ANTENTOP- 01- 2014 # 018

Bridge Effect

By: Igor Grigorov, va3znw

Every day when I drive my car to and from my job I drive under bridges and arches. Figure 1 shows a bridge. Figure 2 shows an arch. Inside my car I usually listen to radio. My favorite radio is 680 News Radio. The radio station works on 680- kHz. This radio transmits useful news for me. It's the weather, what is and what will be news in Toronto and the World, as well as local traffic, which road is open, what the road is closed due to an accident construction. Knowledge of the traffic saves me a lot of time.

Figure 1 Bridge

Figure 2 Arch

I noticed that volume of the 680-News usually is changed when I drove under a bridge or under an arch.

ARCH

As usual the level of volume is drop down when I drive under an arch. There are some arches (very small quantity) that do not affect to receiving. Figure 3 shows area of decreasing reception under the arch. Arch does decreasing of reception for any station at MW Band. Arch does not affect to station at FM-Band.

The arch has stable behavior in influence to the MW station. If an arch does decreasing in reception so the arch always does the decreasing. The effect exists in summer, in winter, in rain, in snow, in traffic and on empty road.

If an arch does not influenced to radio reception the arch always does not influenced to this one. It is right for summer, for winter, for rain, for snow, for traffic and for empty road.

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