SV5FRI

My problem was that when I worked with 40m and over 40 watts of power, the TV (LCD) would start up and shut down automatically.

I tried different ways to solve this problem, but the results were disappointing. After many hours of studying, I found the solution:

The Combined Braid Breaker and High-Pass Filter.

This device prevents HF signal currents from flowing down the inner or outer part of the co-axial cable. L1 has low reactance to HF and VHF signals, bypassing the interfering current. Meanwhile, C1 and C2 have high reactance to HF and VHF, locking signals effectively to the receiver. L2 provides an additional short circuit for HF and VHF signals across the connections on the receiver side of the filter.

At UHF, the conditions are reversed. C1 and C2 present a low impedance path for signals to reach the receiver, while the impedance of L1 and L2 is so high that it can be ignored. R1 provides static discharge protection for the outer braid.

L1 and L2 comprise four turns of 20 SWG wire. 6 mm inside diameter. They are 6 mm long.

C1 and C2 are 4.7 pF disc ceramic capacitors.

R1 is a 1M5, 0.5-watt carbon resistor.

The single-sided PCB measures 25 mm by 50 mm and has grooves approximately 1.5 mm wide, leaving four areas of copper as shown.

The filter should be housed in a suitable aluminium case, with one side connected to the aerial downlead and the other to the TV aerial socket.