Is it just about having 5 bars?

It's nice to think that if you see 5 bars on your phone you've got the best in mobile coverage for calls, texts and data. But perhaps there is more to it than that?

This video explains why some phones might show just one bar whilst others are showing 5 bars:

So it seems a lot of factors are considered in the the signal bar display, signal strength, noise level, amount of traffic on the frequency, even adjacent bands in operation can have an affect!

Other things that can realise a big difference between the signal shown on handsets is whether the handset is set to, or even capable of using, the boosted 3G or 4 G signal. Particularly with the Cel-Fi GO for Telstra, make sure the 3G/4G setting on your handset matches the setting of 3G or 4G on your Cel-Fi. Make sure also that your handset supports Band 28 (700Mhz, Band 5 850Mhz and Band 3 1800Mhz - Optus and Vodafone repeaters will be different)

Here are some USSD codes that allow you to check the raw signal strength being received:


iOS 10.3.1 and newer


  1. Dial *3001#12345#*
  2. Select “LTE”
  3. Select “Serving Cell Meas” signal strength will be displayed as “RSRP0”


  1. Dial *3001#12345#*
  2. Select “UMTS”
  3. Select “Serving Cell Meas” signal strenght will be displayed as “RSCP0”


iOS versions OLDER than 10.3.1

  1. Dial *3001#12345#*
  2. Hold the Power/Lock button until you see “Slide to power off”. Do not power off, but release the power button.
  3. Hold the Home button until the phone goes back to your home screen. At this time you should now see your raw signal strength instead of bars on the top left of your handset.
  4. To go back to bars, dial *3001#12345#* and tap the home button to Exit Field Test Mode.

Most Android Devices

  1. Go to Apps
  2. Settings
  3. General
  4. About Device
  5. Status
  6. You will find Signal Strength on this screen


  1. Dial *#0011#
  2. The Signal Indicator will be displayed as RI or RSRP.

And to make sense of all the figures you might see, this little table may help figure out if your signal is good, bad or indifferent!

3g-4g Signal Strength Table

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  • Hi Marlene, thank you for letting us know. They do work really we and we’re glad it’s made a good difference to your reception.

    Kevin on
  • Very happy with cell fi booster best buy i have made

    Marlene on

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