Reason for change:
While the HGSW beam performed well on 80 meters, it was only marginal on 40 m and not dramatically better than a dipole on the higher bands. Lately though, it has become almost impossible to tune it on 40 meters. The MFJ 993b auto tuner sounded like a machine gun, firing all the relays during the tuning process, and often failing to attain an optimal SWR. This condition needed to be fixed!

In addition to the degrading performance, I have always preferred to have an antenna that the radio’s internal tuner could handle. (Most internal antenna tuners built into radios will not tune an antenna with an SWR above about 3:1.)

Finally, I needed to put something up that was a lot less visible – a lot less conspicuous. I am nearing the end of a remodel project and will be putting the house up for sale soon, but I don’t want to have to take down all my antennas while it is for sale.

The Skywave Loop:
Enter the Skywave Loop design. According to my research, this antenna is resonant on all of the upper harmonics, unlike dipoles that are only resonant on odd harmonics. It also gets a lot of wire up in the air. Think about it, an 80 meter loop puts a full wavelength up at 80, 2 wavelengths at 40, 4 at 20 and so on.

Antenna length is not super critical.  Most of the discussion on this antenna say that, for instance on an 80 meter loop, the length of the loop wire can be off by several feet with little or no noticeable effect.  However, it should be near the resonant length of the lowest planned operating band and not simply the longest random length that can be put in the space.  While a random length will work and will tune up, performance is somewhat degraded by comparison.

Loop antennas can be installed in two basic orientations, either in the horizontal plane or the vertical plane. In the horizontal plane, the antenna will have horizontal polarity no matter how it is fed.   If installed in a vertical plane, the placement of the feed point and the shape of the antenna (square, triangle, etc.) will determine the polarization.

Additionally, height above ground will affect takeoff angle for the horizontally mounted loop. The higher the installation, the better.  Also, the antenna need not be in a flat plane.  Some corners can be above or below the general plane of the antenna.  However, if the antenna is installed close to the ground, it can become an NVIS antenna. Of course, this may be what you want – think local emergency operations on 40 and 80 meters or portable operations, where you want to talk out to up to about 300 miles.  (I’ll leave it to you to research the heights that will induce the best NVIS performance, but figure about 0.15 to 0.2 wavelengths above ground.)

Loop Skywave Antenna Installed:

So, last week, I spent a warm afternoon outside with my spud gun, launching more strings and ropes over trees in the yard.  It’s so much easier in the winter when there are no leaves left on the trees.  I put up four suspension points, each with a 3″ pulley to support the loop. None of the support points are fixed at any position along the loop wire, so it is free to move in response to winds. The feed point is about 1/3 of the way between the two eastern supports, and the slack on the overly-long ladder line feeder is pulled away fron the house with a string to keep it vertical and at least 10 ft above ground. (Deer and other wildlife will forage directly under the feedpoint. It’s their main foraging trail through the area. I need to keep everything high enough so they don’t snag antlers on feed lines.)

After I instaqlled it, I did find a reference to feedpoint location on

Loop Performance:

I was immediately impressed with the performance in comparison to the HGSW. It tuned up easily on every band from 80 to 10 meters, using only the radio’s internal tuner. I’m now able to retire any external tuner.  Reception of signals appears comparable or better. Noise levels seem to be lower too on the lower bands. The next surprise was a comparison to the TA-33jr 3 element beam. On 20 meters and above, the Loop antenna is picking up signals almost as well as the beam antenna! Occassionally, it will do better.

I’m wasn’t sure about DX operation yet though.  So far, I haven’t been hearing much DX on 80 or 40 meters. I was starting to think I had an “extended distance” NVIS with a range of about 1500 miles. I just wasn’t hearing anything beyond North America or the Carribbean. Over days, it just appears that conditions haven’t been good. In comparing signals with other local hams, I found that I’m getting as good or better reception as anyone else in the local area. I was also able to make a contact last night with South Africa, so it looks like the antenna is doing just fine.

