Do wireless extenders actually work?

I have no way of getting ethernet to the rear half of my house, and there are two concrete walls between my two wireless stations (one Airport, one TimeCapsule) in the front half of the house and the rear.

Wireless signal strength there in the back is weak, my iPhone5 and iPad Air get 2 bars (out of 3) max near the front of the rear part (so to speak) and virtually nothing out on the deck. My son’s Mac laptop gets 3 bars (ie full strength) in most parts of that area of the house. I guess that means the laptop has a better aerial than the two smaller devices.

I’ve investigated ethernet-over-AC but it turns out the two halves of the house are on different AC circuits.

So I’m left with the idea of some sort of re-transmitter, that might pick up the weakish signal in the front part of the rear and re-broadcast it amplified somehow. The local store had devices that looked like they might do that (Belkin, Netgear, D-link), but the assistant wasn’t sure and they were so small I don’t imagine their aerial was any better than the iPhone’s. And it seems to me the weak connection that could be established between it and the existing wireless network would be the bottleneck anyway, even if the ostensible signal strength was 3 bars.

So, does anyone know for sure if such a thing is available, and would it solve my problem? Thanks to anyone who has experience in these areas.

Get an Airport Express and use it to extend the network.
I have used as many as three of these to provide coverage in a large house.

I have a NetGear R6300 as my main router and a NetGear Universal Dual Band WiFi Range Extender for the back of the house. 5 bars all around, for four months now. No complaints. Easy to install.

AFAIK these need to be plugged into the ethernet to extend, do they not? I can’t do that, if so.

No, they can extend over wifi too. Apple’s wifi extender mode only works between Apple routers. Other brands might work together, I’m not sure.

Obviously your extender needs to be within range of the main network for it to work. And it does reduce wifi speed somewhat.

Most wireless extender links will reduce network throughput - by 50% (the extender has to run half-duplex to share throughput with the new wireless network). You can get more expensive full-duplex extenders with two wireless adapters - one for the connection to the wireless, one for the new network.

Ducati Jr. is home from college, and has ensconced himself in the man cave/basement with his Xbox and other toys. The wifi signal’s not so good down there, and giving him and his sister fits. I started just to run a cable from my router down there, but we’d need almost 300 feet. It’s a long way away, and down two flights.

He needs to increase his tech savvy and learn more computer stuff, so instead of just solving the problem like I always do, I told him to find an extender, and he did. Well, I explained what an extender was, then he went looking!

It was an easy set-up - no help from me - and he’s connected.

Craigslist, $15, full bars everywhere.