Home mounting of WiFi antenna - advice sought for a too-short antenna mast - Page 3

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Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast

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Yes - look here: http://www.verizonwireless.com/b2c/homefusion/hf/main.do

Scroll down to the bottom of the page to see the concept drawing.

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 16:43:52 -0400, krw@att.bizzzzzzzzzzzz wrote:

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Exactly my concern!

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
wrote:

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I've since found that they do.  Verizon sells one for about $250.

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 13:40:42 -0600, Robert Neville wrote:

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Verizon 4G just got here!

I'm not familiar with how it works, but a neighbor put an antenna on his
car roof and drove up to my house and he was getting 15Mbps down speeds
with it.

My problem is I'm confused how you SHARE the connection to all the
computers. I'm not sure how that works ... but if it does, it could KILL
the WISPs out here who make a business because Comcast doesn't serve us
and DSL is far too far away.

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Tue, 11 Sep 2012 18:21:04 +0000 (UTC), "J.G."

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Well, LTE has been on the local SLV cell sites for about 9 months.

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Samsung SCH-LC11
<http://www.samsung.com/us/mobile/cell-phones/SCH-LC11ZKAVZW
I played with one last weekend.  Connection via Wi-Fi was erratic and
would frequently disconnect.  It does some strange dance for about two
minutes when first turned on.  It looks like it's ready to use, but
it's not.  No special software needed.  No diagnostics or signal
strength indication.  We were in a fringe area for 4G, so speed was
slow.

There's also a USB 4G device.  No 3G so if you're travelling, you may
have coverage problems:
<http://www.verizonwireless.com/b2c/device/usb-modem/pantech-4g-lte
Just read the reviews and draw your own conclusions.  I haven't had
time to try it.





--
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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
wrote:

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It uses WiFi from the hot spot to the computers.  My cell phone will do the
same but its range is limited and I really don't want to hang it on a pole
outside.

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Tue, 11 Sep 2012 20:42:21 -0400, krw@att.bizzzzzzzzzzzz wrote:

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I've been told that we can rubber band our cellphone to the head of a
Dish TV antenna, which is a portion of a parabola, which will amplify the
cell phone signal.

Anyone know if there's any truth to that?

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
wrote:

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I've seen Chinese cookware used as a reflector for WiFi signals.  Some have
gotten a few km range this way.

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Is the cell tower in geosync orbit?

Re: Home mounting of WiFi antenna - advice sought for a too-short
We were about to embark at Dover, when gilmore.justin@gmail.com (J.G.)
came up to me and whispered:

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Maximum range for GSM and CDMA type cellphone is 35km, or about 25 miles.

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981
IF you think this http://bit.ly/u5EP3p is cruel
please sign this http://bit.ly/sKkzEx

---- If it's below this line, I didn't write it ----

Re: Home mounting of WiFi antenna - advice sought for a too-short
On Wed, 12 Sep 2012 15:47 +0100 (BST), usethebl@stedtelephone.invalid
(Paul Cummins) wrote:

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Sorta, kinda, maybe.  It's true in urban jungles and areas with lots
of GSM/UMTS cell sites.  Not true for forested and rural areas.

<http://en.wikipedia.org/wiki/Comparison_of_mobile_phone_standards
   GSM has a fixed maximum cell site range of 120 km,[5] which
   is imposed by technical limitations.[6] This is expanded
   from the old limit of 35 km.
<http://en.wikipedia.org/wiki/Timing_advance
   By implementing the Extended Range feature, the BTS is
   able to receive the uplink signal in two adjacent timeslots
   instead of one. When the mobile station reaches its maximum
   timing advance, i.e. maximum range, the BTS expands its
   hearing window with an internal timing advance that gives
   the necessary time for the mobile to be heard by the BTS
   even from the extended distance. This extra advance is the
   duration of a single timeslot, a 156 bit period. This
   gives roughly 120 km range for a cell.[3] and is
   implemented in sparsely populated areas and to reach
   islands for example.

--
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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Wed, 12 Sep 2012 03:50:59 +0000 (UTC), "J.G."

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It will probably do some good at 1900MHz and not much good at 850MHz.
Anything is better than the stock internal low-SAR antenna.  You would
look rather odd wearing a satellite dish on your head.  A flat piece
of sheet metal or aluminum foil will work almost as well as a dish.

