What is a Cable Modem and TV Amplifier?

Cable Modem and TV amplifiers are designed to boost signals coming from Cable TV/Internet Service Provider. Typically, in a house where Cable Provider provides single input line (in the garage or in a living room), the customer ends up splitting it for multiple devices and multiple rooms.

If you use a regular 2, 4 or a 8 port splitter, the signal level from the Cable Provider degrades and becomes weak.

• If you use a 2- port splitter (1 input and 2 output ports), the signal is reduced by 3.5dB
• If you use a 4-port splitter (1 input and 4 output ports), the signal is reduced by 7dB
• If you use a 8-port splitter (1 input and 8 output ports), the signal is reduced by 11dB

What are effects of lower signal?

Low signal power is not good for cable modems and HD Set top boxes.  You will typically see:

• Pixelation during watching TV on some or most channels
• Reduction in Internet speeds
• High upstream power in Cable Modems causing modems to go offline and constant Internet disconnection

Amplifiers are used to boost existing good signal. If your signal has noise in it, it is best fixed by the ISP outside your house  at the junction node or street node. 

Why not just use a Splitter?

Yes, you could use a splitter in your house to connect multiple devices ( Cable modems, TVs, HD Set top boxes, etc) but you will end up loosing signal power. If your incoming is of good quality and high enough power, you could split it 2 to 4 ways and still accomplish your goal. But for most people it is not true.

What are types of Cable modem and TV amplifiers available in the market?

• Forward Gain Amplifiers: These type of amplifiers typically boost signal in downstream path and with little to no loss in return path
• Return Gain Amplifiers: These type of amplifiers are typically used to boost signals in Upsteam (or return path) in 5-42 MHz frequency range.
• 2-way Active Amplifiers: These type of amplifiers boost both upstream and downstream signals and they are powered by a 12v DC power supply
• Bypass Amplifiers: These type of amplifiers are similar to Forward gain amplifiers (amplify signal in downstream direction) except that they have a bypass port for VoIP/eMTA cable modems so that they can operate in event of power loss.

What are frequency bands of amplifiers?

• Cable Modem Downstream (and Cable TV frequencies) : 54 – 1002 MHz
• Cable Modem Upstream: 5-42 MHz
• There are some amplifiers which support mid-split band (which is 5-85 MHz Upstream and 108 MHz to 1002 MHz in Downstream)