Quick Answer: Two different products hide behind the phrase. An Ethernet-over-coax extender pair puts an IP link on 75 ohm RG6 and gives 100 Mbit/s to about 1,600 ft (490 m), or 1 Gbit/s to about 1,000 ft (300 m), at under 2 ms of latency. An IP encoder and decoder pair turns HDMI into a compressed stream and adds 60 to 200 ms. Baseband parts suit cameras and control traffic; encoders suit signage where a delay is acceptable. Neither works through a live splitter or an amplifier.
Re-using existing coax saves the cost of pulling cable, and the saving only holds if the copper is continuous and sweep tested. Whether the job needs 100 Mbit/s or a compressed video stream is the first decision, because the two answers use different hardware, different latency budgets and different cabling rules.
What the coax can actually carry
RG6 is a 75 ohm line with a copper-clad steel or copper centre conductor of 18 AWG, a foam dielectric and a foil-plus-braid screen. Loss rises with frequency: roughly 1.5 dB per 100 ft (30 m) at 55 MHz and about 6 dB per 100 ft at 1 GHz. An extender has to work inside that budget, which is why reach drops as the bit rate rises.
The screen is the return path, not a spare wire, so the impedance must be continuous from end to end. A 75 ohm cable terminated with a 50 ohm F connector, or a corroded splitter left in line, produces reflections that a link will read as packet loss rather than as an obvious fault.
Three device classes, three different jobs
Ethernet-over-coax extenders
A powered pair presents a normal Ethernet port at each end and modulates that traffic onto the coax. One unit is usually powered at the head end and the far unit by the same pair, which removes a socket at the camera. Expect 100 Mbit/s over 1,600 ft (490 m) and 1 Gbit/s over 1,000 ft (300 m); check the datasheet rather than assuming, because the two rates rarely coexist at full reach.
IP encoders and decoders
These compress HDMI into H.264 or H.265 and send it as a normal multicast stream, so the coax is only carrying Ethernet from an extender or a media converter. Latency runs 60 to 200 ms, which is fine for signage and unusable for a presenter tracking a cursor. Resolution and frame rate are negotiated at the encoder, not by the display.
RF modulators
An HDMI-to-RF modulator places the source on a single 6 MHz channel so any television can tune to it with no receiver box. Reach is limited by the distribution amplifier, not by the cable, and every screen shows the same picture at the same quality. This is the cheapest way to feed many displays with one source.
Comparing the four paths
| Path | Throughput | Latency | Reach on RG6 | Right job |
|---|
| Passive balun pair | 10-100 Mbit/s | Under 1 ms | 100 ft (30 m) | One camera |
| EOC pair, 100 Mbit/s | 100 Mbit/s | Under 2 ms | 1,600 ft (490 m) | Legacy coax re-use |
| EOC pair, gigabit | 1 Gbit/s | Under 2 ms | 1,000 ft (300 m) | Point-to-point LAN |
| Encoder and decoder | 20-100 Mbit/s stream | 60-200 ms | Through a switch | Digital signage |
| RF modulator | One 6 MHz channel | Under 5 ms | Whole building | Many TVs, one feed |
Cable and connector rules
Use quad-shield RG6 for anything run in a wall, and confirm the jacket carries a CL2 or CMR rating before it goes into a stud bay. Compression F connectors with a square-cut dielectric hold 75 ohm geometry far better than twist-on types, and they survive the pull that a cable tie will not. A full sweep to 1 GHz takes ten minutes and finds the crushed section before the hardware is ordered.
Never leave a passive splitter or a distribution amplifier in a data path. Splitters divide power and create a stub that reflects energy, and an amplifier will saturate on a modulated carrier. If the same coax must serve television and data, plan for a dedicated home run rather than a shared tap.
Connector choice and cable choice are separate decisions: read the rg6 75 ohm coax figures for loss at the frequency your device uses, then match the connector to the centre conductor diameter. For a single link, the swept performance of the digital coax run decides whether the link trains at all, and a hdmi coax modulator hdmi path only works when the RF plan leaves a clear channel.
Practical scenarios
- Situation: A warehouse with RG6 already pulled to eight camera positions. Fit 100 Mbit/s extender pairs and keep every run under 1,600 ft (490 m) with no splitter in line.
- Situation: A lobby screen fed from a rack 250 ft (76 m) away. Use an encoder and decoder over the existing switch and accept 80 ms of delay; a baseband kit would need a dedicated run.
- Situation: A bar with six televisions and one game feed. Choose an RF modulator on a clear 6 MHz channel and split the RF output, not the data path.
- Situation: A 300 ft (90 m) run measured at 9 dB loss at 1 GHz. Replace the two twist-on connectors and the corroded splitter before assuming the extender is faulty.
FAQ
Can an extender share coax with cable television?
Rarely, and only with hardware designed to place its carrier above the television band. Most pairs occupy the same spectrum and will fight the signal. A dedicated home run is the reliable answer.
How much delay does a compressed stream add?
Between 60 and 200 ms depending on the codec and the group of pictures setting. H.265 at low bit rate costs more delay than H.264. Any application with a cursor or a live operator needs a baseband path instead.
Does RG59 work?
It will carry a 100 Mbit/s link over short distances, but its smaller centre conductor and higher loss cut reach by roughly half against RG6. Use it only where the run is under 300 ft (90 m) and already installed.
