The Atlantis gate was the only one that could dial the MW!

[jenks]

so 10 years ago puny humans with no advanced tech managed to overide the gate, yet the wraith, the race who defeated the ancients, can't do it?

O'neill did it with the knowledge of the Ancients.

[RepliVeggie]

AscendedThor, you do know what a control crystal is right? It is only a computer program. Nothing more. O'niel included the programming into our DHD System when he was taken over by the Ancient Knowledge. And the Wraith came to Atlantis for the Star Drive and any other technology they could find. Not the gate. How would they know about the gates ability to dial MW.

[Xaeden]

the specific reason for the Wraith going after Atlantis in the first season (when Atlantis didn't yet have any ZPMs) was to take over tis gate so they could use it to get to the milky way which they couldn't do from any other gate in the milky way.
if it was just a matter of programming, surely the wraith would be able to do it. they did after all managed to get to the midway station.

so its pretty clear that without the specific chrystal you can't go to another galaxy.
O'niell only built a powersource, he didn't create any control crystals, so how did the earth gate with no DHD managed to do it?

Actually, the specific reason was to take over Atlantis and use it to get to Earth. How exactly they planned to do so was never stated. Teyla just said that they knew Atlantis was the only way to get to the rich new feeding ground. The idea that they wanted to use Atlantis' gate to get to Earth was just speculation on the expedition's part and it was quickly mentioned that in fact, there was a much more dangerous possibility...

ZELENKA: Yes, well, Teyla said the Wraith are not interested in destroying Atlantis. They're coming here to get to Earth. They can only do that by going through the Stargate ...

WEIR: ... which means stealing the city, which is why we have a self destruct in place.

ZELENKA: Yes, but if they are even the least bit resourceful -- which I must assume that they are -- they can easily reverse engineer their own intergalactic engine from the wreckage on the sea bottom.

The latter seems more likely since an assault on another galaxy using the gate network is limited what with it not being easy to dial back, so anyone who they sent over would be forced to try to create a new life there by establishing a foothold with just ground forces and whatever could fit through the gate. Then trying to rebuild without many of the resources available to them in the Pegasus galaxy. Against such a technological galaxy there wouldn't be a whole lot they could've done under those limitations.

But, on the off chance that was their plan, then for all the expedition knew, it was possible as the Wraith might've had a ZPM in their possession and for all the Wraith knew Atlantis might've been powered by ZPMs (at least, that's what they would've thought until the scout appeared and the fleet was already on their way). And even if the Wraith were to go out of their way to create a workaround to the Ancient's security measure (which could've taken years and as we saw that if they didn't find Earth soon they'd be forced to fight amongst themselves) they'd still need Atlantis for any ZPMs they thought it might have and they'd need to get Milky Way addresses from a computer or someone they captured in the assault. Otherwise, even with a ZPM, they'd be dialing forever, trying to get a lock (they'd try one 7 chevron address 38 times, try another 7, 38 times, and so on - it's hard enough to randomly get a lock with just 7) and if they did, there's no telling that it would lead to a Milky Way gate or that there's anything or anyone on that planet which would allow them to get to other planets without more random dialing. So taking Atlantis was a must one way or another for a variety of reasons.

[Jack_Bauer]

Again...it wasn't the Atlantis Gate its the Atlantis DHD that has the control crystal which made it able to dial earth...I believe the episode "home" dealt with this very problem

Yeah, Shpinxinator is correct. "Home" physically shows Rodney remove it from Atlantis' DHD (see the transcript quote). So as long as the blast didn't completely destroy that part of the room, (which doesn't appear to be the case) it should be fine.

Are you guys talking about the control crystal and DHD that just got blown up in the Control Tower of Atlantis? Hmmm. Maybe dialing Earth won't be as easy as we thought now and maybe the OP was correct without knowing it

[Xaeden]

Are you guys talking about the control crystal and DHD that just got blown up in the Control Tower of Atlantis? Hmmm. Maybe dialing Earth won't be as easy as we thought now and maybe the OP was correct without knowing it

Actually, we're talking about the control crystal and DHD that wasn't confirmed to have been blown up. The point that was trying to be made was that just because the Stargate overloaded, that doesn't mean that they definitely can't dial Earth anymore since the crystal wasn't part of the gate. Thus the line; "So as long as the blast didn't completely destroy that part of the room it should be fine." Obviously we don't know for sure, but based on the weakness of the blast and the possibility that the shield could've been moved to protect the control area, it's speculated that the DHD and control crystal might be fine and so we'll just have to wait and see if that turns out to be correct.

[Jack_Bauer]

Actually, we're talking about the control crystal and DHD that wasn't confirmed to have been blown up. The point that was trying to be made was that just because the Stargate overloaded, that doesn't mean that they definitely can't dial Earth anymore since the crystal wasn't part of the gate. Thus the line; "So as long as the blast didn't completely destroy that part of the room it should be fine." Obviously we don't know for sure, but based on the weakness of the blast and the possibility that the shield could've been moved to protect the control area, it's speculated that the DHD and control crystal might be fine and so we'll just have to wait and see if that turns out to be correct.

Fair enough, but u never know.