How To Convert Coax Cable to HDMI

JamieRead moreMay 30, 2021

Updated: 05/30/2021

If you buy a new TV, chances are it won't have a coax connector. It may have several HDMI, USB, and component connectors but no coax. If you have an older cable or satellite box that only outputs coax, you could have trouble connecting the two.

You may think that coax is a bit outdated, but there are plenty of excellent devices out there that we still use today. Whether you still use that old VHS player or an older game console or perhaps you’re using an antenna, there are plenty of options available for you. In this article, we’ll walk you through the options to make your older tech compatible with your newer devices.

While it may seem an obvious oversight to some of you, not fully considering the output of the receiver is an easy oversight. For many years coax was the default output and has only recently been fully superseded by SCART or HDMI. Many cable and satellite receivers came with coax, SCART, and HDMI. Few were purely coax.

Coaxial cable was invented sometime in the 19th century to carry radio signals. It is comprised of a copper core of two layers surrounded by insulation and shielding. The idea was to deliver analog signals with a minimum of interference. The technology was in use until recently, first in radio and telegraphy, then TV and then broadband. It was gradually replaced with fiber or other technologies that offered faster transmission speeds.

Even though coax is insulated, the signal needs frequent repeating and is subject to data loss over distance. Coax was popular because it was superior to anything else at the time, was cheap and easy to use. It was also very durable. Fiber is faster and can carry more data at once. Though fiber requires more upfront investment, it requires less maintenance.

HDMI, or High-Definition Multimedia Interface is the modern replacement for coax in the home. It is used to carry signals between devices with the maximum amount of data possible for high definition or ultra-high-definition broadcasts. It can carry audio too. HDMI was invented by Japanese TV manufacturers to help improve picture quality and works exceptionally well.

HDMI is purely digital and is therefore insulated against loss and does not need frequent repeating over distance. It can carry more data further for the same size at higher speeds. Digital transmissions are immune to interference when the correct configuration is used so it is very useful in busy households with lots of devices and WiFi networks.

There are a couple of ways you can convert your Coax to HDMI and vise versa. Depending on the devices you’re trying to connect, one option may work better than another. Either way, it will take some upgraded equipment to get everything hooked up and working properly. However, your equipment needs depend on the devices you want to connect. Let's break it down.

For those of you who have indoor/outdoor antennas with coax and no coax input on your TV, you need a simple OTA coax to HDMI adapter, which costs anywhere between $30-$50. The price is low because no major conversion components are required since air signals are not encrypted like cable TV.

Depending on your cable provider, if the receiver has only a coax output, it is due for replacement. You may also need a converter if the RCA outputs on your satellite or cable box failed. Not including SCART or any HDMI output means your satellite/cable box could be anything up to 25 years old and should be replaced. However, if it is working fine or your service provider wants to charge you for an upgrade, it might not be your best option.

The satellite or cable TV coax-to-HDMI converter must include demodulation, which brings the price up to over $100. Coax TV signals use radio frequency (RF) modulation that outputs to channel 3 or 4 on your TV. Also, cable boxes and satellite dishes use encrypted signals that pass through the coax. Therefore, the converter must have decryption technology too. This type of coax to HDMI converter is hard to find, especially with all the similar options out there that don't work for your needs. Just look for a cable TV coax demodulator to HDMI converter.

VCRs and older game consoles did not use HDMI outputs because they didn't exist. Therefore, you need an RCA or NTSC coax-to-HDMI converter. However, it needs a demodulator to convert the RF signal to HDMI out. That scenario means you need one of the same $100+ converters used for cable TV coax to HDMI.

If you’re unable to obtain updated devices with an HDMI to HDMI connection, use these steps to complete the conversion from coax to HDMI.

Whether you need an OTA antenna coax to HDMI converter or a cable TV/satellite demodulator to HDMI converter, the process above is the same.

Aside from the nostalgia users get from seeing those brightly colored coaxial connectors, the everyday user will benefit from making the transition from coax to HDMI. The latter provides a stronger and faster connection making both the video and audio quality better. HDMI cables also require only one connection as opposed to two or more with coax, so they’re easier to use and more visually appealing.

Yes, some TV antenna equipment still use the cables to this day. For those who have cut the cord but still want their local channels, coax cables are still a part of everyday life and therefore, you’ll need a converter to enjoy network content on your TV.

Now, you can get an HDMI to coax adapter if you need to go from an HDMI out to a TV with coax input, but the other way is rather challenging.

What you need is a demodulator (coax demodulator to HDMI.) The item below is around $115.https://amzn.to/3vBKdet

The reason you need demodulation is that you require an already-converted and decrypted A/V out that passes to the HDMI. You cannot send RF modulation through HDMI.

This item below may only cost around $30, but it won't work, so don't waste your money. Why? The item listed below is designed to receive over-the-air (OTA) coax signals that are "unencrypted" whereas cable uses an encrypted signal.https://amzn.to/3yN1vHr

A demodulator (the $115 one) takes in the cable box's modulated signal (coax) and demodulates it for HDMI out. The demodulation occurs just before the HDMI out because its tuner needs modulation to use channel 3 or 4 to receive the cable signal. Just set the channel to 3 or 4 on the demodulator box so it can receive the cable box signal. It then sends an HDMI-out signal.

If you want more confusion, an HDTV with "coax in" receives the modulated cable box signal and decrypts it but still leaves it modulated. It doesn't need to demodulate because it connects directly to the TV and uses channel 3 or 4.

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