...Apart from the obvious that the laptops device is pre-802.11n spec...
Yes, this had already been covered (draft-n), but there was a suggestion that - had they both been Broadcom - then they might have been able to play together nicely.
...and see speed fluctuate between 18 Mbps and 54 Mbps within sixty seconds...
I've hunted around for a little Systray WiFi monitor app that can bring up a floating window and show just the collected basic status details about the current WiFi AP connection
- per the image in the OP - such as SSID, standard (e.g., IEEE 802.11n), the value for mbps (say) every ½-second or so, and the bars for signal quality/strength(?). However, the closest that I could find was an app that only worked in Win XP. There were other apps (Nirsoft has some good ones) that monitor all the WiFi APs within range, but nothing else quite like what I have described above.
...Another reasonably cost effective thing to try would be replacing the antenna on the router with a higher gain omni-directional.
Or try a beer can.
Yes, I already have a design in mind using some cardboard and ally foil. It will certainly affect the signal quality/strength and probably therefore the mbps value too. The beer can idea looked dead simple
, but I'm not sure it will fit nicely on the wall-mounted router I am using here. I shall try it anyway.
...i use a TP-LINK device as well, and i find it helpful to set the bandwidth mode to "11n-only", instead of the default "mixed b/g/n mode". of course this is assuming that you don't have any old devices that are still using 802.11 a/b/g...
Yes, I have set it to "11n only", and the router stats show that it can see the MACs for all the devices it needs to support - including a Kindle
(I hadn't known the Kindle supported the 802.11n standard). All the devices (including the Kindle) seem to work just fine.
Oh, and I also tried changing the Wireless Country/Region (which is a bit naughty), in case the transmission strength might vary, but that didn't seem to make any significant difference, so I restored it to my region.