The new HF antenna atop the NWC is now installed! Installation was handled by Top Hand Tower, the same company that installed the SteppIR some years ago.

We took precautions during the building and installation to insure that we won;t have to do this again for a long, long time. The antenna itself is a DXEngineering Skyhawk 3X10 antenna, with 4 elements on 10 m, and three each on 15 m and 20 m. Each element is riveted together, so there are no hose clamps to fail. Each element has a short length of sash cord in each end secured with urethane glue; these act to dampen any vibrations in the elements that may be excited by the wind. Every piece of threaded hardware is secured by medium strength (blue) thread locker, including the clamps on the rotator. The rotator mast clamp bolts had come loose due to vibration; they will not do so now with the thread locker. The rotator had a new Grade 8 mast pin installed because the loose mast clamp hardware allowed enough play for the SteppIR antenna to break the old mast pin.

The antenna is an OWA (Optimized Wide-band Antenna) yagi design that should be relatively flat across all three bands. With an auto tuner, it can be used as a non-directional antenna on 17 m and 12 m and possibly 30 m. It has been tested and, using the reflectometer indication on the IC-7000 radio we have in the station, the match is good across all of 10 m and 15 m, but the SWR runs a bit high on 20 m with about 1.5:1 on 14 MHz and 2.5:1 at 14.35 MHz. Given that the match is good on 10 and 15, the antenna is assembled correctly. It would be very difficult to assemble it incorrectly due to its construction, but I suppose it could be done with enough ingenuity. I, along with Jorge Duartes, W5/HJ3JDG, assembled the antenna and neither of us are quite ingenuous enough to figure out how to screw it up. The reflectometers in HF radios are notoriously inaccurate (the one in my TenTec Orion II isn't very good, either, though the one in my venerable TS-930S is quite accurate) and I suspect that is the case here: the antenna is likely better than it looks via the display on 20 m though the IC-7000 display. However, the club owns an auto tuner that is... Somewhere. We will find it, install it, and worry no more about such issues.

It's important to recognize that this station would not exist without Doug Forsyth's (WX5DF) foresight, technical support from Ken Brown, N5KUK, support from the University of Oklahoma, and support form the National Severe Storms Laboratory. An antenna of this quality, up 200 ft, driven by a rig as capable is the IC-7000 is an unusually good asset for any club station and a rare treat for anyone interested in HF operating.

Now, go get on the air!

73,

Kim Elmore N5OP
OUARC Faculty Advisor