There are times when we go the extra mile -- or 2000 km -- to help a friend in need. I joined Chris VO2AC on another long drive to Labrador to work on his remote station in Happy Valley-Goose Bay, Labrador. Unlike two years ago, this time it was just the two of us. Other friends had to decline due to obligations despite their willingness.
He had a long list of jobs to be done but we were confident that the two of us could get it done. So he went ahead and booked vacation time from work. The total trip was 10 days: 4 days driving and 6 days working. On several of those days we worked late into the evening. Including driving around town he put over 4500 km on his truck. He had a full load in the bed of his F150 and a full load on the drive back. More on that later.
This article will mostly deal with the work that would most interest readers. Suffice to say that we were spoiled by the hospitality of his mother Thelma and aunt Judy who prepared most of our meals. Other relatives of Chris invited us to their houses with typical Newfoundland hospitality and introduced me to several dishes I'd never heard of before. Then there were his many friends that provided our accommodation, flew a large yagi to Labrador and much more. I'm convinced that Chris is related to half the town and the other half are childhood friends. I felt very welcome even if it was all a bit overwhelming.
What had to be done
These were the major tasks that we needed to accomplish:
- Repair the rotator, or discover what might be interfering with its proper operation
- Matching networks for several antennas
- Upgrade, repair and replace various station equipment, hardware and software
- Non-radio work on the property
The first item was why my presence was particularly useful. I came in handy for the second as well. For the rest I was just another pair of hands to get the job done. I wasn't there for just the "glamorous" work.
The T2X (Tailtwister) rotator failed some time ago and attempts to diagnose and repair it from the ground were unsuccessful. Since that was the most important job we got to work on it the very first morning. That meant lifting the mast and yagis so that the rotator could be removed and brought to the ground for inspection and service.
There are many ways to lift a mast and its complement of yagis that ought to be the subject of its own article. It's one that I've touched on several times on the blog. For now I'll just say that I used a chain, come-along (hand winch) and a pulley attached to the mast to take the weight off the rotator. This seemed to be the most convenient approach for this job among the several alternatives I've used over the decades.
I couldn't fit everything in one photo since I was too close for a wider view. This one will do until I write that article about mast lifts. The chain wraps around tower members and attaches to the winch and a rope through the pulley to pull the mast straight up. The thrust bearings are loosened to allow the mast to slide past.
Without lateral support the yagis can spin freely despite a modest resistance to torque from the lifting mechanism. It is vitally important to put a "block" on the mast or yagis to prevent that, especially if it is windy or the mast and antennas must be left like this for hours or days. Weather is unpredictable It is also recommended to "lock" the mast with, for example, an ordinary muffler clamp sitting on a thrust bearing so that the weight doesn't relax the rope or chain enough to interfere with reinstalling the rotator. However, be warned that almost all thrust bearings used by hams are not designed for axial loads.
Well, that's enough for what I intended to be a brief description. In this case the weight lifted was only about 150 lb (70 kg) but we had to leave it like that until the next day. I roped the bottom yagi (JK Mid-tri) with rope to keep the mast from rotating more than a few degrees. There was some rope relaxation but not enough to get in the way of the rotator installation the next day.
The fault was in the rotator and not the controller, specifically the brake solenoid. This was despite the nominal resistance checks recommended for this series of Hy-Gain rotators. It failed to operate when powered and drew enough current to blow the controller's AC fuse. The solenoid and brake mechanism looked pristine and there were no apparent mechanical flaws. Chris can look into the problem at his convenience now that he has the rotator back home.
The substitute rotator also experienced a fault! After opening it up we found a wire that was cut. I say cut rather than broken because there was evidence of a wire cutter being used. We don't know where or when that occurred but it was easily repaired. The rotator was installed on the tower and performed admirably. Hopefully it'll last for years to come.
We didn't have too many ball bearings escape us during the disassembly and both rotators were quickly reassembled using my usual alignment procedure. Neither T2X needed grease or other attention beyond that already mentioned.
The tower supports verticals for 80 and 160 meters and inverted vees for 40 and 80 meters. Deployment isn't optimal due to the wires being close to the towers and, for the inverted vees, the interior angles are not greater than 90°. Shunt feeding the tower isn't currently an option but could be in the future. For 40 meters Chris also has a 3-element vertical yagi (modified K3LR array) that can point northeast and southwest in addition to omni-directional.
The vees and verticals have fairly narrow SWR bandwidths. Adjusting the lengths of these antennas is not easy and our time was limited. Mounting matching networks at the feed points of the inverted vees was also inconvenient. Chris chose an alternative that can work very well on the low bands: put the matching networks on the ground where they can be easily maintained and adjusted.
Provided that the SWR is reasonable, the mismatch on the coax (LMR400 in this case) from the matching network to the antenna can be quite low. For a given length, type of coax and SWR the mismatch loss rises with frequency. The loss is easily calculated and there are formulae and charts in every antenna design book commonly used by hams, and plentiful online calculators. There is no need to get into the mathematics here. It is up to each station owner to make the calculation and decide what is acceptable to them. There is no excuse not to do the calculation; don't fool yourself.
