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J

Johann Beretta

Guest
On 10/14/20 7:21 PM, Jeff Liebermann wrote:
On Wed, 14 Oct 2020 00:25:08 -0700, Johann Beretta
beretta@nun-ya-bizness.com> wrote:

On 10/6/20 4:35 PM, Jeff Liebermann wrote:

To get some decent speeds, 5GHz
instead of 2.4GHz.

Generally speaking, yes. Practically speaking you can do several
hundred mbps over a 2.4 link. You just need to widen the channel.

While there are 2.4GHz routers available that have a 40MHz channel
bandwidth setting, I prefer not to use it because it reduces the
available bandwidth to other users on 2.4GHz. If one is sufficiently
clueless to use a 40 MHz channel set to CH6, it will effectively
trash most of the 2.4GHz band. Since Wi-Fi pollution can be
symmetrical, it also makes the receiver susceptible to more
interference. Stay with 20MHz channel bandwidth on 2.4GHz.
In dense environments, I agree. In rural areas, interference may not be
a factor. In extremely rural areas, interference PROBABLY won\'t be a
factor.


On the other foot, the minimum channel bandwidth on 5GHz is 40MHz
(depending on channel selected) with an option to use 80MHz or 160MHz
for 802.11AC and AX (Wi-Fi 6).
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.9_GHz_(802.11a/h/j/n/ac/ax)
With 1024-QAM, 802.11AX can theoretically do 1.2Gbits/sec in a 160MHz
channel. Your mileage will certainly be less.
No.. The minimum 5GHz channel bandwidth is 5MHz. Not sure where you are
coming up with 40MHz as a minimum. Out of several dozen transmitters, I
only have two set to 40MHz (backhauls). The rest are set to 20MHz with a
couple at 10Mhz.

My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channels.

Anyway, the performance limiting factor is usually interference from
co-channel users and noise sources. You could have all the bandwidth
in the world, the most efficient modulation scheme, maximum legal RF
power, and still not be able to communicate very well or far if there
is an interference source nearby. In other words, one needs to do
more than just \"widen the channel\".
Once again, sometimes. Sometimes ALL you need to do is widen the channel.
 
J

Johann Beretta

Guest
On 10/14/20 12:45 AM, Arlen Holder wrote:
On Wed, 14 Oct 2020 00:23:10 -0700, Johann Beretta wrote:

Clearly you don\'t do this for a living.

That is an absolutely correct assessment.

You can advise the OP better than I on potential Fresnel Zone issues, as
he\'s apparently asking how best to paint a LOS location 800 feet away with
the transceiver on a pole I believe.

You can run the math to explain to him how high that pole may need to be.
(We do that stuff by trial and error - but you may know the math better.)

Please advise the OP on the math so he knows how high to mount the radio.
All he has to do is search google for \"fresnel zone calculator\"

At 1,056 feet (0.2 miles) the Fresnel for 5.1 GHz is 7.1 feet.
(for 5.8 Ghz it would be 6.7 feet). The higher the freq, the smaller the
zone.

You can intrude the fresnel by 40% (max), but I try to avoid even that.
 
J

Jeff Liebermann

Guest
On Sat, 17 Oct 2020 23:12:08 -0500, Sqwertz <sqwertzme@gmail.invalid>
wrote:

So I was curious and youtubed it....This guy got $1,900 worth (about
an ounce) of .99% gold from 6 pounds of clipped OLDER PCB
connectors.
That\'s a very good yield from older PCB edge connectors, which were
plated with 50 microns gold plating. These days, the commercial stuff
is more like 5 microns. (1 micron = 1µm = 1 millionth of a meter).
Therefore, the yield is much less. I have a small forge that I use
mostly for aluminum and brass casting, but has been used to melt gold.
Also, part of my house once looked like a chemistry lab, but that\'s
long gone.

