Well folks, I've read with with great interest about the the whys and wherefors'
and do's and don'ts regarding Colombo's problems and must admit that you lads seem to have amassed quite a bit of knowledge amongst you, and as this is my first visit as a new member I am impressed. However I do feel that there is one avenue of thought that has been overlooked by some and others who are not even aware of. If you want to fly a spark ignition engine with the least amount of RF emmissions there is only One way to go without worrying if this that or The other is going to break down....screen leads etc, INDUCTIVE DISCHARGE.
CDI ignition requires screen leads while a good electronically switched inductive discharge will not require screen leads. Why is this? Well without getting too technical CDI ignition relies on charging a capacitor up to 200-300 volts and then hitting the primary winding of a 6volt (for example) ignition coil ...wallup..in a flash
so to speak . The resultant first exchange from the secondary coil gives a skyhigh low current voltage which is the evil culprit as far as RFI is concerned. and it
doesn't even contribute to the spark. It is the second oscillation which does the job at a lower less dangerous voltage. With INDUCTIVE DISCHARGE a six volt coil
has six volts switched on for however long the particular type of coil rquires just a couple of milliseconds maybe and then quite simply is switched off. The initial oscillation from the coil will be more like the second oscillation of the CDI igntion
but at a higher current. Very much safer and just as good. No screen leads required ...just a resister plug. I do hope this hasn't seemed to heavy but for sure it's the way to go. I designed my first system in 1979 when I found the early
Quadras were cutting range down by half with those wicked contact points.
I haven't looked back since. I hope this info can be of use to you lads. Lets face it we need all the help that we can get in this hobby.