Re: [WISPA] That black magic

[Scottie Arnett]

LOL, should have been 25G. I guess that is what I get when thinking about 
batteries and towers at the same time.

Scott

-- Original Message --
From: "Scottie Arnett" 
Reply-To: sarn...@info-ed.com, WISPA General List 
Date:  Tue, 23 Feb 2010 21:43:51 -0600

>If he is adamant, I would do an analysis with something like radio mobile and 
>keep adding height to his end to get the best result of the analysis. Then, 
>depending on how high he needs to go, suggest buying a tower that is at that 
>height. A single SU would not need more than rg25 with guides since you have 
>already suggested over 20'.
>
>IF he had to pay full price for Sat, he would be near the $500 range just for 
>install and Equip. We all know it is junk! Last I checked here rg25 was around 
>$100/sec. At that he could go at least 40 - 50 ft and maybe work?
>
>Scottie 
>
>-- Original Message --
>From: "Mike" 
>Reply-To: WISPA General List 
>Date:  Tue, 23 Feb 2010 09:39:46 -0600
>
>>Short squat corn crib.  It has an internal ladder with no outside access,
>>and another ladder on the outside going part way up.
>>
>>I have NOT verified the light is visible at 31 feet.  Maybe I should have
>>him climb it on a clear night to verify he can indeed see the light?
>>
>>I know I would be using knife edge diffraction with OFDM modulation.  This
>>is a horizontally polarized sector operating on a fractional channel.
>>
>>His part of the county, which is northeast of me lies on a Paleozoic
>>plateau; it is flat for miles.  Any neighboring properties would have the
>>same issues. My operations are centered in south county where we have what
>>are referred to as the Bohemian Alps.  My property is one of the highest
>>points in the county, and the tower is 180' above that.
>>
>>Right now, my most distant customer is 11 miles and has no issues.  This one
>>is almost 16 miles.  The farthest path where I *KNOW* I'm using knife edge
>>diffraction is 6.8 miles and has absolutely no issues EXCEPT during those
>>ducting events.
>>
>>
>>
>>
>>
>>WISPA Wants You! Join today!
>>http://signup.wispa.org/
>>
>> 
>>WISPA Wireless List: wireless@wispa.org
>>
>>Subscribe/Unsubscribe:
>>http://lists.wispa.org/mailman/listinfo/wireless
>>
>>Archives: http://lists.wispa.org/pipermail/wireless/
>>---
>>[This E-mail scanned for viruses by Declude Virus]
>>
>>
>
>Wireless High Speed Broadband service from Info-Ed, Inc. as low as $30.00/mth.
>Check out www.info-ed.com/wireless.html for information.
>
>
>
>WISPA Wants You! Join today!
>http://signup.wispa.org/
>
> 
>WISPA Wireless List: wireless@wispa.org
>
>Subscribe/Unsubscribe:
>http://lists.wispa.org/mailman/listinfo/wireless
>
>Archives: http://lists.wispa.org/pipermail/wireless/
>---
>[This E-mail scanned for viruses by Declude Virus]
>
>

Wireless High Speed Broadband service from Info-Ed, Inc. as low as $30.00/mth.
Check out www.info-ed.com/wireless.html for information.



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike]

To get a totally unimpeded 60% Fresnel zone, I had to go to 80 foot.  I have
some 25 sticks behind my barn, and pick up used ones from time to time for
such uses.  I hate guyed towers.  :-) I'd rather limit them to 30 feet and
attach them to a building gable.

Mike

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of Scottie Arnett
Sent: Tuesday, February 23, 2010 9:44 PM
To: WISPA General List
Subject: Re: [WISPA] That black magic

If he is adamant, I would do an analysis with something like radio mobile
and keep adding height to his end to get the best result of the analysis.
Then, depending on how high he needs to go, suggest buying a tower that is
at that height. A single SU would not need more than rg25 with guides since
you have already suggested over 20'.

IF he had to pay full price for Sat, he would be near the $500 range just
for install and Equip. We all know it is junk! Last I checked here rg25 was
around $100/sec. At that he could go at least 40 - 50 ft and maybe work?

Scottie 

-- Original Message --
From: "Mike" 
Reply-To: WISPA General List 
Date:  Tue, 23 Feb 2010 09:39:46 -0600

>Short squat corn crib.  It has an internal ladder with no outside access,
>and another ladder on the outside going part way up.
>
>I have NOT verified the light is visible at 31 feet.  Maybe I should have
>him climb it on a clear night to verify he can indeed see the light?
>
>I know I would be using knife edge diffraction with OFDM modulation.  This
>is a horizontally polarized sector operating on a fractional channel.
>
>His part of the county, which is northeast of me lies on a Paleozoic
>plateau; it is flat for miles.  Any neighboring properties would have the
>same issues. My operations are centered in south county where we have what
>are referred to as the Bohemian Alps.  My property is one of the highest
>points in the county, and the tower is 180' above that.
>
>Right now, my most distant customer is 11 miles and has no issues.  This
one
>is almost 16 miles.  The farthest path where I *KNOW* I'm using knife edge
>diffraction is 6.8 miles and has absolutely no issues EXCEPT during those
>ducting events.
>
>
>
>
>---
-
>WISPA Wants You! Join today!
>http://signup.wispa.org/
>---
-
> 
>WISPA Wireless List: wireless@wispa.org
>
>Subscribe/Unsubscribe:
>http://lists.wispa.org/mailman/listinfo/wireless
>
>Archives: http://lists.wispa.org/pipermail/wireless/
>---
>[This E-mail scanned for viruses by Declude Virus]
>
>

Wireless High Speed Broadband service from Info-Ed, Inc. as low as
$30.00/mth.
Check out www.info-ed.com/wireless.html for information.




WISPA Wants You! Join today!
http://signup.wispa.org/


 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/






WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike]

Even filters didn't help me with 900 MHz.

It is amazing the things we learn.  Who would have thought a corn field
would have less influence on a MW signal than a bean field?

I think I've had all possible challenges the past few months.  Bean fields,
hoar frost, icing on towers, ducting ...  If it weren't for the black magic
I wouldn't enjoy this nearly as much!

A repeater in that area might be in the works, but later.  I just put one up
a couple miles from him, but behind a hill for him.  I can't afford another
until we get some nicer weather and can sell more on the latest repeater.

My business is not so large that I can just tell the difficult ones to go
away.  I DO have some installs that are not by-the-book, and some even seem
to defy the laws of physics.  Some of those are also knife edge diffraction
paths.  

I won't walk away from an install that doesn't work, or one I don't think
will keep working.  If the take rate and population densities were greater
here, I'd be able to apply a cookie cutter approach. Instead, each new
install seems to have its own wrinkles and I adapt.

I have just never done one this distant, and certainly not one this distant
using knife edge diffraction.

If he can see the light and establish we do have LOS I'll proceed.  He
already understands the path qualities may change over time.

Mike

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of David Hulsebus
Sent: Wednesday, February 24, 2010 10:50 AM
To: WISPA General List
Subject: Re: [WISPA] That black magic

We see some of the same interference issues. It was actually much better 
when all the cordless phones were 900, verses meters, farm operations, 
etc...

Yes it's NLOS, if I went up another 40 ft I would have LOS.  With NLOS 
we only have about 25 yards of trees to deal with 100 yards or so from 
the house, but no dirt. He's 1.35 miles from the tower, the AP is 150 
above his GL. We do use a Cushcraft 906 antenna on his end and an Antel 
120 deg, 3 deg electrical down tilt on the tower that puts out 34.8 
EIRP. A filter we changed out a couple of years ago dropped our output a 
bit more than a db. Now that the beans are gone, his signal stabilized 
and improved from a fluctuating -75 to -83 back to a -70

This is an older CCU3100 WaveRider system that doesn't run OFDM, but 
DSSS.  I tried a panel antenna instead of the yagi and it improved the 
fluctuation some, but didn't improve the signal like going up 10 ft did. 
So I think you are correct that the changes in multipath from a little 
wind and lots of hardened leafs and beans reflected the signal more than 
when they had enough moisture to absorb more than reflect.