With a set of measurements made at the base of the tower (where they plugged into antenna switches) I sat down with TLW (comes with the ARRL Antenna Book) and designed L-networks -- there are many alternatives and also online calculators such as this one that I picked at random. Chris already had the boxes built, including high-Q coils, so all I had to do was determine L and C values, and the L-network topology (there are 4).
We had bags of vintage mica transmitting capacitors of every type and value imaginable. A group of us pool our resources and pick what we need for our antenna projects. Despite their age they work well. I have never had one fail.
A perfect SWR is not necessary provided that it was below 2 or, better, 1.5 over the desired range. Those are upper values acceptable to his solid state amplifiers. Careful design will usually find such a solution across a few hundred kHz on 40 and 80 meters, and less on 160 meters. Success is only limited by the Q of the antenna. A simple matching network can move the frequency of the ideal match but cannot broaden it.
For the 40 meter inverted vee I was able to find a solution that worked pretty well from 7.0 to 7.2 MHz (picture above). The L-network for the 80 meter vertical degenerated to a series C since the shunt L approached infinity. The reason is that the measured R value was close to 50 Ω. The positive reactance is cancelled with a series capacitor (see the photo). Since this antenna has a narrow SWR bandwidth and the inverted vee was made switchable between CW and SSB we opted to tune it to the CW segment.
Chris programmed his software to allow operator selection of the various network options. That went well so all we had to do was weatherproof the coax connectors and antenna feed points. A rainstorm moved in during the work so we got quite wet. Letting the connectors get a little wet is not really a problem but then we'd have to thoroughly dry them the next day before wrapping them in tape.
Antenna matching woes
Not everything went smoothly. I'll mention a couple of items that gave us grief since our experience can be educational. We dealt with them easily enough but only because we understood what was happening.
First were the two antenna analyzers: they didn't agree. The differences were small but large enough to matter. One or both of them had to be incorrect. This could be due to poor quality analyzers or damage. I've seen too many hams using inaccurate instruments or not being aware of how they can give incorrect measurements when used improperly.
An antenna analyzer is single port network analyzer that generates a signal at the displayed frequency and compares that to the signal that the network being tested returns. That is, an S11 measurement. In our case both analyzers are by RigExpert (AA54 and AA55-Zoom) which has a well earned reputation for reliability and accuracy. That said, they are designed for field use and are not laboratory instruments. Some compromises are required to harden them for the intended application.
What happened? The X measurements closely agreed but there were significant deviations for the R component of the complex impedance. Chris told me that the AA55 had previously suffered an accident that destroyed part of the bridge circuit. The precision SMD resistors that replaced them were not exactly 50 Ω due to availability. Knowing this I tested the device with a dummy load that showed an SWR of about 1.1 at all frequencies, or an impedance of about 54+j0 Ω. The error was more apparent when measuring low impedances.
I used my AA54 for measurements after discovering the problem despite its lack of features in comparison to the newer AA55. The bridge circuit in a network analyzer is critical to its accuracy and the one in mine was working perfectly.
The second problem was quite interesting, and predictable had we thought about it in advance. To improve ground loss for the verticals -- 80 and 160 meters and the 3 elements of the 40 meter array -- we tied them together at the radial plates. It's a good idea and I do it whenever I can for my antennas where the radials overlap. However, radials are an integral component of the antenna system's behaviour, not only its efficiency (protection against near field ground loss). Except in a very extensive radial field any change to the radials will impact the impedance of the antennas.
The match we had obtained for the verticals was no longer quite so good after doing the work. Realizing what had occurred we disconnected those wires. There was no time to rework the matching networks for each antenna; it was left for the future. In the case of the parasitic 40 meter array the impedance change was less concerning than the pattern changes. Element tuning in an array is critical to its performance. A slightly higher SWR in a single element antenna is easier to live with.
Inter-station interference
Chris's station is fully SO2R and 2BSIQ capable. With so many antennas fit into a tight space there are challenges preventing harmonics from degrading reception on higher bands. This is despite a full complement of high power BPF (band pass filters) and triplexer by VA6AM, and a 2×8 switch and ancillary switches with pretty good isolation between ports. The laws of physics are not negotiable.
The addition of stubs to the BPF to attenuate the second harmonic made no discernible difference. We were pretty sure that the problem was more fundamental than that. As is typical done in many stations, the BPF are placed on the antenna side of the N×M antenna switch. Unfortunately that makes the station susceptible to the relatively poor port isolation of the antenna in comparison to the ultimate rejection of the BPF and stubs.
I can get away with it in my station since most of my antennas are far apart or usually pointing in different directions rather than at each other. The best approach is to place the filters on the transmitter side of the antenna switches. That is really only practical with two sets of high power BPF since you'll otherwise be faced with leakage through the relays that switch the BPF between radios. Most choose to have switchable coaxial stubs after each amplifier and leave the BPF where they are. There is no perfect solution, we do what we can with the situation as it is.
When a station can only be occasionally accessed for brief periods of time there are certain to be overlooked items and other mishaps. I won't go through them all, but I will mention a few related to the tower and yagis.
