We hope that by now most of us know better than renting a modem from an ISP. Buying your own and using it is almost always an easy way to save money, but even then these pieces of equipment will not last forever. If you’re sitting on an older cable modem and thinking about throwing it in the trash, there may be a way to reconfigure it before it goes to the big desk in the sky. [kc9umr] there is a way to turn these devices into capable spectrum analyzers.
The Spectrum Analyzer feature is a crucial component of cable modems that helps you take advantage of the wide range of spectrum available to them over cable lines. With some of them, it is possible to get direct access to this feature by pointing a browser at it, but apparently some of them have a patch from cable companies to restrict access. If you find one that has not applied this patch, it is possible to access the spectrum analyzer once [kc9umr] Attached several adapters and an antenna to his cable modem, he was able to demonstrate it with great effect.
Although it depends to some extent on luck whether a modem will provide access to this feature or not, for those who do, it seems like a powerful and inexpensive tool. This is agnostic for the platform, so any computer on the network can easily access it and has a wider range than the RTL-SDR. There are some limitations, but the price can’t be beat, which will cost less than $ 50 per piece unless you need two inputs like this analyzer .
Thanks to [Ezra] for a tip!