## If the earth revolves at 1000 km / h, then the ground would be moved if someone flew a helicopter in the air and stays in place.

That depends on what you mean by "stay in place".

If you are on the moon and have a long stick, stick the helicopter taped to the end of the stick so it does not move and really stay in place, and you bury the end of the stick deep in Moonlight Rock So, if the helicopter really did not move, you would see that the helicopter is still on top of the stick. Her mother, standing on the ground next to the helicopter, would immediately accelerate the helicopter and make it disappear at high speed. (Depending on where on the ground the helicopter was, between 0 and 1800 km / h)

,

## 8: Find the distance to Lat and Long in KM

I want to find the next things in the vicinity.

I have a radius in KM. For some of the data, there are no correct results for lat and long based on the radius.

``````        \$ lat = 53.2734;
\$ long = -7,778320;

\$ where = & # 39; ACOS (SIN (field_latitude * 0.0175) & # 39;
, # * SIN (: lat * 0.0175) + COS (field_latitude * 0.0175) & # 39;
, # * COS (: lat * 0.0175) * COS ((: long * 0.0175) - (field length * 0.0175)) & # 39;
, & # 39;) * 6371 <= :radius';

\$query->where (\$ wo, [
':lat' => \$lat,
':long' => \$long,
]);

\$ results = \$ query-> execute ();
``````

So I have a query for DB above, but for some lat and long there are no correct results.

Can be output with lat, long calculation based on the radius?

## Privacy – Where can I find a very long range WLAN antenna with a range of 50-100 km? Or is it a DIY project?

I want to increase personal safety by getting Wi-Fi connections 50-100 km away from the physical device location with high decibels in milliwatts (dbm) to overcome the dampening of the path through leaves and other obstacles. This would allow me to avoid the geographic restrictions imposed by the local ISP's Wi-Fi connections because I can access the Internet anywhere within the system (within a 100km radius).

I am considering using a Yagi directional antenna or perhaps a parabolic lattice, but the ones I've been able to find so far are limited in their range, at a maximum of 15-20 km, never more than 50 dBm. Where can I find a Yagi or Parabola grid with a range of 50-100 km? Do I have to buy radio devices for industrial applications for this WLAN frequency range or is it a hardware store project? If it is home improvement, what equipment is needed and are there instructions on how to build one?

Do you not know the RF theory at all, but can you increase the WLAN range, for example on a parabola grid of 15 to 20 km to 50 to 100 km?