I know your pain Catherine. I live in the foothills a few miles from
Downtown Los Angeles. We have a regular Saturday morning group on 40M SSB.
My noise floor can be as low as S7 (rare) or above S9. We talk with local LA
area people as well as Arizona, and Northern California.
One phenomenon is when signals are strong, so is the noise, but the signals
are stronger than the noise. This I would conclude is due to noise
"skipping in" from many miles away: when the skip is good it helps the
signals but it also helps the noise!
Ironically, The more distant locations in quieter areas can copy me at 100w
fine, but one person in nearby North Hollywood has a high noise floor and
cannot copy me well unless I use the AMP but I copy him fine at 100 W on his
end. Then there is a guy in Northridge (NW LA) that I frequently cannot pull
out of the noise even though he is using an AMP.
I live a block away from a big High Voltage transmission line to the east,
and about a half mile from another one to the west.
Location, location, location!
Chris, AB6QK
------------------------------
Message: 2
Date: Wed, 10 May 2017 14:31:56 +0000 (UTC)
From: Catherine James <catherine.james@att.net>
To: <amps@contesting.com>, Jim Thomson <jim.thom@telus.net>
Subject: Re: [Amps] HV MOSFETs for RF
Message-ID: <166019510.6453163.1494426716050@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
"Problem is, the typical ?140 db MDS of today's xcvrs is rendered useless,
since the noise floor in urban areas is way higher than that."
Yes, this is why those of us in rural areas need an amp more than we need
better antennas. We can hear the 100 watt signal from the urban hams no
problem, but they can't hear us. Going to 500 - 1000 watts solves that
problem.
"Same deal with astronomy + light pollution. I gave up on that a while
back. If you cant even see the milky way from your own back yard, throw in
the towel, you are wasting your time."
Or you can go the CCD camera route. Modern CCDs and image stacking can
produce amazing images from light-polluted areas. Unfortunately I have not
found any ham-radio equivalent that can solve interference problems at the
receiver instead of at the source of the in-band interference.
"If I point it at say VK land, I'm also pointed right at a source of
noise. Ditto with every other direction."
I have that problem on 2 meter weak-signal. My greatest noise source, by
far, is the city of Boston, even though it's a good 180 miles away. It's
obvious when the rotor turns the antenna through that bearing. But that's
also the direction where ham stations are most likely to be found. Receive
F/B doesn't help if the signal and the noise are coming from the same
direction.
73,
Cathy
N5WVR
------------------------------
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