There are a number of ways to improve cellular coverage using antennas. Not all options can support all network operators, and not all options will fit everybody’s budget. Also, some of these may simply not work (at all) for a particular setup, so it’s always good to review with the equipment supplier or technician in making sure the proposed fix is a suitable option and not just a money making scheme 🙂

The GO range of repeaters

Cel-Fi (or Telstra) GO
There is a lot of online discussion about the Cel-Fi GO. It’s also referred to as as the Telstra GO when bought direct through Telstra. In this blog I’ll refer to the unit simply as the GO.

The GO is an approved and very effective signal booster. It requires an outdoor antenna such a Yagi and a smaller indoor antenna. This indoor antenna could often be a wall-mounted panel or a ceiling mounted dome antenna, but that really depends on the type of installation.
The antenna and cable selections can be quite overwhelming. It can be as simple or complicated as you want it to be.
Although it’s often important to make sure the best antenna and cable combination is recommended, there certainly comes a point where the focus should be less on the near-perfect cable / antenna options and more pragmatic and realise the fact that the GO can offer up to 100dB system gain. This is a huge advantage over having nothing at all and will improve Telstra coverage signficantly. The GO boosts both traditional voice and the nowadays more commonly used data services, for all devices within range of the indoor antenna.

Vodafone has recently (early 2019) also announced approval for the Cel-Fi GO. Customers are now able to buy a Cel-Fi GO booster solution for both Telstra and Vodafone networks. However, the each network solution only solves the network for that particular network operator, so trying to do it for each operator will require multiple units. Should an end-user want an Optus booster at the moment, the compact GO is not an option yet and one will need to go for the older and slightly more expensive Cel-Fi Pro units.

Passive Repeaters
There are many online ideas for passive repeater systems. In essence, the concept is to have a high gain outdoor antenna and a decent (high preferred) gain antenna indoors as well, with a low-loss cable in-between the two antennas.

A typical phone cradle

A very relevant example where this type of arrangement is used can be found in cradles used in vehicle systems. The outdoor antenna would be a bull-bar style antenna like in a nice mean 4WD and then the phone is passively coupled via the cradle on the dashboard.

Some suppliers also present a similar idea where a squarish panel antenna is placed on a table. The phone or mobile device can be placed on this antenna lying on its back.
There are online stores here in Australia calling this indoor device a Passive Radiator Pad…simply a panel antenna on the table!
But if it works, then great. The trouble, as with the cradle, is that mobility is compromised. Once the phone or device is removed from the indoor cradle or radiator pad the strong connection is lost and the call could be dropped. The benefit of this passive system would be that it only relies on the frequency characteristics of the two antennas (the indoor and outdoor antennas). If these antennas are well designed and covers the full 4G / LTE frequency band it is completely network operator independent. The passive system does not know nor care who you are with as long as their frequency bands pass through the cable it should work.

The problem with passive systems are that they do need very specific network condition. If the outdoor signal is already too weak, there’s not really anything going to re-radiate on the inside. Also, the losses on the indoor end will most likely overshadow the gains and it may end up not working at all. I have seen and heard a lot of positive feedback from cradles and passive radiator pads, so I accept it’s a workable solution. Unfortunately, to me it feels a bit like a hit-and-miss shot in the dark, and is certainly my least favored option.

Some examples of external antenna connections on 4G / LTE modems and USB adapters

An External Antenna
The last option in this blog requires an external antenna connection into the device. With normal modern-day smartphones this is a genuine problem and somewhat of a technical setback.
Modern phones rarely have external antenna ports so the only realistic useful way to boost the signal are with the previous two methods mentioned. However, older phones, purposely designed rugged phones and common data modems do have external antenna ports and normally benefit greatly from a cable extension and an outdoor placed in a good signal area. It’s a fairly simply yet extremely effective way to improve coverage and get better reliable service from your device. It does, unfortunately, only solve the problem for a single device though. However, if it’s for a modem that transmits an indoor WiFi network this no longer matters. Even phones can then connect to the WiFi network and be online despite no voice coverage. In a modern world where data is starting to be more important than voice, it’s definitely a minor drawback that’s becoming less-and-less of an issue. Also, with applications like Skype and WhatsApp having a data connection is almost as good as having a voice connection anyway!