Antenna Comparison

R

Robone

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Over the last few days I have been working and comparing various antennas. However all of them are still using the antenna on the modem fitted into the antenna. All values are max. Still cannot understand why the signal strength varies by about 6% between high and low and this happens in a few seconds.

What I find stange is that I have to point the antenna's away from where I believe the station is. It would be nice to know where these thing are. But I suppose, who cares as long as you get a good signal strength.

5 types have been compared.
1. Modem anttena basic as it stands - (6% signal strength and -100dbm)
2. Ricoffy 125 dia cut to 108mm and hole 36mm from back - (16% and -90dbm)
3. Pringles 75 dia hole 84mm from back - (16% and -91dbm)
4. Patch Antenna - (11% and -95 dbm)
5. Deep dish made from a ricoofy can opened up and bent to a template designed by C M Erskine obtained off internet (address lost but easy to look up) - (13% and -93dbm)

Conclusion Ricoffy and Pringles are the best however the Patch looks the best and costs the most.

Running off the deep dish at the moment however soon to go back to the Ricoffy. Looks nicer than the pringles[:D]
 
I have just had a look around my computer, and all I see is tin cans. Decided that best solution for the moment is the patch antenna and to accept a slightly lower signal strength.[:D]
 
Those values also suggest that the signal percentage is in fact the Signal-to-Noise ratio, and not just some average inaccurate value as previously suggested on the forum....

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Ricoffy rules.

Flashvc, I've sort of insinuated that the Signal "strength" is unreliable. But it's really because I haven't been able to see a genuine mathematical function between RSCP and ISCP.

All logic suggests that signal strength would be a factor of one over the other, but I haven't been able to gronk it.


<center><h5><font color="red">Oo. MyWireless <s>Hacks</s> Tweaks & Tech Info.oO </font id="red"></h5><h6>Have you checked the fawking FAQ?</h6></center>
 
I don't use the usb cable, but what's the value if you subtract the RSCP from the ISCP or the other way around?

I have a funny feeling that the signal percentage is really not a percentage, but just SNR

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Naw currently on my system:

With Antenna:
Signal = 49%, RSCP = -57 dBm, ISCP = -73 dBm and Ber = 5

Without Antenna:
Signal = 17%, RSCP = -89 dBm, ISCP = -98 dBm and Ber = 3


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How is the BER calculated or is it just read from the modem?

My understanding is that a smaller bit-error-rate is better (ie. less errors per bit) so why in MySignal is the BER <i>higher</i> for better signal?
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by ProAsm</i>
<br />Naw currently on my system:

With Antenna:
Signal = 49%, RSCP = -57 dBm, ISCP = -73 dBm and Ber = 5

Without Antenna:
Signal = 17%, RSCP = -89 dBm, ISCP = -98 dBm and Ber = 3
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Hmm..if you take -102 dbm (which is zero signal in wifi terms)
and subtract the RSCP:
-102 - -57 = -45 (your signal is 49% - diff is 4)
-102 - -89 = -13 (your signal is 17% - diff is 4)

take -102 and subtract ISCP:
-102 - -73 = -29
-102 - -98 = -4

take ISCP and subtract RSCP:
-73 - -57 = -16
-98 - -89 = -9

Damn, can't figure out a formula, they probably use the BER to adjust the value...

I'd like to see the RSCP/ISCP when right next to the tower, that should give us a maximum which we can assume is 100% ?

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I am now going to try a tennis ball can (dunlop) it is slightly longer than the pringle can and 74mm dia which gives you a required length of 278mm, and the can length is 274 however, the lip at the front might cause a problem. Its amazing how 1 mm makes so much difference to the required length

Worked out that if I put the modem on its back and using non slip pads supplied with the modem, and then its easy to position the can over the antenna. Tried to use prestick to position the antenna on the modem - not quite right. I will try and get the correct length cable ties tomorrow and see if that holds it.
 
2 things..

1.) Its very difficult to get 100% signal at a tower (if not impossible) since the towers are in high places thus theres a large dropoff when you get &gt; 200m from the tower.

