Toshiba TV29C90 problem; Image fades to black...

[Jeff Liebermann]

On Sun, 8 Jun 2014 16:24:19 -0700 (PDT), Jeroni Paul
<JERONI.PAUL@terra.es> wrote:

>Many printers used to guess the absorver status incrementing an internal counter each cleaning cycle. Do these Canon series have an actual sensor in the pad?

Nope. It's just a counter that can be reset with some software.
<http://www.ebay.com/itm/161204178280>
or by button pushing:
<http://www.printersiam.com/data/Canon%20Waste%20Ink%20Tank%20Reset%20Procedures.htm>
This doesn't include the MP190, but I think the MPC190 proceedure (at
the bottom of the page) will work.

In general, Canon seems to be fairly conservative on their in absorber
counter. I find that the pads are wet, but not saturated or
overflowing when the message appears. My guess(tm) is that it's more
than half way soaked, which means that if you reset the counter
without replacing the pad, the next time the message appears, you'll
probably have ink leaking out the bottom of the printer. Replace the
pad or watch your usage and waste ink buildup carefully.

Incidentally, Canon bargain time:
<http://www.amazon.com/dp/B008YD1V4Y/ref=dra_a_cs_mr_hn_it_P1004_100>
It comes out to about $175 with tax and shipping.

--
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

 

[DannyD.]

trader_4 wrote, on Tue, 24 Jun 2014 06:55:11 -0700:

Let's continue the math. A gallon by your calculations costs $3.32.
It has 12% chlorine. A gallon weighes about 8.3 lbs, so you're getting
1 lb of chlorine for $3.32.

My fault. I should have provided more details about the percentage.

This lousy issue of % Available Chlorine vs. Trade % (volume % Available Chlorine)
vs. % of product (weight % of product) is extremely confusing to me; but,
it makes a huge difference in the calculations of cost for chlorine!

Specifically, bleach percentages are listed by weight, such that 6% bleach
is 6% by weight, or 5.7% available chlorine. However, the HASA liquid chlorine
is listed by trade percentage, so 12.5% trade chlorine is 11.6% available chlorine.

In both cases the actual strength varies with age where the turnover in
the HASA chlorine is extremely fast (they go through a few pallets a day!)
while the turnover in bleach is dismal by way of comparison (however, the
*lower* the percentage of chlorine, the longer it lasts (which seems counter
intuitive, to me, but I have confirmed this will phone calls to Clorox folks).

Given the percentage confusion above, we can then add solid equations,
to finally get these generic equations for calculating the true cost of
sanitizing chlorine for all three types:

a) liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine

b) liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 1/5.7% by wt available chlorine

c) solids:
$cost/pound x 1/??% by wt available chlorine, as listed on the container

(assume 36% if it's not listed, which is what I've found out by calling
*every* manufacturer who didn't list the percentage! They're trying to
hide a lousy number every time!).

 

[DannyD.]

trader_4 wrote, on Tue, 24 Jun 2014 06:55:11 -0700:

If you have issues with too much stablizer building up, then I can
see using chlorine. But here in northeast, the stabilizer works out
just right, and it's free.

You bring up a very good point about the stabilizer!

Every year I empty my pool (a bit under 40K gallons) and fill it back up
again, so, I have to add the cyanuric acid (CYA) stabilizer.

I used to add about 15 pounds of the *granules* to bring up the CYA from
0ppm to about 50ppm (we have a *lot* of sun out here), but this year I
added 15 pounds of the CYA *powder* which is *very easy* to do once you
know how!

I'll never use the granules ever again.

The powder is available from *any* pool store that buys liquid chlorine
from HASA (which is common out here in California), and they sell it in
any desired amount at the *same price* as they sell the CYA granules.

So, in a single sitting (about an hour), I can bring up a pool from
zero PPM to 50ppm CYA, so that the liquid chlorine has a chance of lasting
in this perennial sunlight.

As you noted, all the solid pucks and most of the "shock" powders also
contain CYA, and I also use them (when appropriate, e.g., when I go
on vacation), so, there is nothing wrong with the "slow" method either.

One caution though is that it takes *technique* to distribute the CYA
powder, because it won't work in a sock like the granules do, but, once
you know the technique, it's even easier than using CYA granules, and
certainly far cheaper than the so-called "liquid CYA" you can buy in
the pool stores.

 

[DannyD.]

