@Waycomb 

Hey

Is the garage on the same electrical circuit as the house?   If so you could consider using homeplugs instead, cant say I have ever used them over that sort of distance, but its plausable

In relation to the other 225 idea.  Mesh would only be an option if you have a controller to handle the mesh (something like an OC200), but you hadn't mentioned that.   Just thinking out loud here but the issue may be your USB dongle, its never going to get as strong a signal as an aerial based device.    You could using a TP-WA1201 in client mode at the near corner of your garage, have it cabled into the PC/Laptop. 

In client mode it will basically act as a super wireless card, you then get the advantage of the 4x aerials and its a lot cheaper than a 225 outdoors.  

however, before doing anything I would get WiFi Analyser on your Android device and see what the signal is from your garage corner, ideally, you want less than -65db.  If you are getting -70 or higher then its heading toward dead air and you might want to consider changing the antenna on the existing 225 outdoor to a more directional style, its could get you that extra few db

something like a sector (square) antenna pointed towards the garage may help, generally it will add around 10db to the signal from experience.

@Philbert 

The Garage is not on same electric so would not be possible via homeplugs.

'TP-WA1201 in client mode' that could be a pretty nice option actually, as one of my short term options was going to get a USB to Ethernet extension set so i could put the dongle closer to the corner anyway, so ill already have a long enough Ethernet cable.

Ill do some tests tonight on signal strength and get back to you.

@Philbert 

So set everything back up and did some testing, phone antenna signal was pretty non existent tonight for some reason.

Just kept disconnecting but the strength when connected was below, couldnt even manage a speed test really, it got around 8mbps before disconnecting.

However the A6210 dongle slightly more central and about 6 meters further away (deeper in the garage) got a pretty decent signal 2 bars basically at 5ghz and got decent speeds see below. 

So im thinking about seeing how the dongle gets on when I have a longer extension cable and the EAP225 is in its permenant position and then if i want a more stable connection going for a TP-WA1201 as I will have the ethernet cable to do it and I assume that will get even better signal than the A6210. 

2Ghz got a signal of around -71 (but speeds where unusable) , 5Ghz as you can see is around -80, not sure if that means it could just be a lost cause either way but seems to get okay speeds via the dongle even with that signal strength.

Let me know your thoughts.

@Waycomb 

Hey

ok, so you are looking at a signal strength of -70 to -80db which isn't great if honest.  Usually in an installation, we could classify -70 as the limit, any lower it really classified as dead air as the slightest change will drop you off the network.

Its not uncommon to see 5ghz with a lower strength that 2.4ghz due to the wavelength.  Its much faster but doesn't penetrate anywhere near as well and is more prone to malformation.   However sometimes the massively higher speeds can compensate for that, which seems to be the case for you! 

The good thing is the dongle seems to get a better signal, likely due to the antenna being bigger vs the phone, which would indicate the AP in client mode might be a winner for you.   If you do feel game for it, would be worth considering a directional aerial for the 225, it might squeeze out that extra few db and make it a bit more stable for little cost.  The omni directional that come with it are not what you need for this scenario. 

@Philbert 

I wont be able to do anything with the LOS issue that the EAP225 already has so would the directional antenna still help?

I think ill see how far i can get with the dongle and if i do need a bit more stability ill get the TL-WA1201 to give me that extra boost + potentially the directional antenna if viable without LOS.

Thanks for all your help thus far.

@Waycomb 

Directional antenna does have a slightly better strength over distances and through things when compared to an omni directional

The bad thing about the onmi you have at the minute is that most of the signal is going across the road or down the wrong direction, basically firing all directions (including into the wall).  Therefore a more directional antenna could remove that wasted potential and instead focus the strength in a more controlled direction, which might tip the balance for you

Granted it isn't going to be double the power or anything like that, but could remove some db loss for you and make it more reliable and/or faster.    Something like the one below is what I would go for, my engineers always refer to these as "Claymore" antenna, the old face towards enemy idea!

Just bear in mind that its a 2 way street.  Putting a bigger antenna on the sender is great, however not much use if the receiver cant send back anything. 

There was a guy on the forums recently that couldn't understand that.  He had bought a big CPE Access point and could get therefore see the SSID at 100meters away, then wondered why his laptop couldn't connect.  We tried (in vain) to tell him that he needed the same on the other side

Update -

Managed to angle the antennas as such on the EAP225 that im getting a solid two bars and a solid 20mbps speed with the Netgear dongle. So that setup is working well for now.