Metal Roof And Dipole Hf Antenna Reaction

The first 6x10m are covered by a metal roof with a rather low angle iirc only 50cm difference between the highest and lowest point.

Metal roof and dipole hf antenna reaction.

Many years ago my dad had a 4 element yagi with a rotator for hf and this metal roof did not exist. Here s some of those models showing the same antenna a 40 10m ladder line fed inverted v doublet at various heights above the roof for the same 42 center height of the antenna as well as a couple where i raised the antenna but then also raised the roof to have the same roof to antenna spacing as with the lower antenna. At one point that g5rv was laying on top of a hedge row. Dipole inverted v rotating regular etc yagi etc.

It might work fine with a good tuner. I have a 100 foot dipole that i got from mfj model mfj 1777. When its lower than a few wavelengths and at multiples of 1 4 wavelength like 1 4 3 4 etc the pattern of a vertical antenna can be pushed upward and away from the horizon a bit lowering its gain at the horizon. The net effect is that the metal roof is not as much a shield as it is an active part of your antenna system.

But we can generalize an answer by saying if the ground plane is highly efficient and the dipole is made up of two of the comparatively inefficient elements as used for the vertical component of the vertical antenna the dipole will have twice the inefficiency and therefore have a gain of 3 db compared to the vertical antenna. On using a metal roof as an antenna the joints between panels are likely not soldered and are likely to form corroded diode junctions that generate rfi. It would likely make a lousy antenna. I do have a tv tower with tv rotor that hold my duel band vertical and homemade scanner antennas.

I am using a yeasu 857d all band radio and also have the yaesu fc 30 antenna tuner attached. Here s a guy that operates with a 102 g5rv at 18 and a half wave vertical dipole in a side yard tree about 20 at the top of the antenna covering 10m. I even had someone suggest i use the roof as an antenna. Any big hunk of metal is worth a try though.

My question is regarding the effects of the metal roof on any antennas i may use. I would like to set up an hf rig at this location again. Many types of antenna can be mounted in the attic if you don t have radiant barrier tech shield. I have a ranch home with a metal roof.

I would consider a vhf uhf antenna over a huge metal roof ground plane similar to an hf antenna over earth ground. Need lots of room keep them away from metal objects like heaters and ducts wire antennas can be run near the peak of the roof inside the attic bent in odd shapes to match the space available. All of the electrcial wiring and metal plumbing in the house will also be interacting with the antenna much the same way that a director or reflector in a yagi array interacts with the signal radiated by the driven element to change the radiated pattern giving gain.