Can you help me interpret this 2.4GHz WiFi spectrum analysis noise plot
that I just ran from my Ubiquiti Rocket M2 rooftop antenna?
I'm trying to debug why I have -88dBm of noise at my rooftop radio.
My Rocket M2 rooftop radio is on channel 10.
My home broadband router inside the house is on channel 1.
Here is the "waterfall" plot:
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
Here is the "channel" plot:
http://farm8.staticflickr.com/7310/11427413806_21e93b109b_o.jpg
Here's a site survey:
http://farm6.staticflickr.com/5484/11427682854_0332590c4f_o.png
And, here's a view of the rooftop radio signal to noise strength:
http://farm8.staticflickr.com/7380/11427771814_de0692ea50_o.png
Any observations with respect to the source of the -88dB noise?
(I don't really know how to interpret this stuff.)
So what's the problem?
How much noise would you consider normal?
Thermal noise is -174 dBm per Hz
What's the bandwidth and noise figure of your receiver?
Mark
only guy who can do this is gone, Jeff Liebermann
Incidentally, this is what I've been doing for fun".
Q: What's the bandwidth & noise figure of your receiver?
On Tue, 17 Dec 2013 18:42:50 -0800, makolber wrote:
So what's the problem?
How much noise would you consider normal?
Thermal noise is -174 dBm per Hz
What's the bandwidth and noise figure of your receiver?
Mark
Q: What's the problem.
A: It's my understanding that every dB of noise reduces the dB of signal
by that amount. The less signal, the slower the Internet speeds.
Q: How much noise do you consider normal?
A: I have no idea. That's why I'm asking! :) Googling, I find you "should"
have about 20dB of headroom between noise & signal. My signal is about
-52dBm and my noise is -88dBm, so I'm within that range, but, my
signal to noise ratio is -52dBm - -88dBm = 36
Q: What's the bandwidth & noise figure of your receiver?
A: Googling for the "Rocket M2 bandwidth gain specifications", I find
this datasheet for a "RM2" receiver & "2G-24" 24dBi dish reflector:
http://www.balticnetworks.com/docs/rm_ds_web.pdf
Which says, on page 6:
Rocket M2, Operating Frequency 2412-2462 MHz
2.4 GHz RX POWER SPECIFICATIONS
llg = 1-24 Mbps => -97 dBm min +/- 2 dB
11g = 36 Mbps => -80 dBm +/- 2 dB
11g = 48 Mbps => -77 dBm +/- 2 dB
11g = 54 Mbps => -75 dBm +/- 2 dB
11n = MCS0 => -96 dBm +/- 2 dB
11n = MCS1 => -95 dBm +/- 2 dB
11n = MCS2 => -92 dBm +/- 2 dB
11n = MCS3 => -90 dBm +/- 2 dB
11n = MCS4 => -86 dBm +/- 2 dB
11n = MCS5 => -83 dBm +/- 2 dB
11n = MCS6 => -77 dBm +/- 2 dB
11n = MCS7 => -74 dBm +/- 2 dB
11n = MCS8 => -95 dBm +/- 2 dB
11n = MCS9 => -93 dBm +/- 2 dB
11n = MCS10 => -90 dBm +/- 2 dB <=== this is my channel
11n = MCS11 => -87 dBm +/- 2 dB
11n = MCS12 => -84 dBm +/- 2 dB
11n = MCS13 => -79 dBm +/- 2 dB
11n = MCS14 => -78 dBm +/- 2 dB
11n = MCS15 => -75 dBm +/- 2 dB
Given that my Rocket M2 is 11n MIMO, and on channel 10, I'd say
the receiver sensitivity is from -88 to -92 dBm.
Hmmm... I just noticed, that this is the same (essentially) as
my noise figure. But, I'm not sure what that tells me.
I don't know how to translate those facts into an interpretation of the spectrum analysis noise charts provided in the OP though.
First do you understand what decibel means in the context of voltage,
current or power? Can you calcualte receiver sensitivity of -92dbm
comes out (?) volts? On what modulation mode are we talking about?
Can you calcualte receiver sensitivity of -92dbm
comes out (?) volts?
On what modulation mode are we talking about?
NOTE: The narrow beamwidth is how the antenna gets all that gain in the
first place.
On Tue, 17 Dec 2013 21:19:40 -0700, Tony Hwang wrote:
First do you understand what decibel means in the context of voltage,
current or power? Can you calcualte receiver sensitivity of -92dbm
comes out (?) volts? On what modulation mode are we talking about?
