For Sale: Untested, assumed to be working correctly. Some cosmetic wear. These are some kind of adjustable filters that go between ham radio antenna and receiver.
Online info found:
db selective cavity 174mhz 5" bandpass
The DB4001 series features a quarter wave high Q coaxial c a v i t y. It reduces interf e rence that is frequency rejectable, when installed between the antenna and the re c e i v e r. For incre a s e d rejection two and three cavity models are also off e red. • Adjustable Selectivity – Rotatable coupling loops can be set at 0.5, 1.0 or 2.0 dB to obtain corresponding total attenuations with minimum attenuation of the desired signal. • Field Tu n a b l e – Cavities are shipped factory tuned; however, they can be retuned in the field with measuring equipment. • F requency Stable – An Invar rod, with nearly zero expansion, a s s u res frequency stability over a wide temperature range. • Positive Contact – Maintained by an indented ring with spring compre s s i o n . • R u g g e d – End plates are made of chromated aluminum, coupling loops of copper, and the center conductor and piston of silver-plated copper.
Additional higher resolution photos are available on request.
Send your zip code and city for a ship quote- should be between $14.99 and $39.99 if you are in USA. (Nov. 2022).