[Amps] Urban noise pollution (was HV MOSFETs for RF)
Roger (K8RI)
k8ri at rogerhalstead.com
Sat May 13 16:49:30 EDT 2017
I should have continued, but being after 4:00 AM, it was past
bedtime...way past!
The light pollution scenario I mentioned, mirrors RFI and the noise
floor. Although few "normal" people are aware of either, light pollution
is something you can show to someone and talk about its effects. I can
point to the light over the mall, with no sky visible in that direction.
Still the normal response is "So What?" They don't realize those cool
night photos from space are showing wasted power even if they fail to
see the importance of Astronomy.
Ham radio and the ever increasing noise floor are something they can not
see or hear. Sure, we can demonstrate the noise to them, but again,
their general response is "so what?" We are just a hobby, like model
airplanes, with no practical use, just toys. With cell phones they don't
need hams for emergencies. Try and convince them that the cell phones
are the first to go. You may get them to say, "I never realized that".
All but a few will forget before they leave.
The new, well not quite new, Entitlement Generations, believe they need
do nothing as they will be taken care of. I see the same mentality
toward the year 2000 (Y2K) in computers. This disaster was predicted and
it proved to be a false alarm. They have no idea of the millions of man
hours it took to turn the disaster into a non event before it happened.
Explanations fall on deaf ears.
I have a new neighbor of this mentality. Nothing is ever her
responsibility. Leaves from her un-raked yard plug the catch basin
flooding neighbors yards and with in inches of running into their
basement window wells after heavy rains. That is the responsibility of
those who own the yards at the basin. If she caused RFI. Tough! You
interfere and you'll be in court. You'd most likely win but at
substantial cost.
73, Roger (K8RI)
On 5/12/2017 Friday 4:13 AM, Roger (K8RI) wrote:
> 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
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
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>> ------------------------------
>>
>> End of Amps Digest, Vol 173, Issue 23
>> *************************************
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