Hey Alexey!

 AV> Alas, that's not possible in the large cities... :-/

It is possible but it is considered to be extremely bad behavior despite the
fact that certain commercial routers are doing just that - forcing 40MHz.  For
the record I live in a rural setting but still have to force it since there are
other wireless routers within range of the high power dongles I am deploying. 
Forcing 40MHz only works on an open mesh setup.

 AV> I have two unbeatable 0bda:8187 RTL8187 dongles for that purpose.

I never got mesh to work with those.  I don't have any at the moment but a
neighbour does if push comes to shove for testing purposes.  However doing a
search I don't see any available for purchace so I would tend to call them
abandonware.  I do see newer generation Realteks everywhere and then some.

 AV> I had my first dedicated connection over the WiFi at 64 kbps

It looks to me that things haven't improved that much since then.  As of this
writing the open mesh setup wins and I did manage to get 300N between a TP-Link
WDN4800 pcie card and TL-WN821N usb dongle using the open mesh setup but the
range isn't nearly what is needed here.  For now I am going to have to stick
with the hostapd setup using the 148f:3070 RT3070 outdoor antenna just to keep
a couple of the neighbours' so-called smart devices connected to the outside
world.  They have been getting decent speeds using that setup and the range is
good but we're stuck using 2.4GHz@20MHz which is okay all things considered.

 AV> I think it would make sense to establish the direct link

If you mean wired I have a regular Gbit network connection between them. 
Neither of them needs wireless but they are good for testing ideas so that
explains what I posted in the way of specs.  None of my neighbours can handle
such things as they are stuck with their crippleware devices such as
smartphones and tablets.  I honestly don't see the attraction of those.  Oh
well.

Anyhow I can hosestly say I gave it my best without having to resort to hacking
an unneeded wireless router.  I seriously doubt the results would have been
better especially when it comes to effective range/distance.  Also I think mesh
is the way to go but as of this writing that would mean the neighbours would
have to get better toys.  ;-)

Life is good,
Maurice

... Don't cry for me I have vi.
--- GNU bash, version 4.4.12(1)-release (x86_64-unknown-linux-gnu)