80 meter loop on 160 meters:

A surprise was waiting here. All the articles say that you can’t use a loop antenna below the design frequency, so don’t expect to tune up an 80 meter loop on 160. I can tell you that this is a fact. I tried, and all I saw was an infinite SWR. That means no transmitting on 160. However, I noticed that as a receive antenna, this loop was fantastic.  Previously, with the old antenna, the band was pretty quiet.  Now, the band is loud and crowded. It’s frustrating, because now I can hear it all, but can’t transmit!

Hope is not lost though. Those same articles that say the loop will not tune on a lower band also say that the two leads on the ladder line can be connected together and the system behaves like a vertical antenna.  The feed line becomes a vertical and the loop acts as a capacitance hat!  This is something that I will have to try.

Summary:

It was well worth the effort. The Loop Skywave antenna performs well, is somewhat quieter, tunes nicely with the radio’s internal antenna, and is much less visible above the house. It’s making operating a much easier and pleasant activity.  I’ve been able to make contacts with little or no difficulty. (HK0NA, Malpelo Island DXpedition took about 5 minutes effort – they were working 5 to 15 up and had to find me in the pileup.) I just wish I had room to go to a 160 meter loop!

73,
W4FT

TA-33jr installed on Chimney Mount

Well, “a” TA-33 is up, not the same one.

The upper bands have been heating up all summer and I was getting the urge to do something to improve on my antennas. While the HGSW antenna does a fair job all around, I wanted something better. Back around September, I was set up at a hamfest with a fellow ham, and I was sitting there, staring at a pile of aluminum about three vehicles down from my spot. I don’t remember exactly what antenna it was, it had some missing parts, and it wasn’t all that great a price, but I was getting the urge to get a yagi for the upper HF bands. I had sold off almost everything I had, certainly all the good antennas over a year ago, thinking that I would have long ago had the house up for sale. (The kitchen remodel is just taking forever, but it is almost done now.)

I kept looking at that antenna, trying to justify spending about $125 for it, but I just couldn’t do it. Finally, my friend spoke up. “Don’t you have a bunch of antenna parts at home that you can put something together?” That’s when the light bulb went on. It was pretty dim, but it was turned on. It was about that time that someone else walked right past me, with that antenna in hand. Either it was a sign that I shouldn’t buy it, or that it wasn’t going to sell until I decided that I didn’t need it.

We kept chatting about how and where I was going to put it up. I had long ago sold my push-up masts and tower sections. I had sold all my rotors. Heck, I didn’t think I even had a piece of decent mast to use. Then he started reminiscing about all the chimney mounts he’d put up years ago in New York. The light bulb started to glow a little brighter.

When I got home, I started checking all of my antenna parts and pieces of aluminum laying around in the basement and the back yard. It was getting slim, compared to the collection I used to have, but I actually found all the parts to a Mosley TA-33 junior! It was in pretty rugged shape. I had to repair one trap and splice a new end onto one element that had snapped off. The boom was bent, and straight is a term that could only be loosely applied to any element. Still, I spent about a week straightening, cleaning and repairing, but I got it put together in the back yard.

Next, a trip to Trader Joe’s followed. This guy has several tons of surplus hardware – brackets, components, antenna parts, cable, and on and on. A Saturday afternoon going through his place looking for needed parts is always fun. As it turned out, he had several chimney mount kits that looked like they were new in 1960. Perfect! That and a couple of pieces of aluminum took care of several needs.

What about a rotor? I had one, but after a day of testing and attempted repairs, it turned out that the gearing was too worn to be reliable. With no hamfests in the near future and contests comming up, I went with a standard TV rotor from the local Lowe’s.

Time to put the system up. There was a surprise waiting for me though. I checked the chimney mount kit and found that it came wioth 12 foot long straps to wrap the chimney. Unfortunately, the Chimney was about 15 feet around the outside! Hmmm. No problem, I just made a quick trip to Lowe’s again(seems like I go there every day), and picked up an 8 ft threaded rod and a couple coupler nuts! I cut the threaded rod in two, and easily took up the gap.

With the chimney mount problem solved, everything else followed easily. I had a couple pieces of mast pipe, including an 8 ft piece that filled the bill nicely. In an hour an a half, we had the antenna up and working! Initial testing showed a good match that the radio’s internal tuner could make perfect on any band from 20m to 10m.

