I have a new location to install a weather station.
It has been suggested to save costs that I mount the annenometer/wind gauge & rain gauge to an existing mast that has mounted on it 2 antennas for HF radio. Not sure of the frequencies covered by it may be in the region of 10 to 20 metres. I am told that it is some kind of beacon? of which there are about 15 of around the world ?
Would anyone out there who has Ham Radio experience care to comment on Will either the weather station equipment or Radio interfere with each other ???
Where is the site? The main HF beacon in NZ is ZL6B in Carterton. If that’s the one, then there are beacons on 14.100, 18.110, 21.150, 24.930 and 28.200 MHz. The transmissions work like this…
“Each transmission is repeated every three minutes. A transmission
consists of the Callsign of the Beacon sent at 22 WPM followed by four 1 second dashes. The Callsign and the first dash is sent at 100Watts. The remaining dashes are sent at 10Watts, 1 Watt and 0.1 Watts.”
As it’s a beacon, which is essentially interested in transmitting rather than receiving, you’re unlikely to cause any problems to it.
The problems you’re likely to face are:
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Harmonics (multiples of frequencies) of the HF transmissions might affect the weather station’s receiver, i.e. it might not hear the transmissions. You need to find the freq that the WX station transmits on and see if it divides by an integer factor into the transmission frequencies. For example if your WX station transmits on 162.99 MHz (very unlikely) then 18.110MHz divides into this exactly 9 times and this might cause you problems.
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The WX station receiver might be overloaded by the strong local signals from the beacon. You need to get your receiver into an area with the weakest signal from the beacon. Assuming the beacon is using vertical antennas (quite likely) then the best place for your receiver is vertically below the antenna mast. Also try to keep it as far away from the transmitters and feeders (probably coax) as possible.
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HF getting into the sensor’s electronics. Without knowing the type of sensors you’re going to fit and how they work it’s difficult to say if they’ll be affected. For example, an anemometer which uses optical sensing is likely to be less susceptible than one that uses a magnet and a coil. It’s probably a case of trying it and seeing what happens. The same rule applies to your receiver…try to get the sensors mounted below the antennas where the lowest level of signal can be found and also if possible away from the feeders.
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Assuming the antennas are verticals they aren’t likely to affect your wind measurements too much. However, if you’re mounting the rain gauge below the antennas, watch that you don’t have the end of a radial immediately above the gauge, otherwise you might get a lot of spurious readings due to run-off!
Thanks Chris
It is indeed in Carterton so that must be what it is.
It sounds as so it may be safer to stay off that mast !