Antennas - Rotators

Antennas and Rotators Used at K4SO

VARIOUS UNCONVENTIONAL, SEEMINGLY TEMPORARY ANTENNAS PLUS MORE CONVENTIONAL AND INTENTIONALLY "PERMANENT" RADIATORS AND RECEIVING ANTENNAS HERE IN AMISSVILLE.

      Don't get too excited, the tower below is my part of my former antenna farm in Nokesville. Yes, I miss it.

This is the last iteration of my tower in Nokesville, "fully loaded," before I stripped what I could easily remove, before moving to Amissville.

 All that was left behind was the KT-34XA and 40M yagi. with the Tailtwister rotator and mast.

DECEMBER 7, 2011

Things certainly changes when I left the tower and some of the antennas pictured above when we moved to Amissville. First, I made use of a 100-foot-tall Tulip Poplar right behind the house to support a 160M inverted vee. That antenna went up the day after we moved in. A lucky shot with my low throw-weight fiberglass bow, hollow aluminum arrow with minimal solder load at the tip and 6 lb. test fishing line just cleared the top of the tree .I figured that it was enough wire to tune on several bands, and at 85 feet, was high enough to work on even it's intended design frequency. I was mostly correct. "Any port in a storm" is an apt description of the situation, and at least I was on the air.

As I write this, almost three years since that first shot that put my station back on the air, I've been through a lot of different arrangements, but have settled on a few winners, at least given the competing factors of cost, available support structures, available hardware, and a desire to put out the best signal possible while balancing those considerations.

I hope the information and pictures may be of some help to others not blessed with essentially bottomless budgets in terms of property, available time and energy and finances, to use my successful attempts, and avoid some of my sad failures.

Rather than recount all the chronology, I'll start with the technique that has generated the most interest on the air, when described, and "in person" when visitors get a look at it. This is not my invention, or an entirely new idea, but one that tends to be on the fringes of day-to-day, non-Field Day implementation. I am referring to suspending a multi-element, directive yagi, Moxon, or Spiderbeam (no reason a Hexbeam, Cobweb or other variant wouldn't work), from an overhanging tree branch, and turning it with a ground-mounted rotator. For purely temporary use, hanging a triband or monoband yagi from an overhead support, typically a tree, "armstronging" it with a rope or two attached to it, then tying it off in the desired direction, is certainly not new. For something like Field Day, from the east coast anyway, just fixing it to the west is sufficient. The seed for my setup was doing exactly that at a Field Day in 1974 in nearby Nokesville. For the next  35+ years, I never needed the technique, with a succession of taller and taller, as well as sturdier towers to support my yagis. Still towerless here in Amissville, as I first wrote this (remedied in 2015), I needed to reach back to this concept to make use of antennas and a rotator I already owned. This improved my signal (and DXing results) on the bands, before I fully understood the fact that Cycle 24 would just be a bit of an imposter as a solar cycle like most of us had come to know and love. It was unlike the others I've experienced, but had has some real high spots (pun intended), but will likely be remembered less fondly than those that preceded it.

I started chronicling the genesis of these setups on the homepage of this site, adding details and new configurations as I went, then decided to pull them off and give them their own page. The typical headline was "_________ Without a Tower," as I filled in the blank with an activity or band, as you'll see below. I've just moved those posts, as is, but most contain links in the pictures to more extensive photo albums and captions. Those are where I hope the helpful details live, that might encourage you or save you some time and trouble, and provide a unique, viable option that you might not have considered. I have the benefit of a couple large, stout oak trees, with their tendency to have overhanging branches in their crown, which are themselves relatively large and strong. This means they can be used by putting a line over them with my bow and arrow. Once a rope with pulley (or later, block-and-tackles) is in place, they support (so far) the weight of my HD Spiderbeam (35 lbs.) easily, and naturally, lighter antennas. I have two such spots, differing mostly in terms of the span of the overhang, and open space under the supporting branch. This dictated that the HD Spiderbeam be put in a particular tree, which could also accommodate antennas with shorter booms and elements. The other, original spot, is still viable for either a 6M yagi, 10M yagi (not likely to see much use after this fall, if then), or 2M yagi. A 17M Moxon was deployed there as well, with great success and has moved on to a new home at W4GO. So, let's start with these descriptions and if you want to jump to some details that may be helpful, branch out (the puns just keep on coming), to the Picasaweb albums that are linked.

