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Old August 10th 11, 07:15 PM posted to rec.aviation.soaring
Mike the Strike
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Posts: 952
Default Icom A6 issues - shocks, interference

On Aug 10, 10:07*am, "Craig Funston"
wrote:
Not sure what to say about the lightning thing. *Jan had to be pretty *
surprised...

It seems like the newer electronic ballasts cause quite a bit of radio *
interference. *My first unpleasant encounter was after rebuilding the *
panel in my new shop. *Late into the night it's time for a radio test & *
nothing but static. *Couldn't stop it with the squelch, etc. *Damn... * *
Was sure something was wired incorrectly until I tried it the next morning *
with the lights off. *Bingo! *The florescent lights are nice new high *
quality with the small energy saver tubes, etc. *Biggest change is that *
now most florescents use electronic ballasts.

Craig

On Tue, 09 Aug 2011 19:59:48 -0700, Darryl Ramm *
wrote:









On 8/9/11 5:07 PM, Eric Greenwell wrote:
I recently bought an Icom A6 transceiver for use as a crew radio, and
have discovered several issues with it. Perhaps someone can make
suggestions for improving the situation:


Shocks


My wife was driving the motorhome while I was flying. After about an
hour that included a few transmissions and replies, she got some
tingling, then a shock from the A6. She put it down, and a bit later,
tried it again, with the same result except even stronger. There was
some lightning a few miles away, and some occasional light rain.


The A6 was connected to an external 3/4 wave Rainco antenna, but the
radio was operating on it's own battery and not plugged into the
motorhome battery power. Our previous radio never shocked her in 24
years, but was always plugged into the cigar lighter socket, so I
suspect that might have something to do with it. Has anyone else had
shocks from handheld radios used this way?


Interference


We discovered the some new fluorescent lights in the basement ("troffer"
style) cause a lot of static on the A6 when it's used with the external
whip antenna on top of the house. With the lights off, the squelch can
be set to 2; with the lights on, it must be set to 14 or 15 avoid the
static.


The radio is normally plugged into an Icom CP-20 Cigarette lighter
cable, which is plugged into a 12 volt output/120 VAC input bench style
power supply; however, the static and squelch settings are the same when
it's use on it's battery only.


Oh and it sounds like the florescent ballast is coupling via the AC *
power wiring. That is something every eclectic guitar owner know about. *
You may wan to see if you can power the radio from a different *
electrical circuit in the house or look at swapping the ballasts used in *
the florescent lights. They likely have poor quality electronic *
ballasts. You can get low-interference electronic ones or go for *
magnetic ballasts. Or some combination of all of the above.


Darryl


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The tingling and mild electric shocks are caused by corona discharge
from the top of the antenna. Corona discharge is a pulsed electric
discharge from elevated conductors under the influence of high
atmospheric electric fields (typically 10kV/m). Such high fields
occur around shower clouds, especially thunderstorms. In extreme
conditions, the discharge will become visible as a glow (St. Elmo's
fire). Corona currents charging the capacitance of a coaxial cable
attached to an antenna can increase the amount of stored energy and
give a decent kick.

While not normally dangerous, the discharges involve high voltages
(you get sparking) and can damage sensitive electronics.

Antennas that are inherently grounded (such as the J-pole) are best
for these applications, but some designs use an ungrounded loading
coil that are more susceptible.

Mike