When analog television went QRT for digital television, most digital signals were placed well away from our 6-meter band. As a result of this switchover, many 6-meter operators who previously were hammered by analog TV Channel 2 desensitization found great relief.
However, as suddenly as analog TV went away, interference on 6 meters continued to worsen by home electronics birdies. From eco-washing machines to smart thermostats, grange is now a problem we all must work around.
One claimed solution (OK, reduction of birdies) has been announced by Justin Johnson, G0KSC. After years as a hobby designing DX antennas for his personal use, he began efforts to design a 6-meter Yagi with specific attention to nulling noise below the main lobe and pulling in rear and side lobes to further reduce reception coming in from below and on the back of the beam.
The new 6-meter-band 7-element Innov Antennas (7-element 50-MHz LFA2 WOS Yagi) features a closed-loop feed system, further reducing wind and rain static. The hot side of the feed system includes a grounded matching element, allowing for a direct 50-ohm feed with coax. No matching device is needed. However, it is recommended to add a simple choke balun with five turns of coax at the feed point to minimize any RF returning along the outer sleeve of the coax cable.
direct feed point eliminates any plastic box that could trap moisture inside and de-tune an antenna. No coax connector assembly at the feed point,”comments one of InnovAntennas’technical support personnel. Because of the direct coax connection to the antenna, there is almost no gap between the coax center conductor and the outside braid. More on the direct connection and the choke are below.
The Innov Antennas are built in a former boat factory inCanby Island, England and sold all over Europe —and now in the USA. Our former ham radio student, William Hein, AA7XT, is the USA distributor (see sidebar).
Our 7-element Loop Fed Array 6-meter antenna was shipped directly from England. The 10-foot ultra-heavyweight tube and antenna innards traveled via FedEx. After a stop at Customs for inspection, eventually it arrived on our front porch.
The assembly instructions are at for North American customers and www.InnovAntennas.com> for European customers and include a pictorial diagram of the 50-MHz, 7-element, 9.5-meter long beam, with photos, azimuth, elevation, and SWR plots.
The boom is square and is in four sections. It easily joins together by a series of marked round tubes that fit into the ends of the square boom section (see photo 1). Thus, with the boom we began our assembly of the antenna.
Once we assembled the boom, we then affixed the block-ele-ment insulators on the top of the boom using a metric hex driver (photo 2). We were careful not to overtighten the screws. Next we needed to find a millimeter tape measure so that we could mark the individual element tips that slide into each of the same-length director and reflector shafts (photos 3 and 4). Ultimately, these would be mounted into the insulated block element holders. Each of the elements is held in place with the provided hose clamps, identified as clips.”Next we prepared the coax for the feed-point connection points. We worked up our own home brew choke, which was created by wrapping five turns of coax around a hairspray container (photo 5). Also, we made sure to keep the separated coax sections microscopically short and well-sealed (photo 6). Any exposed center conductor would de-tune the entire affair!
The next step dealt with the distinctive feed-point rectangle. We noted that we could fine-tune the SWR by slightly expanding or contracting the loop elements (photo 7).
A feed-point impedance-matching bar fits perfectly in place with the supplied stainless-steel hardware, and perfect alignment ensures it properly connects to the coax center connector longer bolt photos 8 and 9).
Stainless-steel turnbuckles provide for a boom guy-support bracket system. The boom mounting plate affixes to the beam at the center balance point. The coax feed drapes over the back of the beam reflec--
tor element, and then hangs down to the main mast, just below the mast-to-brack-et mounting point.
After everything was assembled, we declared, ! No extra parts found!”Only one little stainless-steel nut escaped from the plastic bag holding all the other stainless-steel hardware.
After we made a final check of ele-ment-tip lengths, and not waiting for the actual Field Day weekend to doublecheck initial resonance, we tipped the antenna up on end, swept the antenna at 50.000 to 50.200, and were delighted to see a 1.1:1 SWR from 50.080 MHz to 50.200 MHz!
Our test weekend was during the SMIRK 6-meter Contest. With the beam literally only feet off the ground, we started exchanging some decent sky-wave reports!
The Field Day Test
Because we marked element lengths with a black Sharpie™ , we nestled the tip elements, for safe Dune Buggy transport to the Field Day site, separating the boom in the middle.
We stripped the beam down to premeasured sections which would easily fit in our yellow dune buggy gear-transport vehicle (photo 10). We tipped the driven elements up on end, and off we went to the nearby Field Day site.
