17.1 Individual Cases
It is a great temptation to claim interference whenever a model crashes but the plain fact is that outside radio interference is rare and causes very little trouble. If you have crashed a model and think you have been affected then run through this checklist first. These are the main causes of model crashes.
(a) Pilot error – this includes stall/spin incidents on final turns, tip stall incidents everywhere, not ‘keeping up’ with the model so that it doesn’t seem to be doing what you tell it, disorientation, lack of awareness of where the model is in relation to ground features, flying over operating transmitters, the inappropriate use of low specification radio equipment and very many more.
(b) Airborne power failure – including receiver battery failure or lack of capacity, wiring, plug and switch failures, black wire corrosion etc.
(c) Airborne hardware failure – including individual servos and receivers, crystal failures, aerials breaking or being masked, linkage failures, airframe failures etc.
(d) Ground failures – transmitter battery failure or low capacity, transmitter crystal failure, module pins corroding, dirty, faulty or loose transmitter aerial, dirt and oil in transmitter electronics etc.
(e) 35 MHz Club interference – other members switching on without frequency clearance, other transmitters faulty, people wandering over the field with operating transmitters etc.
The list is by no means exhaustive and you can add to it if you give it some thought but these are the things that you should think about very carefully. If you can honestly say that you can eliminate all of these then you MAY have suffered from interference. If so, then you should report the matter to your club committee, setting down all the relevant facts, and your club will then be in a position to file a report with BMFA if necessary.
17.2 Club Cases
(a) If your members are reporting regular cases of what seems to be interference then it is almost certain to be on 35 MHz and your first step is to conduct what on-field investigations you can.
(b) Look very carefully at the individual incidents to see if you can eliminate any. Try to collate the incidents you have to see if there is any pattern. Use your club scanner to see if you can pick up any specific interference.
(c) Investigate the equipment used by anyone suspected of suffering from interference. It may be that your site requires the use of high specification receivers and you can spot this quite easily if those affected are all using single conversion but no high specification receivers are affected. Read the section ‘Radio Control and You’ for more information. A new club site rule may be all that is required to solve the problem.
(d) When you are reasonably sure that you are suffering from 35 MHz interference then contact BMFA Leicester office and ask for an interference reporting form. When you have completed and returned this form, it will be cross-referenced with the BMFA interference database and appropriate action will be taken, usually in conjunction with the UK Radio Control Council (UKRCC) of which BMFA is an active member.
(e) The action taken may range from setting up an independent on-field investigation with specialised tracking equipment to gain more information to directly reporting your problems to Ofcom for immediate action.
Next Section 18. GENERAL MODEL SAFETY