What about antenna height? The TA-33 jr. is mounted about 6 feet above the ridge of the roof. That’s about 20 feet above the front yard or 30 feet above the back yard. (The house is on the side of a hill.) While higher may (or may not) be better, 20 to 30 feet will do a good job!

So how has it worked? I’ve run the CQ WW, the ARRL November Sweeps and 10 meter contests since then. In every one, the 3-element beam has been a champ. It has gotten me QSOs from North Carolina to Australia, New Zealand and Japan. I’ve made contacts with it on almost every continent (still need Antarctica) In comparison with the HGSW, the beam wins hands down. During the 10 meter contest, I made contacts with most of Europe, the Carribbean and South America. I made contacts with both European and Asiatic Russia. The US west coast was easy, as was Alaska. As expected, the east coast and nearby states were almost unheard.

In a word, putting up the 3 element, 20/15/10 meter beam antenna was well worth the effort at minimal cost! If you can, go for it!

73,
W4FT

Link to CQ WW WPX Contest 

I’ve been sitting around here trying to figure out what I want to do about the CQ WW SSB contest.  I’ve already challenged one of the local hams and might throw down the gauntlet in front of a few more.  But do I want to make any changes to the shack?  I still have the HGSW beam hanging in the trees above the houes (see earlier posts), but I’ve been hearing a lot about the upper bands coming to life.  Wouldn’t it be nice to have a tri-band yagi up, at least for comparison?  Maybe it’ll help me get more contacts this year. These thoughts created an itch that I just have to scratch!

Okay, so I didn’t want to invest a ton of money into a new antenna.  That means working with whatever I can find around the house.  I thought that I’d sold everything off at hamfests, but after looking around, I found most of the parts to a Mosley TA-33 junior. To be honest, it is in pretty rough condition.  The bo0m is about as straight as a dog’s hind leg, even though it’s been straightened, and one of the reflector elements had about a foot broken off the end. Otherwise, everything is in worn but usable condition.  The traps don’t show any opens, and everything seems to be there. 

Next problem – how do I put it in the air and turn it?   I did sell all my push-up masts and tower sections.  At least I still have a piece or two of mast laying around.  In the past, I’ve had push-up masts buckle while putting everything in the air, and at best, only cleared the top of the house by a few feet. AB4OZ came up with an idea – try a chimney mount installation.  This immediately puts the antenna about 8 feet above the top of the house, and has the advantage of being cheap.  I found a mount kit for about 8 bucks at a local CB/ham shop and had to add in another 8 bucks worth of hardware to reach all the way around a fireplace chimney with threaded rod and other hardware. (The kit had 12′ straps to go around, but the perimeter of the chimney is more like 16′.)

Finally, I need to be able to turn the antenna.  I had an old rotor that I picked up at a hamfest for a few bucks, but when I tested it, I found the gears were worn out. Crap!  I also sold the TV rotor I bought for about $50 several years ago.  Double crap!  Oh well, time to buy a new one.  Since it’s a relatively lightweight antenna, I figure a TV rotor will work fine.  Of all places, Lowe’s had what I needed at about the best price.  It was the Phillips rotor with the newer control box – memories, a remote control, and an approximate bearing indicator. (Shows bearing  / 10 ) At $75, it’s a little painful, but better than a couple hundred for a tail twister.

So that’s where it stands.  I have all the parts together in the basement.  Over the next few days, I’ll be piecing it all together.  Maybe this weekend, you’ll hear me on the higher HF bands on a TA-33.  I’ll let you know how it works out.

And to the local hams in Raleigh, consider this your challenge to beat my score in the CQ WW SSB contest at the end of the month!

73,

W4FT

Last month brought the CQ Worldwide SSB 2010 contest, presenting an opportunity to test out the High Gain Single Wire Beam antenna (HGSW) described in my last blog entry.  I wasn’t sure what to expect, but I thought I’d give it some exercise.  In spite of losing a day to help a fellow ham with a broken water heater, I managed to put in several hours of happy contesting, covering every band to some degree.  The result was a log with about 242 contacts in 64 countries and 23 zones for a score of over 111,000 points.  Not a bad effort, given that I wasn’t really trying that hard.

