right combination that was actually useful as more than just a dummy load. I finally found a design that doesn't get all squirrely when one end gets close to the ground, has a nice 50 ohm match, a flat SWR across 20 meters and lots of gain. One thing that I did note in my research is that actual gain predictions tend to be somewhat inflated as the program doesn't take the far field ground into account. It is useful though for comparing one design to another. The next step will be to build some of these designs and see if they perform the same in the real world as they do in the virual one.
Monday, January 19, 2009
So what about this island thing? One of the more popular awards, especially in Europe, is the 'Islands on the Air' program sponsored by the Radio Society of Great Britain. The general concept is to work as many worldwide island groups as possible. Many of these numbered groups have NEVER been operated from at all. Even more have only had small operations that made a handful of contacts. As it turns out, there are several very rare island groups that are within reach from here. Here are the ones that I think we (VE8EV and/or VE8DW) might be able to activate:
NA-192 Inuvik Region West Group #15 on most wanted NA island list*
I was on the first expedition that activated this group back in 1994. We went to Hendrickson Island which is just off the mouth of the Mackenzie River in the Beaufort Sea. The winter 'ice road' to Tuktoyaktuk passes within a couple of miles of the island and so we (David VE8NC, Carl VE8CF and myself) drove as far as we could and then snowmobiled the rest of the way. Even with low power at the bottom of the cycle I still recall the huge pileups of Eu stations wanting to get the 'new one'. We made several hundred contacts and no one has been back there since.
This winter there is a drilling operation exploring for gas on Ellice Island which is in the westernmost part of the group. If I play my cards right we may be able to drive up there on the ice road in March right before they shut down and see if we can't knock this group right off the list.
NA-129 Nunavut Banks Island Group #14 on most wanted NA island list*
This one is a no-brainer. Actually located in the Northwest Territories, I travel to Sachs Harbour on Banks Island several times a year. My current plan is to schedule my next trip to coincide with the IOTA Contest weekend in July.
NA-182 Inuvik Region East Group #6 on most wanted NA island list*
The East Group is a little trickier but it appears that Nicholson Island was the site of a former DEW Line station and now hosts an unmanned North Warning System radar site. This means that there is occasional helicopter traffic there to support the NWS station as well as a runway for fixed wing aircraft. Not sure what sort of landing permissions are required but I'll check into it and we can pencil this one for next year maybe.
NA-193 Yukon Territory Group
Already claimed by 15% of the IOTA programme participants this one isn't on the most wanted list but it is semi-rare and located nearby. Lots of summer tourist flights to this island which is administered by Parks Canada. Might be a worthwhile destination if we could catch a free ride there and back.
NA-006 Nunavut Victoria Island Group
Another one that isn't so rare (claimed by 24%) is Victoria Island, home to Cambridge Bay, a town about half the size as Inuvik. For many years it was the QTH of Ken, VE8KM (now a VE6 I think) and many visitors since then so it is fairly well represented. That notwithstanding, there's a little town on the far western corner of Victoria Island called Ulukhaktok. It's in the Northwest Territories as well and another of the communities that I visit on a regular basis. Safe to say you'll hear me on from there sooner or later.
For those island chasers that are drooling all over their keyboards now, let me mention a few last things. First and foremost, these places are difficult to get to on a fixed schedule. Planes are frequently cancelled due to weather and other issues. Another big problem is propagation. They're all in the auroral zone so there's always the chance of being there but having no propagation to anywhere. That said, I will try to advertise in advance as soon as we have a firm date for an expedition but nothing is for sure until it actually happens. I will also try to get special callsigns as well. 73 and cu in the logs!
* Not including the 11 'Mostest Wanted' North American island groups that have never been activated at all.
Operator(s): VE8EV VE8DW
Class: M/2 HP
QTH: Inuvik, NWT
Operating Time (hrs): 6.5
Band QSOs Mults
40: 2 2
20: 65 29
15: 3 1
Total: 70 32 Total Score = 2,240
Got on for a few hours to hand out the multiplier with the transportable station parked in the driveway. Also wanted to test out a new amp and antenna switching so went QRO and submitted as a checklog.
