How much cable and signal does a Bunbury TV antenna need?
A typical three-TV Bunbury house needs about 40 to 55 metres of quad shield RG6, one antenna, a four way splitter and, on a good share of the blocks we attend, a masthead amplifier of 12 to 18 dB. Measure every run along its real path, add 10 percent plus 2 metres of service loop, and check that the worst outlet still lands between 50 and 70 dB microvolts. The estimator below sizes the job first, then prices it.
Size your antenna system
Move the sliders to see the quantity you need, then the price range that quantity implies. This answers how much and how many. For what a finished job costs line by line, use the 2026 price list.
What this estimate assumes
- Assumes quad shield RG6 with a UV stable sheath, compression F connectors with gel boots, and an earth bond to AS 1417 on the mast.
- Includes the antenna, the mounting hardware, aiming with a meter at the antenna, the cable run, the outlets, and a retune of every set in the house.
- Excludes roof repairs, replacement tiles beyond two or three, satellite equipment, data or network cabling, and any mains electrical work.
- Assumes reasonable roof access with a clear side path and a usable roof space manhole.
- Coastal multipliers reflect marine grade hardware, not extra labour. The salt is the reason the parts cost more, not the roof.
- This is a 2026 guide for the Bunbury area only. A firm price needs a measure and a look at the actual cable path.
How to measure it properly with a tape and a phone
Ten minutes of measuring at ground level gets a quote within about ten percent, and it means nobody has to climb anything to price your job.
- Measure along the path, not across the plan. Cable follows battens, goes over hips and turns corners. The straight line from the lounge to the manhole is not the route the cable takes. As a working rule, the roof space leg is about 1.5 times the floor plan distance between the two points.
- Do the vertical legs from known heights. From a single-storey eave down to a ground floor wall plate is usually 3 to 4 metres. On a double-storey it is 6 to 7. From the antenna head down to the eave is typically 2 to 4 metres depending on the mast.
- Pace it if you have no tape. An adult stride is close to 0.75 metres, so pacing a run and multiplying by 0.75 will get you within a couple of metres, which is close enough for a quote.
- Take four photos. The antenna from the ground with the camera zoomed in, the existing wall plate, the eave where the cable enters, and the roof space from the manhole. Those four images and your measurements are enough for us to size a job without attending, which saves you a visit.
- Use the compass and level apps you already have. The compass will tell you which way the existing antenna faces, and every other antenna in your street is pointed at the same transmitter, so the row of roofs down the road is a better reference than any bearing you can guess at. The level app will tell you whether the mast has drifted out of plumb, which is a common cause of a slowly worsening picture.
- Count the outlets you actually want, not the ones you have. If a bedroom TV has not been switched on in two years, do not pay to run a point to it. If the alfresco is getting a screen next summer, run it now while the roof space is open.
Measured it up? Send us the numbers.
Give us your metres, your outlet count and four photos, and we will send a fixed price without needing to visit first.
Rules of thumb, wastage and the safety allowance
These are the numbers we work to on every job. They are worth writing on the back of your measurements.
- Cable wastage: add 10 percent, minimum 3 metres. Cable gets cut short at a plate, a route changes when a purlin is in the way, and a connector gets remade. Running out mid job costs a second visit.
- Service loop: 1.5 to 2 metres at the antenna, 300 millimetres at every plate. The loop at the antenna is what lets a future technician re-terminate a corroded connector without pulling a whole new run. On this coast that is not optional, it is the difference between a $150 repair and a $450 one.
- Round up to a standard roll. Coax comes in standard drum lengths. If you have measured 48 metres, buy the 50 metre roll rather than two short ones joined in the roof space, because every join is another point for water and loss.
- Cable loss: about 0.2 dB per metre at UHF, about half that at VHF. A 40 metre run therefore costs roughly 8 dB at UHF before anything else touches the signal.
- Splitter loss: about 3.5 dB for a two way, 7 dB for a four way, 9.5 dB for a six way and 11 dB for an eight way. Every doubling of outlets costs another 3.5 dB or so.
- Target level: about 50 to 70 dB microvolts at the wall plate, with a modulation error ratio above 25 dB. Below roughly 45 the picture breaks up. Above roughly 80 the tuner overloads and the picture breaks up in a way that looks identical, which is the trap.
- Amplifier gain: match your losses, do not maximise the number. Losses of 15 dB call for a 15 to 18 dB masthead amplifier. A 30 dB amplifier on the same system will push the strong multiplexes into overload while doing nothing useful for the weak ones.
| Where the signal goes | Typical loss | What that means in practice |
|---|---|---|
| Quad shield RG6, per metre at UHF | about 0.2 dB | A 45 m run costs about 9 dB, which is more than most splitters |
| RG59, per metre at UHF | close to double | The single biggest reason an old builder install fails at the far outlet |
| Two way splitter | about 3.5 dB | Cheap in signal terms, and the right default for two sets |
| Four way splitter | about 7 dB | Usually the point at which a masthead amplifier starts to earn its place |
| Eight way splitter | about 11 dB | Needs a distribution amplifier, not a bigger antenna |
| Each connector pair and wall plate | a few tenths of a dB | Small individually, but four sloppy joins add up to a full splitter |
A worked example on a typical Australind house
The house: a four bedroom brick and tile in Australind, single storey, antenna on the north-east gable, three outlets wanted plus the existing lounge point, roughly one kilometre from the estuary.