I (think I) do understand decibels, at least at a rudimentary level.
Here's my simple summary of how I organize my thoughts around decibels:
1) Every 3 decibels is a doubling (or halving) of power.
2) A halving of power would be if it went from -87dBm to -90dBm.
3) My radio is transmits at 27 decibels (compared to the mW reference).
4) When I want to convert dBm to Watts, I google "dbm to watts".
5) The first hit is always the best dbm-to-Watts converter.
6) http://www.rapidtables.com/convert/power/dBm_to_Watt.htm
7) So, 27 dBm is 1/2 Watt (Note: 30 dBm would be 1 Watt, & so on).
8) The receiver is sensitive to -90dBm at 802.11n channel 10.
9) That means it can pick up a signal strength of 1 picowatt.
10) The signal to noise headroom needs to be around 20dBm.
11) That means I need signal to be 1/10 Watt greater than noise.
12) The transmitter is claimed to be 28dBm±2dB at channel 10.
13) So, the transmitter (without antenna) is 6/10ths of a Watt.
14) However, the Rocketdish reflector & antenna add another 24dBi.
15) A dBi is relative to a fictional spherical-radiation pattern.
16) So, my effective isotropic radiated power is 28+24=52dBm!
17) An EIRP of 52 dBm is a whopping 158 Watts!
18) The FCC only allows me an effective power of 4 Watts
19) Googling for "watts to dbm", the first link is the best.
20) http://www.rapidtables.com/convert/power/Watt_to_dBm.htm
21) That 4 Watts is 36dBm
22) Even though the equipment is capable of 52dBm, it's toned
down to that legal limit of 36dBm.
So, given all that, my average noise is rather low, on channel 10,
of about -90dBm or 1 picoWatt (which is the green part of the bottom
graph below).
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
However, my instantaneous noise is rather high, at -40dBm or
10 microWatts (which is the blue line in the bottom graph above).
So, I guess my question is how much will my radio be adversely affected
by 10 microWatts of instantaneous noise, when the average noise is only
1 picoWatt?
I have no experience with what noise levels are good, and which ones
are bad - so I have no background to interpret the spectrum analysis.
REFERENCE:
Transceiver datasheet (Ubiquiti Rocket M2):
https://www.discomp.cz/img.asp?attid=88929
Antenna (Ubiquiti Rocketdish RD-2G-24):
http://dl.ubnt.com/datasheets/rocketdish/rd_ds_web.pdf
When you talk about noise there are many different kinda noise.
First things first. I'm guessing your WISP picked channel 10 and you can't change that. Is that the case?
A waterfall is just time dependent sniffing. If your WISP wasn't spraying
you with wifi on channel 10 (again, my guess), you would examine the waterfall display and find the area with the least activity. Now the waterfall is useful if someone burps wifi at you, as in a telemetry application. If the band was crowded, you would pick the channel with the occasional belch of wifi rather than one that is busy all the time. [If
you were doing SIGINT, you would look for patterns in the occasional wifi belch. This is knows as traffic analysis.]
My next guess is you WISP provider has a customer on channel 2 at the same location that feeds you. [It could be another WISP from a different
vendor.] The WISP provider has a beam antennas at the transmitter site.
One beam for you on channel 10, another beam for somebody else on channel
2.
That person may live near you since you are seeing the signal, but
there are no red blobs in the waterfall, so the antenna isn't pointed directly at you. [And why would it be?] Red means a strong signal. The
WISP on channel 2 is only 7 db less than your signal, but channel 2 and channel 10 have no common frequencies, so nothing to worry about.
You have two neighbors on channel 3, so that would be a bad channel for
you, as would any channel that overlaps channel 3. Probably the WISP installer already knew that from when the site survey was done.
I'm not really sure how they determine the noise floor. At any one time, there is somebody on a wifi channel. It might be really low RF level, but
not zero. Probably the receiver makes a determination that if it can't
sniff a signal, it must be noise. Not a good assumption.
At -50dBm over 3 miles, I'd call it a day and go looking for something
else to fix.
On Wed, 18 Dec 2013 00:21:46 -0700, Tony Hwang wrote:
When you talk about noise there are many different kinda noise.
In the case here, it's all 2.4GHz signals which are not coming
from the access point that I'm connecting to, yet, which the
rooftop antenna sees.