2.) With say a coffee can, when measuring the diameter D for the calculator, is this the opening diameter (with the lip) or the diameter of the actual can say, in the middle ie. width inside the can? which is it since the calculations vary drastically..
 
I am just trying to keep above 12% signal strength, and I used the inside of the can dia because in the case of the coffee can, I cut it exactly to the right length and the lip disappeared anyway.
 
seems like below 12 you will get disconnections. I know since I forgot to put on the can earlier.

you speak of the "right length"? Is this the length from base-to-hole or of the actual can.. speaking of which, what is the ideal length and diameter (I dont think a Pringles can is ideal)
 
I use this to calculate all the dims http://www.saunalahti.fi/elepal/antenna2calc.php
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">1.) Its very difficult to get 100% signal at a tower (if not impossible) since the towers are in high places thus theres a large dropoff when you get &gt; 200m from the tower.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I have found the best signals are when you are level with the Tower and about 2 to 3 ks away.
Also you need to find a Tower with short cables, normally Water Towers or standalone Towers have fairly long cable runs but those ontop of buildings normally have very short runs, so the idea is to find a building roughly the same height and approx 2 ks away, then maybe you will achieve 80% or more.


<hr noshade size="1"><center><font color="blue">MyWireless Stuff</font id="blue">
<font size="1"><font color="black">The opinions expressed here are mine alone and do not necessarily reflect the opinions of my employer</font id="size1"></font id="black"></center>
 
ProAsm, I am hooked up to tower 50, but from your chart it tells me that it is based in northcliff, however, with all my antennas, I have to point towards Hyde Park, which is totally in the wrong direction. Is your list of towers correct?
If it is then I do not understand what is happening
 
This is the beauty with the 3G technology, often a bounced signal is better than a direct one and this could be happening in your case - dont worry about it [:D]
And yes, Northcliff (North Park Plaza)is Base Station 50.


<hr noshade size="1"><center><font color="blue">MyWireless Stuff</font id="blue">
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Hi all

From what I have read so far, the length of the can is not all that important as long as it is longer then 3/4 of the wavelength inside the can aka Lg (see http://www.saunalahti.fi/elepal/antenna2calc.php). If you read th guestbook at this site, you will see that he says that this is the case. Can anyone confirm that the length of the can is not too important provided it is LONGER than 3/4 of the wavelength? I see RobOne has sawn off the end of his coffee can to get the correct length which if I understand correctly was unnecessary. However, I do have a concern regarding the lip on the inside edge of the coffee can. Will this affect reception?

I have just tried to make a temporary cantenna. I got hold of the cable from the grey plastic patch antennas from FastComm and took out the wire. Then I used my coffee can (Diameter = 127mm and length 205mm, hole drilled 35mm from base) and I passed the tip of this wire through the hole and into the can about 30mm. I held the wire in place with prestik. I haven't used any N-connectors or anything fancy. However, I have to say that my signal strength isn't great. I have better results taking a pringles can and slotting it over the aerial of the modem! So I don't know if I need to go and get hold of a pigtail etc from webb industries or if I should just stick with my pringles can at 30 odd percent.

Can I expect a big jump in my signal if I go to the extra trouble?

I have had some really funky tests on the myADSL speed tests. According to ProASM, these tests aren't really all that applicable to MyWireless since it uses UMTS technology. (I hope I remember this all correctly!) Nevertheless they do give an indication I would think. I have had a speed of 502 kb all the way down to 80 kb and all within a few minutes of one another! (I have the 256k connection).

Having lots of fun playing here. [:p]

Cheers
 
Damn... 30% and your mouning? [:0] Keep with the pringles can.. that's a very good signal.

Me thinks![:D]

"i may just be the dumbest guy on the forum"
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">This is the beauty with the 3G technology, often a bounced signal is better than a direct one and this could be happening in your case - dont worry about it
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

This is good since I am on the North facing side of my building and the tower is located to the south. So I am pointing my cantenna in the same direction as the signal is coming from the tower ie. north. Thus, there must be some bouncing. I do get a 18-22% signal so it doesnt really bother me pointing the thing away from the tower. It doesnt make complete sense but I accept that it works. With all the bouncing and multipath fading effects the signal still gets to me and thats all that counts!
 
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