Dave

Mike wrote:
> 900 MHz doesn't work well around here.  The farmers have deployed GPS
> navigation systems using those frequencies.
>
> Was the bean path you had NLOS?  I'm curious what effects it had.  I have
> seen a four foot change in elevation work like black magic.  I think the
> beans get to blowing in the breeze and because there are hundreds of
> thousands of little hard points that randomly diffract the signal it
fades.
> I saw this on a knife edge diffraction path as well as a distant, path
where
> the CPE had to be mounted low to clear large branches of an oak tree 20
feet
> overhead.  The next field over was a bean field one year and caused fits
for
> a couple weeks, I believe because of the low angle.  Is it that OFDM can
> survive in a multipath environment until the individually randomized
signals
> number in the thousands?
>
> Mike
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of David Hulsebus
> Sent: Tuesday, February 23, 2010 3:04 PM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> Mike, Interesting you mentioned soy beans. I have a customer 
> (900-WaveRider) who was installed for 5 yrs next to a corn field. The 
> crop was replaced with soy beans this past year and a month before 
> harvest, as the beans dried out,  we started having signal fluctuation 
> issues. We raised the antenna 10 ft and the problem went away. It was 
> their first issue in 5 yrs.
>
> Dave
>
>
>
> Mike wrote:
>   
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>>  
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>>  
>>
>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>> large, these rural areas are very quiet.
>>
>>  
>>
>> There are no trees or obstru

Re: [WISPA] That black magic

[Mike]

I wondered if you'd weigh in.  I will use a grid at this location.  I think
my grids are 22 dB.  What 24 dB ones are you using?

I had a LOS once where the ONLY thing in the way was a power line.  It
dropped lots of packets until I lowered it a bit and put a little down tilt
to the panel.  The "unseen" energy around that wire must have been enough to
obstruct too much of the Fresnel zone.

I appreciate all of the input.  It's still been too cold and windy to send
him up his Rohn 25 to see if he can indeed see the light.  That will be my
next step.

Mike
-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of Marlon K. Schafer
Sent: Tuesday, February 23, 2010 10:18 PM
To: WISPA General List
Subject: Re: [WISPA] That black magic

First off, with a LEGAL base station AP running 36dB (I used 24db radio with

12dB sector as an example) you should see a -73 at 16 miles.

Personally, to help avoid interference, I use 30dB or so ap power and run 
24dB grids at anything past 8 miles.  Things run pretty well this way.

Multipath is a really hard thing to figure out some times.  Had one today, 
high tension power lines about half way.  Good signals but 80 to 90% retrans

rates.  I finally found a channel that worked well and got 3 megs both ways 
to the customer, but everything else I tried only gave me half a meg down 
and less up most of the time.

I gave the customer a 2 week trial before they have to pay for the install. 
We'll see if it keeps running or not.  I don't have high hopes.

I'll try moving the antenna up or down before I pull it out and see if I can

find a better spot.

In the end, some just never do work right.

marlon

- Original Message - 
From: "Mike" 
To: "'WISPA General List'" 
Sent: Tuesday, February 23, 2010 6:55 AM
Subject: [WISPA] That black magic


>I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>
>
>
>
>
>
>
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>
>
> Perhaps one would look at the path profile and common sense would dictate 
> it
> won't work.  However, I use knife edge diffraction successfully on a 
> handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>
>
> I have never used this technique where the ridge is close to mid point. 
> On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>
>
> The single exception was when the obstructing hill had soy beans growing 
> on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and 
> had
> absolutely no issues.  I think dry beans affect the signal because they 
> are
> no longer "row" polarized and randomly scramble the signal beyond use. 
> Once
> the beans were harvested, the signal came back like usual.
>
>
>
> On this path in question, I found the ridge.  There are no trees, instead 
> it
> is farmed.  There is corn stubble on it right now.
>
>
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>
>
> I went over all the physics involved and told him of my experiences.  Like

> I
> said, he is motivated.  I told him I wouldn't tie him into a contrac

Re: [WISPA] That black magic

[David Hulsebus]

We see some of the same interference issues. It was actually much better 
when all the cordless phones were 900, verses meters, farm operations, 
etc...

Yes it's NLOS, if I went up another 40 ft I would have LOS.  With NLOS 
we only have about 25 yards of trees to deal with 100 yards or so from 
the house, but no dirt. He's 1.35 miles from the tower, the AP is 150 
above his GL. We do use a Cushcraft 906 antenna on his end and an Antel 
120 deg, 3 deg electrical down tilt on the tower that puts out 34.8 
EIRP. A filter we changed out a couple of years ago dropped our output a 
bit more than a db. Now that the beans are gone, his signal stabilized 
and improved from a fluctuating -75 to -83 back to a -70

This is an older CCU3100 WaveRider system that doesn't run OFDM, but 
DSSS.  I tried a panel antenna instead of the yagi and it improved the 
fluctuation some, but didn't improve the signal like going up 10 ft did. 
So I think you are correct that the changes in multipath from a little 
wind and lots of hardened leafs and beans reflected the signal more than 
when they had enough moisture to absorb more than reflect.

Dave

Mike wrote:
> 900 MHz doesn't work well around here.  The farmers have deployed GPS
> navigation systems using those frequencies.
>
> Was the bean path you had NLOS?  I'm curious what effects it had.  I have
> seen a four foot change in elevation work like black magic.  I think the
> beans get to blowing in the breeze and because there are hundreds of
> thousands of little hard points that randomly diffract the signal it fades.
> I saw this on a knife edge diffraction path as well as a distant, path where
> the CPE had to be mounted low to clear large branches of an oak tree 20 feet
> overhead.  The next field over was a bean field one year and caused fits for
> a couple weeks, I believe because of the low angle.  Is it that OFDM can
> survive in a multipath environment until the individually randomized signals
> number in the thousands?
>
> Mike
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of David Hulsebus
> Sent: Tuesday, February 23, 2010 3:04 PM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> Mike, Interesting you mentioned soy beans. I have a customer 
> (900-WaveRider) who was installed for 5 yrs next to a corn field. The 
> crop was replaced with soy beans this past year and a month before 
> harvest, as the beans dried out,  we started having signal fluctuation 
> issues. We raised the antenna 10 ft and the problem went away. It was 
> their first issue in 5 yrs.
>
> Dave
>
>
>
> Mike wrote:
>   
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>>  
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>>  
>>
>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>> large, these rural areas are very quiet.
>>
>>  
>>
>> There are no trees or obstructions in the near field or out quite a ways.
>> However, there is a ridge almost half way between us.  I am embedding an
>> image of the path here created with alphimax.com path estimator.
>>
>>  
>>
>>
>>
>>  
>>
>>  
>>
>> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
>> back.  It lets me hand hold a test unit and see what it sees on a laptop.
>> Standing on the ground on his property we got an ALMOST usable signal in a
>> short test.  He has a 35 foot TV tower next to the house on which we would
>> install.
>>
>>  
>>
>> Perhaps one would look at the path profile and common sense would dictate
>> 
> it
>   
>> won't work.  However, I use knife edge diffraction successfully on a
>> 
> handful
>   
>> of installs.  Besides, black magic sometimes trumps common sense.
>>
>>  
>>
>> I have never used this technique where the ridge is close to mid point.
>> 
> On
>   
>> all others the ridge was closer to the user.  All of them work except when
>> tropospheric ducting enters into the equation, with one exception.  I have
>> told the users this is a 98% link and it WILL go down during those events.
>> Earlier this winter we had a few days of ducting which caused a couple of
>> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
>> only affect this area 20 some hours a year.
>>
>>  
>>
>> The sing

Re: [WISPA] That black magic

[jp]

Columbus and Armstrong were busy using federal $, not running a 
business.

