Will my mac (MacOS Catalina) backup to an external hard drive conected to an apple airport extreme (802.11n)

Are you asking about backups made using Time Machine?

Only one version of the AirPort Extreme......the 802.11ac model......officially supports Time Machine backups to a drive connected to the USB port on the device.

Your post indicates that you may have ordered a much older 802.11n version of the AirPort Extreme. If that really is the case, then it is not possible to say in advance whether Time Machine backups might work if you connect a USB drive to the AirPort Extreme. Some users report they have been able to get things working this way, and some report that they are not able to get things working.

So, the first thing to clarify here is what model of AirPort Extreme that you have. The most recent 802.11ac version that does support Time Machine backups to an attached hard drive looks like a "tower". Older 802.11n versions look like a small white pizza box.

If you have one of the older 802.11n versions, look on the bottom of the device for the model number, which is usually embedded in the foam pad base. The model number starts with an "A" followed by 4 numbers. Post back with that information, please.

Might work, might not. The only way to know whether it will work on your network is try it out on your network.

I do have an older 802.11n AirPort Extreme......Model A 1301.....version here and was able to set up Time Machine as a test with some juggling. No idea whether this would be reliable over time though.

If you have the time and are willing to experiment, post back for some tips when you have the AirPort Extreme set up on your network.

Do you know what model number that you will receiving? If not, when the AirPort arrives, look on the bottom of the AirPort for the model number. It is usually embedded in the foam pad base. It starts with an "A" followed by 4 numbers.

OK, thanks.

Not sure if you had other information about the product, but it was introduced in October 2009 and discontinued in June 2011, so the product is at least 9 years old and as much as 10+ depending on when it was placed into service.

Apple now classifies the A1354 as "Obsolete", so they will not provide any help or support on the product.....even if you are willing to pay them.

The outboard power supply "brick" tended to head downhill after about 5-6 years of use on average. Hopefully, you will be receiving a replacement power supply with the AirPort and will not have to use the original supply, which at this point would be overdue to fail unless the original owner kept the product powered off for long periods of time.

Let us know when the product arrives and we'll give it a try.

If you plan to use the AirPort for a few years, I would keep an extra power supply on hand......just in case.

https://www.savingology.com/ProductDetails.asp?ProductCode=AIRPORT-EXTREME-MA073LL-A&click=2&gclid=EAIaIQobChMIn97zn46v6AIVxJ6zCh3AtAdEEAQYASABEgLrnfD_BwE

Honestly, this is about all that one could do to "re-furbish" an AirPort Extreme other than polish up the case. The product itself was considered a sealed unit......no user serviceable parts inside to repair or replace.

Powerline can be "iffy". Things are usually fine if the main router, powerline adapters and AirPort are all on the same electrical circuit. It can work OK if devices are not on the same electrical circuit, but the speed of the connection usually slows considerably.

Why? Let's say that your main router and powerline adapter are on one electrical circuit in the den and the powerline adapter and AirPort will be working on a different electrical circuit in another part of the house.

The signal will need to travel from your main router over the AC lines all the way back to the main circuit box. At the circuit box, it must "hop phase" to another circuit and then travel all the way to the location of the powerline adapter. Along either path it can pick up electrical "noise" on the AC line.

So again, this is going to be one of those cases where you won't know how well.....or if.....things will work until you try them out in your home.

Hopefully, the powerline adapters will work well enough to accomplish the task at hand.

When you mentioned "external drive" in your original post, Tesserax and I took that to mean a USB drive. A NAS is not really considered to be an "external drive".....it is considered to be a "network drive".

Terminology can be confusing. If you had originally asked whether a NAS would work with the AirPort Extreme, the answer would have been "yes".

It's anyone's guess as to how the powerline adapter connection might work, speed wise. If you can get 100-150 Mbps, that would not be all that bad though. 200 Mbps or higher would be amazing.

Still waiting on the RJ11 to RJ45 connector

What is this for as you have not mentioned it previously.

The only thing we normally use RJ11 to RJ45 cable was PSTN phone to VOIP setup.

is there a way that when I save something to one of the folders on my desktop I can make it also save to the same place on the duplicate folders in the NAS?

If you are using Time Machine the backup will automatically save any files and folders from the computer to the NAS disk.

Any backup software will actually do that.

If you want to go bare knuckles you can use rsync to make a duplicate.

Or you can use a backup software like Carbon Copy Cloner which has rsync running in the background with a decent user interface. It will replicate files and folders to a local or network drive. It can have multiple jobs setup and one can be just a limited selection of user folders / files. Speed will be somewhat slower though. And it will have more issues if you go from APFS drive in the Mac to HFS+ which is the only supported format on the Airport Airdisk for Mac files. (to retain metadata)

The RJ1A to RJ45 connector is a bit pointless and I kinda forgot why I ordered it, but will it work with an airport express (gen 1) connected to an adapter like the one attached that switches it from phone line to RJ11 then the other adapter from RJ1A to RJ45.

No, but it will apparently work with a Sky Hub and Sky Phone.

In other news I set up the power line adapter and it works very well.

Good news, especially with the older AC wiring in the home.