>https://www.youtube.com/watch?v=o3cqZ5kqEB4

Nice video. He points out and demonstrates some of the common
problems with gold recovery. In terms of gross profit and time burn,
I\'ve found it best to just sell the scrap gold and let someone else
deal with the chemicals and gold brokers.

I just emptied my safe deposit box so here is a photo of some gold
extraction that I did about 40 years ago.
<http://www.11junk.com/jeffl/pics/drivel/index.html#Gold-01.jpg>
At about $1,900/oz (spot price), they should be worth $2,470. However,
it\'s not so simple. The two blobs are not pure 24K gold. I don\'t
recall exactly, but I think they\'re only about 90%. I need to refine
them to at least 99% before I can sell them as 24K. Then, I have to
have them assayed by a certified lab for about $135. I don\'t know how
much dealer will take, but I\'m sure it\'s too much.
<https://santacruzgold.biz>

However, I may have done something dumb. I couldn\'t find anyone to
buy my collection of old PCB\'s (printed circuit boards). It was quite
a pile that filled the back of my Subaru. I failed to find anyone who
wanted to buy it all. 1.5 months of office rent was about equal to
what I might obtain from the sale or from gold extraction. So, I
donated the entire mess to a local charity run recycler:
<https://www.greybears.org/our-programs/recycle/electronics-recycling/>
I would have dragged everything home and stored it until I had time to
do another gold extraction, but there was no time and no storage
space.

I suspect getting chemistry glass and HCL delivered to the Santa
Cruz mountains may be difficult and raise some eyebrows.
Not a problem. I\'ve had a chemistry lab of sorts in my house for
years without incident. Over the years, we\'ve also had various meth
labs and recreational chemical factories operating nearby. The
glassware and chemicals are not much of a problem. Disposing of the
waste and cleaning up the mess after the chemists move out, are very
real problems.

Or used
to. It\'s kinda pointless to manufacture domestic meth anymore since
it\'s so cheap from Mexico, so they may have deregulated that stuff.
I prefer not to explain, but if I can contrive a believable and
documented reason for purchasing chemicals, it\'s not a problem.

>Food for thought...

Thanks, but I don\'t think that eating the stuff is a good idea.


--
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
 
J

Jeff Liebermann

Guest
On Sun, 18 Oct 2020 12:05:43 -0700, Johann Beretta
<beretta@nun-ya-bizness.com> wrote:

On 10/14/20 7:21 PM, Jeff Liebermann wrote:
On Wed, 14 Oct 2020 00:25:08 -0700, Johann Beretta
beretta@nun-ya-bizness.com> wrote:

On 10/6/20 4:35 PM, Jeff Liebermann wrote:

To get some decent speeds, 5GHz
instead of 2.4GHz.

Generally speaking, yes. Practically speaking you can do several
hundred mbps over a 2.4 link. You just need to widen the channel.

While there are 2.4GHz routers available that have a 40MHz channel
bandwidth setting, I prefer not to use it because it reduces the
available bandwidth to other users on 2.4GHz. If one is sufficiently
clueless to use a 40 MHz channel set to CH6, it will effectively
trash most of the 2.4GHz band. Since Wi-Fi pollution can be
symmetrical, it also makes the receiver susceptible to more
interference. Stay with 20MHz channel bandwidth on 2.4GHz.

In dense environments, I agree. In rural areas, interference may not be
a factor. In extremely rural areas, interference PROBABLY won\'t be a
factor.
Those are fair assumptions. However, I\'ve been surprised a few times.
For example, I couldn\'t figure out why I was getting miserable 2.4GHz
performance in an isolated farm house that was 2 miles from the
nearest neighbor or potential source of RF interference. I finally
got around to doing a site survey with a spectrum analyzer and
directional dish antenna. I wound that there was a point to point
2.4GHz wireless link between an office building about 5 miles away,
and an isolated pump house about 3 miles away. The farm house was
directly in the line of sight. At first, I simply changed channels
(1, 6, or 11), but the pump house link changed channel every time the
link faded or was obstructed. So much for adaptive channel selection.
So, I switched to 5GHz, and avoided the problem. Yes, interference
can be a problem in the middle of nowhere.

