In a message dated 10/28/2002 3:16:44 PM Eastern Standard Time, VE3LVO@rac.ca
writes:
> Cheers,
> Not to make too big a hoohaw about it, but I am assuming
> everyone is thinking about protecting various devices from "radiating
> interference". That may be the problem, but I invite you also to consider
> another very prevalent cause, particularly with transmitters:
> the connectors........ If you are using RG58 or RG400, who made up your
> antenna lead(s)? If it was you, are you competent to do so? This is not a
> snub but a valid question.
> I was RMI (radio magnetic interference) chairman of our local
> club for many years, sent out to rationalize 'interference' problems
> reported by neighbours and hams. The following is my experience in this
> matter.
> In Amateur Radio, many folk complain of "interference" when in
> fact the problem is 'breakthrough' - their devices are 'listening' to
> frequencies from which they should be properly shielded. The rest are 95%
> caused by faulty connector preparation. If you (or your agent) did the work,
> were they qualified? The instructions, to be found most often in the Am Rad
> Handbook or by the valid manufacturer, are complete and detailed. If they
> were not followed to the letter, faulty connectors are the most prevalent
> cause.
> As well, the correct model connectors are critical.. just
> because it seems the right size does not mean it is the proper connector. In
> addition, moisture, and vibration are the enemies of correct transmitting
> coaxial fittings - and there are several 'classes' of these as well.
> Weatherproof versions have a suffix to denote the specialty.
> In sum, I would say if you worried the connectors onto the
> coaxial cable without following the instructions to the letter, this may be
> the probable cause. Solve that and the 'interference'
> disappears.
> IMO,
> Ferg
######Just to throw a spanner into the works here - I have an interference
problem
with my engine monitor. When I transmit, I get spurious readings. I have tried
to shield, but one interesting thing must be noted. I tried my hand held
radio in the cockpit and I get the same effect on the monitor (although not as
pronounced - lower transmit strength). This eliminates any possibility that I
have a problem with my antenna cables in the airplane. The RF energy is getting
into the system somehow. RIght now, this is low on my priority list and the
long term solution may be to ignore the engine readings when i transmit!
I also have a twin comanche with an electronic OAT gauge which goes nuts when
you
transmit also. I just ignore it.......
Dave
Owner and CEO
Mini U2 Aircraft Corporation
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