Less signal strength with antenna?

Scott · Posted: Wed Jan 24, 2007 1:54 pm Post subject:

Sheesh guys, let's not compare Ford Pintos to Hemi Cuda's or anything. C'mon. LOL. Very Happy

Obviously a parabolic with tuned element will outperform our sub $100 omni antennas. Please. I use custom parabolics in two current situations (one based on a mag grid, the other a solid reflector).

And don't get me started regarding the wind load on a "3 or 4 foot reflector antenna". Do you really think an average human will contemplate the mounting reinforcement needed to correctly secure something like that to their roof? Let alone how much the "other half" will enjoy that thing displayed prominently. I yi yi.

As I have said: commercially available, under a $100, forgiving install requirements, multiple bands, and within FCC limits.

Yet even then, I can tell you that maybe 10% of our customers could/would actually buy and use one.

glenozzy · EVDO User Joined: 03 Jan 2007 Posts: 49

MaximumSignal · Posted: Wed Jan 24, 2007 1:58 pm Post subject:

glenozzy · EVDO User Joined: 03 Jan 2007 Posts: 49

Scott · Posted: Wed Jan 24, 2007 4:55 pm Post subject:

We really don't want to go to "court". We just want to sell/support good antennas. Nor do we want to tick off tower techs/carriers/FCC ('cause you know as well as I do that folks ARE going to connect a signal amp to get "more").

Build me a true ~18dB or better directional the works for both 800/1900, is realistically sized, has good mounting options, a good warranty and manufacturer's support, is fairly easy for end-users to setup, and costs less than $150. We'll be happy to check it out and may even carry it.

While I personally like specific 800 or 1900-band antennas for obvious reasons, and while that is generally easy to nail down for Sprint or Alltel customers, it starts getting complicated for Verizon customers or those Alltel/Sprint customers who may actually be roaming. We're dealing with logistics here (delivery costs money) so need to appropriately specify band instead of playing 're-ship the correct antenna'.

n6gn · Posted: Wed Jan 24, 2007 7:52 pm Post subject:

SteveCA · Posted: Wed Jan 31, 2007 6:06 pm Post subject:

I experienced the same results with the Wilson trucker antenna. Connected to my Merlin 720 (although I doubt the card makes any difference) the signal was consistently no better and in many cases slightly (1-3dBM) worst than the built in flip up antenna on the card.

I also ran a test with the magnetic mount antenna from wilson and found that it was consistently 5-8 dBM worst than the built in antenna.

I can only attribute such losses to cable loss. Both antennas provided positve gain when used with the wilson amp whcih makes sense since the amp has a 26 db gain which more than overcomes the cable loss.

Speedtests confirm the signal loss in the case of the mag mount (5-8 dBM worst resulting in approximately 20-25% reductions in download speeds)

Download speeds for the trucker antenna showed little to no difference in my limited testing.

The antenna booster antenna (from Radio shack) showed 5-6 dBM improvement and slightly faster speeds. The cable length is much shorter at 3 feet plus adapter versus 12 feet plus adapter for the Wilson antennas.

I have not tried the booster antenna with the amp as the connectors (from Radio Shack) are different and don't work with the amp.

I would like to get my hands on some connectors so that I can shorten the cable length to no more than I really need. I'm confident that would help the antenna performance.

MaximumSignal · Posted: Wed Jan 31, 2007 6:08 pm Post subject:

SteveCA · Posted: Wed Jan 31, 2007 6:12 pm Post subject:

How many do the two of you think you could sell a month?

If it helps me get coverage at my house in Tahoe, I'd buy one at that price.

Steve

[you may answer me privately if you like]

n6gn[/quote]

Scott · Posted: Wed Jan 31, 2007 10:03 pm Post subject:

h00ktern · EVDO Fledgling Joined: 25 Jan 2007 Posts: 11

Finally got to test out the Magnetic mount omni & Amp. I'm a believer & I'll try to explain my observations.

The short story:

U720 - -82 to -83 dBi
Mag alone - -75 to -76 dBi
Mag & Amp - -70 to -71 dBi
Mag & Amp (amp off) - Doesn't work. Signal slowly drops-off from wherever it starts... to -80s...-90s...-100s...-110... Seems the passthrough doesn't work. Power it back-up & the signal recovers to it's former.

My "test" was quite simple. Plop the Magnetic mount antenna in the center of the roof of my pick-up. Extend the coax, but lay it out haphazardly. Same with the DC power cord. Place the laptop (a Sony UX280P) on the armrest. Disturb nothing & just plug, unplug connectors as required for the above configurations.

Signal swings, but if you are patient, it will normally settle to one or two signal levels. That's what I noted. I discounted the extremes of signal bounce.

At first, I was disappointed. I didn't understand what I was seeing. After abount an hour, I began "to see" the data in the four groups listed above, repeatedly. I just had to let each "configuration" settle-in for a few moments, wait for the EVDO signal to stabilize, then take mental notes of the numbers.

Over that hour or so, I consistently saw the same numbers. Over & over again. All I had to do was wait for the extreme fluctuations to pass, normally within 15 seconds. When the U720 reached a steady state, it was always -82 to -83 dBi - I just ignored the short lived -75 or -90 extremes.

Throughout the test, without holding me to the "exact" numbers above, I found the antenna, connected directly to the modem, provided a near solid -5-6 dBi. Add the powered amp, and I'd see another -5 to -6 dBi. No matter how I switched configurations, the average results remained the same - I'd see about -5 dBi with the antenna & another -5 dBi with the amp. I was quite pleased to see a -10 to-12 dBi increase in signal.

It was so evident, I can actually see buying another U720 adapter cable to make swapping the amp in & out less destructive on the adapter cable.

I think I also saw a pattern of a more stable signal strength with either the antenna config, or the antenna & amp configurations. I saw more frequent & signal spanning numbers with the modem on it's own.

After feeling basically confident in the above, I ran some speed tests. Ignoring the extremes, I found signal did improve my speeds. Unfortunately, I closed the browser & lost the numbers (repeated tests on each config), but generally speaking I saw 180/210/230 Kb/s upstream and 550, 700, 800 Kb/s down.

I think -75 to -78 dBi is about the break point for signal. Much higher (-83 or so) and speeds begin to suffer. Get much lower (-71 or so) and the gains become less significant.

To summarize, the 5-6 dBi gain on the antenna seems about right. Add the amp and you can see another 5-6 dBi gain. I think -10 to 12 dBi can make a significant difference, especially as has been stated repeatedly "...if you are in a fringe area..." I am curious how much -10 dBi will give me next time I hit fringe coverage...

Lastly, I'm going to consult with Booster-Antenna, from whom I've made all my EV-DO equipment purchases, and see if they have ideas on the pass-through problem noted above. It seems the cables & connectors are good; either the amp doesn't pass through when unpowered, or I've got a bum one. I'm sure I'll have answer when I make the inquiry.

Gotta' call it the way I've seen it tonight; I'd have been just as wordy if my results went the other way. As it stands right now, I have to find credibility in Booster-Anntenna/EV-DO Forums claims & assertions.

Very happy & satisfied consumer (especially if I can fix the pass-through issue)

Hope this adds to the confusion Smile

n6gn