On the other foot, the minimum channel bandwidth on 5GHz is 40MHz
(depending on channel selected) with an option to use 80MHz or 160MHz
for 802.11AC and AX (Wi-Fi 6).
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.9_GHz_(802.11a/h/j/n/ac/ax)
With 1024-QAM, 802.11AX can theoretically do 1.2Gbits/sec in a 160MHz
channel. Your mileage will certainly be less.

No.. The minimum 5GHz channel bandwidth is 5MHz.
Correct. However, 5MHz is not the occupied bandwidth of the signal.
It varies by modulation mode and type. For example, conventional
2.4GHz 802.11b/g is typically about 22MHz wide and occupies four 5MHz
channels. The 2.4GHz band is 83.5MHz wide. Therefore, if it is only
possible to fit 3 non-overlapping 22MHz wide signals in the band
before running out of bandwidth. This is where the recommended CH1,
6, and 11 comes from. Incidentally, picking a channel that lands in
between CH1, 6, or 11 will end up overlapping the two adjacent
channels and interfere with both.

On 5 GHz, it\'s the same story. You divide the available bandwidth by
the occupied bandwidth of the signal to get the number of available
non-overlapping channels. Diagrams such as these show how it works:
<https://www.google.com/search?q=802.11+channel+bandwidth&tbm=isch>

Not sure where you are
coming up with 40MHz as a minimum. Out of several dozen transmitters, I
only have two set to 40MHz (backhauls). The rest are set to 20MHz with a
couple at 10Mhz.
You can use 20, 40, 80, or 160 on *PARTS* of the 5GHz band. 10 MHz is
available but I don\'t know any situation where it might be useful. The
bandwidth situation is a mess on 5GHz. I don\'t have the time to
explain where all the various protocols, power levels, bandwidth
restrictions, and standards, DFS radar protection, etc, fit together.
Also, things get really strange with 802.11ax. See Fig 9:
<https://www.ni.com/en-us/innovations/white-papers/16/introduction-to-802-11ax-high-efficiency-wireless.html>

>My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channels.

In what country? See:
<https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.9_GHz_(802.11a/h/j/n/ac/ax)>
Go to the column marked United States. Notice that 20 MHz is the
minimum allocated occupied bandwidth. 10 MHz is on the chart, but it
look like no country is using it. 5, 8, 30, and 50 MHz are not on the
chart.

Anyway, the performance limiting factor is usually interference from
co-channel users and noise sources. You could have all the bandwidth
in the world, the most efficient modulation scheme, maximum legal RF
power, and still not be able to communicate very well or far if there
is an interference source nearby. In other words, one needs to do
more than just \"widen the channel\".

Once again, sometimes. Sometimes ALL you need to do is widen the channel.
Yep. However, if a wide bandwidth is such a great solution, why
doesn\'t everyone just setup their routers to use as much occupied
bandwidth as possible, or perhaps just use the entire band? Sure,
there are benefits, but compromises must be made to use a larger part
of the band? Hint: Think about how long a radio needs to be
transmitting in order to deliver (for example) 1 MByte of payload
data. If it can deliver the data twice as fast and therefore uses
half the air time, that\'s that much more air time for other users of
the bandwidth used.


--
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
 
J

Jeff Liebermann

Guest
On Sun, 18 Oct 2020 12:12:01 -0700, Johann Beretta
<beretta@nun-ya-bizness.com> wrote:

All he has to do is search google for \"fresnel zone calculator\"

At 1,056 feet (0.2 miles) the Fresnel for 5.1 GHz is 7.1 feet.
(for 5.8 Ghz it would be 6.7 feet). The higher the freq, the smaller the
zone.
The question was for an 800ft link.
800ft / 5280ft/mile = 0.152 miles
Please adjust your computation accordingly.