On Tue, Feb 23, 2010 at 09:43:47AM -0600, Mike wrote:
> Josh said >> I agree with Jason, too.  Just because you can does not mean
> you should.
> 
> Columbus, or Neil Armstrong, or Edmund Hillary never said that!  :-)
> 
> 
> 
> 
> 
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>  
> WISPA Wireless List: wireless@wispa.org
> 
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
> 
> Archives: http://lists.wispa.org/pipermail/wireless/

-- 
/*
Jason Philbrook   |   Midcoast Internet Solutions - Wireless and DSL
KB1IOJ|   Broadband Internet Access, Dialup, and Hosting 
 http://f64.nu/   |   for Midcoast Mainehttp://www.midcoast.com/
*/



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Marlon K. Schafer]

Good point.  We do a lot of those these days.
marlon

- Original Message - 
From: "jp" 
To: "WISPA General List" 
Sent: Tuesday, February 23, 2010 7:19 AM
Subject: Re: [WISPA] That black magic


> On Tue, Feb 23, 2010 at 08:55:31AM -0600, Mike wrote:
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>
> Business reality for me is not to do it if tech support and tinkering
> costs more than it's worth, and that's a known possibility ahead of
> time.
>
> I'd suggest an intermediate repeater location that will work for him
> (and others to make it worthwhile). If the guy is motivated, perhaps he
> can find a spot for you to put a pole or tower or work with a neighbor
> on your behalf.
>
> -- 
> /*
> Jason Philbrook   |   Midcoast Internet Solutions - Wireless and DSL
>KB1IOJ|   Broadband Internet Access, Dialup, and Hosting
> http://f64.nu/   |   for Midcoast Mainehttp://www.midcoast.com/
> */
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/ 




WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Marlon K. Schafer]

First off, with a LEGAL base station AP running 36dB (I used 24db radio with 
12dB sector as an example) you should see a -73 at 16 miles.

Personally, to help avoid interference, I use 30dB or so ap power and run 
24dB grids at anything past 8 miles.  Things run pretty well this way.

Multipath is a really hard thing to figure out some times.  Had one today, 
high tension power lines about half way.  Good signals but 80 to 90% retrans 
rates.  I finally found a channel that worked well and got 3 megs both ways 
to the customer, but everything else I tried only gave me half a meg down 
and less up most of the time.

I gave the customer a 2 week trial before they have to pay for the install. 
We'll see if it keeps running or not.  I don't have high hopes.

I'll try moving the antenna up or down before I pull it out and see if I can 
find a better spot.

In the end, some just never do work right.

marlon

- Original Message - 
From: "Mike" 
To: "'WISPA General List'" 
Sent: Tuesday, February 23, 2010 6:55 AM
Subject: [WISPA] That black magic


>I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>
>
>
>
>
>
>
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>
>
> Perhaps one would look at the path profile and common sense would dictate 
> it
> won't work.  However, I use knife edge diffraction successfully on a 
> handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>
>
> I have never used this technique where the ridge is close to mid point. 
> On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>
>
> The single exception was when the obstructing hill had soy beans growing 
> on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and 
> had
> absolutely no issues.  I think dry beans affect the signal because they 
> are
> no longer "row" polarized and randomly scramble the signal beyond use. 
> Once
> the beans were harvested, the signal came back like usual.
>
>
>
> On this path in question, I found the ridge.  There are no trees, instead 
> it
> is farmed.  There is corn stubble on it right now.
>
>
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>
>
> I went over all the physics involved and told him of my experiences.  Like 
> I
> said, he is motivated.  I told him I wouldn't tie him into a contract, but
> we'd go month by month and if we found later in the year it wasn't 
> working,
> we'd cut our losses.  He was OK with that.
>
>
>
> Since I respect the viewpoints of many of you, bring it on!
>
>
>
>
>
> Friendly Regards,
>
>
>
> Mike
>
>
>
> Mike Gilchrist
>
> Disruptive Technologist
>
> Advanced Wireless Express
>
> P.O. Box 255
>
> Toledo, IA   52342
>
> Mike's
> <http://www.tamatoledonews.com/page/category.detail/nav/5001/Local-Columns.h
> tml>  Weekly Column
>
> 239.770.6203
>
> m...@aweiowa.com
>
>
>
>
>
>





>
>
> --

Re: [WISPA] That black magic

[Scottie Arnett]

If he is adamant, I would do an analysis with something like radio mobile and 
keep adding height to his end to get the best result of the analysis. Then, 
depending on how high he needs to go, suggest buying a tower that is at that 
height. A single SU would not need more than rg25 with guides since you have 
already suggested over 20'.

IF he had to pay full price for Sat, he would be near the $500 range just for 
install and Equip. We all know it is junk! Last I checked here rg25 was around 
$100/sec. At that he could go at least 40 - 50 ft and maybe work?

Scottie 

-- Original Message --
From: "Mike" 
Reply-To: WISPA General List 
Date:  Tue, 23 Feb 2010 09:39:46 -0600

>Short squat corn crib.  It has an internal ladder with no outside access,
>and another ladder on the outside going part way up.
>
>I have NOT verified the light is visible at 31 feet.  Maybe I should have
>him climb it on a clear night to verify he can indeed see the light?
>
>I know I would be using knife edge diffraction with OFDM modulation.  This
>is a horizontally polarized sector operating on a fractional channel.
>
>His part of the county, which is northeast of me lies on a Paleozoic
>plateau; it is flat for miles.  Any neighboring properties would have the
>same issues. My operations are centered in south county where we have what
>are referred to as the Bohemian Alps.  My property is one of the highest
>points in the county, and the tower is 180' above that.
>
>Right now, my most distant customer is 11 miles and has no issues.  This one
>is almost 16 miles.  The farthest path where I *KNOW* I'm using knife edge
>diffraction is 6.8 miles and has absolutely no issues EXCEPT during those
>ducting events.
>
>
>
>
>
>WISPA Wants You! Join today!
>http://signup.wispa.org/
>
> 
>WISPA Wireless List: wireless@wispa.org
>
>Subscribe/Unsubscribe:
>http://lists.wispa.org/mailman/listinfo/wireless
>
>Archives: http://lists.wispa.org/pipermail/wireless/
>---
>[This E-mail scanned for viruses by Declude Virus]
>
>

Wireless High Speed Broadband service from Info-Ed, Inc. as low as $30.00/mth.
Check out www.info-ed.com/wireless.html for information.



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike]

900 MHz doesn't work well around here.  The farmers have deployed GPS
navigation systems using those frequencies.

Was the bean path you had NLOS?  I'm curious what effects it had.  I have
seen a four foot change in elevation work like black magic.  I think the
beans get to blowing in the breeze and because there are hundreds of
thousands of little hard points that randomly diffract the signal it fades.
I saw this on a knife edge diffraction path as well as a distant, path where
the CPE had to be mounted low to clear large branches of an oak tree 20 feet
overhead.  The next field over was a bean field one year and caused fits for
a couple weeks, I believe because of the low angle.  Is it that OFDM can
survive in a multipath environment until the individually randomized signals
number in the thousands?

Mike

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of David Hulsebus
Sent: Tuesday, February 23, 2010 3:04 PM
To: WISPA General List
Subject: Re: [WISPA] That black magic

Mike, Interesting you mentioned soy beans. I have a customer 
(900-WaveRider) who was installed for 5 yrs next to a corn field. The 
crop was replaced with soy beans this past year and a month before 
harvest, as the beans dried out,  we started having signal fluctuation 
issues. We raised the antenna 10 ft and the problem went away. It was 
their first issue in 5 yrs.