Would wrapping the feed in tinfoil give a measure of internally
generated noise?
I think anything the antenna sees which is not a connection signal,
is considered noise.
On Wed, 18 Dec 2013 08:28:49 +0000 (UTC), Danny D'Amico <danny@is.invalid> wrote:
I think anything the antenna sees which is not a connection signal,
is considered noise.
One receiver's signal is another receiver's noise.
Can you help me interpret this 2.4GHz WiFi spectrum analysis noise plot
that I just ran from my Ubiquiti Rocket M2 rooftop antenna?
I'm trying to debug why I have -88dBm of noise at my rooftop radio.
My Rocket M2 rooftop radio is on channel 10.
My home broadband router inside the house is on channel 1.
Here is the "waterfall" plot:
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
Any observations with respect to the source of the -88dB noise?
(I don't really know how to interpret this stuff.)
Here is the "waterfall" plot:
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
Here is the "waterfall" plot:
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
Here is the "channel" plot:
http://farm8.staticflickr.com/7310/11427413806_21e93b109b_o.jpg
Here's a site survey:
http://farm6.staticflickr.com/5484/11427682854_0332590c4f_o.png
And, here's a view of the rooftop radio signal to noise strength:
http://farm8.staticflickr.com/7380/11427771814_de0692ea50_o.png
One receiver's signal is another receiver's noise.
First of all two kinda noises. One is internal, the other is external.
Under this two there are many different kind of noises.
what problem are you trying to solve? Lack of speed?
Variations in speed? VoIP jitter? Disconnects?
Why is your WISP using Ch 10. Is there a problem with Ch 11 or does
he have his AP setup for the dreaded "auto"?
If you look at the lower graph, in the area of Ch 10, you'll see that
the baseline "noise" level for Ch 10 is about -110dBm.
Unplug your antenna and see what manner of "noise" level you get.
The -88dBm "noise" level is what the Rocket M2 hears between
bursts of RF, when there's presumably nothing to hear.
My guess(tm) is that it's mostly other users on Ch 10.
That could be other client radios, such as your neighbors talking
to the same WISP on Ch 10 or the 2-3 adjacent channels.
I know you have a rather directional antenna, which is a big
help at removing such "noise", but if you have the bad luck of having
another client radio in the direction of the main lobe, or nearby to
the side, you'll hear their "noise".
On Wed, 18 Dec 2013 02:21:53 +0000 (UTC), hh <hh@kk.org> wrote:
only guy who can do this is gone, Jeff Liebermann
Rumors of my demise might be a bit premature. I'm buried in projects,
work, Christmas Chrisis', ladyfriend, and trying to untrash my house,
office, and vehicle. Incidentally, this is what I've been doing for
"fun".
<http://www.learnbydestroying.com/jeffl/antennas/dish-move-project/>
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Looks like you have interference from someone nearby using Ch 9.
"Jeff Liebermann" <jeffl@cruzio.com> wrote in message >news:kg52b91u1ijsr8mitn3ea0mjfi358n1arr@4ax.com...
On Wed, 18 Dec 2013 02:21:53 +0000 (UTC), hh <hh@kk.org> wrote:
only guy who can do this is gone, Jeff Liebermann
Rumors of my demise might be a bit premature. I'm buried in projects,
work, Christmas Chrisis', ladyfriend, and trying to untrash my house,
office, and vehicle. Incidentally, this is what I've been doing for
"fun".
<http://www.learnbydestroying.com/jeffl/antennas/dish-move-project/>
Lady friend means untrash house. You should have thought about this
:-).
On Wed, 18 Dec 2013 08:59:51 -0800, Jeff Liebermann wrote:
Why is your WISP using Ch 10. Is there a problem with Ch 11 or does
he have his AP setup for the dreaded "auto"?
Hmmm.... I don't have a clue as to the answer. All I know is
that he had texted me how to set up my radio, and I set it up
just like he had texted me to. I just looked at the settings
in the radio, and I see the channel width set to 20MHz and
channel shifting disabled, but I don't see where the channel
is actually set.
Your equipment is the client, so you don't get to set the channel.
The WISP sets the channel and all you can do is follow their lead.
my friend just retired and moved from a huge custom house in the cold,
snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch gathering (4 guys)
with him presenting us each with a token from our past as part of his de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns.
