@Pitt75 

As you mentioned your gateway is a router and modem combo.  If the Archer A7 is connected and setup as a router then you are already dealing with a double NAT environment.  This can further complicate things by adding the Deco.  My suggest as such is to replace the A7 with one of the Decos.  Then set the Deco to AP mode.  Configure the remaining Deco units and then place them as you need.  This eliminates the Double NAT and may improve service.  For the Deco you want to place in your Barn, due to the range you are going to want to connect the unit you put in the barn to one of the units in the home via Ethernet.  This is because 300 feet is going to be too far for the wireless signal to reach to use the wireless backhaul.  

If you do this then you can disable the wireless on the Gateway and have the Deco be the only SSID in your home. 

  @Carl 

I could certainly run Cat6 cable but I am trying to stay away from that solution as I have concrete slabs at both ends that would be a real pain to work around.  In addition, the barn is made of 1" plywood clad on both sides with galvalume. I could get through that pretty easily but the concrete would be a pain.  In addition I have water, sewer, electric and wires for my electric fence running through all of this so I'd have to be real careful I didn't cut something!

Dumb question but what's a backhaul?

Thanks!

  @Pitt75 

Backhaul is the method that the Deco Satellites connect back to the primary Deco Node. They either use one of the Wi-Fi frequencies(channels) or they use a wired Ethernet cable for the backhaul. 

In your situation you have three options to traverse 300'. 

1. Wired Ethernet either underground or overhead.

2. Ethernet over home Electric circuits (only works if both home and barn are on the same side of the electric panel.

  -  TP-Link AV1000 Powerline Ethernet Adapter(this injects the Ethernet signal from a switch or Deco node onto the home electric circuits, and then it's pair at the other end extracts the Ethernet off the electric lines.

    -  https://www.amazon.com/TP-Link-AV1000-Powerline-Ethernet-Adapter/dp/B08M13B8B6/ref=sr_1_4?crid=12GY4U984YF9T&keywords=tp+link+av1300&qid=1650547504&sprefix=tp+link+AV1%2Caps%2C177&sr=8-4

3. Wi-Fi P2P Bridge

  -  TP-Link 5GHz N300 Long Range Outdoor CPE for PtP and PtMP Transmission | Point to Point Wireless Bridge

    -   https://www.amazon.com/dp/B00N2RO63U/?coliid=I5T77HBWIVVKU&colid=27J18KZ6WBXEZ&ref_=lv_ov_lig_dp_it&th=1

I have found in many cases such as your's the electric circuits in the Home and the Barn are electrically isolated from each other and as such the #2 option fails.

Good Luck

  @Pitt75 

@DAServices is exactly right.  Both on his explanation of what backhaul is and the three options available.  option 2 is also known as powerline adapters and as DA said is only possible if the two units (1 connect to your router and 1 remote) are powered by breakers in the same electircal panel.  PLC as he said does not work accross panels or sub-panels. 

  @DAServices 

Yeah, the Barn has a separate electrical panel so #2 won't work.

I'm familiar with extending cat 6 Ethernet cable so I may have to fall back on that.  I assume that if I didn't do that but could still connect my speed would be significantly slower because the backhaul would be using a different wireless channel as opposed to the Ethernet.  Is that correct?

However, I'm intrigued by #3. I'm not that familiar with this option but my camera is on the 2.4 band so I assume I would want the 2.4 version:

TP-Link 2.4GHz N300 Long Range Outdoor CPE for PtP and PtMP Transmission | Point to Point Wireless Bridge | 9dBi, 5km+ | Passive PoE Powered w/ Free PoE Injector | Pharos Control (CPE210)

Not being familiar with this hardware, would i just link it to the primary Deco Node wirelessly?  Would the network name be the same throughout or would I be installing a separate network?  Are their downsides to this solution that I am missing?

One other question - when trying to read up on this CPE, I happened to see this unit:

AC600 Outdoor WiFi Extender, WAVLINK High Power 1000mW Dual Band Access Point | Supports AP/Router/Repeater/WISP Modes | Weatherproof | Ethernet Port | Long Range WiFi Repeater for Backyard, Garage

Would this be the same as option 3 or better?

Thanks for your help....I really appreciate it!