Top Band @ W5RRR

Older amateur operators often refer to 160 meters as the Top Band. It’s the oldest amateur radio band and was the staple of relaible communication in the earliest days of amatuer radio when almost all communications were over relatively short distances. Today, it’s a popular band with high performance especially at sunset through sunrise, provided you have a good large antenna.

The W5RRR 160m shunt fed tower had been a toying concept for awhile. After pondering for a few weeks/months, we took the plunge earlier this month to give the club a new capability. So we donned our climbing gear (courtesy of K5RG’s excellent tutorage) to scale the tower once again and we installed a parallel shunt fed wire along the outer rails for the 80′ tower. The impedance matching was an unexpected challenge since our grounding radials were poor and the standard tuners used were outside the range of the source impedances from this type of antenna. Ham resourcefulness produced several homebrew matching network tuner prototypes at home and brought to the base of the tower, but none of them were able to match the antenna. Finally, a Dentron Super Tuner was tried (again), but loaded heavily with extra 400pf of series capacitance to allow for a very good impedance match. The Tuner was modified and packed into a Harris RF 231 sealed enclosure (after gutting it) and voila! a water tight tuner will now grace the bottom of the tower and provide an adjustable tuner for 160m. The maiden voyage for this antenna will be tested during this weekend’s CQ SSB 160m contest. The grounding scheme is unique and includes using the adjacent baseball field’s extensive chain linked fencing as an RF ground counterpoise. Who knows? it might be one of the greatest antenna implementation in the southern region – we’ll see this weekend…

View photos from installing the Top Band at W5RRR.

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