When I was in college you could spot a nerd because he had a pocket >protector and a rectangular box of punch cards under one arm. Pocket >calculators came out later, cost around $400.00 and had nerds drooling
over them. I was out of college when I saw my first HP calculator but I >still had boxes of punch cards. ^_^
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold,
snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch
gathering (4 guys)
with him presenting us each with a token from our past as part of his
de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns.
When I was in college you could spot a nerd because he had a pocket >protector and a rectangular box of punch cards under one arm. Pocket >calculators came out later, cost around $400.00 and had nerds drooling
over them. I was out of college when I saw my first HP calculator but I >still had boxes of punch cards. ^_^
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring Dufas <the-daring-dufas@stinky-finger.net> wrote:
When I was in college you could spot a nerd because he had a
pocket protector and a rectangular box of punch cards under one
arm. Pocket calculators came out later, cost around $400.00 and had
nerds drooling over them. I was out of college when I saw my first
HP calculator but I still had boxes of punch cards. ^_^
Yeah, that was the theory but it didn't quite work at Cal Poly
Pomona in the late 1960's. Among other divisions, Cal Poly had an engineering skool and an ABM (agricultural business management)
skool. One would assume that the engineering students carried slide
rules and punched cards, and the ABM students looked like TV cowboys.
Nope. The engineering students wanted to look like cowboys and wore
boots, jeans, flannel, but not the hat. The ABM students wore suits,
ties, hats, and carried briefcases. There was also a skool of
environmental design, which true to the stereotype, everyone looked
like hippies. I tried to make sense of it at the time, and gave up.
Incidentally, it took me about 10 years to work my way through all
the punched card decks I had accumulated and used mostly as scratch
paper. I didn't make the same mistake with paper tape, which I
converted to floppy and burned the tapes.
My first calculator was an analog computer that I built into a brief
case. There were several 10 turn pots to input the numbers, and a
big mirrored meter to read the output. Basically, an electronic implementation of a slide rule. <https://groups.google.com/forum/#!original/scruz.general/Egv8cT2-JGY/SNVk9zi1ULQJ>
When I graduated from college, I could throw everything I owned
into my pickup truck and drive off into the sunset (and actually did
that a few times). If I tried that today, it would take at least two
large moving vans and a project manager.
He who dies with the most toys, wins.
You can by RF shield spray at Frys. Not cheap, well at least compared to
a can of spray paint.
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring Dufas <the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold,
snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch
gathering (4 guys)
with him presenting us each with a token from our past as part of his
de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns. >>>
When I was in college you could spot a nerd because he had a pocket
protector and a rectangular box of punch cards under one arm. Pocket
calculators came out later, cost around $400.00 and had nerds drooling
over them. I was out of college when I saw my first HP calculator but I
still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my
books). Over my senior year, the slip-sticks were being replaced by calculators (and holsters for scabbards ;-). I bought an HP, and yes,
it was $400 (about 10-weeks gross pay).
http://farm8.staticflickr.com/7299/11427414296_de48f3922e_o.jpg
Looks like you have interference from someone nearby using Ch 9.
Oh I had a slide rule too. It was a K&E as I remember and
I wish I still had it. ^_^
That's easy if there's an antenna connector available.Unplug your antenna and see what manner of "noise" level you get.You should replace the antenna with a 50 ohm terminator.
On Thu, 19 Dec 2013 11:45:23 -0600, The Daring Dufas wrote:
Oh I had a slide rule too. It was a K&E as I remember and
I wish I still had it. ^_^
My Dad, bless his heart, taught me how to use a slide rule
when I was in high school trig class. His was bamboo and white,
as I remember it. He bought me a smaller one, and I cherished
it. I hope I still have it, but, I've moved a half dozen times
since so it's somewhere.
On 12/19/2013 10:30 AM, Jeff Liebermann wrote:Hi,
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
When I was in college you could spot a nerd because he had a
pocket protector and a rectangular box of punch cards under one
arm. Pocket calculators came out later, cost around $400.00 and
had nerds drooling over them. I was out of college when I saw my
first HP calculator but I still had boxes of punch cards. ^_^
Yeah, that was the theory but it didn't quite work at Cal Poly
Pomona in the late 1960's. Among other divisions, Cal Poly had an
engineering skool and an ABM (agricultural business management)
skool. One would assume that the engineering students carried
slide rules and punched cards, and the ABM students looked like TV
cowboys. Nope. The engineering students wanted to look like cowboys
and wore boots, jeans, flannel, but not the hat. The ABM students
wore suits, ties, hats, and carried briefcases. There was also a
skool of environmental design, which true to the stereotype,
everyone looked like hippies. I tried to make sense of it at the
time, and gave up.