Dave



Mike wrote:
> I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>  
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>  
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>  
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>  
>
>
>
>  
>
>  
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>  
>
> Perhaps one would look at the path profile and common sense would dictate
it
> won't work.  However, I use knife edge diffraction successfully on a
handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>  
>
> I have never used this technique where the ridge is close to mid point.
On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>  
>
> The single exception was when the obstructing hill had soy beans growing
on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and
had
> absolutely no issues.  I think dry beans affect the signal because they
are
> no longer "row" polarized and randomly scramble the signal beyond use.
Once
> the beans were harvested, the signal came back like usual.
>
>  
>
> On this path in question, I found the ridge.  There are no trees, instead
it
> is farmed.  There is corn stubble on it right now.
>
>  
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>  
>
> I went over all the physics involved and told him of my experiences.  Like
I
> said, he is motivated.  I told him I wouldn't tie him into a contract, but
> we'd go month by month and if we found later in the year it wasn't
working,
> we'd cut our losses.  He was OK with that.
>
>  
>
> Since I respect the viewpoints of many of you, bring it on!
>
>  
>
>  
>
> Friendly Regards,
>
>  
>
> Mike
>
>  
>
> Mike Gilchrist
>
> Disruptive Technologist
>
> Advanced Wireless Express
>
> P.O. Box 255
>
> Toledo, IA   52342
>
> Mike'

Re: [WISPA] That black magic

[David Hulsebus]

Mike, Interesting you mentioned soy beans. I have a customer 
(900-WaveRider) who was installed for 5 yrs next to a corn field. The 
crop was replaced with soy beans this past year and a month before 
harvest, as the beans dried out,  we started having signal fluctuation 
issues. We raised the antenna 10 ft and the problem went away. It was 
their first issue in 5 yrs.

Dave



Mike wrote:
> I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>  
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>  
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>  
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>  
>
>
>
>  
>
>  
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>  
>
> Perhaps one would look at the path profile and common sense would dictate it
> won't work.  However, I use knife edge diffraction successfully on a handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>  
>
> I have never used this technique where the ridge is close to mid point.  On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>  
>
> The single exception was when the obstructing hill had soy beans growing on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and had
> absolutely no issues.  I think dry beans affect the signal because they are
> no longer "row" polarized and randomly scramble the signal beyond use.  Once
> the beans were harvested, the signal came back like usual.
>
>  
>
> On this path in question, I found the ridge.  There are no trees, instead it
> is farmed.  There is corn stubble on it right now.
>
>  
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>  
>
> I went over all the physics involved and told him of my experiences.  Like I
> said, he is motivated.  I told him I wouldn't tie him into a contract, but
> we'd go month by month and if we found later in the year it wasn't working,
> we'd cut our losses.  He was OK with that.
>
>  
>
> Since I respect the viewpoints of many of you, bring it on!
>
>  
>
>  
>
> Friendly Regards,
>
>  
>
> Mike
>
>  
>
> Mike Gilchrist
>
> Disruptive Technologist
>
> Advanced Wireless Express
>
> P.O. Box 255
>
> Toledo, IA   52342
>
> Mike's
>  tml>  Weekly Column
>
> 239.770.6203
>
> m...@aweiowa.com
>
>   
>
>  
>
>
>   
> 
>
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>  
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike Hammett]

I think Mike said that no one in miles would be able to get signal either, 
due to topography.  That said, it sounds like a hell of a market to break 
into, once he solves how to skirt the topographical problems (tower on the 
hill, taller tower, etc.).


-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com



--
From: "Chuck Profito" 
Sent: Tuesday, February 23, 2010 10:55 AM
To: "'WISPA General List'" 
Subject: Re: [WISPA] That black magic

> If he is really motivated he will help with $$ for the repeater. Anybody
> else who will benefit?  They might too.
> Or raise your install cost to a few to cover the solar.
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of Josh Luthman
> Sent: Tuesday, February 23, 2010 7:47 AM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> Columbus was a murderer.  Neil Armstrong was going to the moon.  Not
> giving a farmer access to a global network to check weather, stocks
> and naughty pictures.  Edmund Hillary is nuts.
>
> I would definitely start by making sure you have LOS at 31 feet.
> We've established you can not at ~18, but may at 31.  Maybe he's
> looking in the wrong spot and doesn't know what he's looking for and
> in reality, you can see the light at 18 feet.  I'd definitely get
> these figures before proceeding.
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> "Success is not final, failure is not fatal: it is the courage to
> continue that counts."
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 10:43 AM, Mike  wrote:
>> Josh said >> I agree with Jason, too.  Just because you can does not mean
>> you should.
>>
>> Columbus, or Neil Armstrong, or Edmund Hillary never said that!  :-)
>>
>>
>>
>>
>>
>>
> 
> 
>> WISPA Wants You! Join today!
>> http://signup.wispa.org/
>>
> 
> 
>>
>> WISPA Wireless List: wireless@wispa.org
>>
>> Subscribe/Unsubscribe:
>> http://lists.wispa.org/mailman/listinfo/wireless
>>
>> Archives: http://lists.wispa.org/pipermail/wireless/
>>
>
>
> 
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
> 



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Chuck Profito]

If he is really motivated he will help with $$ for the repeater. Anybody
else who will benefit?  They might too.
Or raise your install cost to a few to cover the solar.

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of Josh Luthman
Sent: Tuesday, February 23, 2010 7:47 AM
To: WISPA General List
Subject: Re: [WISPA] That black magic

Columbus was a murderer.  Neil Armstrong was going to the moon.  Not
giving a farmer access to a global network to check weather, stocks
and naughty pictures.  Edmund Hillary is nuts.

I would definitely start by making sure you have LOS at 31 feet.
We've established you can not at ~18, but may at 31.  Maybe he's
looking in the wrong spot and doesn't know what he's looking for and
in reality, you can see the light at 18 feet.  I'd definitely get
these figures before proceeding.

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 10:43 AM, Mike  wrote:
> Josh said >> I agree with Jason, too.  Just because you can does not mean
> you should.
>
> Columbus, or Neil Armstrong, or Edmund Hillary never said that!  :-)
>
>
>
>
>
>


> WISPA Wants You! Join today!
> http://signup.wispa.org/
>


>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>




WISPA Wants You! Join today!
http://signup.wispa.org/


 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/




WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Josh Luthman]

Columbus was a murderer.  Neil Armstrong was going to the moon.  Not
giving a farmer access to a global network to check weather, stocks
and naughty pictures.  Edmund Hillary is nuts.

I would definitely start by making sure you have LOS at 31 feet.
We've established you can not at ~18, but may at 31.  Maybe he's
looking in the wrong spot and doesn't know what he's looking for and
in reality, you can see the light at 18 feet.  I'd definitely get
these figures before proceeding.

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 10:43 AM, Mike  wrote:
> Josh said >> I agree with Jason, too.  Just because you can does not mean
> you should.
>
> Columbus, or Neil Armstrong, or Edmund Hillary never said that!  :-)
>
>
>
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Steve Barnes]

This is one of those times that I would have to call this a non standard 
install and charge the client for the effort of getting him service.

I agree with others a 1/2 way repeater may be a help to other clients.
Next you have to remember that if not this then probably next year Corn will be 
back on the hill.  What happens when you add 12 more feet to that hill for 4 
months.  Is it worth the frustrated customer.  I have a statement that I have 
instilled in my installers. "I would rather have an unhappy customer for a week 
when I could not give them service than to have a unhappy customer for 1/2 a 
year when their service is bad and they gripe about it to all their neighbors". 

I have 5 customers that I will never make a dime off of due to them being so 
motivated and pushy that I worked my butt off getting them service.  Then more 
noise happened and I changed radios, Neighbor built a barn causing reflection 
so I moved the radio, lightening hit, another radio. After 10 trips out there, 
they are (currently) working, the dogs don't even bark when I pull in anymore.  
So $650 worth of radios + $800 worth labor > $199 install + $45 X 24months= 
$1080  means I loose.

Steve Barnes
RC-WiFi Wireless Internet Service


-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf 
Of Mike Hammett
Sent: Tuesday, February 23, 2010 10:20 AM
To: WISPA General List
Subject: Re: [WISPA] That black magic

We just tore ours down, but our corn crib was 30 - 40 feet tall.


