Медленная передача файлов по Wi-Fi

There is a lot going on during a file transfer. First, there is overhead during the actual transfer. So if you have a transfer rate of 'x' your actual file transfer rate will always be less then 'x' to compensate for the extra overhead in sending packets and transferring files.

Secondly, your wireless speed is measured in bits but your file transfer speed is measured in bytes. To get the file transfer in bits, times everything by 8. So you have 5.3 MB x 8 = 42.4 Mbits per second (if I did the math right)

There's a lot of other devices that operate in the 2.4GHz network that your router is running on. Stick with whatever channel that gives you the best results. This will either be channel 1, 6, or 11.

The increase of speed due to changeing the channel suggests that there are other router broadcasting on the same channel and thus interfering with each other. By switching to a different channel you chose one, where fewer iterferences are.

There are tools like inssider which are able to show you how much is going on a channel. Choosing the one channel where the fewest broadcasting router are is best.

That's basically the best you can expect from the equipment you've paid for.

The rule of thumb for throughput of pure TCP/IPv4 over 802.11n with reasonable 802.11n-layer packet aggregation is about 75% of the PHY rate. By picking a better channel, you increased your PHY rate to 120Mbps, so pure TCP should get 90Mbps, which is 10.7 MiB/sec.

Maybe you're not always getting the 120Mbps PHY rate, and maybe you're using a remote filesystem protocol like SMB that adds its own overhead, or your client or server software is suboptimal. Or a combination of all of those. So a file transfer rate of 5.3 MebiBytes/sec (which is what I think you meant by "5.3 mb/s", judging from context) seems reasonable. The absolute theoretical max throughput your N150 dongle could handle in perfect conditions is 13.4 MiB/sec.

It's 2015. If you want to go fast, buy 3x3:3 802.11ac gear and go 1300Mbps. 300Mbps hasn't been "fast" since 450Mbps 3x3:3 802.11n gear started hitting the market in 2009. 150Mbps N was never "fast" because when N gear first hit the market, everyone did the 2x2:2 300Mbps flavor. Even with a 2x2:2 802.11ac USB dongle which can only do 867Mbps max PHY rate (it's hard to make a good 3x3:3 802.11ac 1300Mbps USB dongle, so I don't think anyone does), you could get close to 80 MiB/sec file transfers in ideal conditions, but I'd be happy with 60MiB/sec with that kind of gear under real-world conditions.

So assuming your client machine has a USB3 port, you could get an order of magnitude better throughput by upgrading your Wi-Fi AP and dongle to something reasonably modern.