DannyD. wrote, on Tue, 24 Jun 2014 20:32:18 +0000:

a) liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine

b) liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 1/5.7% by wt available chlorine

c) solids:
$cost/pound x 1/??% by wt available chlorine, as listed on the container

I have used all three types of chlorine:
https://c1.staticflickr.com/3/2908/14265343766_fc5922732f_b.jpg

Assuming the HASA liquid chlorine averaged $3.59/gallon after all the
value-pack coupon and buy-11-get-one-free complicating shenanigans:

The equation for liquid chlorine is:
$cost/gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine

So that's:
$3.59/gallon x 1gallon/9.7pounds x 100/10.8 = $3.43/pound of available Cl

By way of liquid chlorine local (Silicon Valley) comparison:
Home Depot = $6.86/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.27/pound of available Cl
Lowes = $6.90/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $3.29/pound of available Cl
Leslie = $10.49/2 gallons * 1gal/9.7 pounds * 100pounds/10.8 pounds = $5.01/pound of available Cl

Comparing the Dichlor, we get:
Leslies = $122/40 pounds * 100/55 pounds = $5.55/pound of available Cl
Lowes = $70/22.5 pounds * 100/56 pounds = $5.56/pound of available Cl
Home Depot = $80/22.5 pounds * 100/56 pounds = $6.35/pound of available Cl
Costco = $55/24 pounds * 100/36 = $6.37/pound of available Cl

For Trichlor, we get:
Home Depot = $75/37.5 pounds * 100/90 pounds = $2.22/pound of available Cl
Costco = 84.79/40 pounds * 100/84.65 pounds = $2.50/pound of available Cl
Lowes $75/35 pounds * 100/85 pounds = $2.52/pound of available Cl[/b]
Leslies = $80/35 pounds * 100/90 pounds = $2.54/pound of available Cl

For Calcium hypochlorite, we get:
Leslies = $107.19/25 pounds * 100/73 pounds = $5.87/pound of available Cl

So, the best price for available chlorine (excluding the fact it raises the
CYA), seems to be the Home Depot Trichlor, or (if you don't want to raise
CYA), the Home Depot liquid chlorine (assuming it's fresh).

 

[DannyD.]

DannyD. wrote, on Wed, 25 Jun 2014 13:35:56 +0000:

The sun is brutal here, so I both add isocyanuric acid
(CYA) powder (not granules)

BTW, adding the special CYA *powder* is necessary under circumstances
when you can't run the equipment after having refilled the pool (due
to water levels taking weeks to rise given slow well refilling) and
given a very high sun load (California).

To be sure, adding the *powder* is easy, but all normal methods will
fail miserably, because once the powder gets wet, it *instantly* turns
into a solid brick! (I've never seen anything "set" so fast!)

Bearing in mind that CYA powder will do the same thing in your lungs, if
it ever gets that far, after a few failed experiments, I was able devise
a CYA powder distribution method that *easily* brings a pool from 0 ppm
CYA to about 40 ppm in a single sitting, with *no visible CYA residue*.

Here's a picture of the iso cyanuric acid powder:
https://c2.staticflickr.com/4/3754/14288464215_e1f9945a46_b.jpg

Here's a picture of my starting point:
https://c1.staticflickr.com/3/2921/14290908472_74a42f6d2f_b.jpg

The first thing I did was sift the powder into a 5-gallon bucket of water:
https://c1.staticflickr.com/3/2935/14288463955_ac49c388f9_b.jpg

If I didn't swish the water, and just let the CYA settle, this is
what happened at the bottom of the bucket:
https://c2.staticflickr.com/4/3774/14268701276_421b2bb601_b.jpg

So, I learned to swish the water while shaking the powder over the
skimmer net into the bucket of water.
https://c2.staticflickr.com/4/3717/14105281287_3bd6f33721_b.jpg

Then I poured the water into another bucket:
https://c1.staticflickr.com/3/2905/14292240094_2369793809_b.jpg

And, as I poured, I filtering out any sediment with a skimmer net:
https://c2.staticflickr.com/4/3714/14286472212_ef6b420a5c_b.jpg

Over time, I learned, the more I swished, the less sediment I filtered:
https://c2.staticflickr.com/6/5191/14288462515_d00be45d05_b.jpg

Until I got to a point where four or five 8-ounce cups of the powder
would easily go into a five-gallon bucket of water:
https://c2.staticflickr.com/4/3665/14289847442_356e28031d_b.jpg

