Antenna Comparison Test Results!

powrby4d · EVDO User Joined: 24 Dec 2007 Posts: 45

I finally got around this weekend to testing a variety of antenna types for EVDO to see which worked best for my application (see conclusions section at the bottom for that).
For those of you who have questions about how one antenna design might compare to another, these test results might be informative. Enjoy.

SUMMARY OF ANTENNA TESTS
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Overview of testing

Novatel Merlin s720 card testing Sprint EVDO Rev A
All signal strength values as measured in Sprint SmartView
All throughput values as measured by www.speedtest.net against the closest server

Tested antennas:
s720 internal data card flip-up antenna
ARC Freedom Booster
7dB 13" desktop
9dB 30" super trucker
Digital Antenna 10dB 489-DB yagi
19dB 34" yagi
24dB parabolic grid

Desktop antennas were tested 4 ft off ground level.

Test configuration for all antennas other than the ARC Freedom and 13" desktop antennas consisted of a vertically-leveled 15-foot mast mounted on a tripod using a Radio Shack antenna rotator. Directional antennas were cycled through 360 degrees in 5 -degree increments to determine maximum signal strength.

In this case, maximum signal strengths were obtained at 23 degrees and 175 degrees from magnetic North, accounting for magnetic declination.

All antennas except the ARC Freedom were tested with a * CA-819 amplifier. I didn't have an FME connection for the ARC Freedom antenna that would have allowed me to hook the * amplifier's TNC fitting to it.

Components I had on hand but did not get around to testing. Maybe later.
I have a Wilson 211210 amplifer
Andrew 7dB panel antennna
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OMNIDIRECTIONAL ANTENNA TESTS
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First I tried the data card only with the internal antenna only
-108dBM
This connection was functional but I did not bother with a throughput test as the signal strength was nowhere near what I wanted
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Arc Freedom antenna, no amplifier
-105dBm
A little better but still not in the target range
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7dB 13" desktop antenna with CA-819 amplifier
-98 dBm
This was a big improvement from where I started but still a long way to go
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9dB 30" super trucker antenna
As the most likely contender among the omnidirectional antennas I was testing, I started recording five speed tests to compare variability with the directional antennas

-88dBm 500kbps down / 500kbps up 220ms
-90dBm 831kbps down / 471kbps up 268ms
-91dBm 328kbps down / 300kbps up 264ms
-91dBm 408kbps down / 277kbps up 193ms
-92dBm 418kbps down / 271kbps up 349ms
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DIRECTIONAL ANTENNA TESTS
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HG2424G 24dBi parabolic grid antenna with CA-819 amplifier

tests from strongest signal at bearing 23 degrees

-84dBm 814kbps down / 631kbps up 191ms
-81dBm 882kbps down / 422kbps up 189ms
-85dBm 851kbps down / 320kbps up 183ms
-83dBm 901kbps down / 519kbps up 203ms
-84dBm 763kbps down / 412kbps up 198ms
-82dBm 877kbps down / 472kbps up 186ms

tests from strongest signal at bearing 175 degrees

-82dBm 902kbps down / 378kbps up 180ms
-83dBm 950kbps down / 529kbps up 178ms
-88dBm 923kbps down / 348kbps up 184ms
-83dBm 937kbps down / 632kbps up 182ms
-83dBm 1205kbps down / 531kbps up 187ms
-87dBm 931kbps down / 485kbps up 191ms
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19dB 34"yagi

tests from strongest signal at bearing 23 degrees

-92dBm 950kbps down / 327kbps up
-93dBm 348kbps down / 335kbps up

I did not record the latency on these tests as it was clear that while the thoughput was good, the signal strength was nowhere near what I got with the parabolic grid.
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Digital Antenna 10dB 489-DB yagi

tests from strongest signal at bearing 23 degrees

-115dBm

This antenna cost more than twice that of its closest competitor was not even as good as the data card alone. I had to double check to make sure that it was connected, the signal strength was so bad.
I did not bother testing throughput considering the lack of signal took this antenna out of contention. I may retest this at some point later to see if there was some kind of unobvious problem.
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MY CONCLUSION
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The problem I set out to solve was that VOIP over EVDO Rev A worked passably OK during winter, but starting in spring and summer transmission throughput degraded to the point of being unusable.

By rotating directional antennas, I found that I could get the strongest signal in two roughly opposite directions. While the tower at 175 degrees had slightly higher throughput, I selected the tower at 23 degrees because it allowed me to place the antenna in a more cosmetically appealing location. This turned out to be a tower roughly 13 miles away.

Basically all tested antennas other than the 489-DB did what they advertised. As a general rule, for all the tested antennas the improvement in signal strenth basically was a function of antenna surface area.

On the question of omni trucker versus yagi, my tests showed the signal strength to be comparable between the two but the throughput was higher on the yagi, and competitive with the grid which indicates to me that both the yagi and the grid were reaching maximum throughput for those conditions, but the grid had a better chance of maintaining throughput as conditions (e.g. weather) might degrade.

So, in conclusion, the parabolic grid kicked butt on signal strength and throughput and I went with that. The 34" yagi was a close second but nowhere near the signal strength of the grid. The trucker had comparable signal strength to the yagi and good throughput but considerably less than the yagi.

The panel I didn't test once it became clear that surface area was the key factor and it wasn't going to be the leader.

The Digital Antenna yagi did not work well for me. Your mileage may vary, I suppose.