Class: Single Op HP
QTH: Inuvik, NWT
Operating Time (hrs): 8
Band QSOs Pts Mults
20: 19 44 7
Total: 19 44 7 Total Score = 308
Monday, January 12, 2009
Right around the time I had to dismantle the shack in 2000 the first of the new "soundcard" modes were becoming available. Instead of an expensive box that used the computer only as a dumb terminal these new modes used the sound card and the computer to digitally process and generate signals. I remember experimenting briefly with the first generation of PSK31 software and the resurrection of the Hellschreiber mode. Ever since I got back on the air last year I've been intending to get back into the digital modes and see what has changed since the turn of the century. I'd been reading about the outstanding weak signal performance of some of them and thought that they might hold the key to communicating under the harsh HF conditions we experience in the far North. So, with that in mind, this past weekend I warmed up the shack and set out to get connected.
The first thing that had changed was the software. Instead of dedicated software for each mode now there are several "all-in-one" packages that do many different modes. I tried a few different ones but for the moment I've settled on MultiPSK by F6CTE. This versatile package includes all of the common modes (PSK31, RTTY, etc), all of the nifty new weak signal modes and some of the more esoteric stuff that I'm into like SSTV, HF FAX and HF SELCAL decoding. Thanks to a few sunspots I was able to make contacts in all the modes I wanted to try even with heavy QSB from the aurora.
First up was PSK31. Lots of activity on this mode but it suffers badly from the phase distortion of the aurora. Strong signals (S2 or better) were solid copy but weaker signals frequently produced gibberish. Still, I had no trouble to complete a couple of contacts. I'm sure I'll be spending lots of time here once conditions pick up a bit more.
Next was good ol' RTTY. It also requires even stronger signals than PSK31 for good print. Furthermore, it is also very succeptable to QRM. My opinion is that RTTY has outlived its usefulness. I just can't see any advantage to using this mode any more. Outside of contests I haven't seen much RTTY activity and once the major contest sponsors start allowing PSK31 and other digital modes in "RTTY" contests I think it will seldom be seen on the bands.
One mode that I had experimented with before was Hellschreiber. Invented in 1929 by Rudolph Hell, this mode uses the human brain to perform the signal processing. Very similar to HF facsimile, Hellschreiber (the most popular variation on HF is called FeldHell) transmits and receives individual pixels of letters that appear on a scrolling strip on the screen (originally it printed on a paper tape). Even in the presence of noise it is easy for the brain to discern the exact text received. I found that I could copy signals that were up to 10 dB below the noise floor (according to the MultiPSK software). Even better than that is the fact that the transmitted signal is very low duty-cycle. This means you can run full QRO without hurting anything. All the other modes I tested are 100% duty cycle so even though my radio and amplifier are both rated for continuous duty I always back off 3dB (50%) in continuous transmit modes just to be on the safe side.
The most unusual mode I tried was JT65. Originally developed for weak signal VHF work it has also become popular on the HF bands. Using a very narrow bandwidth and some heavy-duty computer processing this mode can be used to exchange callsigns and short (very short) messages in a timed sequence. I was able to make contacts easily with stations that were 20dB below the noise (again, according to the MultiPSK software). On the downside, at a minimum 7 minutes to exchange only calls, grids, signal reports and a trivial message (like 73 NAME IS JOHN)... I just dunno. I'm undecided on this one. It'll certainly never catch on for contesting, hi hi. Of course using it for something like EME work is a whole different ballgame. Or is it? Like I said, I still can't quite wrap my head around this one but I just know I'm going to be making a bunch of JT65 contacts (mostly off the moon, I hope!).
I saved the best for last. Olivia. This is my new favorite digital mode. Olivia uses MFSK (Multiple Frequency Shift Keying) and two layers of Forward Error Correcting to enable error-free copy at up to 13dB below the noise. Of the several Olivia contacts I made, one was a 30 minute rag chew with VE2FSK (2500 mile path). His signals were -11dB S/N (not even moving the S-meter) the entire time but 100% copy in both directions. I also had a 10 minute QSO with LU6DLL (8000 mile path). Again, signals hovering around -13dB S/N, barely detectable on the speaker (never mind moving the S-meter!) and still perfect copy. If I hadn't overheard a stronger station signing SK with him I don't think I even would have noticed he was there. Wow! It is for this reason that Olivia (and JT65) by convention use dedicated 'channels' on the amateur HF bands. Info on Olivia, JT65 and the HF channel plans can be found at HFLink.com.
