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[TowerTalk] noise

To: <towertalk@contesting.com>
Subject: [TowerTalk] noise
From: K2JAS@worldnet.att.net (Roger L. Elowitz)
Date: Mon, 25 Aug 1997 15:32:15 -0400
Hi Mike,

Seems to me that you've done just about everything to eliminate the
noise except the most important thing.... locate it's source.

Try borrowing a portable shortwave radio and moving it around the
engine compartment to see where the noise is coming from the loudest.
That will easily pinpoint the source. (Naturally you want to start with
the radio tuned between stations but... you may want the radio tuned to
a strong signal as you get closer to the noise source.

If you have noisy ignition cabling.... there are shielded ignition
wiring kits.  If you have a noisy distributor cap.... there are
shielded caps you can buy.

You also don't state if the problem shows up as a change in pitch as
the engine speeds up.  Some ignition noise is generated at the
alternator. This may be heard on your signal as a whining sound that
changes in pitch as you accelerate and decelerate.  Perhaps you are not
going directly to the battery for your power and instead are trying to
take power out of the cigarette lighter. You might try to operate the
radio independently of the car's charging system... off it's own
battery.... but only for the purpose of a test.

There are lots of sources of mobile noise... including static buildup
on tires. You do need to do some snooping with a portable receiver to
isolate the source. Then the solution will present itself.

Good luck.

Roger, K2JAS

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At 07:04 PM 8/25/97 +0000, you wrote:
>I know that this is likely not the correct place to ask this, but has
>anyone had success in solving ignition noise in a 1988 Honda Civic DX  (I
>had a Civix SI of the same year, and it was stone  quiet) .  The ignition
>noise  is hearable up to uhf (FM), but is really affects me on HF when
I am
>mobile.
>
>
>What I have done so far:
>
>Grounded the exhaust system to the frame
>grounded the hood to the body/frame
>grounded the engine to the frame
>grounded the battery to the frame
>resistive plugs
>resistive wires
>new distributor cap
>new rotor
>new condensor (most would call it a capacitor)
>bypassed the fuel pump (this was worth 10db of random noise)
>
>Antenna is a High Sierra (Screwdriver) frame mounted
>
>HF radio lead is connected directly to the battery with 12 guage wire
>
>
>Sorry for the bandwidth, but if someone has any ideas (including other
>reflectors), I'm open to suggestions.  Please reply to me directly.
>
>regards...mike VA3MW
>
>
>
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