2019: Year of the Yagi

Waiting for spring

It's that time of year to look ahead and make my plans for the 2019 station construction season. I've made a habit of doing this every year, and you'll find a similar article about this time of year in the blog's archives. They are also among the least interesting for readers. However this blog is about more than engaging readers at all times; it is a tool for keeping myself honest.

Despite the inward focus it can still be of use to others who could benefit from doing the same, and then measuring their progress at the end of the year. The comparison can be both sobering and instructive.

My ultimate objective is a moderately competitive contest station suitable for both single op and multi op, while also fueling my daily operating habits of DXing and experimenting with new technology and operating aids. It is not intended to be a lifelong project. With some effort the bulk of the "heavy lifting" will be completed in 2019 or early 2020. Since there will be non-radio summertime activities I may not fulfill my entire plan. But it is important to have objectives and a plan to get there.

After failing to fully achieve my 2018 ambitions I remain cautiously optimistic that I can do better in 2019. The major construction project -- a 140' tower -- is more than half raised, and should be complete in early spring. The only substantial mechanical decision to be made with respect to the new tower is whether to go with a conventional heavy-duty rotator or to use my spare prop pitch motor. Construction of the mast and drive system must be complete before the top two tower sections leave the ground.

With that out of the way I can turn my attention to antennas, and antennas means yagis big and small. Indeed, that is the focus of my plan for 2019.

Building yagis

As with most everything in our stations we have a choice between build and buy. Buying can be new or used. Time is limited and none of us can build everything in a large station. I pick my places. One of those places is antenna.

I have booms built for one each of long boom yagis for 20 and 15 meters, and I have most of the material on hand to build identical copies of each. These 4 yagis are slated for the new 140' tower (40 m, more precisely) on these all important contest bands. The lower yagis will be fixed northeast, towards Europe.

Aluminum tubing is available in abundance from just about every industrial metal dealer. The trouble comes when specifying the alloy and the less popular sizes suitable for telescoping elements. For example, one outlet that claims to sell most everything in any length does not actually do so. Alloys are mostly the weaker non-structural and the selection of wall thicknesses and outer diameters is incomplete. Another outlet carries more suitable tubing but only in full 20' and 24' lengths and charges quite a lot for cutting. I would have to cut tubes in their parking lot to fit them in my car!

Another difficulty is acquiring 0.058" wall tubing in Canada. This is classed as aerospace tubing and has a limited market. I am revising mechanical designs and about to begin machining experiments to see what I can do with common 0.065" wall tubing. The rest I will import from the US.

Boom-to-element brackets are another area of concern. Although straight-forward to design and build it is the fasteners that are expensive. Each alone isn't, but I will require a large quantity.

I am searching for good quality and reasonably prices products which, again, will have to be imported from the US. Importing from the US ought to be simple but often isn't since many dealers do not specialize in international sales and can incur substantial brokerage fees. There are alternatives to get around the problem.

Once construction of the yagis is fully underway I will surely devote a few articles to the subject. Compared to many of the components of a large station yagis are relatively simple things. It's the details that can bog you down.

Tri-banders

With mono-band yagis for the high bands I will have surplus tri-band yagis, all Hy-Gain: TH6, TH7 and Explorer 14. I will likely sell the latter and probably the same for the TH7. I would then find another TH6 and stack them on one of the towers, possibly rotatable through 120°. I would use these at a lower height to cover the US and Caribbean, without risking interactions with the mono-band yagis higher up.

Side mounting these yagis is, in part, why I will replace the TH7 with a TH6. On the TH7 the dual driven elements can easily strike the tower when rotated. Further, the electrical design of the TH7 is not optimal for the CW band segments on 20, 15 and 10 meters. I don't want to mess around redesigning the antenna to do better on CW. The gain and performance is acceptable but not the SWR.

Although not the best antennas these large tri-banders will take a lot of the operating burden from their mono-band cousins, allowing instant switching between directions and still have a powerful signal wherever I need it. It's also far cheaper than alternative but will likely need to be refurbished. Getting the TH6 down from the big tower is necessary no matter what because one of the traps is exhibiting intermittent continuity.

80 meters

My vertical yagi project has been proceeding slowly. So slowly that it's almost been standing still. I further delayed working on the switching system due to the deep snow and cold temperatures. Now that the hours of sunlight are increasing and warmer weather approaches I intend to get going on it.

80m vertical yagi switching system - some assembly required

Ideally it would be ready in time for the upcoming ARRL DX CW weekend, but that is unlikely. I'll leave it fixed on Europe as I did in CQ WW CW. I configure it that way except for Pacific area DXpeditions and North American contests.

The 80 meter vertical yagi should be completed before the warm weather when my attention will shift to other projects.

40 meters

When the TH7 comes off the 21 meter tower (70') my plan is to replace it with the XM240. This would become my short path rotatable yagi for this important contest band, covering the US and more. But before it comes down from its current position at 46 meters (150') on the big tower I need to replace it with another 40 meter yagi.

