Model 5352: How can I improve my cable modem/router's wireless throughput?

NOTE: This answer applies to Zoom Cable Modem/Router Model 5352.

1. Especially if you’re in a neighborhood with other wireless routers, use model 5352’s built-in Configuration Manager to set the 802.11 Radio Bandwidth to 20 MHz, NOT 40 MHz. (As an alternative, it should also work to select a Bandwidth of 40 MHz if OBSS Coexistence is Enabled.) To use the built-in Configuration Manager, you need a computer to be connected to Model 5352 either through an Ethernet cable or wirelessly. You open a browser and type in the IP address: http://192.168.0.1  Unless you’ve changed them, the username and password are both admin. Select Wireless on the top menu bar, and the 802.11 Radio page will appear. On that page set Bandwidth to 20 MHz. Click Apply to save the changes.
2. You can also use the Configuration Manager as described above to check that the Control Channel is Auto or another channel with an acceptable interference level.
3. You can try adjusting the antenna positions of the 5352 or whatever is wirelessly connecting to it. At least one of the model 5352 antennas should normally be vertical.
4. You can try putting model 5352 on a metal surface, which increases the effective length of the antennas.

In testing your wireless performance, you can check the download speed by using Speakeasy or one of the other free broadband modem speed testing sites. Speakeasy is at www.speakeasy.net/speedtest/ . You can compare this performance to the performance of something plugged directly into one of Model 5352’s LAN ports.

This How-To Geek article has good information on finding the best Wi-Fi channel for your router:
http://www.howtogeek.com/197268/how-to-find-the-best-wi-fi-channel-for-your-router-on-any-operating-system/