Question about antennas

[i-7ashe]

1. For RF devices that charge/take in energy through RF waves, does it only take in electricity from a frequency it's wired/set to pickup/receive or does it get electricity from all RF waves?
2. Can an antenna fold in (collapse but still connect like tent poles) and still remain operational like it does before?
3. Can a loop antenna receive transmissions from all directions?
4. Can loop antennas be directional while transmitting, especially when they're small?

If you can answer some, that would be great. Have a nice day!

 

[doctordialtone]

1. For RF devices that charge/take in energy through RF waves, does it only take in electricity from a frequency it's wired/set to pickup/receive or does it get electricity from all RF waves?
2. Can an antenna fold in (collapse but still connect like tent poles) and still remain operational like it does before?
3. Can a loop antenna receive transmissions from all directions?
4. Can loop antennas be directional while transmitting, especially when they're small?

It's complicated:

Radiation Patterns

Loop Antennas

Antenna theory

 

[StaticDischarge]

1. It will receive all RF (dependent on received signal strength which is dependent on distance from transmitter and it's output power/direction of signal from the transmitter and the frequency at which the antenna is tuned, it's height, surrounding terrain, etc..).
2. No. If the antenna is "folded" it will still receive RF but the "tuned" frequency will change to the length of the fold therefore if a receiver is set to a certain frequency as the antenna was before folding, the received signal will diminish or become lower than that of the threshold of the receiver and may not be heard as you are changing the length and "tuned frequency" of the antenna when folded.
3. Normally loop antennas are directional front to back of the "wide area" of the loop.
4. Loop antennas will transmit just like reception stated in #3 - directional.

As stated above by doctordialtone it will get way more complicated.. There are way more factors involved than what I have stated.
Terrain, coax, coax connectors, frequency(ies) involved and time of year (foliage not to forget sun spot cycles), height of antenna, and on and on and on.... and on...