Therein lies what is perhaps my biggest roadblock this year. I want to build and raise a full size 3-element yagi to go on that tower. That's a large enough project that it may be impossible to manage this year considering everything else that needs to be done. Indeed this antenna is why the prop pitch was installed on that tower.

It's entirely possible that there will be nothing up there in the fall. That is, if I can build a wire yagi pointed at Europe between the two big towers. That way I would not have a unbridgable gap in my 40 meter capability. Alternatively I could purchase another XM240 or similar yagi as a stop gap measure for the next year or two. Should the opportunity arise I may go for it.

10 meters

This is the least of my worries. I do plan stacked yagis for 10 meters on the 40 meter tower, with one 6-element yagi on top of the mast above the planned 40 meter yagi (where the XM240 is currently situated), and one or two more lower down fixed on Europe but preferably rotatable.

With the sunspots not reappearing to boost 10 meter propagation until 2021 this project will be fit in as time is available, after the other projects are completed.

6 meters

No changes are planned this year. The redesigned A50-6 at 24 meters will be my antenna for this year's sporadic E season. The only change will be the transmission line so that I can recover most of the estimated 3 to 4 db loss in the very old run of RG213 I've been using until now. The reason I've delayed replacing it is to save the Heliax I have for runs to and up the big towers.

If that supply problem is not resolved by April I will install a run of LMR400 up the tower from the antenna switch at the bottom. With the recent rewiring the run from there into the shack is a combination of LDF5 Heliax and LMR400, which is good enough for now.

In future years I would like more gain on 6 meters. This would either be accomplished with a longer boom yagi or a stack of two yagis. They will likely require a new tower. I have some thinking to do.

160 meters

I covered my options in a recent article. As a minimum I will replace the current antenna with full height wire vertical and at least double the current 8 radials. Every decibel I can scrape out of a simple and temporary antenna will pay big dividends. This was emphasized by the difficulty I encountered during the recent CQ 160 meter CW contest when marginal conditions kept a large number of QSOs and multipliers just out of reach. I don't want that to happen again.

Longer term I do want to exploit the towers to achieve gain on top band. I have been running models to explore alternative ways to corral them into either a vertical yagi or phased array. In addition to computer models I would need to experiment to ensure using the towers will not cause serious coupling into the tower mounted yagis, and from into the station. It is a solvable problem.

Receive antennas

The short west Beverage is a stopgap until I improve my low band receive capability. At the least I plan to twin the existing northeast Beverage to make it reversible. A north-south reversible Beverage is also likely. These projects could be put off because they are not mandatory until I run high power and attract many weaker stations. It is also not absolutely needed for 80 meters since the vertical yagi has very good directivity. Receive antennas are primarily needed for 160 meters.

A vertical phased array remains a possibility, if only to simplify maintenance and eke out the best directivity and selection of directions. I have not decided. The small number of planned Beverages will prove adequate until the rest of the station is complete. More receive options raises the possibility of diversity reception, which is a powerful technique for copying weak signals.

In the shack

As I demonstrated last month it is possible to do SO2R and multi-op with no automation or filters, for low power contesting. When I acquire an amplifier that must change. I have been putting off this work until it becomes unavoidable. There is also the prospect of more antennas which will exceed the capacity of my current switching system. When my 2019 tower and antenna plan comes to fruition there will be no more putting off the inevitable.

Automated selection of filters and antennas from two operating positions will be needed by the fall contest season. That will be quite a challenge since much of it will need to customized, a hybrid with commercial equipment. The filters will be bought and the switching system designed and developed by me.

I would like to arrange the first multi-op sometime during the next contest season. Station automation is required since it may be too much to ask others to figure out the unique manual control systems I currently employ. Physical rearrangement of the shack will also be necessary so that two people can comfortably operate together. Of all my challenges this will be the easiest to accomplish.

Transceivers are going to change. I expect to sell both the KX3 and FT950. The FTdx5000MP will remain for one operating position and the other will be a K3 or similar high end transceiver. I will still be able to operate QRP by turning the power down to 5 watts (but not on the 5000 which has a minimum power of 10 watts). Although the KX3 is a wonderful rig I am becoming increasingly frustrated by its limitations; it is not suitable as a high performance base station rig.

For competitive use the FT950's DSP filtering is too noisy and rings and the receive audio is noisy. It has been surpassed by subsequent generations of equipment. I have kept it around to experiment with SO2R and as a backup for the main transceiver.

As with previous years my 2019 plan is ambitious. I have set my objectives and now must do my best to achieve them. That I will probably fall short does not deter me from aiming high.

Administrivia

Google has not only abandoned Blogger development they are also in the process of shutting down Google+. The latter is not of concern to me other than it will mess up reader comments and possibly some lesser things. I won't know until it happens. Anonymous comments unfortunately remain prohibited because every time I allow them there is a flood of spam. I apologize for the inconvenience. It's because of this problem that comments are moderated.

As many have discovered, direct email is the best way to reach me. Those I reply to. Comments on articles are routinely approved although I might not reply to those. Blogger may eventually become unusable and I'll have to find a new home. That would be an unwelcome burden and could kill the blog. But for now it's business as usual.