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I noticed this antenna park in Heidmoosstrasse, Switzerland. What is it used for?

Photo

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I see at least four antennas in that picture: one discone on the left, two log-periodic on towers in the middle, and a dipole above the building. All look like they are designed to work best at relatively low frequencies, specifically (and confusingly) within the High Frequency (HF) region.

The discone and the LPDAs are interesting to compare and contrast:

  • Opposite: a discone is omni-directional (receives/transmits fairly equally all around), while a LPDA is directional (signals focused to/from one direction).
  • Opposite: though the polarization is not terribly critical for HF signals, note that the discone is mounted for the vertical component, while the LPDAs are mounted for horizontal signals.
  • But alike: both the discone and the LPDA are "wide-band" antennas, which means they work well through a whole range of frequencies. Most antennas work best only within say ± 1% of a particular frequency and/or some harmonics, whereas these antennas work continuously from their lowest frequency to something 5–10x higher than that.

The dipole here is the one that almost looks like a telegraph wire coming out of the shack on the right and then T-ing out above the fence in the picture's framing. That one works on one or a small handful of "fixed" frequencies. Coupling "broadside", it's not really omni-directional but it's not particularly directional either. I shouldn't make it sound too boring, because dipole antennas are pretty much the fundamental concept within the rest of antenna theory. Just not nearly so versatile, or cool-looking, as the other two :-)

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There are several antennas of different types. Near the front looks like a discone antenna and the beam on the tower looks like a Log Periodic antenna.

Such an antenna farm is typical of a government or military installation. In the US, the regional FEMA (Federal Emergency Management Agency) sites have similar antenna farms. These are designed to provide multi-frequency (HF, VHF, UHF) communications in times of emergency.

I am not familiar though with Switzerland but likely it is a government site.

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  • $\begingroup$ Also, the the low height of the dipole may imply that it is intended for "near vertical incident skywave" (NVIS) propagation to provide local and regional communications on HF (medium wave) bands otherwise used over longer distances. $\endgroup$ – Brian K1LI Mar 8 at 23:05

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