My usual technique for installing rotators is to loosely bolt it to its tower plate and do the same for the plate to the tower members it mounts on. That way I can ensure that the rotator and mast are aligned and only then tighten the various bolts. I do the same with antennas, only slightly tightening bolts on the boom-to-mast clamps and other mounting hardware until I am satisfied that the yagis are pointing the right direction, are level and the rotation loops have been tested.
It is not uncommon that I'll miss a few bolts when I'm done. I discover the mistakes soon enough and then make sure that all are properly tightened. For a remote station you may not get that second chance. Not only were several nuts only finger tight, a few were entirely missing! I can't be certain that these oversights were my fault but I'll take the blame regardless. I'd have discovered them quickly in my own station since I am frequently on the towers.
When you run cables to a tower you have a few ways of doing it: overhead, on the ground, or underground. The initial install used a conduit buried in the sandy soil common throughout Happy Valley-Goose Bay. Digging a trench isn't difficult, which is good since he needed another one
The new trench was short and was not for coax or control lines. Chris has ample cameras so that he can view the tower and antennas and all the critical equipment inside the shack. He handed me a shovel and I dug a new trench to the fence that separates the tenant's yard from the antennas and tower for more cameras.
Detours on the return drive
After passing through the town of Churchill Falls we made a couple of stops. Public tours at the generating station were temporarily suspended so Chris chose alternatives. The first was a hike to a lookout over the real Churchill Falls (see picture at the start of the article). The waterfall isn't impressive since almost all the water is dammed and diverted to the generating station. If the water gets too high they open the gates to let the excess escape over its natural outlet over the falls. It's a rare event that I am told is very impressive.
Our next stop was at a place where two westward transmission lines abut the highway. We took a close look at the towers. Well, of course we did: hams love towers! One line uses self-supporting towers with 4 legs and the other uses guyed towers. At the end of the article is a picture showing Chris standing next to the pillar base of one of the latter. Their size is impressive, to say nothing of the many megawatts on the wires the towers support.
It would be interesting to watch them erect these monsters. Every tower, pillar and anchor has unique requirements engineered for the the site.
They must work with the local soil and rock, whatever it is and no matter the lack of levelness since the tower position can't deviate far from the transmission line's path. Unfortunately we couldn't tell how the anchors were done.
There are really only two alternatives: drill and set anchors into the rock if its tensile strength and size are sufficient, or excavate the rock for a conventional dead man anchor where the overburden resists the guy tension.
The guy cable and hardware are approximately 1" diameter (2.5 cm) so the breaking strength must be close to 100,000 lb, with a preload of about 10,000 lb. There's a lot of force on each tower and its supports. Failure of the transmission line is really not an option; a reliable electricity supply is critical to our modern civilization.
The real reason for the trip
If you read the article from 2024 you'll see a room full of Heliax, almost all of it AVA5 (⅞"). It came from the decommissioning of a commercial site. Naz VO2NS stored it at the Labrador City club station. They eventually decided that they have no use for it and offered it to us. We had very little room in Chris's truck on the earlier trip. We did better this time.
I have no exact measurement of how much is there other than it's a lot. I don't need all of it, but I can find good homes for the rest. Many hams don't appreciate the difference low loss transmission line can have on their on-air success, especially as the frequency climbs. It's one reason I do well on 6 meters and it is absolutely essential for the long runs necessary to traverse the hay fields and climb my tall towers. The average run on HF is more than 100 meters.
I'm showing my age (on the right)! Chris VO2AC is on the left and Naz VO2NS is in the centre. This is a roll that Naz and I compressed from about 4' diameter to 3' so that it would fit inside another roll. Space in the truck bed was at a premium. Heliax this size can be wound tighter, but only if done carefully. Naz's neighbours were entertained by our (eventually successful) attempt. It was done by rolling the Heliax down the back lane into a tighter bundle while laughing over our many mistakes along the way.
Mission accomplished
Building and maintaining a remote station that is thousands of kilometers away is not for the weak of heart. Much can go wrong, or at least fail to go right. If something fails it can be months until a repair is feasible, even if it's to reset a computer or jiggle a connector. Although it helps to build well it is inevitable that trouble will make an appearance sooner or later.
I must also mention that the climate in FO93 is harsh and the flies are fierce. Working outdoors this time of year is unwise without an ample supply of bug repellent. There are no bugs in winter so you only need to deal with the cold and snow which are both in ample supply. Having come from VE4, I am familiar with what winter tower work is like for Chris and others in Labrador. On the other hand, the electricity supply is ample and unbelievably inexpensive due to the local generating capacity.
Chris is committed to this venture in his homeland and he will make every effort to keep it going, even when that means hopping on a plane or making a 2000 km drive each way. That is less burdensome than it seems since every trip is an opportunity for him to visit with his large family and reconnect with old friends.
I don't expect to make many more trips to VO2, perhaps none if all goes well. I leave Labrador with the satisfaction of helping Chris be successful. I can also look forward to a reliable multiplier in every contest that I enter. Of course there's all that Heliax waiting to be put to good use. That is, once I figure out how to move it the 50 km from his home to mine.
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