4g low signal or 3G high signal

[Stang_]

Hi everyone,

I have just got a new SIM card and it’s behaving strangely - HELP!

When it’s on 3g, it has high mobile signal (4-5 bars) but when it’s on 4g it has low signal (0-1 bars). I have manually toggle the network mode of the SIM between 4g and 3G and able to replicate the issue, but can’t solve it.

I have tested the SIM on multiple phones, it seems to work on phones with 5G giving me both 5G and strong mobile signal but on 4g only phones, I have the same issue.

I have changed the APN settings and of course have tried removing the SIM, putting it back in and, oh yeah, I turned my phone(s) on and off too - the classic but didn’t solve the issue sadly.

Any ideas please?

[MarkD]

Hi @Stang_, when you say you've got a new SIM Card, is this for a new service or did we send you a replacement SIM for an existing service? What phone are you currently using and what devices have you tried the SIM Card in? Also, if you enter your full postcode in our Network Status Checker here, is anything affecting the 4G in the area? 

[Stang_]

@MarkD Hi - I’ve been with Vodafone for 5 years or so on the same service, same SIM, then recently got a new SIM through VOXI for a new service. I’ve tested it on a Samsung A9, Iphone 11 (both 4g only), then on 5g phone - Samsung S10 and IPhone 13.

Tried the coverage checker and nothing is affecting it. I travel for work and the same happens around the UK. Had a replacement SIM too and no change.

[Amanda]

Thanks for getting back to us and letting us know @Stang_ - so we can check your settings and also see how your SIM's updating on the network, please come and chat to us on social media 🙂

[Stang_]

@Amanda Hi, I have been through online chat through both VOXI and Vodafone to no avail, is your social media team any different? Al I was asked to do is check the APN settings, which was already correct, and asked to take the sim card in and out then restart my phone. Obviously didnt work...

[Amanda]

We're a separate team @Stang_ - if you include a link to your community post, you won't need to repeat yourself either 🙂

[HelpfulBadger]

It's quite normal for 4G to be weaker than 3G - I might be getting the numbers wrong but 3G has a range of around 15 miles, whereas 4G has a range of around 8 miles.

The fact that the signal strength changes with the device you're using is also quite normal, as they will (for the most part) all use different hardware and have their antennas in different places etc. And it may well be that if you're not seeing much of a signal change between 4G and 3G on one device that even though you've told it to only use one, it just isn't (the same as the old story when iPhones were connected to WiFi they still chewed through mobile data)

[Stang_]

@HelpfulBadger Hi - totally get that 4g/3G signal strength is different and different phones gets different signal strength.

What’s new to me is that when the mobile signal changes from 5 bar to 1 bar, the SIM switches between 4g/3G or vice versa, I’m not sure which one is setting off the other. Both signal have been quite independent from my experience so far and the two haven’t affected each other on my old SIM.