Incidentally, it took me about 10 years to work my way through all
the punched card decks I had accumulated and used mostly as
scratch paper. I didn't make the same mistake with paper tape,
which I converted to floppy and burned the tapes.
My first calculator was an analog computer that I built into a
brief case. There were several 10 turn pots to input the numbers,
and a big mirrored meter to read the output. Basically, an
electronic implementation of a slide rule.
<https://groups.google.com/forum/#!original/scruz.general/Egv8cT2-JGY/SNVk9zi1ULQJ>
When I graduated from college, I could throw everything I owned
into my pickup truck and drive off into the sunset (and actually
did that a few times). If I tried that today, it would take at
least two large moving vans and a project manager.
He who dies with the most toys, wins.
Here in Alabamastan we actually have a state college, The University
of Auburn, which is both the premier agricultural and engineering
school. I traveled to Auburn one year to visit some friends and drove
past "The Swine Research Unit". The smell could gag a maggot but the
pigs were happy. In the mid 1960's at The University of Alabama, I
started playing with and learning a tiny bit of Basic and Fortran in
order to play with the Univac which was on its way out and the new
IBM 360/50 RAX system which was replacing it. Kids these days have no
idea how user friendly computers are now compared to what I started
playing with like the analog computer at my school but I really
believe computers were more fun all those years ago. Now they're
tools, not so exclusive anymore and any kids gaming computer has much
more computing power than what was considered a super computer at one
time. ^_^
TDD
The Daring Dufas wrote:
On 12/19/2013 10:30 AM, Jeff Liebermann wrote:Hi, You guys are little bit behind me, when I was into it during and
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
When I was in college you could spot a nerd because he had a
pocket protector and a rectangular box of punch cards under
one arm. Pocket calculators came out later, cost around $400.00
and had nerds drooling over them. I was out of college when I
saw my first HP calculator but I still had boxes of punch
cards. ^_^
Yeah, that was the theory but it didn't quite work at Cal Poly
Pomona in the late 1960's. Among other divisions, Cal Poly had
an engineering skool and an ABM (agricultural business
management) skool. One would assume that the engineering students
carried slide rules and punched cards, and the ABM students
looked like TV cowboys. Nope. The engineering students wanted to
look like cowboys and wore boots, jeans, flannel, but not the
hat. The ABM students wore suits, ties, hats, and carried
briefcases. There was also a skool of environmental design,
which true to the stereotype, everyone looked like hippies. I
tried to make sense of it at the time, and gave up.
Incidentally, it took me about 10 years to work my way through
all the punched card decks I had accumulated and used mostly as
scratch paper. I didn't make the same mistake with paper tape,
which I converted to floppy and burned the tapes.
My first calculator was an analog computer that I built into a
brief case. There were several 10 turn pots to input the
numbers, and a big mirrored meter to read the output. Basically,
an electronic implementation of a slide rule.
<https://groups.google.com/forum/#!original/scruz.general/Egv8cT2-JGY/SNVk9zi1ULQJ>
When I graduated from college, I could throw everything I owned
into my pickup truck and drive off into the sunset (and actually
did that a few times). If I tried that today, it would take at
least two large moving vans and a project manager.
He who dies with the most toys, wins.
Here in Alabamastan we actually have a state college, The
University of Auburn, which is both the premier agricultural and
engineering school. I traveled to Auburn one year to visit some
friends and drove past "The Swine Research Unit". The smell could
gag a maggot but the pigs were happy. In the mid 1960's at The
University of Alabama, I started playing with and learning a tiny
bit of Basic and Fortran in order to play with the Univac which was
on its way out and the new IBM 360/50 RAX system which was
replacing it. Kids these days have no idea how user friendly
computers are now compared to what I started playing with like the
analog computer at my school but I really believe computers were
more fun all those years ago. Now they're tools, not so exclusive
anymore and any kids gaming computer has much more computing power
than what was considered a super computer at one time. ^_^
TDD
after school, computers were called electronic calculator as such
containing vacuum tubes, mechanical relays.. from there transistors,
small scale IC all the way into nanotech which is now. I used to use
blank punch card with columms and rows all half pre-punched so we can
push the confetti out to make holes where we want to do Fortran
programming. If you drop the card deck by accident, you have to
resort one by one to make them in proper order before you can have it
read. Also remember 51 column card? Credit card receipts were 51
column card size which could be read after they are punched by key
punch operators(girls) reading the amount written and imprinted
account number. My Ham radio hobby was from the '50s, licensed in
'60. Hold Extra U.S., Advanced/Digital Canadian, First class Korean
licenses. Right now I am busy resetting up our HT system into 7.1
with new AV receiver and speakers. Better be done before X-mas.