-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com



--
From: "Josh Luthman" 
Sent: Tuesday, February 23, 2010 9:11 AM
To: "WISPA General List" 
Subject: Re: [WISPA] That black magic

> That profile suggests at 31 feet the customer should see the light
> (the black LOS line).  Was that where they looked for the light, or
> lower?  I would have to guess the corn crib was not nearly 31 feet.
>
> I think the whole US has 3m and 10m data - 
> http://www.cplus.org/rmw/dataen.html
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> "Success is not final, failure is not fatal: it is the courage to
> continue that counts."
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 10:05 AM, Mike  wrote:
>> I have a bright beacon I can turn on at the top of this tower.  On a 
>> clear
>> night recently, I turned it on.  Even a ways up a corn crib he could NOT 
>> see
>> the light.  I think the terrain data is accurate.  The alphimax site, 
>> once
>> you create the path lets you go into Google Earth and "see" the hill. 
>> This
>> part of the world doesn't have high resolution imagery archived yet, but 
>> I
>> CAN see the ridge when I follow along the path.
>>
>> -Original Message-----
>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
>> Behalf Of Josh Luthman
>> Sent: Tuesday, February 23, 2010 9:01 AM
>> To: WISPA General List
>> Subject: Re: [WISPA] That black magic
>>
>> To begin with, are you sure there is a bump there?  Could it be bad
>> meter resolution?
>>
>> Josh Luthman
>> Office: 937-552-2340
>> Direct: 937-552-2343
>> 1100 Wayne St
>> Suite 1337
>> Troy, OH 45373
>>
>> "Success is not final, failure is not fatal: it is the courage to
>> continue that counts."
>> --- Winston Churchill
>>
>>
>>
>> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
>>> I need to do a reality check with those of you familiar with knife edge
>>> diffraction as a propagation medium.  First, I should paint the scene:
>>>
>>>
>>>
>>> I have a corporate farmer almost 16 miles away who is motivated.  His
>>> options are satellite, dialup he currently uses, or us.
>>>
>>>
>>>
>>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>>> large, these rural areas are very quiet.
>>>
>>>
>>>
>>> There are no trees or obstructions in the near field or out quite a 
>>> ways.
>>> However, there is a ridge almost half way between us.  I am embedding an
>>> image of the path here created with alphimax.com path estimator.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> I have a test unit which is a 19 dB panel/radio with an AP fastened to 
>>> the
>>> back.  It lets me hand hold a test unit and see what it sees on a 
>>> laptop.
>>>

Re: [WISPA] That black magic

[Mike]

Josh said >> I agree with Jason, too.  Just because you can does not mean
you should.

Columbus, or Neil Armstrong, or Edmund Hillary never said that!  :-)






WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike]

Short squat corn crib.  It has an internal ladder with no outside access,
and another ladder on the outside going part way up.

I have NOT verified the light is visible at 31 feet.  Maybe I should have
him climb it on a clear night to verify he can indeed see the light?

I know I would be using knife edge diffraction with OFDM modulation.  This
is a horizontally polarized sector operating on a fractional channel.

His part of the county, which is northeast of me lies on a Paleozoic
plateau; it is flat for miles.  Any neighboring properties would have the
same issues. My operations are centered in south county where we have what
are referred to as the Bohemian Alps.  My property is one of the highest
points in the county, and the tower is 180' above that.

Right now, my most distant customer is 11 miles and has no issues.  This one
is almost 16 miles.  The farthest path where I *KNOW* I'm using knife edge
diffraction is 6.8 miles and has absolutely no issues EXCEPT during those
ducting events.





WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike Hammett]

We just tore ours down, but our corn crib was 30 - 40 feet tall.


-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com



--
From: "Josh Luthman" 
Sent: Tuesday, February 23, 2010 9:11 AM
To: "WISPA General List" 
Subject: Re: [WISPA] That black magic

> That profile suggests at 31 feet the customer should see the light
> (the black LOS line).  Was that where they looked for the light, or
> lower?  I would have to guess the corn crib was not nearly 31 feet.
>
> I think the whole US has 3m and 10m data - 
> http://www.cplus.org/rmw/dataen.html
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> “Success is not final, failure is not fatal: it is the courage to
> continue that counts.”
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 10:05 AM, Mike  wrote:
>> I have a bright beacon I can turn on at the top of this tower.  On a 
>> clear
>> night recently, I turned it on.  Even a ways up a corn crib he could NOT 
>> see
>> the light.  I think the terrain data is accurate.  The alphimax site, 
>> once
>> you create the path lets you go into Google Earth and "see" the hill. 
>> This
>> part of the world doesn't have high resolution imagery archived yet, but 
>> I
>> CAN see the ridge when I follow along the path.
>>
>> -Original Message-
>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
>> Behalf Of Josh Luthman
>> Sent: Tuesday, February 23, 2010 9:01 AM
>> To: WISPA General List
>> Subject: Re: [WISPA] That black magic
>>
>> To begin with, are you sure there is a bump there?  Could it be bad
>> meter resolution?
>>
>> Josh Luthman
>> Office: 937-552-2340
>> Direct: 937-552-2343
>> 1100 Wayne St
>> Suite 1337
>> Troy, OH 45373
>>
>> “Success is not final, failure is not fatal: it is the courage to
>> continue that counts.”
>> --- Winston Churchill
>>
>>
>>
>> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
>>> I need to do a reality check with those of you familiar with knife edge
>>> diffraction as a propagation medium.  First, I should paint the scene:
>>>
>>>
>>>
>>> I have a corporate farmer almost 16 miles away who is motivated.  His
>>> options are satellite, dialup he currently uses, or us.
>>>
>>>
>>>
>>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>>> large, these rural areas are very quiet.
>>>
>>>
>>>
>>> There are no trees or obstructions in the near field or out quite a 
>>> ways.
>>> However, there is a ridge almost half way between us.  I am embedding an
>>> image of the path here created with alphimax.com path estimator.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> I have a test unit which is a 19 dB panel/radio with an AP fastened to 
>>> the
>>> back.  It lets me hand hold a test unit and see what it sees on a 
>>> laptop.
>>> Standing on the ground on his property we got an ALMOST usable signal in 
>>> a
>>> short test.  He has a 35 foot TV tower next to the house on which we 
>>> would
>>> install.
>>>
>>>
>>>
>>> Perhaps one would look at the path profile and common sense would 
>>> dictate
>> it
>>> won't work.  However, I use knife edge diffraction successfully on a
>> handful
>>> of installs.  Besides, black magic sometimes trumps common sense.
>>>
>>>
>>>
>>> I have never used this technique where the ridge is close to mid point.
>>  On
>>> all others the ridge was closer to the user.  All of them work except 
>>> when
>>> tropospheric ducting enters into the equation, with one exception.  I 
>>> have
>>> told the users this is a 98% link and it WILL go down during those 
>>> events.
>>> Earlier this winter we had a few days of ducting which caused a couple 
>>> of
>>> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting 
>>> should
>>> only affect this area 20 some hours a year.
>>>
>>>
>>>
>>> The single exception was when the obstructing hill had soy beans growing
>> on
>>> it.  That particular one went down in late fall when the beans were 
>>> ready
>>> for 

Re: [WISPA] That black magic

[Mike Hammett]

Wouldn't it cost more to rent a lift truck than do an install?