So I guess my old MFJ-1278 is relegated to junk box now. My Kenwood TS-2000 even has a built-in TNC for 9600 baud packet so I don't even need the MFJ for satellites anymore. Ahh, progress!
Wednesday, January 7, 2009
- North American QSO Party SSB, 1800z Jan 17 to 0600z Jan 18
- ARRL International DX Contest SSB, 0000z Mar 7 to 2400z Mar 8
- CQ WW WPX SSB, 0000z Mar 28 to 2400z Mar 29
- ARRL Field Day, 1800z Jun 27 to 2100z Jun 28
- RAC Canada Day Contest, 0000z Jul 1 to 2359z Jul 1
- IARU Contest, 1200z Jul 11 to 1200z Jul 12
- RSGB IOTA Contest, 1200z Jul 25 to 1200z Jul 26 (from Banks Island NA129)
- North American QSO Party SSB, 1800z Aug 15 to 0600z Aug 16
- CQ WW RTTY, 0000z Sep 28 to 2400z Sep 27
- ARRL International EME Competition (2m only, dates TBD Oct/Nov/Dec)
- CQ WW SSB, 0000z Oct 24 to 2400z Oct 25
- ARRL Sweepstakes Contest CW, 2100z Nov 7 to 0300z Nov 9
- ARRL Sweepstakes Contest SSB, 2100z Nov 21 to 0300z Nov 23
- ARRL 160-Meter Contest, 2200z Dec 4 to 1600z Dec 6 *
- ARRL 10-Meter Contest, 0000z Dec 12 to 2359z Dec 13 *
- RAC Winter Contest, 0000z Dec 19 to 2359z Dec 19
* Subject to encouraging propagation forecasts
Tuesday, January 6, 2009
1. There's No One Else Out There
Draw a 500 mile radius circle from your location and take a guess how many active hams there are within that circle. On HF? On VHF? 6m? More than 1000? Maybe more than 10,000? Short-hop skip is the bread-and-butter of ham radio. You can load up the rain gutter on the house as an antenna and make LOTS of contacts. QRP can be fun! Every night on 40m and 80m there are hundreds of 20-over-S9 signals. It's easy! From here my circle is pretty barren. There's a few KL7's and a couple of VE8's and VY1's. That's all. And the next 500 miles after that are almost the same. I coined the phrase "It's All DX From Here" because it's true. Almost everyone I work is long-haul, double-hop skip. And that's hard to do from here because:
2. We're Right in the Middle of the Aurora Zone
You know those days when you can't work over the pole because the K-index is up? For us that bright orange auroral band around the North Pole is right overhead. ALL THE TIME! When the K is high we hear nothing on the radio. That's right, NOTHING! No shortwave broadcast stations, no WWV, zippo. And the K is high a lot. When it's not high things change from impossible to just difficult. Signals are still attenuated like crazy. It's a lot like using a VHF handheld inside a big building. When I first started it didn't take me long to figure out that if I could see the Northern Lights outside I wasn't going to be able to hear much on the radio. To make matters worse, for some reason (likely to do with wave angles) it seems to attenuate my transmitted signal much more than it affects received signals. This contributes to:
3. Diode Propagation
It's the November Sweepstakes contest. Everyone is looking for the elusive Northern Territories (it's NOT Yukon!) multiplier for the Clean Sweep award. I'm on 20m listening to two ops discussing the contest and lamenting that there's no VE8's on to give them the Sweep. And I'm calling them over and over and over but they don't hear a thing. Diode propagation is one of the more frustrating aspects of operating from up here. It's caused by three main factors. First and foremost is the auroral absorbtion. The second is the lack of noise. The noise floor here is extremely low. Very little man-made or natural noise is propagated here mainly because of (1) and (2) above. The end result is we can hear VERY weak signals. I've made many, many contacts where a true signal report would be five and zero. In most cases "down South" the noise floor is much higher so they just can't hear me over the noise. The third factor is directional antennas. Yagi's, four-square arrays, beverages, all work wonders to improve signal-to-noise in a particular direction. Unfortunately, "Northwest" is not a direction that people usually listen to. I can't count how many times I've struggled to make a contact and finally the guy at the other end says "Let me turn the beam" and SHAZAAM! He's 10 over S9. And when guys ARE pointing up here they don't want to talk to me. They're working Asian DX or West coast to Europe.