Conditions, like appearances, can be deceiving.

On Friday, my sense was that the antenna performed great on 80, but not well on 160 or 40.  It was too late to assess 20. Somehow, I expected better.

My effort started late Friday night.  Hey,  I was tired from taking that water heater out, so I wasn’t really in the mood to work a contest. But finally, I couldn’t resist the urge any longer. Around 11:30 pm local time, the radio came to life and I started looking around. Twenty meters had already gone dead, so I dropped down to 80 meters.  A quick scan showed a target rich environment.  I spent a fair amount of time making contacts from all around North and Central America and Europe. Contacts were easy and getting through pileups was a quick effort.  Having made a pass through the band, it was time for a change.

Forty meters had different results. Like 80, I was hearing stations from North America and Europe again, but they weren’t hearing me quite as well.  Pileups meant doing battle with everyone else trying to make the contact and results were mixed. In spite of the difficulty, I still made a full pass through the band with fair success. Next, I went on to 160 meters.  Hey, nothing ventured, nothing gained.  Well I didn’t gain much.   If 40 was marginal, 160 was a disaster.  I managed only two contacts on the band.  Fortunately, most people were on the higher bands, but I’d had enough for the night.  Time for some sleep.

Saturday morning was spent putting a new water heater in (I really, really want to make sure my friends have access to hot showers.    ), so I didn’t get back to the contest until around an hour before sunset. I started with a few contacts on 20 – zones 16, 11, 7 and 9- but the band was rapidly dying for me already.  I operated sporadically for about 6 hours, making roughly another 34 contacts – mostly on 40 meters.  This time, I added three Northern Africa stations – CR3, CN3 and EF8, all on 40 meters.  Oh yeah, I added another 160 contact.

My perception was that 80 was solid, but the antenna wasn’t so hot on 40 or 160.  I wasn’t too sure about 20 either (the HGSW is designed for 20 meters.) I’m beginning to wonder if the height is the real controlling factor here. I’ve had several wire antennas up in the trees – trap dipoles, simple 80 meter dipoles, etc. – all about 65 to 85 feet above ground.  It seems like they all did well on 80 meters, but marginally on 40 and really bad on 160.  The only antenna to have even marginal performance on 160 was the B&W 160 thru 20 trap dipole.  I’ll chalk the performance on 160 to the nature of the top band in general. The band just takes a well-tuned and installed antenna to get good results.  Honestly, I haven’t had one of those up yet for the band.

On 80 meters, almost every antenna I’ve put up has had good to excellent performance.  The HGSW falls into the good category, maybe excellent, but I haven’t really had enough time on the air to be certain.  I do know that making contacts and busting through pileups is easy on this band.  I’m wondering if the antenna height is the real secret here.  I’ve been installing antennas at 65 to 85 feet, with the current HGSW at about 80 feet.  Based on some reading, that looks like the sweet spot for 80 meter antennas.

So the result looks to be good overall performance, better on some bands, not as good on others.  More to follow in later blogs.

Oh yeah, my friend is enjoying his hot showers again, all without a single leaky pipe!

73,
W4FT

Testing began the next day, but the results weren’t good.  SWR readings were in the 9:1 or higher range.  So what did I do wrong?   I had installed the antenna at about 75 to 80 feet up, with the last 15 feet on either end hanging down because of space limitations.  I thought about it for a while and decided that the likely culprit was the feed line, or at least, it’s a starting point. Another issue might be the hanging ends.  Anyways, I pulled the antenna back down and replaced the RG-8 coax with 100 ft of 450 ohm ladder line.  I also put a 4:1 balun on the end of the feed line.  This gave me moderate improvement on some bands:

I should point out that there was a change in design by the author.  The January 2010 edition of QST has a letter from the antenna’s designer and the author of the original article, Rob Wilson, AL7KK.  Rob had found that simply removing the inductor at the feed point resulted in a close match to 50 ohm coax, so a direct feed was possible.  In emails that I exchanged with Rob, he also suggested that feeding with 80 ft. or 100 ft. of 450 ladder line would yield good results on most bands.  Given the performance we had with two of these antennas cut for different bands, I believe they will operate nicely on all bands.

