Received noise has alway been a bugaboo at WA2HOM. So, after the successful repair to the beam last week, I took it upon myself to reduce noise input to the receiver. We took a big step in the right direction with the purchase and installation of a bhi DSPKR, an amplified digital-signal-processing speaker. Even weak signals are clear now.

Today, Dan and I installed toroids in different places at the Omni VII and I’m pleased to report that putting a clamp-on unit on the coax cable as it enters the receiver reduced the noise level from S6 to S5. That may not seem like a lot until you consider that the forward gain of our three-element beam is 6 dB, which is the equivalent of an S-unit, a fourfold signal gain.

I’m searching around for more ideas to lower the noise even more. Stay tuned!

Ovide K8EV

A week and a half ago, my friend, Bob, WD8BNA, came up to me at our Rotary Club meeting and said, “Have you taken a look at your beam lately?” referring to our three-element Yagi at WA2HOM.

“No,” I replied, “what’s up?”

“Part of the antenna’s missing,” he said. “It must have come off during the high winds we had last week.” I drove by the next day, and sure enough, we were missing half the reflector.

Jack, WT8N, who was majorly responsible for us getting the beam up in the air in the first place, jumped right on this. He got up onto the roof, found the missing element, and organized a work party to re-attach it.

The work party was this afternoon. Jack; Ovide, K8EV; yours truly; and Jerry, head of maintenance for the museum and the son of a ham headed up to the roof to lower the antenna and fix the antenna.

Lowering the antenna proved easier than I expected. We unbolted the tilt-over tower from the mounting bracket and it came down relatively easily. Re-attaching the errant element was also pretty straightforward. All the bolts were there. It looks like we just didn’t tighten it down well enough the first time.

Tilting the tower back up proved to be a little more difficult. We first tried it with two men pushing and two men pulling on one of the guy wires. When that didn’t work, we tried three guys pushing it, and one pulling. That didn’t work either.

Ovide then went in search of another helper. He returned shortly thereafter with one young museum employee, and with four guys pushing, we finally got the tower into an upright position. We inserted and tightened the bolts, and now we’re back in business with all of the elements in the right position. Overall, this took just an hour to do.

Despite missing half of the reflector, the beam seemed to work just fine. It tuned up just fine, and was still quite directional. I’m sure with the complete reflector, it works even better, though. If I knew more about antenna modeling, I’d run a simulation and figure out how much directionality we were actually using.

Has anyone done this? If you have, or have some idea what the effect of losing half of a reflector has on a three-element Yagi, I’d like to hear from you.

Here’s a video that was recently made by the Ann Arbor Hands on Museum about WA2HOM and the exhibits we sponsored.

I am a member of the Ann Arbor Rotary Club. The Rotary Club was founded in Chicago on February 23, 1905, and in commemoration of that event–and to promote awareness of the Rotary Club’s End Polio Now campaign–I’ll be calling CQ Polio on Saturday, 2/15/12 at WA2HOM.

I plan to operate primarily on 20m phone on or about 14.280, plus or minus QRM. If you’re in the Ann Arbor, MI area, I’d like to invite you to come down and help me. I plan to be there from 10am until at least 4pm EST (1500 – 2100Z).

If you’re not in the are, I’d like to invite you to work us. We’ll send out a commemorative certificate to anyone who’d like one.

If you’d like to know more about Rotary, you can go to www.rotary.org.  If you’d like to know more about the End Polio Now campaign in particular, go to  End Polio Now section of the Rotary website.

It’s been one heckuva project, but the tower and beam are now up and running at WA2HOM.

I’d like to thank everyone involved in this project: Roger, W8OMB, for donating the beam; Jack, WT8N, who really spearheaded the project; Jim, K8ELR; Ovide, K8EV; Rob, KD8PUC; and of course, all the museum people: Mel, the museum director; Dave, the old facilities manager; and Doug, the new facilities director.

As you can see from the photos below, we still have some work left to do. We’re going to be taking down the 30-ft. mast (in the foreground) and moving the dipoles back so that they hand from the tower. And, since we no longer need a 20m inverted vee, we’ll be disconnecting the 20m elements and attaching some 30m elements.

After raising the tower yesterday, Ovide and Jim made a couple of contacts, one on 15m phone and one on 20m phone. They report that both guys gave us 59 signal reports. What a change from the puny signal we used to have on 20m.

Tomorrow, we’re really going to be putting this antenna system to the test as we operate the MI QSO Party. We’ll be using the callsign W8CWN, which used to belong to Dr. Richard Crane, the U-M physicist who was a great science educator and built many of the early displays down at the museum.  Listen for us, and give us a call if you hear us.

The tower is up! This the view of our tower and beam from the north, facing the main entrance of the museum. In the foreground is our 30' mast, with the 40m and 20m inverted vees.

This is Doug (left), the museum's new facilities manager, and Ovide, K8EV (right), discussing how best to raise the tower.

From left to right: Dan, KB6NU; Jim, K8ELR; and Jack, WT8N in the WA2HOM shack after the tower-raising. We can't believe that the tower is finally up and the beam is working like a charm.