Then, I simply poured the suspended-particle CYA "milk" slurry
into the pool:
https://c1.staticflickr.com/3/2901/14286472672_53c71a9dd0_b.jpg

The lovely clouds of suspended CYA particles in the water were
a beautiful sight to see (these clouds are *in* the water!):
https://c2.staticflickr.com/4/3799/14106114938_496f8fb243_b.jpg

By way of failed experimentation, simply shaking the CYA powder
over the pool with a skimmer net fails if there is any wind,
as the powder blows away; and it fails the moment you accidently
get the powder wet (which turns it into an instant brick)
https://c2.staticflickr.com/4/3793/14312945613_a53920d46e_b.jpg

And, even if you're successful at shaking the powder over the pool
on a calm day, the powder floats on the top of the water like an
island, due to its propensity to form clumps:
https://c2.staticflickr.com/6/5113/14106128430_5d9d55434f_b.jpg

But, I'm happy to report that the double-bucket swishing filter
method works just fine, and it's very easy and satisfying to do!
https://c2.staticflickr.com/6/5517/14106225077_1ff36835bd_b.jpg

Here is another picture of the lovely cloud of CYA dispersing
throughout the pool, with each CYA particle surrounded by water:
https://c2.staticflickr.com/4/3723/14269641626_f4931740a1_b.jpg

IMHO, this is the easiest, cheapest way, to add CYA to your pool
if you recently refilled it, and if you have a huge sun load, like
I do (which will murder you in chlorine costs otherwise):
https://c2.staticflickr.com/6/5571/14286473342_6af9853124_b.jpg

 

[DannyD.]

trader_4 wrote, on Wed, 25 Jun 2014 08:06:58 -0700:

> With 4 floaters, isn't the chlorine through the roof?

I understood everything you imply, as I am familiar with
the increasing ratio of CYA to target free chlorine level
as per this common table:

(Stabilizer) (Minimum FC) (Target FC) (Shock FC)
20 2 3 10
30 2 4 12
40 3 5 16
50 4 6 20
60 5 7 24
70 5 8 28
80 6 9 31
90 7 10 35
100 7 12 39
etc.

There is plenty of full sun here in summer in the NYC area
and with a 48,000 gallon pool, 1 floater loaded with
about 7 tabs keeps the chlorine at about 2 PPM.

I actually only have about 50 ppm CYA, even with adding the
powder, which means I need to target Free Chlorine at 6 ppm.

> The question is why you need so much chlorine?

I realize it's not often stated at the pool store, but,
the chlorine number is wholly useless without the associated
CYA value.

For example, with your 2ppm of free chlorine, if you had
a 40 ppm CYA, you'd already be below the minimum, and far
below the target chlorine levels for your pool (based on
my read of the chart above).

I can only hope, for your sake, that your CYA is at or
below 30ppm, which, for a sunny area out here, would not
be enough stabilizer.

I've never seen a pool with more than one floating dispenser,
let alone four.

You haven't seen "my" pool!

Seriously though, I'm welcome and open to ideas, as I can't
seem to keep chlorine in this pool, even though the biological
load is nearly zero (nobody even swims in it lately).

 

[DannyD.]

Zaky Waky wrote, on Wed, 25 Jun 2014 21:30:36 +0000:

> Can you post some pics of the labels of the chlorine that you are using?

Here is a picture of the chlorine "I" am using (Costco tablets & HASA liquid):
https://c2.staticflickr.com/6/5527/14507593172_cee66fd6c3_c.jpg

But, here is a more complete explanation of what *you* might find on the labels:

1. Liquid chlorine at 12.25% trade percentage available chlorine by volume (aka 10.78% available chlorine by weight, aka 11.31% weight percentage of sodium hypochlorite):
$cost/gallon liquid x 1gallon liquid/9.7pounds liquid x 100 pounds liquid/10.78 pounds available chlorine = price per pound of available chlorine

2. Bleach at 6% weight percentage of sodium hypochlorite (aka 6.17% trade % available chlorine by volume, aka 5.71% available chlorine by weight):
$cost/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/5.71 pounds available chlorine = price per pound of available chlorine

3. Bleach at 8.25% weight percentage of sodium hypochlorite (aka 9.08% trade % available chlorine by volume, aka 7.86% available chlorine by weight):
$cost/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/7.86 pounds available chlorine = price per pound of available chlorine

