I just watched Stargate Atlantis Season 4.
Planetary Gate 1 with its DHD/Power source dials Gate Bridge #1. This begins a cascade effect of each gate activating, holding the pattern in a buffer and then dialing Gate #2 with the stored energy of the first wormhole.
The problem is losses. Passing through 34 gates even with 99.9% efficiency you end up with ~ 96.75% of the original power at the halfway station.
There is also no sign that the energy of the wormhole is recovered and stored,
You might argue that the storage function was disabled on the prison world they rescued Linnea (Destroyer of Worlds) from to prevent escapes.
You still need to explain why it wasn't working on Ernests world or the one with the two religious factions fighting over their origin (the gate was embedded in rock strata there). Also the world where they gated into a museum with a fake DHD and were mistaken for terroists. They should have been able to manually dial using the stored power in those circumstances but could not, they needed more power. That leaves you needing power sources with each gate unless you can explain why those gates could not dial out with stored power.
The pattern itself with sufficient error correction in the system could be retransmitted but the wormhole energy would seem to be lost. No reason it couldn't be self correcting when ZModem had that feature ~20 years ago.
The program is controlled (I believe back on atlantis itself).
It seems to be controlled from the 1st gate in system, either at the edge of the Milkyway or the Pegasus galaxy as appropriate. When the Wraith tapped into the system and reached the SGC MacKay created a modified copy of the "macro" on a crystal that had to be installed into the DHD in a different Solar System (the orignal sending planet was occupied by wraith blocking them off) so that they could get to Halfway station and fight the wraith.
It is based on the technology established by Ba'al when he modified a virus program created by Lt. Colonel Carter that was implanted in various DHD (to track his movements through the Gate system and find his secret base).
Which episode was that? I don't seem to recall them tracking Ba'al that way.
The Bridge Station is exactly that, a space station connecting the two bridges.
I just saw the episode where the Wraith reached the station and their "rationale" for no iris seemed excessively weak to me. Even if it was accepted having an iris would be an extra level of security that would not be turned down.
I also don't see why they would leave the crystal in an unguarded gate instead of installing and removing it as needed or putting it on the 1st extra galactic gate at each end and dialing directly from the SGC or Atlantis with a GDO signal to activate the macro. A return signal would indicate the iris was open and the macro activated before transit began. The GDO signal could be sent ahead using subspace from that gate faster than the "macro" gate could dial the next unit deactivating each iris in sequence.
I did like that they fixed one thing that bothered me towards the end of Season 3. Doctor Keller when she took over as head of medicine and complained how she couldn't handle it. But she not only had the time but the resources to be made up like a fashion model. In Season 4 they cut down the make up and she is much more convincing.