Connected but "No Internet Access"

I have a long distance WiFi system that works great, that I setup myself.

I am using a Alfa AWUS036H Upgraded to 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with a 2.4GHz 24dBi High Performance Die Cast Reflector Grid Wireless LAN Antenna. Also I am using just an 18" low-loss pig-tail cable, with a 10 meter usb active repeater cable

I am located about 1 mile out of town, (& from the closest signal), & I can pick up several strong signals that I can utilize; some are 2 - 3 miles away.

I assembled the dish cabled it to the adapter plugged the adapter into my pc.
IT WORKED!

Now I am trying to set up an identical system, only it will be located right in the middle of a large city. I thought it would be a breeze, assuming there would be more & closer access points.

I WAS WRONG! There are fewer (un-secured) APs, but I can find a few; & I can connect to them with 70% - 80% signal strength & 70% - 80% link quality. It shows I am connected but, with "NO INTERNET ACCESS"

I'm not all that versed in technical knowledge, but have stumbled through enough stuff to know the basics of systems like my own, pretty well. (or so I thought)

This is beyond me... I've tried everything that I can think of to try. The next thing I was going to try (& the one thing I haven't tried) is radically raising the dish, get it higher in the air. Idk? Hate to go to the trouble & it not work, & get the same results as all the other tweeks/adjustments I've made to no avail.

Why would the signals be so strong but can't access the internet???
I am totally exasperated & I am obsessed with it, & it's DRIVING ME CRAZY! (LOL!)

**********OTHER POSSIBLY RELEVANT INFORMATION**********

Due to my anticipation of easier targets at this location... .. .

Originally I already had a Hawking 9dBi panel (directional) antenna. So I just purchased the Alfa 1W - 1000mW network adapter. Done a very sloppy temporary install, just mounted the antenna on a 7' - 8' pole & leaned it against the outside wall, within 5-10 minutes, located & connected to a strong signal & was ONLINE! Streamed Netflix ALL-NIGHT with absolutely no problems.
Woke up the following morning, was no longer connected when I re-connected I acquired the same strong signal again, (or so I thought), but - NO INTERNET ACCESS.
MESSED WITH IT & MESSED WITH IT, NOPE - COULD NOT GET IT BACK.
Until, about 3-4 days later; on a whim, I tried connecting & it was magically working again! Think it lasted, a day & a half.

So I thought, must be on the far extreme reach of the 9dBi antenna.
Must need a better antenna. Right?

So, I purchased a 18dBi Yagi. Never did get online with the Yagi. It was the same story, "CONNECTED, NO INTERNET ACCESS"

So then I thought,
"Man, but my set-up works so well. I have a PARABOLIC DISH ANTENNA (24dBi); must be the antenna design."

So then, I purchased another PARABOLIC DISH, only smaller, (15dBi I think). When I received it, I unpacked it & half-hazardly mounted it, connected the adapter, & Voila!
My problems were over. IT WORKED GREAT!
For about a week, that is. Never worked again. (Except for well, you know, "CONNECTED, NO INTERNET ACCESS")

By then, I was so frustrated I said " F#%@ IT! I'm getting another antenna identical to mine. I KNOW that one will work.
My browser hasn't opened one (1) page since I installed it....

"CONNECTED, NO INTERNET ACCESS"


HELP! Anyone know what the problem could be?

Any/all advise/suggestions would be deeply appreciated...

This is a first for me I've never posted on any forum before, so I hope I stayed within the proper etiquette.

Thanks for taking the time to read my post.

Sometimes you have to tell the router to work with your wireless system.
It is easy to do if you can access the router, if not, forget it will never work.

You will need the wep key.

When it woks you probably connect to an open wifi, switched on from time to time.

As far as the signal is strong, you do not need extra antenna or dish.