So here I sit, with mixed results on match, but a pretty good first glance at the receive on this antenna.  I just haven’t had a chance to tinker or do much operating yet.  I’ve seen this antenna in action at Field Day and it produces good results.  I’m just not convinced that I’ve really done it justice in this installation.  I still need to throw an antenna tuner in line and test it.  When I get more info, I’ll pass it along.

73,
W4FT

To make a long story short, OXIDATION!  I should have soldered all the connections instead of depending on just the mechanical connection of twisted wires.  The oxidation looks to be disrupting the antenna connections between the wires and the traps.  One of the 40 meter traps may be bad too. 

Now, I’m thinking that it is time to replace this antenna with something else for 160 through 40 meters. 160 is a bonus, but 80 and 40 are absolutely required.  I have 20 and up covered with a yagi.    I’ve been thinking about loops, dipoles, etc., but this probably needs to be some kind of wire antenna.  I do have several trees to serve as supports.

Throw out your suggestions!  What would you go with?

73,   W4FT

TA-33M and Cushcraft 11 element Yagi are halfway up!

I’ve been remodeling my house for a while now, so the radio shack and the antennas have seen frequent changes and moves.  Earlier this summer, I found myself wanting more than just my B&W 160-20 trap dipole hanging in the trees.  This would be a temporary install only. Sometimes, you just have to scratch an itch.  

Conveniently, I had not one, but two TA-33M antennas in the basement, along with the add-ons for 17 and 12 meters and for 40 meters. Over in another corner was a Cushcraft 147(?) 11 element 2 meter beam, along with a cheap but functional rotor. Looked like I had most of the pieces.  All I needed was something to put the antennas on.  A quick trip to a local supplier netted me a 50 ft. Rohn push-up pole.  That’ll do it.

Over the next few days, I built up the antenna stack on the ground.  First, the TA-33M with the 12m and 17m driven element. Next, I assembled all the other components into the stack – an 8 ft. mast, the rotor, the TA-33M and the Cushcraft 2m Yagi.  Add in coax, rotor cable, guy ropes, and tiedown straps, and that makes the full set.  Everything checked out for SWR, so it was time to put it up.

As they say, necessity is the mother of invention, or in this case, creativity.  The next problem was how to get the assembly up. Plan A was to stand it up with the mast extended only enough to clear any low items that would interfere with the antennas – like the house.  But what’s the best way to stand the stack up?  Fortunately, I had a set of compound pulleys and a lot of rope to go with it.  I through a heavy line over the house, tied it to a tree on the other side and hooked one of the pulleys to the other end.  With about an 8 to 1 advantage, it was fairly easy to stand the whole assembly up.

I figured that once it was vertical, it should be easy enough to extend the mast straight up.  Bad idea. First, I should have had a clue from the weight of the stack as I was standing it up.  It actually went to vertical easily enough, but extending it was a lot tougher.  Raising about 80 lbs straight up on the edge of a deck isn’t that easy.  Also, I didn’t think I needed guy wires – worse idea.  I was able to extend it up, but while securing everything, the top heavy antenna buckled one of the mast sections and the whole thing folded over.  Ugh!  All you can do is watch it fall and either laugh or cry!

The resulting damage was moderate, but not insurmountable.  I had to cut about 3 ft. out of one section of the telescoping mast, so now my 50 footer was more like 44 ft. Next, the antenna needed attention.  Two element ends were buckled and there was some minor bending.  Remember that I said TWO TA-33-M antennas?  Spare parts!  I spent a couple more days reworking and reassembling everything and thinking of a new way to put it all up.  This time though, a new plan – maybe riskier in one way but more stable in others.  Instead of standing it up and then extending it, I decided to extend the mast to about 35 ft. on the ground and stand the whole thing up with guys already attached.  The pulley system would bring it up and the guy lines would keep it from falling past vertical or off to one side.  By shortening the mast, it put extra overlap between mast sections to strengthen it.  I just needed to go slow and keep everything straight.  

Did I mention that I did all of this by myself? Not a practice I recommend, but sometimes, it’s the only way to get the job done.