I managed to install rtl_tcp on TP-Link TL-MR3420 v1 despite it has just 4MB FLASH / 32MB RAM. I did it a some dumb way - installed by using standard opkg install command, that did not end well. Then after reboot got a recommendation to clean up '/usr/bin' where rtl_sdr tools are. I left there just rtl_tcp, rtl_fm and rtl_test. Restarted and it is working.
Tested by using Gqrx client on a pc that is connected by ethernet cable. And I was able to use almost maximal possible sample rate. At sample rate 2400000 it works very well. Just at 2880000 and 3200000 Gqrx start to lag and also I managed to kill rtl_tcp process on the router. That's any way for such old router with rather limited hardware seems very well for me.
I hoped that I will be able to reach the same perfomance by using wifi, because I thought that wifi speed should handle it. But I managed to get stable working with Gqrx just by using sample rate 240000 max 300000 i.e. ten times less.
So the question: do I understood right - that wifi data transfer takes reasonable part of processing resources and therefore limiting rtl_tcp performance (while cable transfer not)?
Or there are some possibilities to tune it? F.ex. by changing rtl_tcp parameters ( i.e. -b number of buffers and -l length of single buffer)...
Gqrx has the ability to change the rate, etc. of the rtl_tcp service.
Yes. That's already clear. And that I am already doing by changing sample rate of Gqrx settings.
Yes edit the settings; but are you actually experiencing an issue?
Did you mean Settings of rtl_tcp on the router or Gqrx?
I am not experiencing an issue but want to understand better how the router with openwrt and rtl_tcp is working - and why the same connection to rtl_tcp by wireless cause much more load than cable connection. But this a bit explain:
Routing/firewalling will also cause CPUs to be used, so wired doesn't solve everything necessarily.
Currently my router is linked into a local network as WDS client only (no master AP is set up). And I am connecting to it from another router AP.
Probably I'll make a test to connect by wifi to rtl_tcp router directly...