>You can intrude the fresnel by 40% (max), but I try to avoid even that.

That depends on whether the intruding material is absorptive or
reflective. You can get a way with much less clearance if the signal
is absorbed. Yes, the signal level goes down, but it also stays down
and does not vary. However, if it\'s reflective, then it will refract
(bend) part of the signal, creating the opportunity for fades, nulls,
cancellation, etc. It can also create reinforcement and stronger
signal levels, but those tend to change radically if anything moves.

40% intrusion is a usable number for real links, but only works if you
have a sufficiently large fade margin, also known as SOM (system
operating margin). 20 dB would be a good minimum. I carry 20dB and
30dB attenuators in my toolbox. If the system still works reasonably
well with 20dB loss inserted at one antenna, it will probably be
reliable. If it dies completely, you need a bigger antenna or more
transmit power.

While I\'m ranting on the topic, fade margin (or SOM) is related to
reliability (or downtime):

SOM dB Reliability % Downtime per year
8 90 876 hrs
18 99 88 hrs
28 99.9 8.8 hrs
38 99.99 53 minutes
48 99.999 5.3 minutes
58 99.9999 32 seconds

99% reliability might sound great, but that means your link will be
useless for 1% of the year, or 3.6 days per year. Don\'t go below 20 dB
fade margin, which is 70 hours of downtime per year.


--
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
 
J

Johann Beretta

Guest
On 10/18/20 1:45 PM, Jeff Liebermann wrote:

The question was for an 800ft link.
800ft / 5280ft/mile = 0.152 miles
Please adjust your computation accordingly.
Yep. And the calculator I used could handle tenths.

That\'s why I calculated for .2 miles. I couldn\'t do 0.152 miles.
 
J

Johann Beretta

Guest
On 10/18/20 1:25 PM, Jeff Liebermann wrote:


My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channels.

In what country? See:
The United States. I\'m using official firmware on a US radio. I had
heard that newer radios were limited to 10MHz as the smallest slice, but
older gear is grandfathered in.

10 MHz is
available but I don\'t know any situation where it might be useful.
As for the usefulness of 10Mhz, well... Seriously?

I can think of all sorts of things.. Namely anything where you need
70mbps or less.

Or, in a really crowded area, you might be able to find 10Mhz of clean
spectrum..

My own link to my WISP is 10Mhz (I have my own dedicated AP). Delivers
me everything I need without having another 10Mhz just polluting the area.

I could probably get away with 5Mhz, but I\'ve upgraded to the AC line
and that is no longer an option. It is, however, still an option in the
M series.
 
J

Jeff Liebermann

Guest
On Sun, 18 Oct 2020 19:32:40 -0700, Johann Beretta
<beretta@nun-ya-bizness.com> wrote:

On 10/18/20 1:25 PM, Jeff Liebermann wrote:



My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channels.

In what country? See:

The United States. I\'m using official firmware on a US radio. I had
heard that newer radios were limited to 10MHz as the smallest slice, but
older gear is grandfathered in.
I\'ll assume a Ubiquiti M5 radio. I have some really old M5-Bullet
radios, with firmware that can\'t be upgraded to the latest greatest.
However, my house is a mess resulting from my office move, and I\'m not
inclined to dig one out and check what it can do. I did some Googling
and found that the Rocket-M5 does support 5 and 10 MHz channel
bandwidth, so I\'ll assume that your unspecified M5 version also does
the same.
<https://community.ui.com/questions/Channel-width-max-bandwidth-and-max-clients-per-AP/cdf020af-0d11-4982-8c0d-785e3e1c2030>

The article conveniently explains part of the logic behind using wider
channels and mostly answers my question from my previous rant, which
you deleted and/or ignored. Basically, the approximate math is
simple. If your WISP configures their access point for a 40 MHz
bandwidth channel and the ISP has 10 full time connected users, the
system can deliver no more than 4 Mbits/sec to each user. If the WISP
reduces the occupied bandwidth to 5 MHz, and still has 10 full time
users, each one will only get 0.5 MBits/sec, which is inadequate. If
your WISP doesn\'t have much of a user load, or doesn\'t overload the
channel with too many wireless users, 5 MHz occupied bandwidth will
work just fine. Note that this simplistic channel loading estimate
ignores various factors that will either increase or decrease the
channel loading. For example, I\'m assuming that the channel usage is
sustained at the maximum available rate, which is sometimes a bad
assumption. This becomes really messy if the streaming media provider
adjusts their deliver rate based upon error rate levels returns from
the viewers computer or media player.