Let's do the math.  A DBS dish is about 0.6 meters wide.  
At 850MHz, the maximum gain for a parabolic reflector is:
   gain = 9.87 * Dia^2 / wavelength^2 * (feed efficiency)  
   gain = 9.87 * 600mm^2 / 353mm^2 * 0.4
   gain = 11.4
   dBi = 10 log(11.4) = 10.6dBi
At 1900MHz, the gain = 17.5dbi

The 40% feed efficiency (that's the 0.4) is probably optimistic.
That's also if everything is lossless, perfectly matched, built
correctly, and properly designed, which is not the case for hanging a
cell phone on a DBS dish.  In receive, all of the RF that hits the
reflector from a distant source hits the dish and is reflected toward
the cell phone.  Therefore 10.6 and 17.5dBi are the maximum receive
antenna gains.

However, it's much worse in transmit.  The cell phone transmits RF in
all directions.  With an electrically shortened antenna, it's almost a
spherical pattern.  Only some of that RF hits the dish.  Most of it
flys off in useless directions.  The percentage is the area of the
dish divided by the surface area of a sphere at the same distance from
the dish focus.  The area of an 600mm dish is about:
   Pi * 300mm^2 = 283,000 sq-mm
The surface area of the sphere is:
   4 * Pi * radius^2 = 4 * 3.14 * 350^2 = 1,538,600 sq-mm
Therefore, the percentage of RF that actually hits the dish from the
cell phone antenna is:
   283,000 / 1,538,600 = 18.4%
In terms of antenna gain, that's a loss of:
   10 * log(0.184) = -7.4dB
Therefore, the transmit antenna gain will be no better than:
   10.6dBi - 7.4dB = 3.2dBi gain  (850MHz)
   17.5dbi - 7.4dB = 10.1dBi gain (1900MHz)

That's an improvement over the internal antenna, but hardly worth the
effort at 850MHz.  Not too horrible at 1900MHz.  However, you can do
better with an external antenna connector and a high gain yagi, panel,
patch, other cellular antenna, or just a bigger dish or plate.

--
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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 08:53:01 -0700, Jeff Liebermann wrote:

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That's a wonderful idea.

The Ubiquiti dish came with all stainless steel bolts. Do you still wrap
them if they're all stainless steel?

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 16:18:58 +0000 (UTC), "J.G."

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Thanks.  It's original and has worked great for the last 30 odd years.
The teflon tape cold flows into all the cracks and joints.  It
prevents capillary action.  Best of all, when removed, the original
connectors are as shiny as when they were new.  I use 1" wide plumbers
tape.  BC Hardware used to stock it, but they haven't had it for
years.  Common 1/2" is available anywhere and will suffice.

Hmmm... I just found some on eBay.  Time to restock:
<http://www.ebay.com/itm/140808957532

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No.  Not the bolts.  Stainless doesn't need any protection.  Don't
even bother greasing the nuts as a slipper nut tends to loosen if the
dish vibrates in the wind.

The teflon plus electrical tape wrap is for electrical and RF
connectors.  Most of those are internally protected inside the Rocket
housing.  The four rubber boots over the four RF connectors is
probably adequate.  However, I like to wrap the connector with teflon
tape, and then slide on the boot.  The boot will deteriorate after
about 5 years in the sun.  After it crumbles and falls apart, just
rewrap the teflon, layer the electrical tape, and spray on the acrylic
(mask the radio) and you're good for another 10 years or so.

--
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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 09:41:45 -0700, Jeff Liebermann wrote:

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One thing that is driving me crazy is that I have to climb the ladder to
disconnect the Rocket M2 to run tests with my (now spare) Nanobridge M2.
  


The Nanobridge is even worse! Taking the connector out of the Nanobridge
requires dexterity and you need three or four hands (hard to do on a
ladder!).
 


So, my next investment is in waterproof RJ45 couplers!!!!!!!!!!

Funny the things you learn only AFTER doing stuff for the first time!

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Tue, 11 Sep 2012 18:34:29 +0000 (UTC), "J.G."

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I bet they have some kind of boot you can put over the splice.