4. Solids & powders (available chlorine is as listed on the package):
$cost/pound solid x 100 pounds solid/?? pounds available chlorine = price per pound of available chlorine

Where the demominator for 99% by weight Sodium Dichloro-s-Triazinetrione, anhydrous, is 64.
And, where the denominator for 99% by weight Sodium Dichloro-s-Triazinetrione Dihydrate is 55
(which is the same chemical as Sodium Dichloro-s-Triazinetrione, typically 85% by wt & 14% water,
available chlorine 55%). But, the denominator can be as low as 36 for certain formulations
(e.g., Costco item #175121, aqua chem Shock Plus 4 in 1 pool shock 24 pack, EPA REG No 67262-27
telephone 800-252-7665).

For trichlor aka trichloroisocyanuric acid or richloro-s-triazinetrione, the available chlorine
varies by weight as listed on the package):
a. Home Depot & Leslie's Pool 99% trichlor is listed as 90% available chlorine.
b. Lowes 95% trichlor is listed as 85% available chlorine.
c. Costco 94.05% trichlor is listed as 84.65% available chlorine.

Note: Sometimes, Dichlor Dihydrate available chlorine is shown as 56% (even though 100% pure product
would be 55.4% and 99% pure product would be 54.8%), possibly because there may be some anhydrous
Dichlor mixed in with the Dichlor Dihydrate (manufacturing processes are not perfect).
Also, most confusing, is that sometimes they leave out the "dihydrate" in the ingredients even
though it is really there. The easiest way to tell is by looking at the % available chlorine.

 

[DannyD.]

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

I've never seen that table.
What makes you think it's right?

While it stands to logic in that the more stabilizer you have, the more
free chlorine you need to maintain its effectiveness, I didn't make that
table up.

The original Chlorine/CYA "Best Guess" chart was developed by Ben Powell.
Richard Falk had refined and expanded on that original to produce the
Chlorine/CYA Chart by Chem Geek as described here:
http://www.troublefreepool.com/threads/2177-Chlorine-CYA-Chart

The point is that most people don't even realize that the free chlorine
that they need depends on the existing CYA level that they have!

 

[DannyD.]

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

what I've seen is a recommended range of 1 -3,
with no adjustment for CYA. I know CYA has an effect, in the sense
that while it stabilizes it, it also lessens the sterilizing
effect if it gets too high.

Exactly.

It's a bit too complicated for me to fully understand,
but, it's all summarized in this chart:
http://richardfalk.home.comcast.net/pool/HOCl.gif

Which is explained here:
http://www.troublefreepool.com/threads/558-Pool-Water-Chemistry

End result?

The sanitizing goal is *not* a particular free chlorine level!
It's a particular free chlorine level that offsets whatever
your CYA level is.

 

[DannyD.]

trader_4 wrote, on Wed, 25 Jun 2014 15:21:36 -0700:

A lot of this pool stuff is just handed down and a lot of it is
wrong.

I don't disagree.

Take, for example, the pool-store recommendations to reduce
phosphates to prevent algal growth.

Sure, algae need phosphates, but, free chlorine, in and of
itself, kills algae.

On the other hand, I did try to source industrial lanthanum
chloride salt crystals (active ingredient in Orenda PR-10000),
but, failed.

So, if anyone here can get a good price on industrial grade
lanthanum chloride, you can make a killing on the pool stores!

 

[Zaky Waky]

"DannyD." <DannyD@is.invalid> wrote in news:lofd4a$b5k$4@news.albasani.net:

I understood everything you imply, as I am familiar with
the increasing ratio of CYA to target free chlorine level
as per this common table:

Can you post some pics of the labels of the chlorine that you are using?

 

[Zaky Waky]

"DannyD." <DannyD@is.invalid> wrote in
news:lofn79$b5k$6@news.albasani.net:

Subject: Re: Actual price/gallon for 12% Hasa Pool Chlorine (for SMS
and the Silicon Valley) From: "DannyD." <DannyD@is.invalid
Newsgroups: alt.home.repair,sci.electronics.repair

Zaky Waky wrote, on Wed, 25 Jun 2014 21:30:36 +0000:

Can you post some pics of the labels of the chlorine that you are
using?

Here is a picture of the chlorine "I" am using (Costco tablets & HASA
liquid):

Thanks.

 

[DannyD.]

