Sunday, September 13, 2020

Transition Season

This is the time of year when I prepare for the transition from summer to winter. Some of the tasks are unavoidably annual tasks and others are due to the incompleteness of my antenna farm. The former includes the following:
  • Clearing brush from antennas and cables
  • Inspecting low band receive antennas for damage and make repairs
  • Inspect towers, including cables, bolts, guys and antenna connections
  • Inspect exterior electronics and clean or repair if needed
Our winters are not a good time for precision work outdoors. It can be done but it can be very unpleasant. Usually I try to limit myself to critical repairs and work that requires nothing more delicate than a large wrench. Even then I schedule work during the rare warm days. 

In the second category are these items:
  • Disconnect the 6 meter antenna and connect the 160 meter antenna
  • Put up the full size 160 meter vertical antenna
It doesn't look like much but it adds up. Were I not retired it would be difficult to get it done. Most items in the second category will vanish when the station is more complete. So I've been busy.

Beverages

The ticks are gone but the vegetation is in full growth. However I did have to evict a colony of earwigs from a junction box at the base of one of the towers, and wasps are beginning their annual infestation of the towers that they are attracted to for some reason. They are not a danger in this state.
 
The northeast-southwest Beverage developed an intermittent problem and then complete failure in late spring that primarily affected the reverse (southwest) direction. I don't use it much in the summer so there was no reason to risk the ticks or tripping over invisible obstacles. I suspected a loose ground wire at the northeast termination.

On a wet day when not much else could be done I donned suitable clothing, filled a bucket with tools and parts and entered the "jungle". I took the picture below to give you an idea of what it looks like. There is a two-wire Beverage in there that is very difficult to pick out amidst the vegetation!
 
Much to my surprise the intermittent and total failures had independent causes. The intermittent was due to rapid bush growth into the two wire Beverage that pushed the wires together in two places. This is despite the aggressive cutting I did in late winter when I twinned the Beverage to make it reversible. When the wires touch the differential mode required for the returning southwest signal is disrupted.
 
 
I cut the worst of it and the rest can wait until winter when the growth dies and the ground is more walkable. The total failure was due to the lower wire being severed a few meters from the northeast terminal. A brief forensic analysis suggested an encounter with deer antlers rather than malice and no trees had fallen. I have never seen signs of other humans that deep in the bush and the broken ends were not cut with a tool. The wires slope down toward the termination and that makes them vulnerable to deer. That it was only the lower wire reinforces the conclusion.

Luckily aluminum fence wire isn't difficult to splice by hand since the one tool I needed -- pliers -- wasn't in my bucket. I tensioned the wires after the repair and made sure it lifted off the bushes and trees during the walk back. There's a lot to cover over the 175 length of the Beverage. I'll improve the splice and make a few improvements after the ground freezes. Perhaps a bit of yellow hazard tape hanging from the wire will persuade deer to duck their heads! The antenna now works as it should.

Protecting aerial cables

Due to trees and other obstacles all the cables from the big towers and other distant antennas is not buried near the house. I have an aerial messenger cable to carry multiple runs of Heliax and control wire from the surrounding stone wall to the Trylon tower near the house. All switching and wire connections are done at the base of the tower.

There are many trees surrounding the yard and unfortunately most are birch. I say unfortunate because they grow like weeds and only live for 40 years. These trees are 25 years old. Branches grow quickly in the space over the aerial runs and threaten them by breaking off in high winds and ice storms. Regular trimming is mandatory to avoid catastrophe.

This was my first major trimming the aerial run was built in 2018 and there was a lot to clear. There is one major limb left to be cut but that will require more care since cutting it risks damage to the cables below. For now I am relieved to see daylight around the aerial cables.
 
I am very tempted to chop down the two adjacent trees and remove other obstacles so that I can safely bury the cables. That's for the future and until then I will continue the annual trimming ritual.

160 meter antenna

Unlike previous years I am using a buried Heliax run to the new 140' tower for the seasonal 160 meter antenna. It is connected and ready to go. The antenna cannot yet be deployed because the 20 and 15 meter stacks are incomplete. The tram rigging for the final antenna -- the upper 5-element 20 meter yagi -- cannot coexist with the wire antenna supports. 
 
There is also the matter of radials which lie on the ground. Those are a serious safety hazard for my crew. I like to protect my friends from injury! Deploying of the radial will have to wait.

Another matter is the location of the antenna which will be different from previous years. There is modelling work to be done to ensure there are no coverage gaps. The towers act like reflectors and although poorly tuned as parasitic elements they skew the pattern several decibels and increase ground loss (via the lightning ground rods). After the modelling and other antenna work on the towers are done I will proceed with the installation.

My summer 160 meter antenna is marginally acceptable. I find it frustrating calling DX stations that hear me weakly or not at all that would be easy with the full size vertical. The smaller antenna serves its purpose well enough but it is not suitable for serious DX and contest use. I estimate that 1 kW to it works as well as the full size vertical with 200 watts. That's an estimated deficit of 6 to 7 db, a little worse than the model predicts. Ouch!

Yagi on deck

Rigging of the heavy 5-element 20 meter yagi is being installed. The tram for a 110 lb (50 kg) antenna (add 30% for the rigging) has to be stronger than for antennas half that weight. The yagi is tuned and almost ready to go. It is shown below in position for attachment to the tram. The lift should take place before the end of September.

 
The delay has several causes which I won't go into in this article. The most important is completion of the mast system. The missing piece is the prop pitch rotator which is needed to control the mast direction and to hold it in position for the lift operation. The motor is installed and operational but not yet coupled to the mast. The weather hood and the direction indicator remain to be built.

With the completion of the 15 and 20 meter stacks the summer construction season will officially be at an end. Despite delays the project should be complete in October.

Howling at the...train?

We have a lot of coyotes. They roam in packs or solo and are occasionally seen in the fields or the verges of the bush. My farmer neighbours take a dim view of their presence and will shoot them if they threaten their livestock. They have mostly learned to avoid humans and their dwellings. 
 
In winter their tracks are found everywhere in the dense bush snow cover. When I revisit my Beverage sites on consecutive days I find their tracks alongside mine. Most nights their howls are heard from afar and sometimes close by. They are not often heard in the daylight.

One recent exception is a pack in the large bog that covers the east corner of my property and several adjacent properties. It's dry this time of year and easily traversed by wildlife. The coyotes hunt throughout the area killing deer, turkeys and anything else they can catch. In a way I can claim that they are protecting my Beverages from deer damage (see above).

The passenger train service between Ottawa and Toronto passes 1.5 km to the east and following the pandemic lock down service is back to normal with frequent passages of the trains. When the trains toot their horns at road crossings the coyote pack have taken to howling in accompaniment. 
 
While on the tower this week the howling was quite loud and was also heard by my friend on the ground. I can pretty well locate where the pack is located although I cannot possibly see them in the dense bush despite being 40 meters high, far above the tallest trees.

Despite the coyotes not being welcome their howling along with the trains is entertaining. I've gotten to the point of stopping and listening when I hear the trains and like clockwork the howling begins. Living in the middle of nowhere has its advantages.

Upcoming articles will include ones about the prop pitch rotator, the 15 and 20 meter stacks and the new full-size 160 meter vertical. Amidst this and other responsibilities I am having trouble finding time to write articles for the blog. Hopefully this one is interesting enough to fill the void.

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