Re: My putty analogy in Wireless Service Providers http://www.dslreports.com/forum/r16157527 en Wed, 25 Nov 2009 11:53:19 EDT Wed, 25 Nov 2009 11:53:19 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16169136 korym :
said by superdog See Profile :

I agree. The problem though, is that we already have quite a few stickies up there, and if we add to many, it will push all of the newest relevant threads to a second page??, Maybe?? :uhh:
Well, FWIW, I posted it to Start a WISP, with full credit to Rich, of course, specifically at:

»www.startawisp.com/content/view/417/53/

In fact, I'm starting to put useful posts there strictly for organization purposes. Radialink mentioned recently a bunch of lightning arrestor threads. I've posted some of them there too.

And, (I don't want to hijack the thread, of course, but since it came up...), I'm almost done with the Wiki site as well.

Hope this helps. :)

Regards,
Kory
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WISP Directory : WISP News : Start a WISP]]> http://www.dslreports.com/forum/remark,16169136 Thu, 25 May 2006 11:57:53 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16169062 superdog :
said by kewlkeed See Profile :

I vote for Sticky on this thread :)

Very good explanation.
I agree. The problem though, is that we already have quite a few stickies up there, and if we add to many, it will push all of the newest relevant threads to a second page??, Maybe?? :uhh:
--
»www.wavecrazy.net Join WISPA today! »www.wispa.org/]]> http://www.dslreports.com/forum/remark,16169062 Thu, 25 May 2006 11:47:30 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16168900 kewlkeed : I vote for Sticky on this thread :)

Very good explanation.]]> http://www.dslreports.com/forum/remark,16168900 Thu, 25 May 2006 11:23:25 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16166744 thewildthang : Good example Rich, one that I can finally use in mixed company(as if this has ever been a topic of discussion in mixed company). An old radio man once explained it to me as: when a bull walks across the highway and makes a deposit, that is as a unity gain antenna, if a vw bug comes along and runs over it that makes it as a 3 db gain antenna, but if an 18 wheeler comes along and runs over it that makes it as a 9 db gain antenna. In all cases you have the same amount of crap, it's just spread wider and thinner with the higher the gain.]]> http://www.dslreports.com/forum/remark,16166744 Wed, 24 May 2006 23:54:01 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16158274 anon : Rich;

I debated mentioning this but your analogy is SO good that I think I should.

A 3 dB increase is worth 1.414 times as much distance. A 6 dB increase is worth 2.0 times distance. Clearly you know this, and I have forgotten it many times; but as I said, your example is just SO good that this deserves mention.

-m-]]> http://www.dslreports.com/forum/remark,16158274 Tue, 23 May 2006 20:50:50 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157868 Airplane777 : Rawgerz:

Really neat sector illustrations.]]> http://www.dslreports.com/forum/remark,16157868 Tue, 23 May 2006 19:56:37 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157825 rawgerz : Sectors with about 10* down tilt. The towers and antennas aren't even close to scale I'm sure haha
I never did CAD so mine are basically a shot in the dark :uhh:
Haha, Rich using my image when your site says 'sorry our images are copyrighted' I see how it is ;) Just kidding
--
"Hows your French toast?" "Smelly and ungrateful, but this AMERICAN toast is great!"
Click for full size
]]> http://www.dslreports.com/forum/remark,16157825 Tue, 23 May 2006 19:51:15 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157736 Airplane777 : Hi Rich:

Very good practical explanation.]]> http://www.dslreports.com/forum/remark,16157736 Tue, 23 May 2006 19:37:10 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157606 rawgerz : I can't imagine the outcome of that, highgain's examples were easy to follow. But judging from RM examples I've done I'd say going from 50-250mw would give you 25-30% better dBm's in a given area, so you might see 55dBm in a spot that was previously 64 with 50mW.
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"Hows your French toast?" "Smelly and ungrateful, but this AMERICAN toast is great!"]]> http://www.dslreports.com/forum/remark,16157606 Tue, 23 May 2006 19:17:02 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157527 inova : Nice photoshopping! Can you take one of those pics and demonstrate the effect of varying the power applied?]]> http://www.dslreports.com/forum/remark,16157527 Tue, 23 May 2006 19:05:13 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157411 40883644 : rawgers

