Hope now most of us know not to rent a modem from an Internet service provider. Buying your own equipment and using it is almost always an easy way to save money, but even so, these equipment will not last forever. If you sit on an older cable modem and consider throwing it in the trash can, there may be a way to reuse it before it reaches the big workbench in the sky. [kc9umr] already A way to turn these devices into powerful spectrum analyzers.
The spectrum analyzer function is an important part of cable modems, helping them to utilize the wide spectrum available on the cable line. Some of them can directly access this feature by pointing a browser to it, but apparently some of them have patches from cable companies to restrict access.By finding someone who has not applied this patch, you can access the spectrum analyzer, once [kc9umr] Connecting some adapters and antennas to his cable modem, he was able to prove that it works well.
Although whether any given modem will grant access to this feature depends to some extent on luck, it seems to be a powerful and cheap tool for those who do. It has nothing to do with the platform, so any computer on the network can easily access it, and it has a wider range than RTL-SDR. There are some limitations, but its price is unbeatable, and unless you happen to need two inputs like this analyzer, the parts cost will be less than $50.
thanks [Ezra] tip!