Hai-Lee
Old and Bold RC PILOT
Now that the ESC safety features have been covered I will add a little
General Knowledge - Antennas
The most important thing you can ever do to protect your model from damage is understand what the antenna installation will allow and what it will not. I am forever battling against the "I don't worry about it because it just works". They terrify me!
The first thing about the wire and dipole antennas found in radio control systems is the oldest rule in radio. The antenna normally points at where the signal does not go!
Because of rule one I either use transmitters and receivers with dual antennas or even installations with satellite antennas. Where i am required to test a model for use with a single antenna system I will use vertical BUT I will keep it close and fly flat and level. A single manoeuvre could result in a LOS crash.
For dual antenna installations I try to position the antennas so that I have maximum time in the plane of strongest signal but I also use a manual trick to enhance the radio performance. I prefer the horizontal plane and so position my antennas in the model at right angles to each other and on the underside or on the top of the wing. with my transmitter antennas positioned vertical and horizontal I achieve a fairly good signal level for medium to long range BUT where I enter an manoeuvre at long range I actually rotate my transmitter to mimic the attitude of the model.
The reasons for the right angle positioning of the antennas is the dreaded rule number two! Rule two is that where 2 antennas cross each other at right angles, (and the same applies for wires carrying AC current), the coupling between the two wires in at a minimum. In practice if your transmitter antenna is at right angles to the receiver antenna the signal loss can be around 99%.
With two receive antennas as one antenna approaches the dreaded right angle cross angle to the transmitter antenna the other receive antenna is getting close to parallel and so to maximum coupling.
The simplest way to "SEE" what your antenna installation is like just visualise a very large FLAT disk with the antenna acting as an axle for each antenna. When looking at the transmitter antenna disks and the receiver antenna disks actually overlap greatly then the received signal will be greatest. you will note that with the antennas pointing at each other the disks NEVER cross or touch each other and so no coupling and finally where the disks meet at right angles to each other the contact area is a single line of little area and so their is a little signal but nothing significant.
Never use a receiver with a damaged or missing antenna. Whilst the antenna less receivers are quite popular they will have shorter range as it is a simple rule of electromagnetic radiation.
Antenna obstruction. I never allow my receiver antennas to be buried in my planes fuselage and always seek to use receivers with long antenna leads. They need to be long to exit the fuselage and sit on the wings as previously mentioned. where the antennas are short or less than ideal I deliberately will place my receiver and its antennas as far from all other metal and components as I can manage.
The truth is that all metal objects receive and re-radiate the radio frequency energy the encounter. The energy has a phase component and this phase component from multiple sources especially can provide an actual cancellation of signal at the receive antenna in an other wise area of high levels of radio signal. It can also improve signal but always shoot for or expect the worst possible result. This reflected energy dissipated in strength very quickly so any improve in separation between a receive antenna and a metal object can make a huge difference.
I hope the basic antenna instalment isn't to simple as I deliberately tried to avoid any real reference to any technical terms which have people spending hours on Wikipedia looking up meanings about what I was talking about.
Have fun!
General Knowledge - Antennas
The most important thing you can ever do to protect your model from damage is understand what the antenna installation will allow and what it will not. I am forever battling against the "I don't worry about it because it just works". They terrify me!
The first thing about the wire and dipole antennas found in radio control systems is the oldest rule in radio. The antenna normally points at where the signal does not go!
Because of rule one I either use transmitters and receivers with dual antennas or even installations with satellite antennas. Where i am required to test a model for use with a single antenna system I will use vertical BUT I will keep it close and fly flat and level. A single manoeuvre could result in a LOS crash.
For dual antenna installations I try to position the antennas so that I have maximum time in the plane of strongest signal but I also use a manual trick to enhance the radio performance. I prefer the horizontal plane and so position my antennas in the model at right angles to each other and on the underside or on the top of the wing. with my transmitter antennas positioned vertical and horizontal I achieve a fairly good signal level for medium to long range BUT where I enter an manoeuvre at long range I actually rotate my transmitter to mimic the attitude of the model.
The reasons for the right angle positioning of the antennas is the dreaded rule number two! Rule two is that where 2 antennas cross each other at right angles, (and the same applies for wires carrying AC current), the coupling between the two wires in at a minimum. In practice if your transmitter antenna is at right angles to the receiver antenna the signal loss can be around 99%.
With two receive antennas as one antenna approaches the dreaded right angle cross angle to the transmitter antenna the other receive antenna is getting close to parallel and so to maximum coupling.
The simplest way to "SEE" what your antenna installation is like just visualise a very large FLAT disk with the antenna acting as an axle for each antenna. When looking at the transmitter antenna disks and the receiver antenna disks actually overlap greatly then the received signal will be greatest. you will note that with the antennas pointing at each other the disks NEVER cross or touch each other and so no coupling and finally where the disks meet at right angles to each other the contact area is a single line of little area and so their is a little signal but nothing significant.
Never use a receiver with a damaged or missing antenna. Whilst the antenna less receivers are quite popular they will have shorter range as it is a simple rule of electromagnetic radiation.
Antenna obstruction. I never allow my receiver antennas to be buried in my planes fuselage and always seek to use receivers with long antenna leads. They need to be long to exit the fuselage and sit on the wings as previously mentioned. where the antennas are short or less than ideal I deliberately will place my receiver and its antennas as far from all other metal and components as I can manage.
The truth is that all metal objects receive and re-radiate the radio frequency energy the encounter. The energy has a phase component and this phase component from multiple sources especially can provide an actual cancellation of signal at the receive antenna in an other wise area of high levels of radio signal. It can also improve signal but always shoot for or expect the worst possible result. This reflected energy dissipated in strength very quickly so any improve in separation between a receive antenna and a metal object can make a huge difference.
I hope the basic antenna instalment isn't to simple as I deliberately tried to avoid any real reference to any technical terms which have people spending hours on Wikipedia looking up meanings about what I was talking about.
Have fun!
