PDA

View Full Version : Antenna Tests



ProAsm
04-03-2004, 08:09 PM
Firstly I'd like to thank Andre at Fastcomm and also Webb Industries for organising me a IPWireless Modem connector so speedily.
It works great - thanks guys [:)]

Now for the tests........

Test setup:
P4 - HP 2.6 gig Laptop 512 megs memory - WinXp Pro.
MySignal.exe version 2.5 (needs BIG percentage display) [:)]

19 dB gain Panel Antenna centered on 2.4 gigs
-20 dB return loss at 2.4 gig
-16 dB return loss at 2.53 gig
The Antenna therefore has a usable gain of 15 dB at 2.53 gigs
8 meters RG214 cable with N-Type (Barrel) joining onto Modem pigtail (N-Male to special connector)
Estimated loss in cable - 4 dB

The Antenna system therefore has a usable gain of 12 dB

Well things work very differently in practice than in theory.

Dont for one minute think because the modem picks up a good signal in a particular spot that the antenna is gonna work there.
At the end of the day, the antenna likes to be in a wide open area and as high as possible. Antenna adjustment is critical and moving it just a small bit the signal totally dissapears.
In area's low down (gutter height) there was no real significant gain over the modem - about 5% to 10%
My final resting place was attached to my tower about 2 meters above the roof (need longer and better cable)
Signal obtained here was 54% but due to the design of the tower and the brackets on the antenna I could not point it directly at the Tower so it is currently about 5 degrees to the right.

K1 | 04/03 - 19:14 | 102 | 2530000 | 51% | -54 dBm

When I hold the modem up at this point it reads 22%
After running cable straight down through my study window and into Modem and now connected to my Desktop PC - readings are still the same at 51%

K2 | 04/03 - 20:06 | 102 | 2530000 | 51% | -54 dBm

Observations:

1. Was hoping for better ping results but before with modem at 25% my pings were 137 (ave), they are now 96 (ave) to Mweb Kalahari 196.2.33.21
I will test them ingame to see if the spiking has dissapeared.

2. I logon on immediately (first time) something that does not happen with modem alone at 25%
Still need to test at some time if I will get disconnected etc.

3. Downloads are very steady, no packet loss, just rocks in.

Overall everything feels more responsive and solid.

The Patch Antenna (10 dBi)

Make: Andrew QD-2327MX10
Frequency: 2.3 to 2.7 gigs
Cable: 3 meters unknown make but thin.

Here I was very dissapointed and maybe all the gain is lost in its inferior cable as it only gave me about a 5% signal increase regardless of where I tested it.

Moral of the story, get the highest gain antenna possible, mount it as high as possible in as clear a space as possible and use the best cable money can buy.

Next test (Saturday) will be the 28 dBi Grid antenna with some good cable mounted approx 5 meters above roof level.
[;)]


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

flashvc
04-03-2004, 09:07 PM
Cool man, now if only Fastcomm can get us those pigtails aswell [:)]

--

AcidRaZor
04-03-2004, 10:05 PM
okay, that 28dbi one, is that from poynting themselves? (the one you were talking about in the press release thingy you posted?)

It would be very interesting to see that... and then you could post how to build that damn thing.

/me pre-orders his gold plated cable

ProAsm
04-03-2004, 11:58 PM
No its not the one from Poynting, its a grid mesh antenna.
First I gotta find some decent cable else I defeat the object.
Also with tomorrow being the launch I'm gonna be very tied up so probably wont get time to get cable etc [:(]


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

Karnaugh
05-03-2004, 07:38 AM
Pitty, I got rid of a 100M+ drum of good coax a few months ago when I moved [:(]

<hr noshade size="1">
"Since light travels faster than sound, people appear bright until you hear them speak."

NetLink Research

ajax
05-03-2004, 01:05 PM
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">19 dB gain Panel Antenna centered on 2.4 gigs
-20 dB return loss at 2.4 gig
-16 dB return loss at 2.53 gig
The Antenna therefore has a usable gain of 15 dB at 2.53 gigs
8 meters RG214 cable with N-Type (Barrel) joining onto Modem pigtail (N-Male to special connector)
Estimated loss in cable - 4 dB
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I don't know if maybe you made a typo here,
the antenna's gain at 2.53 GHz is probably the same. This is why.
There is little difference in the overall signal loss when comparing a return loss of -20 dB or -16 dB. The signal loss for the return losses mentioned is both less than 0.3 dB. So your antenna gain at 2.53 GHz can be assumed to be 19 dB. So the antenna system's gain is probably 15 dB if you take the cable loss into account.

The patch antenna system's gain is probably around 5 dB if you take the cable into account. So there's a 10 dB difference between the 2 antenna systems. It is not surprising then that the signal with the panel antenna is so much better.

Looking forward to your next test, ProAsm!

Ajax

ProAsm
05-03-2004, 06:19 PM
Yeah sorry, you are right about the return loss.... mmm... getting old [:D]
I want to wait till I got the cable etc and connectors as that is the expensive part then I will set it up, maybe next weekend.
I brought home a 13 dB gain Yagi today and will test that tomorrow - if this flippin rain stops [V]


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

cAde
05-03-2004, 08:44 PM
where did u buy that yagi? , cause im looking to find some places to buy some antennas... yagi or some other..



[:D][:D][:D]

Imaginet ADSL 512 Kbps = :-) , 3Gb Cap = :-( on A SMC 7401BRA Router + SMC Switch

ProAsm
05-03-2004, 10:33 PM
Buy [:D]
Hehe, no I had this one "lying" around [;)]

But you can get them at Poynting:

http://www.poynting.co.za


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

ProAsm
07-03-2004, 11:14 AM
Pictures of my test antenna now on the site (signature) - check "ProAsms Antenna Tests"
[^]


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

sneaky
08-03-2004, 12:38 PM
Whoa!!!! thats quite serious [8D]

________________________
Must think happy thoughts about the antenna!!!

nroets
09-03-2004, 10:09 PM
I tested with an old DSTV dish (62cm x 68cm) tonight. Got rid of the LNA and the upper part of its bracket. Used the lower part to guestimate the focal point.

Standing up on the roof with the modem aerial in the focal point I got
K9 | 3/9/2 - 9:04: | 66 | 2518000 | 44% | -62 dBm
Without the dish I got
K7 | 3/9/2 - 9:05: | 66 | 2518000 | 35% | -72 dBm
Back in the computer room, on the top shelf I am getting
K9 | 3/9/2 - 9:32: | 66 | 2518000 | 24% | -82 dBm

The fact that I'm about 3 times as far away from the tower as ProAsm
explains the differences in our measurements fully.
(3 times nearer means 9 times more energy which is 10 dB approx)

So my big question is : Will someone with a proper antenna have coverage at 10km from the tower ? He'll get at about 34% and -72dBm, so SNR wouldn't be a problem. But by the time the signal gets to his block, the tower may already have given up on him.

ProAsm
09-03-2004, 11:50 PM
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The fact that I'm about 3 times as far away from the tower as ProAsm
explains the differences in our measurements fully.
(3 times nearer means 9 times more energy which is 10 dB approx)<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Rhino lives 4.5 Kms from the tower and he gets 45% in his room with just the modem.
Another client lives 7.5 km from a tower and gets 38% just on his modem also.
2 of my Beta testers live less than 500 meters from 102 and they struggle to get 20%


<hr noshade size="1"><center>http://www.unrealza.co.za/proasm/mywireless.html</center>

AcidRaZor
10-03-2004, 08:16 AM
haha, they suck [:p]

martin
10-03-2004, 10:50 AM
[:D]