Can I Daisy Chain an Airport Time Capsule with an Airport Extreme with WiFi?

I need to setup an Airport Extreme at signal's source; a location not generally accessible.

Does this mean that an AirPort Extreme will connect to the modem using a permanent, wired Ethernet cable connection?

I am thinking of using an Airport Time Capsule near (location) my iMacPro, connecting

my printer (HP Office Pro 8600) via USB,and using wireless connections with

my other devices including: HomePod, iPads, PC, et.al

This might work.....IF....the Time Capsule is located where it can receive a fast strong wireless signal from the AirPort Extreme. Line-of-sight between the AirPort Extreme and Time Capsule would be ideal. If the WiFi signal must pass through 3-4 walls between the AirPort Extreme and Time Capsule, things will likely be dicey as far as reliability.

Keep in mind that even if a wireless connection will work, you will lose at least half of the potential wireless speed on the entire network when you connect AirPorts using wireless. A wired Ethernet connection between the AirPort Extreme and Time Capsule would be highly recommended, since it will provide far better performance than a wireless connection between the AirPorts.

The end result desired is a completely cloaked network.

Not sure if you were aware that Apple does not recommend "hiding" a network. iPhones, iPads, and other mobile devices are known to have difficulties connecting to this type of network, so things may or may not work reliably.

As far as "security" is concerned, there are any number of free utilities available on the Internet that will reveal a "hidden" network in seconds, so anyone who wants to "see" your network will be able to do so very easily and very quickly. But, it's your call.

Finally, you will likely find that only the print function will work when you connect the HP device to the USB port on the Time Capsule. Advanced features like Scan, Fax, Copy, etc will very likely not be available since these functions are not usually supported over USB on a network connection. It would be much better if you connected the HP device to the Time Capsule using Ethernet, which should allow full functionality.

If the TC is very close to the Mac you can wire it by ethernet.. that will give you much better performance for both backup and internet because you will knock out one wireless hop.

An alternative if you cannot run ethernet to this location and wireless behaves poorly.. (it does in my experience).. you can try powerline adapters.. they don't always work but when they do tend to be faster and more reliable than wireless links.

Your second post has some vital info missing from the first. ie you are adding to a network you don't own.

I have the issue of absolutely and totally cloaking my printer

By this I am guessing you simply mean that the homeowner does not see it on his network.. that is fairly simple to arrange depending on your access to the main router and if it has suitable controls.

So I guess what we need first of all, is the homeowner happy to help you do this setup or give you access to the main router.. ? If so you can use a function called DMZ, or secondary IP. Either of which will allow you to isolate your network from the homeowner.

If you do have access (with homeowner's help or otherwise) tell us make and model so we can look up specs and tell you what and how to configure your Extreme.

For the second part putting the TC in upstairs and setting up the link.. that is relatively easy to do with the warning that wireless links of this sort carry all sorts of problems. I used to have a pair of airport extreme in almost exactly the setup you describe.. one placed above the other on different floors. It caused lots of problems when using clients running wireless upstairs to the upstairs extreme.. then double hop to the extreme downstairs. The worst was using mobile phone on wifi with WhatsApp. Try to talk over the phone was completely hopeless.. yet the link was as fast as possible with that model.. it is just that data (not time sensitive) stuff worked fine so I discounted it as issue.. but anything interactive was woeful. Eventually I twigged by taking the phone downstairs and connecting it to the main router.. so cutting out one wireless hop.. and everything worked fine.

Soon after I did what I should have done in the first place.. run ethernet.

That is why I do recommend using powerline adapters.. if the owner agrees. They are much less of a problem.

I can use an Ethernet to Extreme connection for the printer

A bit lost here.. the Extreme is going downstairs.. TC upstairs.. do you mean the printer will be downstairs.. or it was a typo and you meant ethernet to the TC.

If the printer is full network compatible then use network for sure.. that gets around all the USB issues Bob listed.

I was thinking I could hard wire my iMacPro to the Time Capsule

And using ethernet from the iMac to the TC will also help the setup so you get fast speeds and only one wireless hop.. which works 10x better than using 2 hops.

while having my PC go wifi

Depends on what you use the PC for .. anything interactive like online gaming.. then definitely try to hard wire it.

For simple connection to the internet and data only usage it should be OK.. if somewhat less reliable.

For my wireless link through the floor / ceiling.. I needed to reboot both ends once a week.. but that is with older GEN 5 AE.. if you are using new AC extreme and TC it might work better.. (or worse.. if you have interference issues etc).

Just to explain the problem with wireless is half-duplex.. it cannot Transmit (Tx) and Receive (Rx) at the same time.. half a moment's thought will tell you a transmitter cannot work with a receiver at the same time.

Powerline adapters are full duplex.. it is just they tell big lies.. even bigger perhaps than the wireless people do.

So AV500 for example.. are actually 250Mbps duplex.. and the manufacturer add the traffic in both directions.

Gigabit on the other hand, is 1000Mbps in both directions.. so it would classify as 2000Mbps in powerline terms.

Nor are the max speeds ever realised in real world.. AV2000 is barely faster than AV1000 in most normal homes.