Which NZ Network Has the Best Indoor Reception? What Really Decides Signal Inside Your Home

No single NZ network has the best indoor reception everywhere. Indoor signal depends mostly on how far you are from that network's nearest site, whether it serves your area on the low 700 MHz band, and what your building is made of, so the best network for your home is the one that tests strongest at your address.

One NZ, Spark and 2degrees all run 4G on similar bands, which means the differences come down to local site placement. Here is how to work out which one wins at your place, and what to do if none of them is good enough indoors.

What decides indoor reception?

Three things matter most, and only one of them is the network brand:

• Distance and line of sight to the site. The closer and clearer the path to your network's nearest site, the stronger the signal at your walls.
• The frequency band. Low bands such as 700 MHz travel further and pass through walls much better than high bands. 5G on 3500 MHz is fast but struggles indoors.
• Your building. Corrugated iron, Coloursteel and other metal roofs, foil-backed insulation, double glazing and concrete block walls all absorb signal. A modern, well-insulated home can lose much of the signal that reaches it.

Do all NZ networks use the same bands?

Broadly, yes. All three networks use 4G on 700 MHz and 1800 MHz, and each adds other 4G bands and 5G in some areas. 700 MHz is the one that matters most indoors and in rural areas, because it penetrates buildings and covers long distances. With 3G now closed, calls run on 4G as well, so a strong 4G signal indoors is what you need for both calls and data.

Because the bands overlap, a network with a site 500 metres away will usually beat a network with a site 5 kilometres away, whatever the brand.

How can you tell which network is strongest at your address?

• Check all three coverage maps for your address, looking at indoor coverage. Our guide to NZ coverage maps explains how.
• Ask neighbours with similar houses which network works for them inside.
• Borrow a phone or buy a cheap prepay SIM on another network and compare readings in dBm in the same rooms.
• Test at different times of day, because busy periods can affect data speed.

A difference of 10 dBm or more between networks in the same room is significant. If one network is clearly stronger indoors and switching suits you, that may be the simplest fix.

What if no network is good indoors?

This is common in rural homes, baches, new builds with heavy insulation and buildings with metal roofs. Often all three networks are usable outside, on the deck or at the gate, but none is reliable inside.

That is the situation a mobile signal booster is made for. An outdoor antenna picks up the signal where it is strongest, the booster amplifies it, and an indoor antenna spreads it through the house. Because all three networks share 700 and 1800 MHz, one 700/1800 MHz kit such as the Dual Core Signal Booster V2 can serve a household on different networks. For a larger home, the Dual Plus Signal Booster V2 covers more area.

Do you need signal outside for a booster to work?

Yes. A booster amplifies an existing signal; it cannot create one. One or two steady bars at the roofline or the highest point of the section is usually enough. If there is no signal at all outside, look at Wi-Fi calling or satellite texting instead. Our guide to options when there is no coverage covers both.

For rural properties, see our range of rural signal boosters and our guide to choosing an antenna.

Does your phone make a difference indoors?

Yes, a little. Newer phones generally support more 4G and 5G bands, including 700 MHz, and handle weak signal better than older models. If one person in the house has good reception and another does not on the same network, check that both phones support the bands your network uses and that their software is up to date. Phone cases with metal parts or magnetic mounts can also reduce reception slightly.

Even so, the phone cannot overcome a building that blocks most of the signal. If several people on the same network struggle in the same rooms, the building is the problem, and a booster or a different network is the fix.

What should you do next?

Test all networks you can at your address, note the best readings outside and inside, and decide whether switching or boosting suits you better. If you want to keep your network, our pages for One NZ, Spark and 2degrees list compatible kits. Delivery is free in 5 to 7 working days, and you can return a kit within 30 days.

FAQ

Which NZ network penetrates buildings best?

None by brand. All three use 700 MHz, the band that penetrates best. The nearest site to you matters more.

Is 5G better indoors?

Usually not. High-band 5G is fast but weakens quickly through walls. 4G on 700 MHz is more reliable indoors.

Why is my signal fine outside but bad inside?

Building materials such as metal roofs, insulation and double glazing absorb signal.

Can one booster cover people on different networks?

Yes, a 700/1800 MHz kit covers the shared 4G bands of all three networks.

Tell us your address and which networks you tested, and we will suggest the right kit. Try the booster finder

Signed: Mobile Booster NZ