Re: Gas Engine Electronics

god i love this stuff. where do these general rules come from? answer -

> someone makes them up. 8"....so at 7" its going to be noisy? > > how far you need to isolate depends a whole lot on how noisy the system is, and > sometimes it ain't got much to do with distance. first, PCM will go a long way > in solving many ignition related interference problems. second, DA and 3W > engines use shielded spark cables which are extremely quiet, and when coupled > with a decent receiver, will allow you to stack everything - ignition, > receiver, pack, main battery packs, all within a couple of inches of each > other, and there are no side effects. how do i know this? cause we did it, and > the airplane (a glider tug) is routinely flown to over 1000' and on any given > day may burn two gallons of fuel. so it works. but your results may > vary...especially if you use a low end ignition with a cheap receiver ...

Great set of RULES for those who don't HAVE ignition systems provided by your sponsors.

The shields can be acquired for several ignition makers and are reasonably effective at stopping spark splatter, as are resistor plugs.

The problem *I* have had with PCM Rx's and ignition is that it works absolutely great until that day when something in the ignition module raises the threshold of 'noise' a little or the RX develops a little vibraton or age problem. Then, suddenly, you have a flying gasser and NO WAY TO GET IT BACK unless you happen to have the correct "lock out response"! BTDT and it was expensive but worse than that it was scary to watch a 20+ pound bird with a 3 inch engine on the nose fly at WOTwith no hope of recovery. Just stand there and hope it suffers an upset and splashes before it finds people.

No sir, YOUR generalization is not for me either. I will continue to separate my radio equipment from my ignition equipment (of ALL brands as I happen to have several) as much as possible with 12 inches being a goal since MOST (but certainly not all) ignition module splatter is low powered enough to be avoidable at a distance. Mount them up close and it the IF section of the RX gets swamped with a signal stronger than your transmitter at a distance. In other words, the further from your transmitter the plane fly's, the better the chance it will get rotten.

Since you obviously are so much smarter than I, you are welcome to do it your way.

Jim Branaum AMA 1428

Six_O'clock_High Target snipped-for-privacy@Guns.com

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Six_O'Clock_High
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Ed Cregger wrote: > "MasterKopp" wrote >

Forgive me if I'm not impressed with your credentials. You aren't the only one with an education in electronics who frequents this group. IMHO, JR's PCM receivers are far superior to their FM ones. This may have nothing to do with the modulation scheme. But, there is little doubt that JR's PCM receivers are among the best. I have seen many cases where their ABC&W (single-conversion) FM receivers did a lousy job of rejecting noise. But, some of my friends with ignition engines swear by their PCM systems. I won't argue with them.

Jim - AMA 501383

Reply to
James D Jones

So you don't like me and now I don't like you. (yawn)

Who cares?

Ed Cregger

Reply to
Ed Cregger

If you don't like me because I called you on your swagger, then I'm pleased. I'll bet you don't like anybody who has the balls to call you on your really silly brags.

Jim - AMA 501383

Ed Cregger wrote:

Reply to
James D Jones

No, you don't get off that easy. I still like you.

Ed Cregger

Reply to
Ed Cregger

OK, Buddy :-)

Jim - AMA 501383

Ed Cregger wrote:

Reply to
James D Jones

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