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I built this antenna when the 50Mhz band first became available to UK amateurs. It proved to be a winner,

but beware it is a big antenna and needs to be constructed like a battleship or it will not survive the high winds.

Mine managed to live through a hurricane of 105mph, next door house lost his roof.

To give some idea of it's performance, I worked all continents and perhaps the very best was to KG6 on the Island of Guam,

in the Pacific, this was with 3 watts cw, I received a 559 report.

Give it a try, the 50Mhz will soon be bursting into life on the new sunspot cycle.

This simple 9 element, Chebyshev low pass filter, has the cut frequency at 34MHz for a 50 Ohm of impedance and 0,001 ripple. Attenuation is better than -50dB at 55MHz (TV channel 2).

The filter is housed in a box made of aluminum of 125mm x 150mm x 70 mm. The components of filter are fixed in a simple printed circuit board .The input/output connectors are SO239 sockets. The air-core inductors were wound from 1mm diameter copper wire, stripped from some 75 Ohm TV coaxial cable, details below:

L1, L4 5 Turns, 0.5in (12.75mm) inside diameter, 3/8 in (10.0 mm) coil length.

L2, L3   6 Turns, 0.5in (12.75mm) inside diameter, 0.5in (12.75mm) coil length.

C1, C5   56pF Silver Mica.

C2, C4    100pF in parallel with 47pF Silver Mica.

C3          150pF in parallel with 10pF Silver Mica.

The capacitors should be rated for 500 volts or up. It is important that the capacitors are 5% tolerance.