[Amps] Urban noise pollution (was HV MOSFETs for RF)

[Roger (K8RI)]

I'm in a rural subdivision only 5 miles from downtown Midland MI. During 
the day, the S meter sets on 0 or 1. So it's a quiet location, most of 
the time.  DX is easy to work on 40 with 200 W barefoot unless they are 
near a city, then "Power Rules"

Light pollution? I'm only a 1/4 mile from the "county farm" that 
guaranteed with their new installation, there would be no light 
pollution. Sure...Their lights cast shadows in my yard!  Then "the mall" 
is about 7 mi NE with their unshielded parking lot lights creating a 
blank quadrant where nothing is visible.  With a "little" haze, nothing 
is visible. The 10" Meade hasn't been out in the yard in more than 10 
years. Of course, at my age, I can't lift it and the tripod. Well, I 
can, but Arthritis will have me on the heating pad for the next two days 
and with the poor seeing with light pollution it's certainly not worth 
the effort even were I younger without the Arthritis.

73, Roger (K8RI)


On 5/10/2017 Wednesday 1:31 PM, Chris Hays wrote:
> 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 at att.net>
> To: <amps at contesting.com>, Jim Thomson <jim.thom at telus.net>
> Subject: Re: [Amps] HV MOSFETs for RF
> Message-ID: <166019510.6453163.1494426716050 at 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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>
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