Zaky Waky wrote, on Thu, 26 Jun 2014 07:36:37 +0000:

> Thanks.

I made a slight typo on the HASA liquid chlorine; it's 12.5%, not 12.25%,
but the equation is otherwise correct (AFAIK).

 

[DannyD.]

trader_4 wrote, on Thu, 26 Jun 2014 05:31:48 -0700:

B - I find it hard to believe it's right, because if you look
at the water quality recommendation from pool standards organizations,
public health depts, etc, I've never seen the chart or anything
that says your high levels of chlorine are needed.

Hi trader_4,

I understand what you're saying, so, we need to look at this
closely, scientifically, and logically.

Both you and I can understand the *logic* of the CYA-to-chlorine
argument. It's why pool stores test CYA in the first place.

The higher the CYA, the less effective any one level of chlorine
is. We all know that, so, at least the "inherent" logic is
underlying the charts.

But is it science?

This technical bulletin lists a few scientific references:
http://www.aquaticspecialtyservices.com/msds/Techbulletin1.pdf

Namely, the following which, the bulletin says, conclude:
"cya inhibits chlorine's ability to kill bacteria".
a) American Journal of Public Health, October 1965, Anderson
b) Applied microbiology, May 1967, Fitzgerald

Yet, we are saying most "official" recommendations don't mention
the CYA level, right?

Here's an 'advisory', that says, essentially, the same thing:
http://www.accu-tab.com/Portals/0/pdfs/Accu-Tab_FYI%20on%20CYA_Advisory.pdf

So, maybe together, we can flesh this out, to understand why most
official chlorine recommendations don't seem to take into account
the CYA levels.

One potential "error" in our assumptions is that an *indoor* pool
probably doesn't have *any* CYA; so, any "official" recommendation
for chlorine levels in an indoor pool wouldn't be pertinent.

Another potential complicating factor is that, for outdoor pools,
the CYA levels might be "assumed". I don't know, as we'd have to
look at each official recommendation to be sure.

This post is getting long, so let me google for "official"
*outdoor* pool chlorine recommendations to see what I can dig
up to support or disprove the hypothesis.

 

[DannyD.]

UPDATE: Here is the final summary of the cost equations, to date ...

Fact Sheet on Cyanuric Acid and Stabilized Chlorine Products

1. Liquid chlorine at 12.5% trade percentage available chlorine by volume
(aka 10.78% available chlorine by weight)
(aka 11.31% weight percentage of sodium hypochlorite):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.7pounds liquid x 100 pounds liquid/10.78 pounds available chlorine


2. Bleach at 8.25% weight percentage of sodium hypochlorite
(aka 9.08% trade % available chlorine by volume)
(aka 7.86% available chlorine by weight):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/7.86 pounds available chlorine


3. Bleach at 6% weight percentage of sodium hypochlorite
(aka 6.17% trade % available chlorine by volume)
(aka 5.71% available chlorine by weight):
price per pound of available chlorine =
$price/gallon liquid x 1gallon liquid/9.0pounds liquid x 100 pounds liquid/5.71 pounds available chlorine = price per pound of available chlorine


4. Sodium Dichloro-s-Triazinetrione, anhydrous at 99% by weight
(available chlorine is 64% by weight, or as listed on the package):
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/64 pounds available chlorine

5. Sodium Dichloro-s-Triazinetrione dihydrate at 99% by weight
(available chlorine is 55% by weight, or as listed on the package):
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/55 pounds available chlorine

Note: This is sometimes listed as Sodium Dichloro-s-Triazinetrione,
typically 85% by weight with 14% locked up as water, but the available
chlorine is still 55%)

6. Trichlor from Home Depot & Leslie's Pool at 99% by weight
(aka trichloroisocyanuric acid, listed at 90% available chlorine)
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/90 pounds available chlorine

7. Trichlor from Costco & Lowes at 95% by weight
(aka trichloroisocyanuric acid, listed at 85% available chlorine)
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/85 pounds available chlorine

8. Shock Plus 4 in 1 pool shock, Aqua Chem Costco item #175121, 24 pack
(where available chlorine is 35.6%, confirmed by phone 800-252-7665
and 800-859-7946 technical support for 'product code' 22112AQU).
price per pound of available chlorine =
$price/pound solid x 100 pounds solid/35.6 pounds available chlorine
================================================
================================================
Note1: The Costco #175121 product is labeled EPA REG No 67262-27,
Here is the EPA lookup for that product:
http://pesticideinfo.org/Detail_Product.jsp?REG_NR=06726200027&DIST_NR=067262
According to that page, the product is 58.2% Sodium dichloro-s-triazinetrione.
So compared to Dichlor dihydrate, which is 85% Sodium dichloro-s-triazinetrione
(i.e. not including the dihydrate), the Costco product is 68.5% of what you
would get with a normal Dichlor dihydrate product.