I still have mine in a leather case on my study desk shelf.
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my
books). Over my senior year, the slip-sticks were being replaced by >calculators (and holsters for scabbards ;-). I bought an HP, and yes,
it was $400 (about 10-weeks gross pay).
On 12/19/2013 11:13 AM, krw@attt.bizz wrote:
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring DufasOh I had a slide rule too. It was a K&E as I remember and I wish I still
<the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold, >>>> snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch
gathering (4 guys)
with him presenting us each with a token from our past as part of his
de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns. >>>>
When I was in college you could spot a nerd because he had a pocket
protector and a rectangular box of punch cards under one arm. Pocket
calculators came out later, cost around $400.00 and had nerds drooling
over them. I was out of college when I saw my first HP calculator but I
still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my
books). Over my senior year, the slip-sticks were being replaced by
calculators (and holsters for scabbards ;-). I bought an HP, and yes,
it was $400 (about 10-weeks gross pay).
had it. ^_^
On Thu, 19 Dec 2013 11:45:23 -0600, The Daring Dufas <the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 11:13 AM, krw@attt.bizz wrote:
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring DufasOh I had a slide rule too. It was a K&E as I remember and I wish I still
<the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold, >>>>> snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch >>>>> gathering (4 guys)
with him presenting us each with a token from our past as part of his >>>>> de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns. >>>>>
When I was in college you could spot a nerd because he had a pocket
protector and a rectangular box of punch cards under one arm. Pocket
calculators came out later, cost around $400.00 and had nerds drooling >>>> over them. I was out of college when I saw my first HP calculator but I >>>> still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my
books). Over my senior year, the slip-sticks were being replaced by
calculators (and holsters for scabbards ;-). I bought an HP, and yes,
it was $400 (about 10-weeks gross pay).
had it. ^_^
Mine is a Post Versalog. I still have it, as well as the HP-45 that
had its 40th birthday last month. ;-)
On 12/19/2013 3:50 PM, krw@attt.bizz wrote:
On Thu, 19 Dec 2013 11:45:23 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 11:13 AM, krw@attt.bizz wrote:
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring DufasOh I had a slide rule too. It was a K&E as I remember and I wish I still >>> had it. ^_^
<the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold, >>>>>> snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch >>>>>> gathering (4 guys)
with him presenting us each with a token from our past as part of his >>>>>> de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns. >>>>>>
When I was in college you could spot a nerd because he had a pocket
protector and a rectangular box of punch cards under one arm. Pocket >>>>> calculators came out later, cost around $400.00 and had nerds drooling >>>>> over them. I was out of college when I saw my first HP calculator but I >>>>> still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my
books). Over my senior year, the slip-sticks were being replaced by
calculators (and holsters for scabbards ;-). I bought an HP, and yes, >>>> it was $400 (about 10-weeks gross pay).
Mine is a Post Versalog. I still have it, as well as the HP-45 that
had its 40th birthday last month. ;-)
Oh man, the HP-45 cost as much back then as a desktop computer costs
now. ^_^
On Thu, 19 Dec 2013 21:58:05 -0600, The Daring Dufas <the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 3:50 PM, krw@attt.bizz wrote:
On Thu, 19 Dec 2013 11:45:23 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 11:13 AM, krw@attt.bizz wrote:
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring DufasOh I had a slide rule too. It was a K&E as I remember and I wish I still >>>> had it. ^_^
<the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold, >>>>>>> snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch >>>>>>> gathering (4 guys)
with him presenting us each with a token from our past as part of his >>>>>>> de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns.
When I was in college you could spot a nerd because he had a pocket >>>>>> protector and a rectangular box of punch cards under one arm. Pocket >>>>>> calculators came out later, cost around $400.00 and had nerds drooling >>>>>> over them. I was out of college when I saw my first HP calculator but I >>>>>> still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my >>>>> books). Over my senior year, the slip-sticks were being replaced by >>>>> calculators (and holsters for scabbards ;-). I bought an HP, and yes, >>>>> it was $400 (about 10-weeks gross pay).
