As I noted in an earlier post, I’ve purchased an InnovAntennas 3-element LFA yagi for six meters. It was the best antenna that would fit in my side yard. I would have liked more elements, but just didn’t have the room.
Ordering and Shipping
I ordered the antenna from Force12 thanks to their current discount on their six meter antennas. I had been somewhat concerned about the $56 shipping cost from England, but the discount helped me over that hurdle.
About a week after the order, Federal Express notified me that the antenna had been picked up in England and would arrive by the next morning. I was skeptical, but there it was, delivered to my front door by 10:30 the next morning. Amazing work on the part of FedEx.
Antenna Parts – Documentation Free Zone
That afternoon I opened up the long shipping tube and found all the parts needed to assemble my new antenna, but no instructions. I then found the chat feature on the Force12 website. They reported that instructions would be emailed to me. Nothing further heard. Although I did get an email message later in the day from Force12 advising me that the antenna had been shipped… That was Friday.
On Saturday, I contacted Support at the InnovAntennas main site. I used both the contact form and their online chat (chat apparently wasn’t online). Justin Johnson, G0KSC, got back to me and a short while later forwarded the instructions with an apology that they should have been forwarded much sooner. It was nice to get this resolved during the weekend.
Assembly – with Documentation
So I began the assembly but not without issues around the documentation. For the mechanical assembly there was a drawing of the antenna with measures shown at various places. I’m sure they were meant to be helpful.
The reflector was shown with a main tube measure of 750 mm along with an extension end section at 762 mm. That didn’t seem right. So I measured the main tube. It was actually 1500 mm. This didn’t inspire confidence in the documentation.
Next, the driven element showed that the end loop extension should be inserted to 25 mm. A later page went on to state several times in bold type that the overall inside loop dimension should be 2.468 meters. Of course, following the 25 mm directions carefully led to the overall inside loop dimension of 2.420 meters.
I was less concerned about the driven element as I’ll be tuning that to resonance. It’s the reflector and director that need to be spot on to achieve the promised performance characteristics.
Another snag was the connection to the driven element. The instructions were very clear about how to connect the coaxial cable, along with some insight into why it needs to be done this way. But it was not at all clear why the bolt provided for the connection had four nuts, two lock washers, and two regular washers. The crimp on connector was pretty obvious.
Fortunately, a quick email and photo sent to G0KSC got the answer that the driven element went between the lockwashers and that the extra nuts were to provide optimum spacing to align the connection with the insulated clamp that holds the driven element.
I could have experimented with the connection and with some fiddling eventually found the right assembly. But it seems to me it would have been far better to just provide instructions or even a photo.
Missing My Days at Heathkit
Relatively early in my career I spent 11 years at Heathkit. I was an educational writer and later product line manager. In everything we did we relied on Heathkit’s strength in communicating exactly how to assemble their products. Their entire success depended on products that could be easily assembled and that worked the first time.
Over the last few years I’ve built a few kits and assembled antennas. Elecraft, NorCal, Par Electronics, and even QST articles provided excellent insight into the steps required for assembly. It may take time to write-up the instructions, but it’s not onerous by any stretch of the imagination.
Setup and Tuning
Next it was time to get this puppy onto the mast. I decided that I’d set the driven loop to the specified 2.468 meters, which required the inserts to go in at 49 mm rather than the specified 25 mm. I spent some time crafting the coaxial connection and assembling the elements to the boom. All worked well save for a connector bolt through the driven element that wouldn’t quite fit. With a press with an awl, it opened up nicely.
Then it came time to attach the boom to mast bracket. Nothing shown in the instructions. Checked the glamor photo on the front cover of the instructions and went online to the G0KSC page that highlights this antenna as a building project. The mounting brackets were shown both inside the loop (glamor photo) and just outside closer to the director. I chose the outside toward the director as it is also the physical center of the boom. It’s not necessarily the center of gravity for the antenna, but since it’s a tight squeeze to fit the boom length into my side yard, I made the choice to center the boom.
Once on the mast and with coax in place, I ran in and tested the SWR using my transceiver. My antenna analyzer (Autek RF-1) only runs to 30 MHz. The transceiver showed about 1.8 to 1. Good enough at that stage. Then I extended the mast and got it into the air. Once at 25 feet, the SWR worked great at 1.0. Which tells me that 2.468 meters was exactly right, not the diagram.
This wasn’t a simple build. It could have been greatly improved by a bit more effort around the documentation. The parts quality is very high and the antenna design has had some great reviews and results.
I’m really eager to put it into action with some six meter Es and meteor scatter. Just last night I heard FK8CP with weak CW. He couldn’t hear me with 100 watts into the stressed moxon. The LFA Yagi might be just the trick with significantly improved gain and lower noise levels. I’ll keep you posted.
Update on 4-July-2016
I’ve updated my antennas, replacing the cheap yagis with Diamond 2m and 70cm yagis, primarily for satellite work. In the process, I’ve taken down this LFA Yagi and will eventually replace it with the Par Electronics two-element moxon.
Once the 3-element LFA was on the ground, I took the overall measures before I packed it away. Here they are for reference:
- Reflector = 119.5″ tip to tip
- Driven Element = 98″ outside edge to outside edge
- Director = 106.375″ tip to tip