Sounds like corona discharge problem like we used to have on a 2-meter
machine here.
It's not unusual to have this effect using a co-linear style antenna at
some sites.
----- Original Message -----
Sent: Wednesday, April 07, 2004 9:10
AM
Subject: [Repeater-Builder] Severe
Weather vs. Repeater Performance
Hi All!
My Weather Spotters are mad at me! Help!
Are there any technical papers out there that describe repeater/radio
performance as a function of heavy rain / thunderstorms / severe weather?
Where the weather is an attenuation of RF?
Let me describe the scenario.....
As we all know its tornado season and as the weather turns
bad, all the spotters and spotter want to be's show up for the weather
nets. When the weather hits the area and the storms are moving
through the coverage area of the repeater, it's range drops
off. Some of my spotters claim the coverage area drops up to 50%!
We have talked about the silly stuff:
1. Ht's don't work well inside your car, when you are trying to stay out
of the rain.
2. Ht's that are marginal when the weather is good don't work better in
bad weather.
3. Bases don't work well inside your house, when you disconnect the
base antenna for an indoor antenna.
4. Mobiles don't work well from inside your garage or when you are under
a highway overpass!
As for the repeater, it is on our wish list to upgrade the current 10
year old 4-pole antenna with new. I have joking suggested if
someone would like to go and check the VSWR during a storm they have my
permission! Suprisingly, no takers! The repeater is a 40 watt
Micor.
Assuming the antenna is OK and the silly stuff is not going on, here are
my questions:
1. How does severe weather affect short term range?
2. Is it the rain alone, or the moisture on everything?
3. Does lightning effect the noise floor enough to drown out weak
signals?
I remember reading a paper back in college that describe broadcast signal
RF attenuation in deep woods and forests as an effect of the leaf canopy, and
the moisture of the rain/dew on the leaves and its effects during the summer
vs. winter months (winter has no leaves to effect RF)
Any Help and ideas would be great!
Sorry for the long post!
Respectfully,
Brian, WD9HSY