At thesite we marveled how that 6-meter 7-element 30-foot boom Yagi went back together in less than half an hour!For your assembly (or reassembly), just remember to bring metric hex drivers and a set of metric deep-socket wrenches.
We used our stout telescopic flagpole mast from UnCommon USA® (http:// www.uncommon flagpoles.com/) anchored to our communications van,to get the antenna up about 1.5 wavelengths in the air. This is our ”commu-nications-van antenna-support telescoping mast.
We attached the beam, did one more SWR check, and then, with a little effort, we raised the mast and beam so that the mast was vertical (photo 11). Then we pushed up each section of the telescoping mast, listening for the telltale ”when the mast sections lock into place.
This mast-antenna combination is no lightweight assembly. Therefore, it required some effort getting each telescoping section of the flagpole mast to click into place. Another quick SWR check gave us no reflected power at 50.100 MHz.
Once up, the beam looked really good. For Field Day we did not use the boom support assembly. The sag at each end was considered to be minor.
With ”rotation, directivity was nicely tight. Seasoned 6-meter DXers marveled at the extreme drop-out of signal strength when the Yagi was pointed no more than 15 degrees off the signal direction.
Propagation —or Lack of It
During the evening before Field Day, 6 meters opened up (photo 12). We eas
Innov Antennas was launched in 2011 by Justin Johnson, G0KSC, after his hobby of designing antennas for his personal use led to a flood of requests to one for me”from amateur radio operators who recognized that Johnson designs outperformed what they could buy in a store. Today, InnovAntennas is building antennas at a former boat factory in Canvey Island, England and selling its products directly via InnovAntennas.com and via a network of dealers in Europe, Australia, and now, the United States.
InnovAntennas’ highly regarded designs include LFA (Loop Fed Array) and OP-DES (Opposing Phase-Driven Element System) Yagis. Performance of G0KSC designs routinely tops the charts in their boom-length class on the survey of ”antennas (list compiled by VE7BQH and available online at: ). ”are among the ham worldmost demanding operators.
William Hein, AA7XT, the U.S. distributer for InnovAntennas, has been an entrepreneur in the music and technology business since 1978. Now he makes his home in Grand Junction, Colorado, where he oversees the U.S. distribution of the InnovAntennas. Bill reports that the entire antenna and accessory line is available and supported from the Grand Junction office. Orders can be taken via
ily received several sky-wave beacons that some other southern California hams could not hear! Some of these operators were so impressed that they drove over to our site to see what antenna we were using.
For the West Coast, Field Day propagation on 6 meters started out and ended with . . . you guessed it —no sky waves] Even so, we easily worked fellow
ground-wave stations up to 200 miles away with solid results.
About 0000 UTC Saturday of Field Day the beam brought in an interesting phenomenon: Local signals to the sides and back of the beam gave us an eerie multipath echo with our InnovAntennas looking for sky waves due east. Along with those echoes, there emerged Texas--
sounding drawls that were coming from 5-land. Within 30 seconds the band opened for 1500-mile sky-wave contacts with signals 20 dB over 9!
The opening lasted for only a half hour. To our surprise, almost none of the other southern California Field Day stations got in on the action.
This phenomenon is not uncommon for 6 meters. Sometimes stations 20 miles away will hear nothing, yet our reception was a slam dunk. As if to prove our point about these freaky landing patterns of 6-meter signals, we learned after the opening that only a couple of the other southern California stations had logged any of the 5s that were coming in to us.
While that Texas opening was under way, Baja California came in. Remarkably , when we turned the antenna to the south, those 20 dB over S-9 Texas signals disappeared into an eerie echo (photo 13). Short skip into Mexico was fun, but also short-lived!
End of Field Day
After all of the propagation was gone and Field Day was over; it was time to take down the antenna. Photos 14 through 17 show the disassembly and stowing of the antenna back into the dune buggy. You can see by the series of these four photos that despite the antennasize it came down and was stowed without incident. Even so, a three-man crew handling the chore made it that much easier. With everyone working together, the task of disassembling and stowing was a cinch.
And Finally ...
Bottom line: The beam works! More important, it is man--
ageable from site to site, and it didnoverwhelm our Field Day telescoping flagpole. It will soon go up on the home tower and our ”method of rotating the flagpole will make way for the big Yaesu rotator.
Final observations: Excellent craftsmanship, no leftover parts, minimum quandaries concerning the preliminary instruction manual, and with metric tools and a metric mm tape measure, you’be all set to get this kind of antenna system on the air, spot-on frequency on the first try!