Also, there is a problem. This assumes that the WISP has exclusive
use of the channel and that there are no other users on the same
channel. Any co-channel users will appear as interference causing the
WISP access point to lower the data rate to a level where the BER (bit
error rate) is high enough to produce usable throughput. In many
cases, this throughput reduction can be drastic, but for this
discussion, I\'ll assume it reduces throughput to half. That means
that delivering a given amount of data will double the air time (how
long the transmitter occupies the channel) and delivery will therefore
take twice as long. Actually, it\'s longer because the packet size is
also reduced, but to keep things simple, I\'ll ignore that. The result
of slowing down due to interference is that every users connection
slows down, and data takes twice as long to deliver. Instead of ten
happy Netflix viewers, the ISP support phone will have 10 irate
customers complaining of buffering.

So, what can an WISP do? Well, it could not load the channel to the
maximum capacity for a given occupied bandwidth. It could add another
radio on a different channel and move some of the customers there. Or,
it could just size the occupied bandwidth setting to match the actual
channel loading with some overhead left for interference and high
usage peaks.

So, why did your WISP use 5 MHz. None of the advanced 5GHz mode
beyond 802.11a are going to work well crammed into a 5 MHz occupied
bandwidth channel. I\'m not sure if 802.11a will work in a 5 MHz
channel. 802.11ac requires an 80 MHz channel. It would be
interesting to sniff the traffic between your Ubiquiti M5-something
radio and the WISP access point with a Wi-Fi Analyzer (Android) or
something similar. My guess(tm) is you\'re running 802.11a.

So, what kind of performance can one expect in a 5 MHz wide channel
compared to a 20 MHz channel? That would 1/4th the speed *OR* double
the range due to increase in power density (dBm/Hz). That\'s why it
was attractive to your WISP. Cut the data rate in half yields a range
increase of sqrt(2) or 1.414.

That\'s also why the FCC and other regulators seem to have purged 5 and
10 MHz occupied bandwidth from the rules-n-regs. It\'s much too close
to narrow band modulation and carries some of the detrimental effects
of narrow band modulation. It was fine when the typical 5 Ghz signal
used 20 MHz modulation. However, with 40, 80, and 160 MHz now
available, the narrower occupied bandwidths had to go.

10 MHz is
available but I don\'t know any situation where it might be useful.


As for the usefulness of 10Mhz, well... Seriously?

I can think of all sorts of things.. Namely anything where you need
70mbps or less.

Or, in a really crowded area, you might be able to find 10Mhz of clean
spectrum..

My own link to my WISP is 10Mhz (I have my own dedicated AP). Delivers
me everything I need without having another 10Mhz just polluting the area.

I could probably get away with 5Mhz, but I\'ve upgraded to the AC line
and that is no longer an option. It is, however, still an option in the
M series.
--
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
 
S

Sqwertz

Guest
On Sun, 18 Oct 2020 05:03:41 -0500, Arthur Conan Doyle wrote:

Sqwertz <sqwertzme@gmail.invalid> wrote:

It\'s kinda pointless to manufacture domestic meth anymore since
it\'s so cheap from Mexico, so they may have deregulated that stuff.

Afraid not. The stupid federal regulation about restricting the amount of
pseudoephedrine (Sudafed) that can be sold to an individual and requiring it be
sold blister packs still exists.
Yeah, that does. But I was referring to the glassware and the HCl.

