Technical Information
Do 35 MHz and 2.4 GHz systems cause interference to each other?
No, it is possible to use IFS systems and existing 35 MHz systems in parallel.
Are Spektrum and IFS systems and the various transmitter / receiver modules compatible with each other?
Spektrum is not compatible with IFS. The two systems do not cause interference to each other, but it is not possible to control a Spektrum receiver with an IFS transmitter module. However the two systems can be used side by side without interference.
The nose section of my own-design competition glider is made entirely of CFRP, which means that the IFS receiver is completely “encapsulated” in carbon fibre. I assume that range and interference rejection will be adversely affected by this; is this so? Would it be possible to remove the receiver aerial and install it in such a position that good reception will be obtained - perhaps using a co-axial connector?
It is not possible to obtain satisfactory results with an aerial mounted inside an all-carbon component. However, if just the canopy were made of a different material, effective range would be restored. Current receivers are not suitable for modification involving remote aerial deployment. We are currently developing new receivers for this type of application.
Can the aerials of the XR16 + XR20 receivers be removed from the receiver and installed in a different location in the model? At present these receivers are very difficult to install in the driver’s cab of a model truck.
The aerials of both the above-named receivers cannot be mounted remotely. However, we have IFS receivers under development which are suitable for your application.
Are effective range and reception quality adversely affected by rain and mist, or by trees and bushes in the flight path?
We have tested the systems with obstacles in the flight path and under varying climatic conditions - with very good results. However, we work on the assumption that models are operated at “average” model flying sites.
European and World Championship events seem to be plagued by heavy rain, and the contest is not always halted in such circumstances. With this in mind, how safe is the system in the wet?
We have tested these systems in rain and light fog - with positive results. Range is adversely affected (slightly) by high, wet grass, due to the ground damping effect, but this has always been true with conventional systems in any case.
The aerial of my mc-24 swivels and tilts. Which aerial position is best for use with 2.4 GHz?
The transmitter aerial features an articulated base, and its position influences the primary radiation pattern. As a general rule, signal field strength is at a minimum in an imaginary line extending straight out of the aerial tip. If you use a transmitter tray, or are accustomed to holding the transmitter in a particular position, with the effect that the tip of the aerial is pointing straight at the model most of the time, then we recommend that you angle the aerial or rotate it slightly.
I have the impression that a working IFS system does not switch frequencies if interference occurs. It seems that the system only seeks a vacant frequency when initially switched on, but never switches channels in operation if interference strikes.
The IFS system employs an intelligent frequency-hopping process which monitors particular criteria, e.g. the rise in background noise over time, and the threshold value for a possible frequency hop. After assessing the situation, it searches for a more suitable working channel using a specially developed algorithm.
If saturation occurs - i.e. powerful, wide-band interference suddenly swamping the signal - it is safe to assume that the whole band will be affected by this. In this situation the “intelligence” of the IFS system will fail to find a new, cleaner channel on which to operate.
What must I take into account when selecting a power supply for my IFS receiver?
Special care is required when designing the power supply for an IFS receiving system - as for any other computer-controlled receiver. Particularly important aspects are the maximum load capacity of the connector contacts and the conductor cross-section of the battery cables. If you intend to use a “conventional” arrangement - receiver battery connected to battery socket - you must bear in mind that the total current drawn by all the servos flows through the receiver battery socket and its contacts. Use a high-quality switch - or no switch at all.