So what's the answer? Just accepting it for what it is helps a lot. Being diversified is also a good solution. Nothing on HF? Work satellites! Try different modes. CW is a good one. The Coast Guard radio station here is the last one in Canada that still operates CW because many times it is the only mode that can get through. My CW skills are sorely lacking but it is something I'm working on. One solution I've found is to operate during contests when there's lots of activity. The best answer, though, is to adopt a "Go Big or Go Home" philosophy. High-gain, low angle antennas and lots of power help a lot. QRP is NOT an option.
Note: The above piece was written at the bottom of the solar cycle based on experiences at the bottom of the previous cycle. I missed the last solar maximum and I'm looking forward to seeing what its like.
Monday, January 5, 2009
Class: Single Op HP
QTH: Inuvik, NT
Operating Time (hrs): 8
Total: QSOs = 26 Total Score = 212
With the K-index at zero I was hoping for better but I ended up spending most of Saturday in the RAC Contest. I did manage to get on for a bit in mid-afternoon and worked a few Europeans. Saturday night there were many good signals (including GM3POI for several hours after Eu sunrise) but once I worked them I didn't hear anyone new. My CW still isn't up to calling CQ but maybe soon. I got up early on Sunday hoping for JA's but the aurora was back and I couldn't hear them. K7RAT was S-9 all the time. Did they hijack a 100kW broadcast station for the contest?
posted to 3830 Mon, 29 Dec 2008
Class: SO Mixed HP
QTH: Inuvik, NT
Operating Time (hrs): 12
Band CW Qs Ph Qs CW Mults Ph Mults
160: 4 2 2 2
40: 1 8 1 3
20: 9 380 5 13
Total: 14 390 8 18 Total Score = 53,616
Didn't get started until after midnight as I spent several hours getting set up and then working on the low-band antennas. I made a few contacts on 160m and then called it a night. I had planned to alternate between RAC Winter and Stew Perry on Saturday but 20m was wide open and I even had many comment on how loud I was. Tried 40m and 80m in the last hour and the bands were ok but there didn't seem to be much activity left.
Highpoint: Putting my 12 year old son in the chair on Sunday and hunting for RAC stations. He was thrilled and so was I. I got so excited I forgot I had worked VE6RAC before and had him call them for the dupe (apparently he tried to tell me the computer was saying 'Possible duplicate'!) Too bad he'll be headed back to school before Kid's Day.
No low points, it was all good other than having to set up and tear down the station and antennas in the dark at -35C...
John - VE8EV
posted to 3830 Mon, 29 Dec 2008
Since this year is the 40th anniversary of the Apollo 11 moon landing I decided we should get serious about setting up for EME. Its been something of a long-term goal for a while now but with a deadline I'm hoping to motivate myself to pull together all the pieces that I've been collecting for so long. In addition to VHF EME there will also be a UHF antenna for satellite work.
The VHF antennas (a pair of Cushcraft 13B2 yagis) are sitting in storage ready to go. The 10-turn UHF helix antenna has the reflector and boom completed, just need fabricate a mount and install the element and antenna connector. I have a cheapo antenna rotator for azimuth and an old dish jackscrew for elevation. I've got a LabJack box and an plan to tie them all together with the computer to provide fully automatic tracking of satellites (including the moon). I've got piles of 50 ohm hardline for antenna cables and 75 ohm hardline for the phasing harness. On its way as belated xmas gifts are a pair of VHF preamps. Several big coax relays with N-connectors are waiting in the junk box. And then there is the amplifier.
A couple of years ago, before I was even back on the air, I decided I was going to build a 2m EME amp. After lots of research I settled on a 2 x 4CX250B design by LA0BY. I had an old semi-functional HF amp that could be sacrificed to provide the power supplies and chassis so all I needed to get started was tubes and sockets. Fortunately, I came across a fellow selling a driver stage from a Collins broadcast transmitter that had a pair of 4CX250B's, the sockets, chimneys, and an assortment of other useful parts. I picked that up for the same price as a pair of tubes and its been collecting dust on my shelf since then. The only thing I don't have yet is the RF deck enclosure which I'm hoping to have fabricated from aluminum by an acquaintance who fixes airplanes and the tetrode board. This little piece of electronic magic by G3SEK is available in a reasonably priced kit and will provide all the required control, protection and voltage regulation circuitry. After all that, the rest is mostly just wiring and plumbing...