This 68.5% is purity relative to 99% pure Dichlor Dihydrate product,
NOT an absolute % Available Chlorine. The % Available Chlorine of 100%
pure Dichlor Dihydrate is 55.4% while the typical 99% pure product is
54.9% (i.e. 55%). 0.99*55.4%*0.685 = 37.6% so it's close to the 35.6%
the company quotes when you call them in Georgia.
------------------------------------------------
Note2: Sometimes, Dichlor Dihydrate available chlorine is shown as 56%
(even though 100% pure product would be 55.4% and 99% pure product
would be 54.8%), possibly because there may be some anhydrous Dichlor
mixed in with the Dichlor Dihydrate (manufacturing processes are not
perfect). Also, most confusing, is that sometimes they leave out the
"dihydrate" in the ingredients even though it is really there.
The easiest way to tell is by looking at the % available chlorine.
------------------------------------------------
Note3: Although the ingredients may say "Sodium Hypochlorite" at
12.5% on a bottle of chlorinating liquid, which would normally
imply that to be the weight percent of sodium hypochlorite; however,
in practice, it's the Trade % that is listed ast 12.5% on the bottle
of liquid chlorine. It's very confusing and really hard to know the
truth. Also, higher chlorine levels degrade faster, which is why
most don't worry much about it. Look at this link for a product
specification for "12.5 Trade Percent Available Chlorine"
chlorinating liquid with 10.55 - 10.8 Weight % Available Chlorine
and 11.0 - 11.3 Weight % Sodium Hypochlorite.
http://www.odysseymanufacturing.com/product_spec.htm
------------------------------------------------

 

[gregz]

Jon Elson <elson@pico-systems.com> wrote:

etpm@whidbey.com wrote:

Before I got
the chance to put my foot in my mouth they both informed me that
lightning had struck the chainlink fence 15 feet behind me and didn't
that scare me enough to get inside? I had just been ignoring the
thunder and lightning and had no idea it was such a close strike. I
think I was pretty lucky that day not to have been cooked.
Yes, it is a fairly easy to understand phenomenon that lightning that
strikes REALLY close to you doesn't make a lot more noise.
If the strike is essentially end-on to you, all the sound goes
outward from the bolt. What you hear sounds more like a car door
being slammed than a lightning bolt. I assume you were on a
tractor of some sort? That prevented you from getting zapped by
currents in the ground. You really DON'T want to have (both) feet
on the ground anywhere near where lightning touches down.

I've been fairly close to a few lightning strikes (and not operating
noisy equipment at the time) and was interested to observe that while the
strike was really close (visually) it didn't make a huge noise.

Jon

I think the noise was huge, but it was a sharp crack that didn't last long,
and I didn't notice echos after hearing that. That's when I found a split
tree in my backyard about 100 feet away.

Greg

 

Domingo, 5 de Dezembro de 1999 8:00:00 UTC, Dennis Grech escreveu:

Hi to everyone,
I need to know the correct resistance value for R471 on
an ESCOM monitor model EM1438LR. This resistor is connect to pin 8 of the
flyback transformer (LOPT).
Please confirm also the part for IC U201 if it is CD4070BCN.

Thank in advance
Dennis Grech

Email : dgrech@global.net.mt

 

[Clément Durand]

ClĂŠment Durand wrote, on Sat, 09 Aug 2014 21:05:32 +0000:

How do I find what machines are connected & their traffic?
I can log into my ubiquiti Rocket M2 radio from Linux using:
$ ssh -l ubnt <IP ADDRESS
I know the IP address of the home broadband router (192.168.1.100) which
is connected to the radio, but my first question is how I would find that
router IP address if I didn't already know it?

