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Flat Earth Theory / Amateur radio shows the earth is round
« on: September 11, 2018, 02:23:33 PM »
I am an amateur radio operator (aka radio ham) and my everyday observations are consistent with the round earth model.
I take part in SOTA (Summits on the Air). I climb to the tops of hills and mountains and set up a radio station. I make contacts using various different radio bands and communicate with people both locally and over long distances.
If I use the 2m band (145MHz) I make mostly local contacts but I also manage to talk to others also on summits up to about 150km. If I switch to HF (also known as short wave) then I can communicate much further. On 40m (7MHz) contacts are usually between 500 and 1000km and on 20m (14MHz) they are 1000km to 2000km, sometimes getting as far as the US (5000km from the UK).
The round earth model can explain these observations:
VHF communication is mostly line of sight although signals can travel a little further as they are refracted by the atmosphere. For the summit to summit contacts, if I enter the altitudes of the two stations into an online calculator it will tell me the maximum line of sight range. These figures are always entirely consistent with my observations.
HF radio signals bounce off the ionosphere which is the upper atmosphere. Radiation from the sun strips electrons from the air molecules to form ions which can refract radio signals back down to earth. The degree to which this refraction happens depends on the amount of radiation from the sun, the frequency used and the angle at which the signal hits the ionosphere. If you send a radio signal straight up you can find the critical frequency. This is the highest frequency where the signal is bounced straight back down again. At the moment this is about 4MHz during the day so signals higher in frequency go straight out into space. But if the signal hits the ionosphere at a lower angle then it will be refracted, effectively reflecting it back to earth. As the frequency increases, the angle has to be lower and lower for the signal to return to earth. So this explains why my 7MHz signals can reach nearer stations than the 14MHz signals.
The time of day and year has a big impact on how far signals will go on any particular frequency. For example, during the afternoon I might be working stations around Europe. As the earth rotates and the sun's strength moves west I can no longer work Europeans but there are now Americans audible. And then at about 11 or 12 o'clock it all goes quiet and there are no more signals.
From my home location, in a valley, I can not hear many stations on VHF unless they are on a hill top. But I can still work stations far away on HF even though they are blocked by the hills around me, because they are bouncing off the ionosphere.
In the flat earth model, why would the frequency affect how far the signals travel? Why would the time of day matter? How can I still make contacts over long distances even though I live in a valley?
I take part in SOTA (Summits on the Air). I climb to the tops of hills and mountains and set up a radio station. I make contacts using various different radio bands and communicate with people both locally and over long distances.
If I use the 2m band (145MHz) I make mostly local contacts but I also manage to talk to others also on summits up to about 150km. If I switch to HF (also known as short wave) then I can communicate much further. On 40m (7MHz) contacts are usually between 500 and 1000km and on 20m (14MHz) they are 1000km to 2000km, sometimes getting as far as the US (5000km from the UK).
The round earth model can explain these observations:
VHF communication is mostly line of sight although signals can travel a little further as they are refracted by the atmosphere. For the summit to summit contacts, if I enter the altitudes of the two stations into an online calculator it will tell me the maximum line of sight range. These figures are always entirely consistent with my observations.
HF radio signals bounce off the ionosphere which is the upper atmosphere. Radiation from the sun strips electrons from the air molecules to form ions which can refract radio signals back down to earth. The degree to which this refraction happens depends on the amount of radiation from the sun, the frequency used and the angle at which the signal hits the ionosphere. If you send a radio signal straight up you can find the critical frequency. This is the highest frequency where the signal is bounced straight back down again. At the moment this is about 4MHz during the day so signals higher in frequency go straight out into space. But if the signal hits the ionosphere at a lower angle then it will be refracted, effectively reflecting it back to earth. As the frequency increases, the angle has to be lower and lower for the signal to return to earth. So this explains why my 7MHz signals can reach nearer stations than the 14MHz signals.
The time of day and year has a big impact on how far signals will go on any particular frequency. For example, during the afternoon I might be working stations around Europe. As the earth rotates and the sun's strength moves west I can no longer work Europeans but there are now Americans audible. And then at about 11 or 12 o'clock it all goes quiet and there are no more signals.
From my home location, in a valley, I can not hear many stations on VHF unless they are on a hill top. But I can still work stations far away on HF even though they are blocked by the hills around me, because they are bouncing off the ionosphere.
In the flat earth model, why would the frequency affect how far the signals travel? Why would the time of day matter? How can I still make contacts over long distances even though I live in a valley?