there are many different types of antennas, for this discussion, i will only talk about 2 of them.... those that work, and those that dont ....
for educational purposes only, any mods you make are your responsibility and only yours....do so at your own risk..
an effective antenna, is one that is tuned to the frequency in use, has a low vswr, and transfers its signal to the surrounding air efficiently... every thing else, is a so called dummy load .... or resistor that just eats up your power
.
radio signals never leave the antenna.... what does happen, is the voltages and currents that are on the antenna elements impress them selves on the sourounding airs electrons and continue to do that to the next electrons next to them... its just like tossing a rock into a puddle of water and watching the rippling effect that comes from the rock hitting the water... radio signals do not fly off the antenna like a bird flys off a tree...
microwave signals are so small even the morning due can attenuate them, so, can you imagine what will happen to them if the antenna your using is not constructed with the right components and material, or even built to the right length ..yes, each radio signal has a specific length....and it can be calculated...
with hand controllers useualy the power amp of the transmitter feeds the antenna directly .... but. if the antenna is to thin, or made to work on several frequiencys, your loosing antenna gain, also hand controllers are useualy made of plastic, so, your loosing half of your signal because half of the antenna is missing, since the basic antenna design is a dipole, that is an antenna with both a positive and negitive element,and is called a ballenced antenna....its the minimum antenna you need for it to be efficient..
the thickness of the antenna, its material and what its housed in all effect its performance,.. did you know that all plastics will not pass microwave signals ... thats why there are speical microwave dishes ,etc that are used in your microwave oven,.to cook your meals or what ever...they will pass microwave signals, if not, they would heat up and melt
just because a manufacturer claims that a certain antenna has such and such amount of db gain, dont mean it does .... a true antenna here on earth is measured in dbd over a referenced dipole, and in space, its measured as an isotropical radiator ... there is a difference of 3 db between the two readings .... radio waves travell at the speed of light ,only in a pure vacuum, when they go through anything else, including oxygen, they slow down, or, get attinuated .. what does this mean...well your antenna and all its components must take this in account, when its designed, else, you will loose signal .. and there by have a poor radiating antenna, that goes for receiving also .... by the way, 3 db could be as much as half you transmitted or received signal , thats a lot to loose with a 100 milliewatt transmitter.
dont think antennas make a difference ??? go look at you local radio or tv station antenna, most likely, they spent more money on the antenna system than there transmitter ...
in order to make antenna comparisoms mean anything, you need the right test equipment for the frequency in question, there are so many thing that effect radio signals ...so just saying that... i think one antenna is better than the other just dont get it, your tests need to be done in a controlled environment where each antenna is subjected to the same conditions, real antenna manufactures have an antenna test range to do there testing on ..not some ones word of mouth from a test they did in there back yard ..
i build my own antennas, and i use circular polarization, that is switchable, from right to left hand polorization, i fly my drones on a 1000 acer farm, havent lost one yet ... why, because my signal gets to the drone, and the drone gets back to me... how, through the antenna system.. an out board amp is in certian situations useful, but i can gain the same amount of signal with a good designed antenna ...and, it works for receiving as well as transmitting...
if any of this is of interest to you, pick up a copy of the radio amateurs hand book, it costs around 35 or 40 bucks, thats nothing when you have spent thousands on drones and assorted equipment.... the book will tell you all you need to know .....
fly safe, fly smart
MADMAX
for educational purposes only, any mods you make are your responsibility and only yours....do so at your own risk..
an effective antenna, is one that is tuned to the frequency in use, has a low vswr, and transfers its signal to the surrounding air efficiently... every thing else, is a so called dummy load .... or resistor that just eats up your power
.
radio signals never leave the antenna.... what does happen, is the voltages and currents that are on the antenna elements impress them selves on the sourounding airs electrons and continue to do that to the next electrons next to them... its just like tossing a rock into a puddle of water and watching the rippling effect that comes from the rock hitting the water... radio signals do not fly off the antenna like a bird flys off a tree...
microwave signals are so small even the morning due can attenuate them, so, can you imagine what will happen to them if the antenna your using is not constructed with the right components and material, or even built to the right length ..yes, each radio signal has a specific length....and it can be calculated...
with hand controllers useualy the power amp of the transmitter feeds the antenna directly .... but. if the antenna is to thin, or made to work on several frequiencys, your loosing antenna gain, also hand controllers are useualy made of plastic, so, your loosing half of your signal because half of the antenna is missing, since the basic antenna design is a dipole, that is an antenna with both a positive and negitive element,and is called a ballenced antenna....its the minimum antenna you need for it to be efficient..
the thickness of the antenna, its material and what its housed in all effect its performance,.. did you know that all plastics will not pass microwave signals ... thats why there are speical microwave dishes ,etc that are used in your microwave oven,.to cook your meals or what ever...they will pass microwave signals, if not, they would heat up and melt
just because a manufacturer claims that a certain antenna has such and such amount of db gain, dont mean it does .... a true antenna here on earth is measured in dbd over a referenced dipole, and in space, its measured as an isotropical radiator ... there is a difference of 3 db between the two readings .... radio waves travell at the speed of light ,only in a pure vacuum, when they go through anything else, including oxygen, they slow down, or, get attinuated .. what does this mean...well your antenna and all its components must take this in account, when its designed, else, you will loose signal .. and there by have a poor radiating antenna, that goes for receiving also .... by the way, 3 db could be as much as half you transmitted or received signal , thats a lot to loose with a 100 milliewatt transmitter.
dont think antennas make a difference ??? go look at you local radio or tv station antenna, most likely, they spent more money on the antenna system than there transmitter ...
in order to make antenna comparisoms mean anything, you need the right test equipment for the frequency in question, there are so many thing that effect radio signals ...so just saying that... i think one antenna is better than the other just dont get it, your tests need to be done in a controlled environment where each antenna is subjected to the same conditions, real antenna manufactures have an antenna test range to do there testing on ..not some ones word of mouth from a test they did in there back yard ..
i build my own antennas, and i use circular polarization, that is switchable, from right to left hand polorization, i fly my drones on a 1000 acer farm, havent lost one yet ... why, because my signal gets to the drone, and the drone gets back to me... how, through the antenna system.. an out board amp is in certian situations useful, but i can gain the same amount of signal with a good designed antenna ...and, it works for receiving as well as transmitting...
if any of this is of interest to you, pick up a copy of the radio amateurs hand book, it costs around 35 or 40 bucks, thats nothing when you have spent thousands on drones and assorted equipment.... the book will tell you all you need to know .....
fly safe, fly smart
MADMAX