-sw
 
J

Jeff Liebermann

Guest
On Sun, 18 Oct 2020 19:26:40 -0700, Johann Beretta
<beretta@nun-ya-bizness.com> wrote:

On 10/18/20 1:45 PM, Jeff Liebermann wrote:
The question was for an 800ft link.
800ft / 5280ft/mile = 0.152 miles
Please adjust your computation accordingly.

Yep. And the calculator I used could handle tenths.
That\'s why I calculated for .2 miles. I couldn\'t do 0.152 miles.
That\'s an input error of (0.2 - 0.152) / 0.2 = 24%
Perhaps using the online calculator which I provided might have been a
better idea? Or maybe a different Fresnel Zone calculator?
<https://www.google.com/search?q=rf+fresnel+zone+calculator>

This is interesting and might explain a few things:
<http://radiomobile.pe1mew.nl/?Calculations:propagation_calculation:Fresnel_zones>
Since the F2 zone is detrimental to receive signal level,
antenna heights are often selected so that F1 is an
unobstructed path and F2 is obstructed by a hill or the
earth bulge along the path.
In other words, the area around the F1 line is where you get your
usable signal, while the area around the F2 line is where you get your
problems. The reason you can get away with 40% incursion into the F1
zone is that reflecting objects on or near the F1 line will add, not
cancel. I guess it really should be something like:
0.0 to 0.6 F1 = OK. Direct path.
0.6 F1 to 1.4 F1 = problems due to destructive cancellation.
1.4 F1 to 0.6 F2 = OK
1.4 F2 to 0.6 F3 = problems due to destructive cancellation.
I\'m not too sure the exact coefficients are correct. I\'ll check
(later). In other words, there is a \"band\" straddling the various odd
numbered Fresnel Zone lines which define areas that should not contain
reflective objects.


--
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
 
J

Jeff Liebermann

Guest
On Sun, 18 Oct 2020 23:58:58 -0500, Sqwertz <sqwertzme@gmail.invalid>
wrote:

On Sun, 18 Oct 2020 05:03:41 -0500, Arthur Conan Doyle wrote:

Sqwertz <sqwertzme@gmail.invalid> wrote:

It\'s kinda pointless to manufacture domestic meth anymore since
it\'s so cheap from Mexico, so they may have deregulated that stuff.

Afraid not. The stupid federal regulation about restricting the amount of
pseudoephedrine (Sudafed) that can be sold to an individual and requiring it be
sold blister packs still exists.

Yeah, that does. But I was referring to the glassware and the HCl.
-sw
To the best of my knowledge, access to chemistry glassware is not
restricted in California.
<https://en.wikipedia.org/wiki/Amateur_chemistry>
In the United States, some regions have stringent
regulations concerning the ownership of chemicals
and equipment. For example, Texas once required
the registration of even the most basic laboratory
glassware.[20] However, this requirement was
repealed on June 6, 2019.[21]

Just buy what you need online:
<https://www.ebay.com/sch/i.html?_nkw=chemistry+glassware>
<https://www.amazon.com/Glassware-Labware/b?node=318049011>
Or, you can make your own:
<https://www.google.com/search?q=make+your+own+laboratory+glassware>
I have some glass tubing which I use to make the small stuff. However,
I haven\'t had much luck with glass blowing.

For HCL, if you can\'t get the real stuff, buy some muriatic acid and
distill it:
<https://www.google.com/search?q=how+to+purify+muriatic+acid>
I\'ve never had to do this but it doesn\'t seem difficult. (famous last
assumption).