10M CONTESTING WITHOUT A TOWER 

With the success of hanging directional, rotatable antennas from an  overhanging branch in a good-sized oak to the side of our house, I've been at it again. There are descriptions of the 6M yagi, a 5 element 10 lb. antenna which was the first, and then a 17M Moxon, which became a dual-bander, with a 10M Moxon added to the same spreaders. The latest use of this skyhook, is as a support for a 4 element 10M yagi. This antenna is a Cushcraft model 12-4CD, which was there on “opening day” when 12 meters became available for amateur radio use. The antenna was parted out for elements for a 6 element OWA 10M monobander, built on a TH6-DXX boom, with two HyGain elements (what taper schedule?) and the boom saw duty as a lightweight mast for VHF antennas. Fast forward to the new QTH, and a bundle of aluminum in the pole barn, unused. The 10M ARRL Contest was approaching, conditions picked up for a while, but when conditions dropped, I decided the Moxon wouldn't provide enough gain for the conditions. So, I got the plans for the 10-4CD, and with some vital additional data (dimensions for the gamma match) from my cousin Art, W4ACM, who has a REAL 10-4CD at a local ham‘s location, I rebuilt the antenna into a slightly ruggedized 10-4CD.

In case you'd like to try the same technique, the saddle support rope should carefully positioned to balance the antenna front-to-back. Also, I have used a short piece of tubing with a boom to mast plate to act as a keel, keeping the antenna level, side-to-side. I wouldn't recommend leaving antennas up in windy or icy conditions, but the ease in raising and lowering it allows for convenient safe stowage. The keel tubing can also be used to hold the antenna up, sleeved into the short mast on the rotator below, providing a good landing spot.

The results, performance-wise, and construction-wise, were very gratifying. I used LMR-400 coax for low loss and as importantly, low weight due to its aluminum center conductor, and also added a pulley to the system. The pulley should have been added months ago, but this entire installation became "temporary permanent" as time has passed. This antenna is about 25 lbs., with feedline and the slightly heavier elements, but goes up easily, and seems well within the branch's capability. If you have a similar branch, I encourage you to give it a try. This has always been an easy way to hang an inverted vee, but clearly has greater potential for other antenna purposes.

Thanks to all for the Qs in the contest. 

Spiderbeam HD Joins the Antenna Farm  ANOTHER OAK TREE HELPS THE CAUSE

After a slow build of the antenna itself, my HD (heavy duty) my presious Spiderbeam went up in a different oak tree, very close to where the Rohn 25 foldover tower is now located. I certainly underestimated the time to cut and prepare all the Kevlar string trusses and copperweld elements, so the construction took much longer than I anticipated, but the performance was heartening! I had't had a rotatable, gain antenna for 20, 15 or 12 meters at this QTH until 2013, and with both the October/November 2013 peak in conditions, and the lower numbers too, the extra few dB and the ability to aim the antenna for its five bands of operation really helped. The best tip learned in assembly was to use clear nail "hardener," a variant of nail polish with extra fast drying action caused by additional hardeners in it's formulation, to dress the cut ends of the Kevlar string. 

same pole or tower to hold it up, especially for the standard version (which is 10 lbs. lighter). Note that the standard version is designed more for temporary, portable use and is not as durable as a full-time station antenna, with thinner fiberglass poles, and hub plates. The cost of the HD Spiderbeam and the K4KIO hexbeam are roughly comparable, but there's more measuring, cutting, and knotting of Kevlar line, insulated copperweld wire, and fishing line with the Spiderbeam.

This useful antenna has now moved on to put DX in the log of W4GO. Matt's meticulous rebuilding of it was a delight to see when I visited him in the summer of 2016. GUD DX Matt!

The Best Topband Antenna I've Ever Had  MUCH TO MY SURPRISE AND DELIGHT

At our former home, I had two primary radiators for 160M, a dipole broadside roughly NNE, SSW at 100 feet between my tower and a tree, and a series of 1/4 wave end-fed wires, top fed and suspended from the top of the 100 ft. tower. The dipole was open-wire fed, and also worked great on 80M as two half-waves in phase, and was a very effective stateside transmit antenna. The slopers were sloped NE, NW, SE, and SW, and used a remote antenna switch that floated the unused elements. The feedline added approximately 5% of additional length. The concept was that they'd act as reflectors. I also added about 2 dozen radials to the tower for both DC and RF purposes. In the end, the NW sloper got me the JA contacts I had hoped to get, and worked into the midwest pretty well also. The SW was okay to the west and for Pacific DX, but the NE antenna and the SE antenna were very mediocre. I had tried a shunt-fed technique on the tower, as well as elevated radials with a reverse feed (coax center conductor to the radials and braid to the tower) as well as three drop wires from the top of the tower to a skirt wire, in an attempt to use the tower as a vertical. In all, I had reasonable results and these final two options were much better than the simple coax-fed  halfwave dipole at 65 feet or so, which I used for many years for nightly stateside chats, and some DX here and there.

