In the market for a amp (Have Questions)

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 151

My Verizon Evdo has been an experience to say the least. I had bought it back in February of this year and could only get connected to National Access with a -89dBm. When forcing HDR my signal bounced around -115dBm as low as -91dBm but could never connect or even identify the connection as Rev-A.

Once the weather broke I purchased a 800Mhz 14dBi Yagi (Yes its the right antenna) 30 feet of Ultra low loss Wilson 400 cable. I then took a 16 foot 4X4 and ran a 10 foot PVC section off the top of it to get the Yagi mounted roughly 24 feet in the air.

After making some adjustments over a few weeks I finally found a good signal at a tower located 7 miles away. I had the best LOS to this tower. There is one at roughly 5 miles but there are a lot more obstructions in the way and the signal was erratic.

So now when I get connected I average roughly a -75dBm on Rev-A with my current setup.

But here is the problem. When the weather gets really bad and overcast/foggy my signal will disappear. If I'm not connected and try and get connected when its bad VZW access manager will launch and give me the generic broadband signal that hops around.

I've noticed that it seems to happen mainly in the early morning after I get off work. Then after it identify's the signal when it clears up as Rev-A sometimes it dials right in and others it takes 20+ attempts to connect.

Now after I finally get connected I do a constant google ping. If my connection goes dormant the signal starts to go erratic and web pages will not load although it still says its connected. If I run a google ping constantly the signal always stays strong -75dBm and I get a steady 800-900Kbps down 500-650kbps up. And I never get this page will not load messages.

Example right now the weather is starting to cloud up and the rain is coming. If I disconnected right now I'm willing to bet my signal will disappear and I wouldn't be able to dial back in until tomorrow morning. But if I leave it up and active it should stay connected all night.

I'm starting to think the reason I have a difficult time connecting sometimes is because its just not sending the signal out to the tower to get connected. Its very annoying if I just want to get online for a little bit and have to dial over and over just to get connected.

Questions

1. Will the amp help locate the signal in bad weather?
2. Will the amp help send my signal out so I can get connected without dialing several times? Also without the need to ping google to keep the connection active after connected would be nice.
3. When I had a Verizon tech at my home doing diagnostics before I got my antenna I asked him about amps and he said I had to notify Verizon if I added an amp to my setup. Is this true?
4. How close can I put the amp to my computer and evdo modem? I have 30 foot of cable currently and want to buy as little as needed.
5. Any special cable adapters that I need to connect to an amp? I purchased the FME adapter from one end of my cable to plug into the phone adapter of the 595U. The other end is large but screws right in to the Yagi antenna.

I think thats it for the moment. As I was writing this post up my connection hung up and I was disconnected. I tried about 5 times to get reconnected to Rev-A while showing 3 bars and it gave the Ras error where the remote computer did not respond. Just frustrated and a bit pissed off right now. Day off from work and I can't get it to connect so back to national access tonight which almost makes me want to turn my computer back off....

n6gn · Posted: Tue Jun 03, 2008 10:52 pm Post subject:

You have more questions than I have answers. But here are a couple of thoughts anyway.

Your weather and time-of-day behavior sounds like it probably relates to an indirect path and increased absorption due to moisture and moisture content in foliage. I would suggest you do *everything* you can to reduce the amount of clutter between your antenna and the cell site. This probably means you should work at going even higher than you are. Maybe borrow a telescoping push-up mast and try it out sometime when it's sunny, just to see the sensitivity to height. Reducing the intervening clutter will both increase signal strength and reduce weather related variation.

Put the amplifier as close to the antenna as possible. I know that's not what you wanted to hear but that's where it will do you the most good. Signal lost before the antenna on receive is lost forever. RSSI may improve with an amplifier downstream but the noise , Signal/Noise ratio and Ec/Io (if you can display it) won't.

The good news is that in many situations a little increase in height can go a long way. For over-the-horizon paths there used to be a rule of thumb that doubling the height bought you 6 dB. For short paths buried in clutter, sometimes 20' will make 20 dB difference. Of course, sometimes it won't too.

n6gn

widgetman101 · EVDO Junkie Joined: 02 Apr 2008 Posts: 151

Thanks for the reply. I've done quite a bit of mapping and my overall height is close to the top of the tree line.

I'm out in the country and there are many hills but thankfully my LOS to the tower isn't to obstructed. There are a few places in between my antenna and the tower that are relatively the same height.

At this time I don't think I'm ready to go any higher since I would need to purchase longer length cable not to mention all the time etc involved. At this point the amp would be cheaper and easier for me since I already have a good working signal for the most part.

I don't know how I'd get the amp much closer to the antenna though. As is I'd probably need to feet to get back to the house to wire to the amp. I already have 30 feet so I was hoping I could just do a small section inside then wire the 30 feet thats already run to the antenna on the other side.

My HDR Ec/lo is at 8-9 when the signal is present during the day and clear nights. I'm not sure if thats good or bad.

I know it was working for a short period last night then I lost the connection. Its calling for thunderstorms and rain today but I'll should be up this morning and I'll see if I can locate the signal today. It will be a bit hit and miss some days it connects fine in the rain and others the signal doesn't seem to exist.

As of now its still on generic broadband signal that is constantly roaming towers but will lock on after it clears up. I guess I'll report back later today with more info.

powrby4d · EVDO User Joined: 24 Dec 2007 Posts: 34

I'm dealing with exactly the same problem with the bad weather disconnects (usually preceded by packet dropout and big latency fluctuations), compounded by LOS that is pretty much straight through 7 miles of trees right at the horizon (lending credence to the moisture theory also).

Downlink is generally OK but uplink is the problem, indicating to me a choice between additional height or transmit power/gain (in my case further elevation is not an option). Looking forward to hearing if you resolve your problem.