Array Status at K1VR
2-wire version in place since December ‘97 (4-wire version to be completed this spring)
Biggest technical challenge: need for careful tuning of parasitic elements
Observed gain: ~ 1 S unit over tower alone
Observed F/B: ~ 15 dB on DX (may improve with more fine tuning of parasitic elements)
First 160 DX QSO with new array: VK6HD . . . on long path!
Magazine publication in works
Notes:
A 2-direction Spitfire has been up and running at K1VR since December 1997. Based on the very encouraging results obtained so far, we are ready to proceed with upgrading to a full 4-direction configuration soon. We have learned that the biggest technical challenge is the need to carefully tune the parasitic elements to resonance, for the reasons discussed earlier. The main obstacle to perfect tuning appears to be the residual unwanted coupling of the tower and other element during the resonance-measuring procedure. We are still in the process of perfecting the setup. At this point, we see about 1 S-unit of gain over just the tower fed as a single vertical. The observed F/B on DX signals is about 3 to 4 S-units, or around 15 dB, and could be improved with more fine tuning (although we don’t expect the gain to be improved much). Does it work? Well...the first DX QSO with the new array on 160 meters was VK6HD on long path at local sunset. Generating runs of Europeans is easy. There is little or no waiting in line to work DX. In summary, the Spitfire appears to be the most effective DX antenna yet on 160 at K1VR. Look for a future article on the Spitfire in one of the amateur magazines.