Nice, it even looks like putty :D

I took your art and doubled the RF from 100mW to 200mW to help answer inova's question. ;)

rich
»www.highgainantennas.com]]> http://www.dslreports.com/forum/remark,16157411 Tue, 23 May 2006 18:50:25 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16157308 rawgerz : I was bored so I tried some photoshop
I think that's how it should be?
Click for full size
]]> http://www.dslreports.com/forum/remark,16157308 Tue, 23 May 2006 18:37:56 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16156931 rfnut : Very nice analogy.
BTW.
VSWR is Voltage Standing Wave Ratio.
When a transmission line is terminated with an impedance, that is not equal to the characteristic impedance of the transmission line, not all of the incident power is absorbed by the termination. Part of the power is reflected back so that phase addition and subtraction of the incident and reflected waves creates a voltage standing wave pattern on the transmission line.]]> http://www.dslreports.com/forum/remark,16156931 Tue, 23 May 2006 17:46:08 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16156875 anon : Excellent analogy, Rich. Well explained.

-m-]]> http://www.dslreports.com/forum/remark,16156875 Tue, 23 May 2006 17:36:53 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16155751 uscomputing : Great post, Rich.

Unfortunatly my hands smell like play-doh now!!

Oh well:

»home.businesswire.com/portal/sit···sLang=en]]> http://www.dslreports.com/forum/remark,16155751 Tue, 23 May 2006 14:58:33 EDT Re: My putty analogy http://www.dslreports.com/forum/remark,16155499 PersComp : ***I didn't see this thread until after I had posted in the other one, so I copied it here as it fits better.***

Excellent method of illustrating!!! I thought I had the antenna concept ironed out (flattened doughnut, etc), but this makes me think a little deeper.....and tell me if I am thinking correctly.

So as you created the 8 dBi 180 sector and then flattened it , the gain returned to 16dBi. However since the coverage distance did not reduce when the putty was folded in half, the 16 dBi sector has the potential to cover MUCH more area than the 16dBi omni (not a true doubling, but probably 20-30% further).

I guess I just thought that 16dBi was 16dBi and was only concerned with additional interference when using an omni vs a sector. But, your illustration tells me that not all antenna gain is created equal!!!]]> http://www.dslreports.com/forum/remark,16155499 Tue, 23 May 2006 14:23:33 EDT My putty analogy http://www.dslreports.com/forum/remark,16155215 40883644 : After seeing the omni vs. sector comparison come up again, I have decided to share my putty explanation

My putty analogy

An omni and sector antenna comparison is easy to explain, but you must understand a few characteristics of antennas.

1. Antennas do not create RF, they only shape it
2. A properly manufactured and installed antenna should not consume much RF or reflect it back to the radio if the VSWR (Voltage Standing Wave Ratio) is kept to 1.2:1 to 1.5:1 by the manufacturer

An omni antenna

Imagine or ”just do it”… A ball of soft putty about the size of a baseball is a good size.

Form the putty into a nicely shaped ball, lay it down and poke your finger into the center until you touch whatever’s at the bottom. What you have done is created a somewhat doughnut shape. Taller then a doughnut and rounder then a doughnut but starts to take on the shape. Let’s call this a 1dBi radiation pattern.

Now start to flatten the ball until it is half as high but twice the diameter. You now have a 4dBi radiation pattern.

Flatten the ball again until it is half as high as the previous and again twice the diameter. You have now created a 7dBi radiation pattern.

Every time you flatten the ball to half the height and double the diameter you increase the gain by 3dBi

If you continue to do this 3 more times you create a 16dBi radiation pattern and what you’ll have in front of you is a very flat but very large diameter putty disc.

As you noticed, the height decreased as the diameter increased which is exactly what your ability to reach customers will do. You can now reach out further but may start to overlook close customers due to the thinner pattern.

A sector antenna

Right where you left off, you can now make a sector antenna.

Fold the flat putty disc over like a perfect omelet, and now what you have created is an 8dBi 180 degree sector pattern. You have not changed the distance it will travel in one direction but you have doubled your vertical height.

Now flatten the omelet shaped putty until it reaches out twice as far and is half as high but still retains the 180 degree / omelet shape. You have just doubled your gain.

Fold the putty now into a quarter round shape by folding it sideways. This creates a 90 degree sector pattern that has the same capable distance but the vertical coverage has doubled again.

Disclaimer

This should help explain RF shaping differences between omni antennas and sector antennas. I use it when talking to my customers and hope it doesn’t insult anyone’s intelligence

To keep the explanation simple I have not brought into the mix what side lobes, front to back ratios, down tilt etc are. If this makes some sense, you can go on to study what that’s all about some other time.

Rich
»www.highgainantennas.com
Click for full size
]]> http://www.dslreports.com/forum/remark,16155215 Tue, 23 May 2006 13:43:17 EDT