As I noted above, the first antenna I put up at our Amissville home was the 160M dipole, now as an Inverted Vee, at about 85 feet in a tree. It produced good domestic signals, and supplemented with two, and later three beverages, proved a serviceable antenna for some topband operating. Since I didn't have an easy support for one end of a dipole (a tower), and also don't have two, 100-foot trees, with proper spacing, recreating the dipole was not possible. Clearly, it was going to take something different to hopefully nab me the next layer of DXCC entities that I needed on topband. Given the lack of a conductive support (tower), and the slightly more open territory here in a couple spots, and also given the widespread use of inverted Ls and alternative verticals on the band, I figured it was time to give the vertical another chance, It's obvious they work, now I needed to see if I could make it work for me. KT3Y, Philip, has had excellent results with his tall T (top-loaded) vertical wire on both 160M and 80M, fed against a very extensive radial system. Something about the symmetry of the T seemed appealing to me, and I knew I'd need to suspend the antenna between trees, so I pulled out all the "extra" wire I could muster, and began making 75 foot radials, in an effort to make a denser radial field, rather than a resonant one. An aluminum plate and plenty of stainless screws gave me the centerpoint of a modest radial arrangement of 33, 75-foot wires, and a bit of lump capacitance and a copper pipe as the ground rod, produced a reasonable match. That was as far as I got the first year, and the winter DXing season showed a pronounced improvement into the Caribbean compared to the SE sloper from the tower at the Nokesville station. Not that the Caribbean had much new, DXCC-wise, but it's an important multiplier region, and since the vertical is more-or-less omnidirectional, it encouraged me to stay the course. EU signals were a bit better too, and seemed consistently better on the T than on the Inverted Vee, as well as west-coast US stations.

By the summer of the next year, I decided I probably needed to double or triple the number of radials to make a significant difference. Without deciding the final location of the vertical, in light of a possible tower and wanting it out of what was becoming a crowded backyard, antenna-wise, I started reading about the K2AV folded counterpoise. I'm a hobbyist as a ham, and so I didn't have the technical expertise to affirm or dispute the theory or physics involved. So, with the facts not getting in my way, I looked at the cost of the materials, the space I had to deploy this "ground" system, and the portability of it if I decided to move it out to the septic drain field, a couple hundred feet to the west of the house. For well under $100, I thought it was worth the gamble. I assembled the isolation transformer, as exactly as I could manage from the published plans, stripped the 66 feet of #12 solid copper wire that I needed  to supplement the 99 feet of stripped wire provided by my friend Buddy, WD4AKS, and cut and drilled the PVC spacers needed to complete the FCP. I was surprised how heavy this apparatus was, and had to get a little creative with a center support (a Rubbermaid compact tool shed was used), and use a catenary support rope to try and get the geometry right. The first go-around with the FCP was in the backyard, mounted above the radial system, to try and permit some rough A-B comparisons. It wasn't practical to quickly switch between the two, but after some back and forth feedpoint changing, I got a sense that the FCP was at least as good, and maybe just a bit better than my nominal radial system. With little to lose, I made the new FCP/T as weatherproof and weather resistant as I could, and hunkered down for the mid-winter DXing season, still with time to

decide whether this antenna would be a keeper, and be moved to the front of our lot, with more room, and no fear of interaction with the 160M inverted vee. This first winter for us in Amissville turned out to be pretty mild, overall, and that allowed antenna work to continue, I was still "retired" and highly motivated, with both the NE and NW beverages in place by this point too. The Inverted Vee was louder for the high volume of domestic stations in the Northeast and Mid-Atlantic states, and even into the eastern edge of the midwest. Further west, northeast, and east, the T really started to shine. While CQing, calls from the Dakotas, Nebraska, New Mexico, and even California, Washington and Oregon, began showing up in the CQ160M SSB log earlier in the evening than I was used to. What had been shown by the early tests of the T, with radials, was that I was clearly getting out to the south far better than in Nokesville and while not a world-beater into Europe, I sensed that I was being heard there better as well. I continued to dabble with DX, adding 3C0E in March, and 7O6T in May. That one was worked with a clear sense that neither the Inverted Vee, or any antennas I had in Nokesville would have put Yemen in my topband log. By the time the band got noisy, and I got distracted by Seasonal E-Skip on 6M and my enjoyment of 17M with a new, spindly but surprisingly effective Moxon, On balance, I had mostly concluded that the antenna "worked," and would be redeployed out front, once the summer weeds were bush hogged, and I had a clear antenna field.

The new location was much friendlier to good geometry for the FCP itself, and a new center support of PVC pipe was constructed. Of course, a much longer feedline was needed, and luckily, there was enough LMR-600 to reach the new location. The new spot was much closer to power lines, but I had also added the SE beverage in the summer, so even if powerline noise proved to be a problem, I had options. Also, the transmit antenna was now about 250-300 feet away from the feedpoints of the beverages, and the protection relay in the K3 was now silent when transmitting with the T. PT0S was added to the log for a new country, followed by RI1ANF and C50S, showing me that the antenna performed well to the east. These Qs were in mid- to late-November, and I knew the shakedown cruise would be the ARRL 160M contest. I had some concerns about heating, since I would be QRO, but the ambient air temperature gave me some hope of not smoking the feedpoint components. Also, the counterweight system for the antenna and the feedpoint were new and untried in winter temps and gusty winds. 

See the homepage of this site, for more updated successes with this antenna (and a few disappointments too, of course.)

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