Mine is a Post Versalog. I still have it, as well as the HP-45 that
had its 40th birthday last month. ;-)
Oh man, the HP-45 cost as much back then as a desktop computer costs
now. ^_^
The HP-45 was $395 in 1973 but very different dollars. About 50x
different, for me.
On 12/19/2013 10:34 PM, krw@attt.bizz wrote:
On Thu, 19 Dec 2013 21:58:05 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 3:50 PM, krw@attt.bizz wrote:
On Thu, 19 Dec 2013 11:45:23 -0600, The Daring Dufas
<the-daring-dufas@stinky-finger.net> wrote:
On 12/19/2013 11:13 AM, krw@attt.bizz wrote:
On Wed, 18 Dec 2013 22:59:04 -0600, The Daring DufasOh I had a slide rule too. It was a K&E as I remember and I wish I still >>>>> had it. ^_^
<the-daring-dufas@stinky-finger.net> wrote:
On 12/18/2013 5:14 PM, ps56k wrote:
my friend just retired and moved from a huge custom house in the cold, >>>>>>>> snowy, Chicago area
down to the middle of FL - sitting out on the lanai....
He coined the term ---> de-crapification
Just prior to his leaving, we had our little college ski group lunch >>>>>>>> gathering (4 guys)
with him presenting us each with a token from our past as part of his >>>>>>>> de-crapification.
Some were FORTRAN puch cards, from our CS days,
some were check/receipts from our skiiing in Austria,
some were photos from frat parties - with fuzzy hair and long sideburns.
When I was in college you could spot a nerd because he had a pocket >>>>>>> protector and a rectangular box of punch cards under one arm. Pocket >>>>>>> calculators came out later, cost around $400.00 and had nerds drooling >>>>>>> over them. I was out of college when I saw my first HP calculator but I >>>>>>> still had boxes of punch cards. ^_^
Punch cards were for the CS weenies. ;-) The real nerds had
slip-stick scabbards hanging from their belts (I carried mine with my >>>>>> books). Over my senior year, the slip-sticks were being replaced by >>>>>> calculators (and holsters for scabbards ;-). I bought an HP, and yes, >>>>>> it was $400 (about 10-weeks gross pay).
Mine is a Post Versalog. I still have it, as well as the HP-45 that
had its 40th birthday last month. ;-)
Oh man, the HP-45 cost as much back then as a desktop computer costs
now. ^_^
The HP-45 was $395 in 1973 but very different dollars. About 50x
different, for me.
That was a heck of a lot of money for me in those days considering
minimum wage was $1.60/hr and I was paying 22 cents a gallon for regular
at the San-Ann gas station. In 1971 I was working at a defense
plant that made some munitions parts for the military and I was paid
$1.68/hr because I was working 11pm to 7am. The 8 cents was called a
shift differential paid to those who worked the night shift. ^_^
The pot's been boiling for a long time and the frogs still haven't
jumped out. o_O
Also decrease the feed line loss...
Is the radio mounted up at the antenna?
On Fri, 20 Dec 2013 19:24:55 -0800, makolber wrote:
Also decrease the feed line loss...
Is the radio mounted up at the antenna?
Hi Mark,
Here is a picture of the mount when I had installed it:
http://farm4.staticflickr.com/3688/11474128726_aa955239ba_o.jpg
The radio itself is the classic Ubiquiti Rocket M2:
http://store.netgate.com/Assets/ProductImages/ROCKETM2%20US.jpg
That radio is clipped directly onto the back of the dish:
http://www.ubntstore.eu/images/detailed/0/tmp_FEWrpH.jpg
One mistake I made was to use non-shielded cable, so,
there's about 75 feet of the plenum stuff outside going
from the roof to the first floor office where the
router and POE lie.
From a practical (noise) standpoint, how much do you think
that matters?
B4 you ask that question think about shield? Why do you think we use shielded cable in AF or RF cabling
Looks like your radio is repeater? All in all if you have reliable connection, what's the worry? One way of increasing signal strength
will be using a bigger dish or did you picked best height of the
antenna. The higher the better is a myth. Is it LOS install.?
I don't really want to go *bigger* than the Rocketdish, so, that's
why I'm asking how to lower the noise.
