Ham Station Sheet Metal Ground Plane

K7trf aug 19 2016.

Ham station sheet metal ground plane.

Why or when is a ham station ground necessary. It is found that for a monopole antenna like a quarter wavelength vertical the ground acts as a plane to reflect the radio waves so that an image of the top half of the antenna is seen in the earth. Then connect the bonding strap or pipe to your ac safety ground rod with a heavy wire. I guess what i m simply not clear on is how a mag mount antenna s ground plane is connected electrically.

Both of these should result in some level of electrical isolation between the antenna feed shield and the sheet metal. You can bond equipment together at rf by connecting each piece of gear to a copper strap or pipe with a short piece of strap or wire. That s only 05 wavelengths at 30 mhz which is a tiny ground plane. Copper strap is sold at hardware and roofing stores as flashing.

Ideally you d have a ground plane of around 1 4 wavelength in radius which a pizza sheet can provide on vhf uhf bands but isn t even close on the hf bands. A very large pizza sheet might be around a meter in diameter or iow 50cm in radius. Consider also that most cars have a coat of paint between the mag mount and the sheet metal. Ham gear usually has a ground terminal just for this purpose.

3 the problem is not rf at all but is a dc power supply ground loop back into the audio system. As the name indicates the antenna ground plane acts as a simulated ground. Each time a ground loop is created a small inductive coil is formed the ground wire completes the loop. It is possible to simulate this function by replacing the real earth.

5 we have poorly installed connectors or defective cables. The individual station equipments already have their own ground reference but when they are interconnected grounding each equipment to the main ground bus as shown in fig 1 creates ground loops. Antennas requiring ground planes are called ground plane dependent and having an appropriate ground plane can greatly affect performance. A ground plane is a reflective metal surface that the signal from an antenna bounces off of to better meet the antenna s design goals.

Sometimes we set ourselves up for problems without knowing it. 4 equipment has a design defect.