UHF YAGI ANTENNA MODIFICATION

Here is my modified design of two OTA antenna's. The Radio Shack U-120 UHF antenna design was modified with 2 parasitic elements from an Antennacraft UHF section. This was added for increased gain to the driven elements. These floating directors couple the signal to the driven elements and add gain over the stock grounded design.

The Winegard CH-9075 (Vintage 1982) antenna had a CS-7082 (1985) UHF powerpack added using the upsidedown mounted director coupling method used in the monster CS-9095. I used a CH 9075's smaller footprint design that Winegard used to add gain with less boom then the CS 9075 counter part. This added even more gain because of it's multiple parasitic director design that added increased gain to the driven elements. When coupled with the CS series longer director design it gave even more impressive gain then the stock CS series.

Signal on WSBT 22.1 South Bend 80 miles.

Signal on WITI 6.1 Milwaukee 90 miles.

Here is my design for a low band VHF trap. This is used to attenuate a OTA signal so a new one can be injected into a MATV or SMATV system. It consists of a small pf value capacitor, some enamled wire for an air wound choke and a 5~65pf variable trimmer cap. Usually for Channel 4, Nine turns of enamled wire and a 50pf capacitor will get you in frequency range. Adjust capacitor and inductor values accordingly for other channels. Higher frequencys require less inductance and capacitance, Lower frequencys require more. After parts value is determined adjust trimmer for nulling out of desired signal. Traps can be hooked together to notch out more than one channel or tuned to same frequency to achieve more attenuation for a desired frequency. Inductors and capacitor values can be experimented with to build a notch for most any frequency. I do not support this so don't contact me for additonal information and help. This is a building block for those wishing to experiment and understand electronic theory.