-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com



--
From: "Ryan Spott" 
Sent: Tuesday, February 23, 2010 9:15 AM
To: "WISPA General List" 
Subject: Re: [WISPA] That black magic

> Well, before he invests in an install, have him rent a lift truck or
> something to see what he can see.
>
> I have a few links that have this type of knife edge defraction. I run 
> them
> using 802.11 gear (Mtik/Tranzeo). When I allowed full on access to all the
> speed I could provide, complaints came from these clients. When I 
> throttled
> them down to256/768/1M connections.. the complaints stopped and things 
> were
> more normalized to these clients.
>
> ryan
>
> On Tue, Feb 23, 2010 at 7:05 AM, Mike  wrote:
>
>> I have a bright beacon I can turn on at the top of this tower.  On a 
>> clear
>> night recently, I turned it on.  Even a ways up a corn crib he could NOT
>> see
>> the light.  I think the terrain data is accurate.  The alphimax site, 
>> once
>> you create the path lets you go into Google Earth and "see" the hill. 
>> This
>> part of the world doesn't have high resolution imagery archived yet, but 
>> I
>> CAN see the ridge when I follow along the path.
>>
>> -Original Message-
>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
>> Behalf Of Josh Luthman
>> Sent: Tuesday, February 23, 2010 9:01 AM
>> To: WISPA General List
>> Subject: Re: [WISPA] That black magic
>>
>> To begin with, are you sure there is a bump there?  Could it be bad
>> meter resolution?
>>
>> Josh Luthman
>> Office: 937-552-2340
>> Direct: 937-552-2343
>> 1100 Wayne St
>> Suite 1337
>> Troy, OH 45373
>>
>> “Success is not final, failure is not fatal: it is the courage to
>> continue that counts.”
>> --- Winston Churchill
>>
>>
>>
>> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
>> > I need to do a reality check with those of you familiar with knife edge
>> > diffraction as a propagation medium.  First, I should paint the scene:
>> >
>> >
>> >
>> > I have a corporate farmer almost 16 miles away who is motivated.  His
>> > options are satellite, dialup he currently uses, or us.
>> >
>> >
>> >
>> > A spectrum sweep of the property found absolutely no 2.4 signals.  By 
>> > in
>> > large, these rural areas are very quiet.
>> >
>> >
>> >
>> > There are no trees or obstructions in the near field or out quite a 
>> > ways.
>> > However, there is a ridge almost half way between us.  I am embedding 
>> > an
>> > image of the path here created with alphimax.com path estimator.
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > I have a test unit which is a 19 dB panel/radio with an AP fastened to
>> the
>> > back.  It lets me hand hold a test unit and see what it sees on a 
>> > laptop.
>> > Standing on the ground on his property we got an ALMOST usable signal 
>> > in
>> a
>> > short test.  He has a 35 foot TV tower next to the house on which we
>> would
>> > install.
>> >
>> >
>> >
>> > Perhaps one would look at the path profile and common sense would 
>> > dictate
>> it
>> > won't work.  However, I use knife edge diffraction successfully on a
>> handful
>> > of installs.  Besides, black magic sometimes trumps common sense.
>> >
>> >
>> >
>> > I have never used this technique where the ridge is close to mid point.
>>  On
>> > all others the ridge was closer to the user.  All of them work except
>> when
>> > tropospheric ducting enters into the equation, with one exception.  I
>> have
>> > told the users this is a 98% link and it WILL go down during those
>> events.
>> > Earlier this winter we had a few days of ducting which caused a couple 
>> > of
>> > them to fade.  I saw a 15 dB fade on those.  Statistically, ducting
>> should
>> > only affect this area 20 some hours a year.
>> >
>> >
>> >
>> > The single exception was when the obstructing hill had soy beans 
>> > growing
>> on
>> > it.  That particular one went down in late fall when the beans were 
>> > 

Re: [WISPA] That black magic

[Josh Luthman]

I see.  So at ~18 feet there is no light but at 31 you see the light,
suggesting that hill is actually there and as you said, Fresnel zone
is blocked.  You should expect the link to be troublesome.

I agree with Jason, too.  Just because you can does not mean you should.

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 10:19 AM, jp  wrote:
> On Tue, Feb 23, 2010 at 08:55:31AM -0600, Mike wrote:
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>
> Business reality for me is not to do it if tech support and tinkering
> costs more than it's worth, and that's a known possibility ahead of
> time.
>
> I'd suggest an intermediate repeater location that will work for him
> (and others to make it worthwhile). If the guy is motivated, perhaps he
> can find a spot for you to put a pole or tower or work with a neighbor
> on your behalf.
>
> --
> /*
> Jason Philbrook   |   Midcoast Internet Solutions - Wireless and DSL
>    KB1IOJ        |   Broadband Internet Access, Dialup, and Hosting
>  http://f64.nu/   |   for Midcoast Maine    http://www.midcoast.com/
> */
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[jp]

On Tue, Feb 23, 2010 at 08:55:31AM -0600, Mike wrote:
> I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
> 
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
> 

Business reality for me is not to do it if tech support and tinkering 
costs more than it's worth, and that's a known possibility ahead of 
time.

I'd suggest an intermediate repeater location that will work for him 
(and others to make it worthwhile). If the guy is motivated, perhaps he 
can find a spot for you to put a pole or tower or work with a neighbor 
on your behalf.

-- 
/*
Jason Philbrook   |   Midcoast Internet Solutions - Wireless and DSL
KB1IOJ|   Broadband Internet Access, Dialup, and Hosting 
 http://f64.nu/   |   for Midcoast Mainehttp://www.midcoast.com/
*/



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

Re: [WISPA] That black magic

[Mike]

The ladder on the outside of the corn crib is probably a little less than 20
feet.  I have seen the beacon close to 25 miles away.  It is a bright amber
rotating beacon. Yes at 31 foot, the LOS should be there, but more than half
of the Fresnel zone will be impeded.

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of Josh Luthman
Sent: Tuesday, February 23, 2010 9:12 AM
To: WISPA General List
Subject: Re: [WISPA] That black magic

That profile suggests at 31 feet the customer should see the light
(the black LOS line).  Was that where they looked for the light, or
lower?  I would have to guess the corn crib was not nearly 31 feet.

I think the whole US has 3m and 10m data -
http://www.cplus.org/rmw/dataen.html

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 10:05 AM, Mike  wrote:
> I have a bright beacon I can turn on at the top of this tower.  On a clear
> night recently, I turned it on.  Even a ways up a corn crib he could NOT
see
> the light.  I think the terrain data is accurate.  The alphimax site, once
> you create the path lets you go into Google Earth and "see" the hill.
 This
> part of the world doesn't have high resolution imagery archived yet, but I
> CAN see the ridge when I follow along the path.
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of Josh Luthman
> Sent: Tuesday, February 23, 2010 9:01 AM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> To begin with, are you sure there is a bump there?  Could it be bad
> meter resolution?
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> “Success is not final, failure is not fatal: it is the courage to
> continue that counts.”
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>>
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>>
>>
>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>> large, these rural areas are very quiet.
>>
>>
>>
>> There are no trees or obstructions in the near field or out quite a ways.
>> However, there is a ridge almost half way between us.  I am embedding an
>> image of the path here created with alphimax.com path estimator.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> I have a test unit which is a 19 dB panel/radio with an AP fastened to
the
>> back.  It lets me hand hold a test unit and see what it sees on a laptop.
>> Standing on the ground on his property we got an ALMOST usable signal in
a
>> short test.  He has a 35 foot TV tower next to the house on which we
would
>> install.
>>
>>
>>
>> Perhaps one would look at the path profile and common sense would dictate
> it
>> won't work.  However, I use knife edge diffraction successfully on a
> handful
>> of installs.  Besides, black magic sometimes trumps common sense.
>>
>>
>>
>> I have never used this technique where the ridge is close to mid point.
>  On
>> all others the ridge was closer to the user.  All of them work except
when
>> tropospheric ducting enters into the equation, with one exception.  I
have
>> told the users this is a 98% link and it WILL go down during those
events.
>> Earlier this winter we had a few days of ducting which caused a couple of
>> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting
should
>> only affect this area 20 some hours a year.
>>
>>
>>
>> The single exception was when the obstructing hill had soy beans growing
> on
>> it.  That particular one went down in late fall when the beans were ready
>> for harvest.  The previous 2 years the field had corn planted on it and
> had
>> absolutely no issues.  I think dry beans affect the signal because they
> are
>> no longer "row" polarized and randomly scramble the signal beyond use.
>  Once
>> the beans were harvested, the signal came back like usual.
>>
>>
>>
>> On this path in question, I found the ridge.  There are no trees, instead
> it
>> is farmed.  There is corn stubble on it right now.
>>

Re: [WISPA] That black magic

[Ryan Spott]

Well, before he invests in an install, have him rent a lift truck or
something to see what he can see.

