Yes, it is possible to convert an HDMI signal to a coaxial cable signal, but with some limitations. Here’s what you need to understand:

• Signal Differences: HDMI carries digital audio and video signals, while coaxial cables traditionally transmit analog video signals. A direct conversion wouldn’t work because of this fundamental difference in signal formats.

• Conversion Method: To bridge this gap, you’ll need an HDMI to coaxial converter which is sometimes called an HDMI modulator. This device essentially converts the digital HDMI signal into an analog format suitable for transmission over a coaxial cable.

• Output Options: These converters typically output the signal on a specific channel on your cable TV system (usually channel 3 or 4). This allows you to connect an HDMI source (like a laptop or game console) to an older TV that might only have coaxial inputs.

• Quality Considerations: The conversion process from digital to analog can introduce some signal quality loss. You might experience a slight decrease in video resolution and picture quality compared to a direct HDMI connection.

• Not a Two-Way Conversion: These converters typically only work in one direction, converting HDMI to coaxial. You cannot use them to convert a coaxial signal back into HDMI.

Here are some additional points to consider:

• Alternatives: If your goal is to connect an HDMI device to a newer TV, consider using an HDMI cable directly. Most modern TVs have multiple HDMI ports.
• Composite Option: In some cases, you might be able to use an HDMI to composite converter instead, which can also work with some older TVs. However, composite video also offers lower quality compared to HDMI.

Overall, HDMI to coaxial converters can be a solution for connecting HDMI devices to older TVs that lack HDMI inputs. However, be aware of the potential signal quality loss and the one-way conversion limitation.