Adding up the cable. Antenna head to the eave, 3 metres. Down the wall and in through the sealed entry, 4 metres. Roof space to the lounge plate, 14 metres. Roof space to bedroom one, 9 metres. Roof space to the theatre room, 11 metres. That is 41 metres of actual path. Add 10 percent for wastage, which is 4.1 metres. Add a 2 metre service loop at the antenna and 300 millimetres at each of the three new plates, which is another 2.9 metres. Total to order: 48 metres, so buy the 50 metre roll.
Adding up the signal on the worst path. The longest run is antenna to theatre room: 3 plus 4 plus 11, so 18 metres. The antenna delivers about 62 dB microvolts at the head on that block. Cable loss is 18 metres at 0.2 dB, so 3.6 dB. The four way splitter takes about 7 dB. Connectors and the plate take about 1 dB. The theatre outlet therefore sits near 50 dB microvolts, right at the bottom of the comfortable band, which is where evening dropouts come from when a neighbour’s new shed or a growing tree takes another two decibels off the path.
The fix, and the size of it. A 12 dB masthead amplifier lifts the worst outlet to about 62 and the best to about 68, so every set sits inside the comfortable band and nothing is anywhere near overload. A 25 or 30 dB amplifier on the same system would push the strong multiplexes past 80 and cause exactly the fault it was bought to cure.
The money. Antenna and installation around $330, 48 metres of fitted quad shield at $4 to $8 per metre, three extra outlets at $70 to $130 each on the same visit, and a masthead amplifier with its injector at $150 to $240. The estimator above returns roughly $800 to $1,500 for those inputs, and an itemised quote on this house lands in the middle of that range. The spread is what a site measure removes.
The sizing mistakes that cost the most in Bunbury
- Over-amplification, by a distance. More gain feels like the safe choice and it is the most expensive mistake on this list. A tuner fed above roughly 80 dB microvolts breaks up exactly like a tuner fed below 45, so the owner buys a bigger amplifier, makes it worse, and concludes the antenna is faulty. Losses first, then gain to match. Never the other way around.
- Sizing the splitter for today. A four way splitter costs a few dollars more than a two way and leaves you a capped spare output. Replacing a two way with a four way in two years means a technician back in the roof space, and that is a callout rather than a component.
- Buying cable by the straight line. Somebody measures 12 metres across the floor plan, buys 15 metres, and the real path turns out to be 20. The job stops, or worse, a join goes into the roof space where nobody will ever find it when it corrodes.
- Mounting the antenna too low to save on mast. On the flatter blocks around Eaton and Withers, lifting the antenna 600 millimetres clear of a ridge line frequently buys more usable signal than several decibels of extra antenna gain would, and a longer mast costs $40 to $90. Height is the cheapest gain there is.
- Ignoring mobile network interference. Where an old install still uses thin single braid cable near a mobile tower, signal from the mobile bands leaks in and swamps the top of the UHF range. The fix is a filter at $40 to $110 and proper quad shield cable, not more gain. The symptom list is on the bad signal page.
When more cable and more gain are the wrong answer
If one outlet drops out and every other set in the house is perfect, the fault is downstream of the splitter and no amount of extra cable, extra gain or a bigger antenna will change it. That is a connector, a plate or one bad leg, and it is a $130 to $280 repair rather than a new system. Equally, if you have four TVs and two of them have not been switched on since the last election, do not pay to run and terminate four points. We would rather cap a spare output on the splitter and leave you the option than bill you for outlets nobody uses.
We also do not run data or network cabling, and we do not install satellite dishes, so if the real answer to your coverage problem is either of those, we will say so instead of quoting for it. For the hardware grade that suits your street, see choosing an antenna for coastal Bunbury. For the money side, the budget install page breaks the three tiers apart. For what the day itself looks like once the sizing is agreed, see installation day stage by stage, and for the cover on the finished job, the warranty page.
Send your measurements and get a fixed price
Give us the metres, the outlet count and four photos and we will reply within one business day with a fixed price, usually without needing to visit first.
Sizing questions
How many metres of coax does a typical Bunbury house need?
How much signal do I actually need at the TV?
How much signal does a splitter cost me?
How do I measure a cable run without going on the roof?
What size amplifier do I need?
Is it cheaper to run four points now or add them later?
Get the quantities checked on site, free
We meter the signal, measure the real cable path and put a fixed price in writing. Bunbury, Australind, Eaton, Dalyellup, Gelorup and Withers.