I have a few links that have this type of knife edge defraction. I run them
using 802.11 gear (Mtik/Tranzeo). When I allowed full on access to all the
speed I could provide, complaints came from these clients. When I throttled
them down to256/768/1M connections.. the complaints stopped and things were
more normalized to these clients.

ryan

On Tue, Feb 23, 2010 at 7:05 AM, Mike  wrote:

> I have a bright beacon I can turn on at the top of this tower.  On a clear
> night recently, I turned it on.  Even a ways up a corn crib he could NOT
> see
> the light.  I think the terrain data is accurate.  The alphimax site, once
> you create the path lets you go into Google Earth and "see" the hill.  This
> part of the world doesn't have high resolution imagery archived yet, but I
> CAN see the ridge when I follow along the path.
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of Josh Luthman
> Sent: Tuesday, February 23, 2010 9:01 AM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> To begin with, are you sure there is a bump there?  Could it be bad
> meter resolution?
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> “Success is not final, failure is not fatal: it is the courage to
> continue that counts.”
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
> > I need to do a reality check with those of you familiar with knife edge
> > diffraction as a propagation medium.  First, I should paint the scene:
> >
> >
> >
> > I have a corporate farmer almost 16 miles away who is motivated.  His
> > options are satellite, dialup he currently uses, or us.
> >
> >
> >
> > A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> > large, these rural areas are very quiet.
> >
> >
> >
> > There are no trees or obstructions in the near field or out quite a ways.
> > However, there is a ridge almost half way between us.  I am embedding an
> > image of the path here created with alphimax.com path estimator.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > I have a test unit which is a 19 dB panel/radio with an AP fastened to
> the
> > back.  It lets me hand hold a test unit and see what it sees on a laptop.
> > Standing on the ground on his property we got an ALMOST usable signal in
> a
> > short test.  He has a 35 foot TV tower next to the house on which we
> would
> > install.
> >
> >
> >
> > Perhaps one would look at the path profile and common sense would dictate
> it
> > won't work.  However, I use knife edge diffraction successfully on a
> handful
> > of installs.  Besides, black magic sometimes trumps common sense.
> >
> >
> >
> > I have never used this technique where the ridge is close to mid point.
>  On
> > all others the ridge was closer to the user.  All of them work except
> when
> > tropospheric ducting enters into the equation, with one exception.  I
> have
> > told the users this is a 98% link and it WILL go down during those
> events.
> > Earlier this winter we had a few days of ducting which caused a couple of
> > them to fade.  I saw a 15 dB fade on those.  Statistically, ducting
> should
> > only affect this area 20 some hours a year.
> >
> >
> >
> > The single exception was when the obstructing hill had soy beans growing
> on
> > it.  That particular one went down in late fall when the beans were ready
> > for harvest.  The previous 2 years the field had corn planted on it and
> had
> > absolutely no issues.  I think dry beans affect the signal because they
> are
> > no longer "row" polarized and randomly scramble the signal beyond use.
>  Once
> > the beans were harvested, the signal came back like usual.
> >
> >
> >
> > On this path in question, I found the ridge.  There are no trees, instead
> it
> > is farmed.  There is corn stubble on it right now.
> >
> >
> >
> > I am curious what others have found in these NLOS situations.  Because
> the
> > obstruction is mid path, will the signal still be there next fall as it
> is
> > now?  Are mid path obstructions on a long path better than obstructions
> > closer to one end?  Am I absolutely stupid for even considering this
> > install?
> >
> >
> >
> > I went over a

Re: [WISPA] That black magic

[Josh Luthman]

That profile suggests at 31 feet the customer should see the light
(the black LOS line).  Was that where they looked for the light, or
lower?  I would have to guess the corn crib was not nearly 31 feet.

I think the whole US has 3m and 10m data - http://www.cplus.org/rmw/dataen.html

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 10:05 AM, Mike  wrote:
> I have a bright beacon I can turn on at the top of this tower.  On a clear
> night recently, I turned it on.  Even a ways up a corn crib he could NOT see
> the light.  I think the terrain data is accurate.  The alphimax site, once
> you create the path lets you go into Google Earth and "see" the hill.  This
> part of the world doesn't have high resolution imagery archived yet, but I
> CAN see the ridge when I follow along the path.
>
> -Original Message-
> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
> Behalf Of Josh Luthman
> Sent: Tuesday, February 23, 2010 9:01 AM
> To: WISPA General List
> Subject: Re: [WISPA] That black magic
>
> To begin with, are you sure there is a bump there?  Could it be bad
> meter resolution?
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> “Success is not final, failure is not fatal: it is the courage to
> continue that counts.”
> --- Winston Churchill
>
>
>
> On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
>> I need to do a reality check with those of you familiar with knife edge
>> diffraction as a propagation medium.  First, I should paint the scene:
>>
>>
>>
>> I have a corporate farmer almost 16 miles away who is motivated.  His
>> options are satellite, dialup he currently uses, or us.
>>
>>
>>
>> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
>> large, these rural areas are very quiet.
>>
>>
>>
>> There are no trees or obstructions in the near field or out quite a ways.
>> However, there is a ridge almost half way between us.  I am embedding an
>> image of the path here created with alphimax.com path estimator.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
>> back.  It lets me hand hold a test unit and see what it sees on a laptop.
>> Standing on the ground on his property we got an ALMOST usable signal in a
>> short test.  He has a 35 foot TV tower next to the house on which we would
>> install.
>>
>>
>>
>> Perhaps one would look at the path profile and common sense would dictate
> it
>> won't work.  However, I use knife edge diffraction successfully on a
> handful
>> of installs.  Besides, black magic sometimes trumps common sense.
>>
>>
>>
>> I have never used this technique where the ridge is close to mid point.
>  On
>> all others the ridge was closer to the user.  All of them work except when
>> tropospheric ducting enters into the equation, with one exception.  I have
>> told the users this is a 98% link and it WILL go down during those events.
>> Earlier this winter we had a few days of ducting which caused a couple of
>> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
>> only affect this area 20 some hours a year.
>>
>>
>>
>> The single exception was when the obstructing hill had soy beans growing
> on
>> it.  That particular one went down in late fall when the beans were ready
>> for harvest.  The previous 2 years the field had corn planted on it and
> had
>> absolutely no issues.  I think dry beans affect the signal because they
> are
>> no longer "row" polarized and randomly scramble the signal beyond use.
>  Once
>> the beans were harvested, the signal came back like usual.
>>
>>
>>
>> On this path in question, I found the ridge.  There are no trees, instead
> it
>> is farmed.  There is corn stubble on it right now.
>>
>>
>>
>> I am curious what others have found in these NLOS situations.  Because the
>> obstruction is mid path, will the signal still be there next fall as it is
>> now?  Are mid path obstructions on a long path better than obstructions
>> closer to one end?  Am I absolutely stupid for even considering this
>> install?
>>
>>
>>
>> I went over all the physics involved and told him of my experiences.  Like
> I
>&

Re: [WISPA] That black magic

[Mike]

I have a bright beacon I can turn on at the top of this tower.  On a clear
night recently, I turned it on.  Even a ways up a corn crib he could NOT see
the light.  I think the terrain data is accurate.  The alphimax site, once
you create the path lets you go into Google Earth and "see" the hill.  This
part of the world doesn't have high resolution imagery archived yet, but I
CAN see the ridge when I follow along the path.

-Original Message-
From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On
Behalf Of Josh Luthman
Sent: Tuesday, February 23, 2010 9:01 AM
To: WISPA General List
Subject: Re: [WISPA] That black magic

To begin with, are you sure there is a bump there?  Could it be bad
meter resolution?