--
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
 
P

pfjw@aol.com

Guest
https://www.actsretirement.org/latest-retirement-news/blog/2019/3/22/is-pennsylvania-a-good-place-to-retire/#:~:text=Pennsylvania%20is%20one%20of%20two,of%20most%20tax%2Dfriendly%20states.

https://www.zillow.com/homedetails/1706-Erlen-Rd-Elkins-Park-PA-19027/9911913_zpid/

Pennsylvania is a tax-friendly state for retirees. The second link is for a $200,000 house in our general neighborhood (note the high taxes and that it is a twin, however). b

Few wildfires. Quite diverse in the best sense of that word. And a 2,936 mile move would definitely scrape off the barnacles.
If you prefer more country-style living, but with college-town amenities nearby, there is central PA (near our summer house).

https://www.coveredbridgesrealty.com/newly-listed-homes-for-sale-in-columbia-county-pa Bloomsburg is a college town.

Then, of course, there is always Ranger, TX. https://www.zillow.com/ranger-tx/

Peter Wieck
Melrose Park, PA
 
F

Fox\'s Mercantile

Guest
On 10/19/20 11:17 AM, pfjw@aol.com wrote:
Then, of course, there is always Ranger, TX.
https://www.zillow.com/ranger-tx/
Which is where I ended up.
Real estate is cheap. Albeit most of it is going to need
work to some extent.

Added bonus: You get to make my life miserable.



--
\"I am a river to my people.\"
Jeff-1.0
WA6FWi
http:foxsmercantile.com
 
M

Mike S

Guest
On 10/17/2020 9:12 PM, Sqwertz wrote:
On Sat, 17 Oct 2020 22:19:23 -0500, Sqwertz wrote:

I see alchemy as your next hobby: Turning all that computer stuff
into Gold! In which case you don\'t have to move any of. Rain won\'t
hurt it.

I know it\'s hard to let go, but .....

So I was curious and youtubed it....This guy got $1,900 worth (about
an ounce) of .99% gold from 6 pounds of clipped OLDER PCB
connectors.

https://www.youtube.com/watch?v=o3cqZ5kqEB4

I suspect getting chemistry glass and HCL delivered to the Santa
Cruz mountains may be difficult and raise some eyebrows. Or used
to. It\'s kinda pointless to manufacture domestic meth anymore since
it\'s so cheap from Mexico, so they may have deregulated that stuff.

Food for thought...

-sw
Interesting video, thanks, I live near downtown SC I wonder the same.
 
J

Johann Beretta

Guest
On 10/18/20 10:09 PM, Jeff Liebermann wrote:

That\'s an input error of (0.2 - 0.152) / 0.2 = 24%
Perhaps using the online calculator which I provided might have been a
better idea? Or maybe a different Fresnel Zone calculator?
https://www.google.com/search?q=rf+fresnel+zone+calculator
Yeah, but the whole point was that the OP didn\'t have to guess nor did I
need to educate him/her on the formulas for calculating the Fresnel.
There are online calculators for it. Hell, I have an app for it on my
phone.

This was what I was replying to, in the first place:

You can run the math to explain to him how high that pole may need to be.
(We do that stuff by trial and error - but you may know the math better.)

Please advise the OP on the math so he knows how high to mount the radio.
I replied with:

All he has to do is search google for \"fresnel zone calculator\"

At 1,056 feet (0.2 miles) the Fresnel for 5.1 GHz is 7.1 feet.
(for 5.8 Ghz it would be 6.7 feet). The higher the freq, the smaller the
zone.

You can intrude the fresnel by 40% (max), but I try to avoid even that.
The first bit of text I gave was the information for him to do it
himself. First and upfront.

I also ran a quick calc with the values I could. Clearly not the 800 ft
required (I made this blatantly obvious), but close enough (on the safe
side) that if the OP didn\'t want to bother looking up the precise
amount, my calculation was on the \"safe side\" and would work just fine.

I wasn\'t trying to expend the calories to give a precise answer,
otherwise I\'d have gotten up, walked across the room, and used my app.

I also figured that if the OP wanted the precise calculation, that I had
not provide, he/she could burn the calories to type \"fresnel zone
calculator\" in google and have at it.
 