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Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Tue, 11 Sep 2012 18:34:29 +0000 (UTC), "J.G."

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The two "U" clamps holding the dish are slightly twisted.

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Once I tie myself off with a safety belt, I don't have to keep one
hand on the ladder, or risk my life using both hands on the antenna.
Throw an 11mm rope over the roof and tie it to something really
sturdy.  Get a safety belt, sit harness, or just tie yourself off with
more rope.  Then, you get to use both hands.

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No such thing.  Shove some clear silicon waterproofing grease (the
same stuff used by the phone company) into the RJ45.  The best place
to find that is at the local scuba dive shop.  It's used to seal
camera housings.  Don't use too much.  When done, just wrap some clear
cellophane wrap around the coupler, and then embalm it in electrical
tape.  If exposed to sun, spray with clear acrylic to keep the tape
from crumbling.

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Learn by Destroying(tm).
Remember, you have only one life to give for this 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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 08:53:01 -0700, Jeff Liebermann wrote:

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Funny you should mention the rope.

I bought a 100' length from the local surplus store on Winchester, along
with a harness. When I bought it, I had thought the harness was a
climbing harness - but it was actually a 'safety' harness.

Also, I was wondering HOW to anchor the rope at the top - but I had not
thought about just throwing it over the house. That's a GREAT idea!

I'm not sure what the ascenders are for because I was planning on
climbing the ladder with the rope tied to me just in case I fell.

I guess you're intimating I don't need the ladder ... and, well, it 'is'
steeply sloped so that might not be a bad idea.

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 16:22:05 +0000 (UTC), "J.G."

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Doing the math.  40ft up to the eaves.  My guess is about 40ft over
the roof plus 20ft to the ground and around a tree.  Total is 100ft.
This is going to be close.

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Been there, done it that way.  Worked just fine.  However, you're
going to destroy the tiles on the roof peak if you fall.  That's fine
because they're easy to replace.  Your life is worth more than the
tiles.

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Easy. Pretend the cheap Made in China ladder just buckled in the
middle and you're hanging a few feet below the roof eave.  You're tied
in with your hardness so you're not going to fall any further.  How
are you going to get down?  You can't have an assistant untie the
other end of the rope because they're unlikely to lower you safely
without belaying.  If you have climbing experience and know how to
handle the ropes and hardware, lowering yourself is no problem.  For
everyone else, a stop descender will be much easier.

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You need the ladder, which should also be tied to a rope thrown over
the roof peak and tied to a tree with a separate line.  It doesn't
need to be 11mm.  Just enough to keep the ladder from sliding
sideways.  The safety rope is just in case something goes wrong.

I can tell you've never done this before.  I suggest you find someone
with experience to do the install.  (Not me.  I'm getting too old for
this stuff).  Also, if you move the project to the roof peak, you can
climb up the other side of the house, which presumably is closer to
the ground.

--
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

Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Sun, 26 Aug 2012 09:55:12 -0700, Jeff Liebermann wrote:

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I just bought 100 feet of parachute cord at the surplus store. I bought
it for shoelaces, but it will work just fine for the ladder tie.

Funny, I hadn't even thought of tying the ladder down!

Here's an install I just did at a different location:
 


Re: Home mounting of WiFi antenna - advice sought for a too-short antenna mast
On Tue, 11 Sep 2012 18:28:01 +0000 (UTC), "J.G."

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No.  Parachute cord is too thin and too bouncy.  Tie some to a tree
and put your weight on it.  Notice how it stretches.  The local ACE
Hardware stores have 100ft lengths of shoddy 11mm rope in assorted
garish colors for $10 to $17.  However, for stabilizing the ladder,
yellow polypropylene utility rope (wire pull rope) is good enough.

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I've seen the results a few such sideways slips.  Usually, it's from
improper placement of the ladder legs.  If one ladder leg goes into a
gopher hole, the ladder (and you) will go sideways.  

I've also had it happen to me, when I put a ladder leg onto a knot
hole on my redwood deck, which popped out and sent the ladder
sideways.  Fortunately, it wasn't very high and I broke my fall by
ripping out the rain gutter (and shredding my hands).

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As I mentioned, the two clamps are slightly twisted.  It's not enough
to make any difference, but it just looks odd.

--
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

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