The desktop and booster antennas worked OK for Web browsing but insufficient for a VOIP application in the boonies through 13 miles of trees.

Jim_in_VA · Posted: Tue Sep 02, 2008 12:52 pm Post subject:

Well done. No doubt the logical choice is the grid for a fixed location, and considering the minimal difference in price, a good value as well.
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ChoP · EVDO User Joined: 13 Jul 2008 Posts: 30

This was also my conclusion with the HG915G 900MHz Parabolic Grid Antenna. It outperformed any of the other Antennas I tested. One that came close was a corner reflector I constructed, but the Grid Antenna still outperformed it by –5 to -7 dbm. It’s clear here today and I’m showing a –77 dbm from a tower 9.89 miles away, without a direct line of sight and no Amp attached to the system!!!

ChoP · EVDO User Joined: 13 Jul 2008 Posts: 30

Jayson · Posted: Wed Sep 03, 2008 9:21 pm Post subject:

I am anxious to try the grid antenna ... when I dopurchase one I will post my results aswell...I get around 550 dlaod and 150 up right now... I am out of the mapped coverage area by about a mile or so ....I use sprint u720 the wilson amp and wilson trucker antenna right now ...but I am sure that the 24Dbi grid antenna will greatly improve my internet proformance!!!

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 153

Wow I can't believe the grid did that much better than the Yagi. So I'm wondering if a 900Mhz Grid might be a bit better for me. Right now I've got a 14dBi 800 Mhz yagi.

Do the 900Mhz Grids work alright on Verizon's network? They use the 800Mhz frequencies in my area.

I was glancing at the HG915G-NM and the HG918G-NF-2. The HG918G-NF-2 is like $230 more though for what seems to be a 3dBi increase over the cheaper model.

What advantage do these grids have over Yagi's that give them better connection/speed? The Grid gains don't seem to be much higher rated than my Yagi. My signal remains constant for the most part but I do have times when it will jump around. As for LOS I can't see the tower and I'm aiming through trees as is. I know were there at but I can't actually see them.

Jim_in_VA · Posted: Thu Sep 04, 2008 12:18 pm Post subject:

The difference is that big'ol RF collector on the grid vs the yagi, and the narrow focus of its pattern. BTW the HG915G-NF for $70 is the one you want.
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n6gn · Posted: Thu Sep 04, 2008 2:49 pm Post subject:

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 153

Thank you very much for that detailed explanation. I was just curious and I'm always interested in a better signal.

Right now I've got 2 towers one at 5 miles out and one at 7 miles out. Ever since June I can't get dialed into the tower 7 miles out. I had added a Intelligian amp to my setup and that didn't help to that tower. It stabilized the signal though to the closer tower.

The thing is this tower is slower and for some reason from time to time the signal fluctuates. For the most part is stays around -69dBm to -72dBm. But sometimes it will just drop way off and go to like -110dBm. It doesn't happen often but it gets annoying when it does. Especially when I'm trying to game.

It was actually funny after I finished my setup. I was talking to a co worker and said one of the higher ups had just took a tower down back and threw it out basically. So I'm going to scarf it up next week. Its a full 30 foot tower with a mounting mast. I doubt I'll do anything with it this year but at the start of the new year I'll probably clean it up and paint it and set it up. Right now I've got a 16 foot 4X4 with a 10 foot extension PVC pipe. So my Yagi is around 24 feet up.

I'm just watching the tress right now. Can't wait for the leaves to fall so I can rotate back to the other tower for faster speeds and a more reliable connection. A few days I've jumped the connection by rotating the antenna after connecting to the slow tower. Then rotate to the fast tower to get it to stay connected. Works great sometimes, other times it just drops the connection after 15 minutes.

God I love EVDO but yet I hate it at the same time Twisted Evil

ChoP · EVDO User Joined: 13 Jul 2008 Posts: 30

I thought I would add this to the discussion as some may find it useful when dealing with directional antennas and tweaking their preformance.

There are also other factor that affect signal and through put. In the debug screen you will see references to Active, Candidate, and Neighbor pilots. An Active pilots is the tower you are locked on to, Candidate pilots is the tower you would be handed off to if you were mobile, Neighbor pilot is the towers you have around you.

An Active pilot or tower in most cases has three to four lobes (PN) that extend the signal out in radius around the tower. Each PN has an individual strong point but shares part of its radius with the other two or three PN on the tower.

If you see two active PN's in the debug screen that means that the pattern of your antenna is intersecting two lobes of the cell tower.

If you have more than one active PN show up as active in your debug screen it can causes a performance degradation.

If the tower you are pointing at has two active PN showing in the debug screen, try to adjust your antenna so you only intersect only one lobe so only one active PN shows up in the debug screen.

ChoP · EVDO User Joined: 13 Jul 2008 Posts: 30

Lnd Svyr · Posted: Sat Sep 06, 2008 3:04 pm Post subject:

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 153

Lnd Svyr · Posted: Sat Sep 06, 2008 5:34 pm Post subject:

Thanks for the reply. I was under the impression that the zBoost was an amplifier, too. All of the sites selling repeaters and amps list them both as having such and such db gain. The zBoost actually lists higher gains than some Wilson amps. Perhaps I am not understanding all of the tech jargon here.

I would be happy to get half of your posted speeds.

I tried to Google intelligian amp and got nothing. Can you tell me who the maker is? Thanks.

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 153