Buzzard Droppings June 2006

Radiated (Arc Welder, Plasma Cutters, etc.)

The above are a few examples of possible sources for interference.  Radiated interference signals can come from many types of sources.  Arc welders, plasma cutters, etc., come in many varieties, the most common being DC arc, which is a high current (amps) device that creates an electrical arc to create high temperatures which welds the two pieces of material together.  Your aircraft would have to be in close proximity to the welder to be affected.  Plasma Cutters/Welders us a very high frequency to start the arc used for welding.  This is normally of short duration, but could be a source of momentary interference causing momentary loss of control of your aircraft.    Radio Frequency Welding is used for plastics and other materials and could cause complete loss of control of your aircraft.  Electric fences can also cause erratic behavior.  When an electrical pulse

Electrical Interference (Power Lines, Transformers, etc.)

When driving and listening to an AM stations, you hear a buzzing sound as you drive under power lines, this is caused (In some cases) by loose hardware, dirty insulators, or faulty transformers.  The interference from this scenario can be due to arcing in the hardware, etc.  When an arc occurs, it radiates an infinite number of harmonic frequencies, which include the frequencies that our RC radios operate on (72 MHz) and if strong enough, will interfere with your aircraft receiver.  Power tools can also radiate interference.  The brushes used in some power tools will arc causing interference.

Electronic (Fishing Gear, Two Way Radios, Etc.)

The list in this category is almost endless, devices from A to Z can be considered harmful if the circumstances are just right.  Cell phones, computers, pagers, electronic battery chargers, DC to AC converters, televisions, and the list goes on, can be a source of interference.  Considering the BBMAC flying field location, I think the most common would be related to electronic fishing gear, two way radios, etc used on the river.

Two RC Radios On The Same Channel

Of course the worse of them all – Hopefully we have placed our membership card in the correct frequency control board location before turning on our radio.

Non-Interference

Static magnetic fields from any object in almost all cases are NOT harmful to RC receivers.  The railroad trestle located at the east end of the BBMAC flying field or the goal posts at the Northwest side are not a source of interference.

Relationship to Aircraft

From my observations, we tend to follow the aircraft with our radios when flying.  This means that the antenna is pointing at the aircraft.  When the aircraft is flying away or towards us, (I’m referring to the two areas where suspected interference has occurred) and we are subconsciously pointing the radio antenna to the aircraft (If you remember from Figure 2, this is worse case signal strength). If you loose control of the aircraft, trying turning the radio 90 degrees to the aircraft, maximizing signal strength to the aircraft, and mostly horizontal to the ground.  This may save the day, however, I must point out, this is not a full proof solution.

 

Receiver – Transmitter

Do Your Checks!  I have noticed that not everyone checks radio range before flying for the first time each day.  Without doing this important radio check, you are putting your aircraft (and perhaps others) at risk – You don’t know if something has changed or failed since the last time you flew.  Radio on, antenna collapsed, 40 to 45 paces away – can you still control your aircraft reliably?

 

Most Important

ENJOY FLYING YOUR MODEL AIRCRAFT