B

Bertrand Sindri

Guest
etpm@whidbey.com wrote:
I got all the probes to display a nice square wave in the 10x
setting.
But with the probes set at 1x the square wave isn\'t quite square.
You got lots of answers in this 1.5 year old thread, but the group
seems to have missed one explanation that might make sense to you.

Someone posted the bandwidth of two different probes in 1x mode, and
that bandwidth was 6Mhz.

A square wave can be represented as an infinite sum of sine waves, one
sine wave at the base frequency, and every odd harmonic of that base
sine wave up to infinity.

See: https://en.wikipedia.org/wiki/Square_wave#Fourier_analysis

Your probes, when in 1x mode, are acting as low pass filters, with a
-3db point at the 6Mhz bandwidth of the probe. So for the input square
wave, consisting of an infinite sum of odd harmonics, the 1x probe is
filtering away most of the harmonics above 6Mhz.

When you low pass filter away most of the higher frequency harmonics
that sum to create a square wave, what you have left is a *distorted*
square wave.
 
J

John Paul Duarte

Guest
Hello Can I get the solutions manual of Principles of Electronics by Malvino 7th edition. Thanks!

my email: dirayjohnpaul@gmail.com
 
F

Fox\'s Mercantile

Guest
On 10/24/20 12:57 PM, John Paul Duarte wrote:
Hello Can I get the solutions manual of Principles of Electronics by Malvino 7th edition. Thanks!

my email: dirayjohnpaul@gmail.com
He doesn\'t read the news groups he spams with this shit.
You have to reply directly to one of the many email
addresses he uses.


--
\"I am a river to my people.\"
Jeff-1.0
WA6FWi
http:foxsmercantile.com
 
J

Johann Beretta

Guest
On 10/18/20 9:32 PM, Jeff Liebermann wrote:

The article conveniently explains part of the logic behind using wider
channels and mostly answers my question from my previous rant, which
you deleted and/or ignored. Basically, the approximate math is
simple. If your WISP configures their access point for a 40 MHz
bandwidth channel and the ISP has 10 full time connected users, the
system can deliver no more than 4 Mbits/sec to each user. If the WISP
reduces the occupied bandwidth to 5 MHz, and still has 10 full time
users, each one will only get 0.5 MBits/sec, which is inadequate. If
your WISP doesn\'t have much of a user load, or doesn\'t overload the
channel with too many wireless users, 5 MHz occupied bandwidth will
work just fine. Note that this simplistic channel loading estimate
ignores various factors that will either increase or decrease the
channel loading. For example, I\'m assuming that the channel usage is
sustained at the maximum available rate, which is sometimes a bad
assumption. This becomes really messy if the streaming media provider
adjusts their deliver rate based upon error rate levels returns from
the viewers computer or media player.
I wasn\'t deliberately ignoring anything. I was just picking/choosing
what to reply to. (Limited time and all that jazz)

I disagree with the 4mb/s for each user though. Clients with less than
ideal signals should be put into low priority on the AirMAX scheduling
priority. This prevents them from hogging up transmission time. (for M
radios - AC radios apparently are able to handle that with whatever
programming logic UBNT has come up with as you no longer have to specify
priorities)

There area also various modulating schemes to help with bottlenecking
(TDMA, CDMA, and various new ones I\'m sure).

My own tests flat out contradict that 4mb/s bs.. I can deliver a lot
more to customers than that.. And yes, these are netflixers so they\'re
using bandwidth constantly. Maybe back in the day this was true, but
that post you referenced is 5 years old and it is no longer the case.
 
J

Johann Beretta

Guest
On 10/18/20 9:32 PM, Jeff Liebermann wrote:
simple. If your WISP configures their access point for a 40 MHz
bandwidth channel and the ISP has 10 full time connected users, the
system can deliver no more than 4 Mbits/sec to each user. If the WISP
Just out of curiosity, where are y\'all getting this idea that a 40MHz
signal can only deliver 40mbps? The 40MHz signals I use will deliver at
300MB/s (roughly)
 
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