This is why you dont use unauthorized mobile signal booster

Forums › New Zealand Mobile and Wireless › This is why you dont use unauthorized mobile signal booster

BioNz

46 posts

Geek

# 257104 15-Sep-2019 15:02

4 people support this post

hi.

this is just a quick post to say dont go out and buy a cheap mobile signal booster from places like trademe or aliexpress or even mobilesignalbooster.co.nz

the ones on there are mostly unathorized units that can and do go faulty causing a headache for people like me who have to track the down and ask you to please turn the device off and not to turn it back on due to the interference it is causing to the networks.

what does the interference look like?

places like mobilesignalbooster.co.nz give the look that they are selling approved units but they are in no way approved for use in nz and they wont.

the only approved one for people to buy are the cel fi units from powertech. they are a great product and are so easy to install. any questions im happy to help out.

save me the trouble dont waste your money on the cheap ones.

this post is more about education more than anything.

Bung

2998 posts

Uber Geek

# 2318133 15-Sep-2019 15:32

One person supports this post

"mobilesignalbooster.co.nz give the look that they are selling approved units but they are in no way approved for use in nz and they wont. "

They claim to have been around for over 10 years and have 1000s of satisfied customers. Is it that hard to shut down the supply of unapproved equipment?

alasta

4386 posts

Uber Geek

Trusted

Subscriber

# 2318134 15-Sep-2019 15:33

One person supports this post

I am assuming that when these things cause interference on the telco's network you can trace the source and report it to MBIE for enforcement?

What happens if one of them is not interfering with the telco's network but causing other problems for nearby residents, for example interference with radio/TV or wifi reception? Presumably the neighbouring residents would have no idea of the source of the problem and therefore no enforcement would occur.

There really needs to be a crackdown on the people who are selling them, otherwise the genie is out of the bottle.

Linux

5410 posts

Uber Geek

Trusted

Lifetime subscriber

# 2318145 15-Sep-2019 16:08

One person supports this post

US uniden cordless phones do the same thing thing in the 2100Mhz band

hio77

'That VDSL Cat'
11034 posts

Uber Geek

Trusted

Spark

Subscriber

# 2318151 15-Sep-2019 16:40

One person supports this post

Great Post. I think the one thing missing though is how it translates real world.

I could see non techys not quite understanding the graph.
Maybe put it in terms of 5g rf radiations?

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

sbiddle

28270 posts

Uber Geek

Moderator

Trusted

Biddle Corp

Lifetime subscriber

# 2318172 15-Sep-2019 17:51

Linux: US uniden cordless phones do the same thing thing in the 2100Mhz band

The US uses different frequencies for its DECT handsets than anywhere else in the world.

BioNz

46 posts

Geek

# 2318190 15-Sep-2019 18:59

3 people support this post

what your seeing in the graph is from a spectrum analyzer we use in the field to hunt down the interference. the way 3g and most 4g in nz works is what is known as FDD - frequency division duplex( this is when the transmit and receive are is 2 different frequency allocations. when the rx has an interfering signal on it the cell tower/base station will send more time trying to process this signal as it thinks its a cell phone trying to communicate with it. this causes the other phones in the area to wait. this split sec of waiting is really all it needs for a dropped call to happen or when the phone goes to voice mail/ delayed txt mgs / slower than normal data speeds

as you can see this is a freq grab from a 850mhz network and it has 2 lines on it. one is in real time(a) the other is max hold (b) this is showing the interfering signal at the high end of the band. this in a way is taking out of service this band.depending on how the operator has set up the band will depend on where the signal is sitting ( eg how wide the band is be it 2mhz,5mhz etc wide)

if the conditions are right a faulty mobile signal booster can be picked up a long way away ( had over 30kms before)

we find a lot of faulty old tv signal boosters in winter and the dect phones are a real pain as well as baby monitors from asia

Handle9

2520 posts

Uber Geek

Trusted

Subscriber

# 2318221 15-Sep-2019 20:21

One person supports this post

Bung: "mobilesignalbooster.co.nz give the look that they are selling approved units but they are in no way approved for use in nz and they wont. "

They claim to have been around for over 10 years and have 1000s of satisfied customers. Is it that hard to shut down the supply of unapproved equipment?

How would you suggest RSM in NZ shutdown an overseas company? If it can't be done for weapons or drugs it sure can't be done for a signal booster.

Bung

2998 posts

Uber Geek

# 2318231 15-Sep-2019 21:07

Sorry, hadn't realised it was an overseas company. NZ Customs already have dog tracking collars, high power laser pointers and radio jammers on the prohibited import list. Mobile boosters seem to be in a similar class.

BioNz

46 posts

Geek

# 2318236 15-Sep-2019 21:20

a mobile booster in simple terms is not illegal. its the operating on the band with an unauthorized device thats the issue. the networks have what is called a non interference licence with their management rights and that means that they get to say who and what is ok to transmit on the freq bands they have spent a lot of money on.

the celfi are the only ones approved for consumer install etc but there are others that are used from different companies. all of these ones have network safety protection built in. if the device goes faulty it will shut down. in the higher end celfi units they will send for help.

gareth41

627 posts

Ultimate Geek

# 2320240 19-Sep-2019 11:36

BioNz:

a mobile booster in simple terms is not illegal. its the operating on the band with an unauthorized device thats the issue. the networks have what is called a non interference licence with their management rights and that means that they get to say who and what is ok to transmit on the freq bands they have spent a lot of money on.

the celfi are the only ones approved for consumer install etc but there are others that are used from different companies. all of these ones have network safety protection built in. if the device goes faulty it will shut down. in the higher end celfi units they will send for help.

I'm interested to know the occupied bandwidth on that carrier - any spurs around the carrier and offset?, possibly also the phase noise if you were able to measure it. I suspect there will be in band spurs due to the cheap components the Chinese use in these things. I suspect they're probably using a low grade DDS synthesizer or VCO and then picking off its harmonics to get the higher carrier frequency, then amplifying this while attempting to filter out all the other stuff lower down the band. A DDS also has a lot of nyquist products that *need* to be filtered out, another thing which I suspect they probably have paid little attention to.