On Fri, 20 Dec 2013 21:54:28 -0700, Tony Hwang wrote:
Looks like your radio is repeater? All in all if you have reliable
connection, what's the worry? One way of increasing signal strength
will be using a bigger dish or did you picked best height of the
antenna. The higher the better is a myth. Is it LOS install.?
Hi Tony,
The radio is not set up as a repeater. It's set up as a router:
http://farm8.staticflickr.com/7380/11427771814_de0692ea50_o.png
As you noted, I do have a reliable connection to the 2.4GHz WiFi
access point about 3 miles away, but, since my service is unthrottled,
the lower I can get noise, the faster I can get the speeds!
For example, here are side-by-side screenshots of the Rocket M2
speeds versus the Nanobridge M2 speeds the day I switched them out:
http://farm8.staticflickr.com/7448/11475595375_740ac269e1_o.png
Notice, with *nothing* changed other than the dish & radio, on the
smaller Nanobridge, I got 78Mbps but on the larger Rocket, I got 117Mbps.
I don't really want to go *bigger* than the Rocketdish, so, that's
why I'm asking how to lower the noise.
Note: I see the noise on the Nanobridge was -97dBm, and that of the
Rocket is -89dBm, so, it's interesting that the Rocket is noiser than
the Nanobridge, considering the beamwidth of the Rocket is far narrower
(but the gain is far higher).
On Sat, 21 Dec 2013 07:29:25 +0000, Danny D'Amico wrote:
I don't really want to go *bigger* than the Rocketdish, so, that's
why I'm asking how to lower the noise.
I should explain that, while I can *fit* a bigger unit on my roof,
the RocketDish is already 24dBi and the Rocket M2 radio is already
28dBm, so, the maximum (claimed) gain is 52 dBi (158 Watts), while
the maximum legal gain is 36dBm (4 Watts), so, the Rocket is already throttling itself automatically just to keep within legal limits.
So I don't think a bigger dish is really the solution.
The solution is to figure out how to lower the noise...and,
the RF Armor seems to be the best answer (albeit pricey).
What is operating power of the two radios and what is the sensitivity of
two RX? They are built on same design specs? Is it real LOS install
or radio horizon install?
even POE injectors are not created equal.
Danny D. wrote:
On Fri, 20 Dec 2013 19:24:55 -0800, makolber wrote:Hi, B4 you ask that question think about shield? Why do you think we
Also decrease the feed line loss... Is the radio mounted up at
the antenna?
Hi Mark,
Here is a picture of the mount when I had installed it:
http://farm4.staticflickr.com/3688/11474128726_aa955239ba_o.jpg
The radio itself is the classic Ubiquiti Rocket M2:
http://store.netgate.com/Assets/ProductImages/ROCKETM2%20US.jpg
That radio is clipped directly onto the back of the dish:
http://www.ubntstore.eu/images/detailed/0/tmp_FEWrpH.jpg
One mistake I made was to use non-shielded cable, so, there's about
75 feet of the plenum stuff outside going from the roof to the
first floor office where the router and POE lie.
From a practical (noise) standpoint, how much do you think that
matters?
use shielded cable in AF or RF cabling(wiring) CAT 7 spec. ethernet
cable is best one. I believe your noise is radio related unlikely
Ethernet cable related. Looks like your radio is repeater? All in all
if you have reliable connection, what's the worry? One way of
increasing signal strength will be using a bigger dish or did you
picked best height of the antenna. The higher the better is a myth.
Is it LOS install.?
Way back when I was working on microwave, troposcatter links biggest
one was troposcatter link shooting from Nha Trang, S, Vietnam over to
Thailand. Triple diversity, antenna was 120 ft. square parabolic
pair. Nitrogen gas filled wave guides were used. No coax. SWR was
around 1.2. One night VC rocket sharpnels made some holes in wave
guides plumbing, SWR went upto about 1.4
Tri diversity is based on antenna spacing, frequency, polarization.
RX was parametric cavity tuned preamp, and all tube based RX, TX was
10W TWT exciter to 10KW water cooled Klystron driving 100KW bigger
Klystron also with water cooled. HV on them were around 27KV DC.
This all became obsolete soon when RCA launched first Commsat. That
was end of my career in RF telecomm. going into Digital Data comm,
main frames, etc. Worked on autovon/autodin, Arpanet(origin of
Internet). Now I am no good any more, things changing too fast to
grasp all.
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