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
> I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>
>
>
>
>
>
>
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>
>
> Perhaps one would look at the path profile and common sense would dictate
it
> won't work.  However, I use knife edge diffraction successfully on a
handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>
>
> I have never used this technique where the ridge is close to mid point.
 On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>
>
> The single exception was when the obstructing hill had soy beans growing
on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and
had
> absolutely no issues.  I think dry beans affect the signal because they
are
> no longer "row" polarized and randomly scramble the signal beyond use.
 Once
> the beans were harvested, the signal came back like usual.
>
>
>
> On this path in question, I found the ridge.  There are no trees, instead
it
> is farmed.  There is corn stubble on it right now.
>
>
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>
>
> I went over all the physics involved and told him of my experiences.  Like
I
> said, he is motivated.  I told him I wouldn't tie him into a contract, but
> we'd go month by month and if we found later in the year it wasn't
working,
> we'd cut our losses.  He was OK with that.
>
>
>
> Since I respect the viewpoints of many of you, bring it on!
>
>
>
>
>
> Friendly Regards,
>
>
>
> Mike
>
>
>
> Mike Gilchrist
>
> Disruptive Technologist
>
> Advanced Wireless Express
>
> P.O. Box 255
>
> Toledo, IA   52342
>
> Mike's
>
<http://www.tamatoledonews.com/page/category.detail/nav/5001/Local-Columns.h
> tml>  Weekly Column
>
> 239.770.6203
>
> m...@aweiowa.com
>
>
>
>
>
>
>
>
>


> WISPA Wants You! Join today!
> http://signup.wispa.org/
>


>
> WISPA Wireless List: wireless@w

Re: [WISPA] That black magic

[Josh Luthman]

To begin with, are you sure there is a bump there?  Could it be bad
meter resolution?

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

“Success is not final, failure is not fatal: it is the courage to
continue that counts.”
--- Winston Churchill



On Tue, Feb 23, 2010 at 9:55 AM, Mike  wrote:
> I need to do a reality check with those of you familiar with knife edge
> diffraction as a propagation medium.  First, I should paint the scene:
>
>
>
> I have a corporate farmer almost 16 miles away who is motivated.  His
> options are satellite, dialup he currently uses, or us.
>
>
>
> A spectrum sweep of the property found absolutely no 2.4 signals.  By in
> large, these rural areas are very quiet.
>
>
>
> There are no trees or obstructions in the near field or out quite a ways.
> However, there is a ridge almost half way between us.  I am embedding an
> image of the path here created with alphimax.com path estimator.
>
>
>
>
>
>
>
>
>
> I have a test unit which is a 19 dB panel/radio with an AP fastened to the
> back.  It lets me hand hold a test unit and see what it sees on a laptop.
> Standing on the ground on his property we got an ALMOST usable signal in a
> short test.  He has a 35 foot TV tower next to the house on which we would
> install.
>
>
>
> Perhaps one would look at the path profile and common sense would dictate it
> won't work.  However, I use knife edge diffraction successfully on a handful
> of installs.  Besides, black magic sometimes trumps common sense.
>
>
>
> I have never used this technique where the ridge is close to mid point.  On
> all others the ridge was closer to the user.  All of them work except when
> tropospheric ducting enters into the equation, with one exception.  I have
> told the users this is a 98% link and it WILL go down during those events.
> Earlier this winter we had a few days of ducting which caused a couple of
> them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
> only affect this area 20 some hours a year.
>
>
>
> The single exception was when the obstructing hill had soy beans growing on
> it.  That particular one went down in late fall when the beans were ready
> for harvest.  The previous 2 years the field had corn planted on it and had
> absolutely no issues.  I think dry beans affect the signal because they are
> no longer "row" polarized and randomly scramble the signal beyond use.  Once
> the beans were harvested, the signal came back like usual.
>
>
>
> On this path in question, I found the ridge.  There are no trees, instead it
> is farmed.  There is corn stubble on it right now.
>
>
>
> I am curious what others have found in these NLOS situations.  Because the
> obstruction is mid path, will the signal still be there next fall as it is
> now?  Are mid path obstructions on a long path better than obstructions
> closer to one end?  Am I absolutely stupid for even considering this
> install?
>
>
>
> I went over all the physics involved and told him of my experiences.  Like I
> said, he is motivated.  I told him I wouldn't tie him into a contract, but
> we'd go month by month and if we found later in the year it wasn't working,
> we'd cut our losses.  He was OK with that.
>
>
>
> Since I respect the viewpoints of many of you, bring it on!
>
>
>
>
>
> Friendly Regards,
>
>
>
> Mike
>
>
>
> Mike Gilchrist
>
> Disruptive Technologist
>
> Advanced Wireless Express
>
> P.O. Box 255
>
> Toledo, IA   52342
>
> Mike's
>  tml>  Weekly Column
>
> 239.770.6203
>
> m...@aweiowa.com
>
>
>
>
>
>
>
>
> 
> WISPA Wants You! Join today!
> http://signup.wispa.org/
> 
>
> WISPA Wireless List: wireless@wispa.org
>
> Subscribe/Unsubscribe:
> http://lists.wispa.org/mailman/listinfo/wireless
>
> Archives: http://lists.wispa.org/pipermail/wireless/
>



WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/

[WISPA] That black magic

[Mike]

I need to do a reality check with those of you familiar with knife edge
diffraction as a propagation medium.  First, I should paint the scene:

 

I have a corporate farmer almost 16 miles away who is motivated.  His
options are satellite, dialup he currently uses, or us.

 

A spectrum sweep of the property found absolutely no 2.4 signals.  By in
large, these rural areas are very quiet.

 

There are no trees or obstructions in the near field or out quite a ways.
However, there is a ridge almost half way between us.  I am embedding an
image of the path here created with alphimax.com path estimator.

 



 

 

I have a test unit which is a 19 dB panel/radio with an AP fastened to the
back.  It lets me hand hold a test unit and see what it sees on a laptop.
Standing on the ground on his property we got an ALMOST usable signal in a
short test.  He has a 35 foot TV tower next to the house on which we would
install.

 

Perhaps one would look at the path profile and common sense would dictate it
won't work.  However, I use knife edge diffraction successfully on a handful
of installs.  Besides, black magic sometimes trumps common sense.

 

I have never used this technique where the ridge is close to mid point.  On
all others the ridge was closer to the user.  All of them work except when
tropospheric ducting enters into the equation, with one exception.  I have
told the users this is a 98% link and it WILL go down during those events.
Earlier this winter we had a few days of ducting which caused a couple of
them to fade.  I saw a 15 dB fade on those.  Statistically, ducting should
only affect this area 20 some hours a year.

 

The single exception was when the obstructing hill had soy beans growing on
it.  That particular one went down in late fall when the beans were ready
for harvest.  The previous 2 years the field had corn planted on it and had
absolutely no issues.  I think dry beans affect the signal because they are
no longer "row" polarized and randomly scramble the signal beyond use.  Once
the beans were harvested, the signal came back like usual.

 

On this path in question, I found the ridge.  There are no trees, instead it
is farmed.  There is corn stubble on it right now.

 

I am curious what others have found in these NLOS situations.  Because the
obstruction is mid path, will the signal still be there next fall as it is
now?  Are mid path obstructions on a long path better than obstructions
closer to one end?  Am I absolutely stupid for even considering this
install?

 

I went over all the physics involved and told him of my experiences.  Like I
said, he is motivated.  I told him I wouldn't tie him into a contract, but
we'd go month by month and if we found later in the year it wasn't working,
we'd cut our losses.  He was OK with that.

 

Since I respect the viewpoints of many of you, bring it on!

 

 

Friendly Regards,

 

Mike

 

Mike Gilchrist

Disruptive Technologist

Advanced Wireless Express

P.O. Box 255

Toledo, IA   52342

Mike's
  Weekly Column

239.770.6203

m...@aweiowa.com

  

 

<>


WISPA Wants You! Join today!
http://signup.wispa.org/

 
WISPA Wireless List: wireless@wispa.org

Subscribe/Unsubscribe:
http://lists.wispa.org/mailman/listinfo/wireless

Archives: http://lists.wispa.org/pipermail/wireless/