Would pilot pollution cause slow speeds with a good signal?

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8

Hello-

I have been getting slow speeds lately. I got into the ##DEBUG screen in the connection manager, and noticed I have sometimes four active service pilots operating at the same time, and also an active pilot in the 1xRTT column.

I researched this on the forums here, and I was wondering if this could cause the slow speeds even with the good signal.

Would a directional antenna help? I recently got an amplifier with a dual band antenna which is not, I guess, able to be pointed in a certain direction.

Thanks very much for any information.

n6gn · Posted: Tue Oct 27, 2009 9:55 pm Post subject:

I don't know for sure, but unless you simultaneously have pretty good paths to multiple carriers/sites, I doubt that your slowdown is due to pilot pollution.

So many things go into a correctly functioning(e.g. high speed) up/down link that it's hard to say without a lot of study what's going on. I suppose some hints would be whether or not you see a diurnal variation in performance that might correlate with multiple users, whether you have large signal strength, whether the other PNs are similar in strength etc etc.
A directional antenna should help simplify things and let you isolate performance degradation though. I'd think even a moderately low gain reflector antenna having reasonable F/B ratio should greatly reduce the potential for contribution from multiple sites.

On top of physical/link layer issues there are the questions of backhaul and network capacity too, I suppose.

When things are slowing down, you might try driving underneath the preferred carrier's antenna and see if doing so restores performance. I'd suspect that if you get close enough to the site and close enough to free space path loss that you'll have removed many of the physical layer possibilities and problems from the equation.

n6gn

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8

Below is the debug screen when I had the powered amp and non-directional dual band antenna hooked up.

Thanks very much for all the information and advice. I have started keeping track of my speeds during the day and night, so I can tell if there is any pattern. I have already noticed that when the signal strength increases, the download speed decreases.

As you noted, there could be several causes for the slow speeds, so I will use your advice to try to narrow it down. Driving by the tower and noting any speed changes is an excellent idea.

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8

n6gn · Posted: Tue Nov 10, 2009 3:36 pm Post subject: Re: broadband info

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8

Hello-
Thanks very much for your reply. I was using an in-line powered amp with a magnetic mount non-directional antenna. I got a good signal strength increase with it, but not a speed increase.

I drove over to the towers this weekend - there are two located about 4 miles away within 200 feet of each other (I don't know if I get signals from both or just one of them). My speed at the towers was 1.7 megabits/sec with the amp and antenna hooked up. I used antennasearch. com to find the towers.

I got a different antenna today, a Yagi type, and hooked it up to the same amp, pointed it at the towers, and now have speeds of 1.0 - 1.15 Mb/s, which very pleasantly surprised me. Right before I hooked the yagi up the speed was .30.

These forums have great information and have helped me a bunch. I guess wired broadband is pretty straightforward, but the wireless kind takes a lot of tweaking to get it just right.

n6gn · Posted: Tue Nov 10, 2009 9:51 pm Post subject:

From the previous slowdown-with-amp-antenna problem you reported, I'd suggest pitching the amplifier and just using as much directional antenna (yagi or better) as you can muster.
n6gn

Gator · EVDO Fledgling Joined: 26 Jan 2007 Posts: 15

Multipath can impair data speed regardless of signal strength. It is similar to ghosts on an analog tv. The reflected signal arrives later than the desired signal. The directional antenna rejects signals from the sides and back of the antenna.

n6gn · Posted: Thu Nov 12, 2009 10:12 am Post subject:

xrayman · Posted: Thu Nov 12, 2009 10:20 am Post subject:

After you ditch the amp and get the directional antenna as N6GN said, I would also ditch the Franklin device. Some think the Franklin device is more likely to lock onto multiple pilots than other Sprint devices.

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8

I am posting another debug screen below where I have my new yagi antenna hooked up to the powered amplifier. It shows the increased speeds.

I also took a speed test with the modem in the router about 15 minutes later, and that was even faster.

It will take a different connector to plug the yagi cable directly into the modem, bypassing the amplifier, but if I can find one I will see what speeds I get with just the antenna hooked up.

Thanks very much for all the information-I appreciate all of you taking the time to respond and help with my problem.

snowmane36 · EVDO Newbie Joined: 08 Oct 2009 Posts: 8