Signal je potreban za mobilne podatke.

• Signal = signal / reception
• je = is
• potreban = needed, necessary, required
• za = for
• mobilne podatke = mobile data

So grammatically, it is literally something like:

• Signal is needed for mobile data.

In everyday English, you might also think of it as:

• You need a signal for mobile data.

Because potreban agrees with signal.

In Serbian, adjectives change form to match the noun’s:

• gender
• number
• case

Here:

• signal is masculine singular
• so the adjective must also be masculine singular
• that gives potreban

Compare:

• Signal je potreban. = The signal is needed.
• Veza je potrebna. = The connection is needed. (veza is feminine)
• Uputstvo je potrebno. = The instructions/manual is needed. (uputstvo is neuter)

So potrebno would not match signal here.

Je is the 3rd person singular present tense of biti = to be.

So:

• signal je potreban = the signal is needed

It links the subject (signal) with the adjective (potreban), just like is in English.

After the preposition za, Serbian usually uses the accusative case when it means for.

The basic dictionary form is:

• mobilni podaci = mobile data

But after za, it changes to accusative:

• za mobilne podatke

So the sentence uses:

• za
  • accusative

That is why you do not see mobilni podaci here.

Because the adjective must match the noun phrase in case and number.

Base form:

• mobilni podaci = nominative plural

After za, the phrase becomes accusative plural:

• mobilne podatke

So both words change:

• mobilni → mobilne
• podaci → podatke

This is normal adjective-noun agreement in Serbian.

In Serbian, data is commonly expressed with the plural noun podaci.

Singular:

• podatak = a piece of data, a datum, a data point

Plural:

• podaci = data

So mobilni podaci literally means mobile data.

This is very normal in Serbian, especially in tech and phone-related language.

In this context, signal usually means phone signal / reception / network signal.

So when Serbian speakers say:

• Nemam signal.

they usually mean:

• I have no signal / no reception.

In your sentence, signal is understood as the network signal needed for mobile data to work.

Yes, it is natural and understandable.

It sounds like a general statement such as:

• Signal je potreban za mobilne podatke.
• You need a signal for mobile data.

A Serbian speaker might also say:

• Za mobilne podatke potreban je signal.
• Potreban je signal za mobilne podatke.

These are all natural, with only slight differences in emphasis.

Yes. Serbian word order is more flexible than English word order.

These are all possible:

• Signal je potreban za mobilne podatke.
• Za mobilne podatke potreban je signal.
• Potreban je signal za mobilne podatke.

The meaning stays basically the same, but the emphasis changes:

• Signal je potreban... puts signal first.
• Za mobilne podatke... puts emphasis on for mobile data.
• Potreban je signal... sounds a bit like What is needed is a signal...

Because Serbian has no articles.

English uses:

• a signal
• the signal

Serbian simply says:

• signal

The exact meaning depends on context.

So signal here could be understood in English as:

• a signal
• the signal
• or just signal in a general sense

That is completely normal in Serbian.

Yes, often you can.

For example:

• Signal je potreban za mobilni internet.

This is also natural and may sound even more everyday in some situations.

Very roughly:

• mobilni podaci = mobile data
• mobilni internet = mobile internet / mobile data connection

In many real-life contexts, they overlap a lot.

Yes. Some common alternatives are:

• neophodan = necessary / essential
• nužan = necessary (a bit more formal or strong in some contexts)

For example:

• Signal je neophodan za mobilne podatke.
• Signal je nužan za mobilne podatke.

But potreban is very common, neutral, and natural.

They might, especially in instructions, explanations, or tech support.

In casual conversation, people might also say things like:

• Treba ti signal za mobilne podatke. = You need a signal for mobile data.
• Bez signala nema mobilnih podataka. = Without signal, there’s no mobile data.
• Moraš imati signal da bi radio mobilni internet. = You need to have signal for mobile internet to work.

So your sentence is correct and natural, but everyday speech may use a few different patterns.