Route -n doesn't seem to report the router (which is 192.168.1.100):
XM.v5.5.6# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.50.0.0 0.0.0.0 255.255.255.0 U 0 0 0 ath0
0.0.0.0 10.50.0.1 0.0.0.0 UG 0 0 0 ath0

I'm surprised Jeff Liebermann hasn't responded, since he knows
everything about setting up WiFi security, but, luckily, I *think*
I have figured out one potential way to tell what the home broadband
router IP address might be from the Ubiquiti AirOS command line.

Assuming the rooftop antenna Rocket M2 is at IP 192.168.1.20 and the
home broadband router connected to it by wire is at 192.168.1.1 ...

$ ssh -l ubnt 192.168.1.20
XM.v5.5.8#

At that prompt, cat this file:
XM.v5.5.8# cat /tmp/dhcpd.leases

More often than not, that file seems to contain the IP address of the
home broadband router which is connected to the rooftop transceiver.

If you know of a *better* way to find the IP address of the router which
is connected to your Ubiquiti AirOS device, please let me know.

The router IP address will also be in the radio /proc/net/nf_conntrack
file, so, I think we can grep for it using a syntax sort of like the following:

XM.v5.5.8# grep 192.168.1. /proc/net/nf_conntrack

 

[Clément Durand]

ClĂŠment Durand wrote, on Sat, 09 Aug 2014 21:05:32 +0000:

How do I find the IP addresses of the machines that are connected *to*
that router? And how do I find their traffic?

I tried "netstat -n", "ifconfig", etc., but none tell me the IP addresses
connected to the home broadband router, nor their traffic IP addresses.

Any ideas how to get a list of the IP addresses connected to the home
broadband router?

I wish Jeff Liebermann would weigh in, because I'm way out of my league
here, but, the /proc/net/nf_conntrack (and /proc/net/ip_conntrack) file
on the rooftop Ubiquiti Rocket M2 radio seems to be logging some sort of
IP connections.

Let's say a home has two PCs attached wirelessly to one home broadband
router (192.168.1.1) which itself is attached by cat5 cable to the rooftop
Ubiquiti Rocket M2 radio (192.168.1.20) which I can ssh into.

Logging into port 22 (ssh) as user "ubnt" of that radio is as simple as:
$ ssh -l ubnt -p 22 192.168.1.20

Then, I'm at the "XM.v5.5.8#" prompt.

From there, I *think* I can get the IP address of the home broadband router
(if I didn't know it) by running "cat /tmp/dhcpd.leases".

But, more importantly, I *think* I can get all the IP addresses that the
two PCs are connecting to by running either of these two commands:

# cat /proc/net/nf_conntrack (for ipv6)
# cat /proc/net/ip_conntrack (for ipv4))

Is that the easiest way to figure out what IP addresses are being connected
to at any one time, while logged into the rooftop transceiver (i.e., modem)?

 

[Clément Durand]

Jeff Liebermann wrote, on Mon, 11 Aug 2014 09:43:50 -0700:

Try:
arp -a

Hi Jeff,
I had tried that. While "route" exists, "arp" is not installed on
the default Ubiquiti Rocket M2 2.4GHz WiFi radio:
$ ssh -l ubnt -p 22 192.168.1.20
BusyBox v1.11.2 (2014-02-05 18:21:05 EET) built-in shell (ash)
Enter 'help' for a list of built-in commands.
XM.v5.5.8# arp
-sh: arp: not found

Also, play with iwlist and iwconfig to see if they show connected
wireless devices (by MAC address).

Both iwlist & iwconfig exist, so I will try to learn their syntax.

Are you perhaps trying to build a network map from scratch? If so,
there are network mapping tools that will do the heavy lifting for
you.

I'm mainly trying to understand what's going on, by looking at
whatever information is available to me as I log into the rooftop
radio.

Some of the key stuff I'm trying to figure out remotely is what
IP addresses are connected to the home broadband router, and, what
destination IP addresses those clients are attempting to visit.

I think I have made headway on finding the home broadband router
IP address by lookint at the /etc/dnsmasq.conf file.

I think there's a ton of information about the destination IP
addresses in the /proc/net/nf_conntrack file.

Since there is so much IP information in the conntrack file, I'm
now looking for a command-line method of querying the destination
IP addresses found (some of which are suspiciously from China and
Russia) in the conntrack file, to find out who they belong to.

The one problem with the huge amount of IP data found in the
conntrack file is that I can't tell which client device initiated
the connection to those IP addresses.

So, I have a long way to go ... but every bit of advice helps,
and, I, for my part, will echo back what I've learned to the
group by way of payback.