Jo bedre dækningen er hos udbyderen, desto stærkere er mobilsignalet.

It is a correlative comparative structure, equivalent to English the ..., the ....

So:

• Jo bedre dækningen er hos udbyderen, desto stærkere er mobilsignalet.
• literally: The better the coverage is with the provider, the stronger the mobile signal is.

This pattern shows a relationship where a change in one thing is linked to a change in another.

A few more examples:

• Jo mere du øver dig, desto bedre bliver du.
  = The more you practise, the better you get.
• Jo tidligere vi tager afsted, desto mindre trafik er der.
  = The earlier we leave, the less traffic there is.

It is the same written word, but it is being used in a different way.

Danish jo can have several functions. In this sentence, it is part of the fixed comparative pattern jo ..., desto ... and does not mean after all.

So in this sentence, do not interpret jo on its own. Think of the whole structure:

• jo bedre ..., desto stærkere ...
  = the better ..., the stronger ...

Because in this structure, Danish normally puts the comparative adjective first.

So the pattern is:

• Jo + comparative + subject + verb
• Desto + comparative + verb + subject

That gives:

• Jo bedre dækningen er ...
• desto stærkere er mobilsignalet

This is different from a normal main clause like:

• Dækningen er bedre.
  = The coverage is better.

In the jo ..., desto ... construction, the comparative element is fronted.

These are comparative forms of adjectives:

• god / godt → bedre = better
• stærk → stærkere = stronger

So:

• bedre dækning = better coverage
• stærkere signal = stronger signal

Danish comparatives are often formed with -ere, as in:

• stærk → stærkere
• hurtig → hurtigere

But some common adjectives are irregular:

• god → bedre
• dårlig → værre

Dækningen is the definite form: the coverage.

In Danish, the definite form is often added as an ending:

• en dækning = a coverage / coverage
• dækningen = the coverage

Here the sentence is talking about a specific kind of coverage, namely the provider’s network coverage in general, so the definite form sounds natural.

Danish often uses the definite form where English might use either the or no article at all, depending on context.

Here dækning means network coverage or signal coverage.

In mobile-phone contexts, dækning refers to how well a provider’s network reaches a given area.

So:

• god dækning = good coverage
• dårlig dækning = poor coverage

It does not mean a physical cover here.

Here hos udbyderen means something like:

• with the provider
• from the provider
• on the provider’s network

The preposition hos often means at someone’s place or with someone, but in contexts involving companies, doctors, service providers, etc., it can mean with / at / from that provider or institution.

Examples:

• Jeg er kunde hos Telia.
  = I’m a customer with Telia.
• Hun arbejder hos en advokat.
  = She works for/at a lawyer’s office.

So hos udbyderen is idiomatic Danish for with the provider.

Udbyderen is the definite form: the provider.

• en udbyder = a provider
• udbyderen = the provider

The sentence is talking about the relevant provider in a general or contextually known sense, so the definite form is used.

Also, in Danish, definite forms are very common when referring to something understood from the situation.

Udbyder means provider.

In this sentence, it means a company that provides mobile service, such as a phone or network provider.

It comes from the verb at udbyde, meaning to offer or to provide.

So:

• en mobiludbyder = a mobile provider
• internetudbyder = internet provider
• udbyderen = the provider

Because Danish often forms compound nouns as a single word.

So:

• mobil
  • signal → mobilsignal
• mobilsignalet = the mobile signal

This is very common in Danish:

• mobiltelefon = mobile phone
• togstation = train station
• sommerferie = summer holiday

English often writes these as separate words, but Danish usually joins them.

Mobilsignalet specifically means the mobile signal or cell signal.

Using signalet alone would just mean the signal, which is less specific. The compound noun makes it clear that the sentence is about mobile-phone reception.

So:

• signalet = the signal
• mobilsignalet = the mobile signal

Because Danish main clauses follow the verb-second rule.

When something other than the subject comes first, the finite verb usually comes next.

Here, the sentence begins the second clause with the comparative phrase:

• desto stærkere = fronted element

So the verb comes next:

• desto stærkere er mobilsignalet

Instead of:

• mobilsignalet er desto stærkere

This inversion is normal in Danish after a fronted element.

Compare:

• I dag kommer han.
  = Today he is coming.
• Jo mere jeg læser, desto mere forstår jeg.
  = The more I read, the more I understand.

Because each part is a clause with its own subject and verb.

First clause:

• dækningen er ...
• the coverage is ...

Second clause:

• mobilsignalet er ...
• the mobile signal is ...

Even though English also does this, learners sometimes expect one verb to cover the whole structure. In Danish, both clauses are complete, so each has its own er.

Yes, that is possible in modern Danish.

You may hear both:

• Jo bedre dækningen er, jo stærkere er mobilsignalet.
• Jo bedre dækningen er, desto stærkere er mobilsignalet.

Both are correct. Desto can sound a little more formal or traditional to some speakers, but it is still very normal.

So as a learner, you should recognize both patterns:

• jo ..., jo ...
• jo ..., desto ...

Because the sentence has two clauses, and Danish writes a comma between them here:

• Jo bedre dækningen er hos udbyderen, desto stærkere er mobilsignalet.

The comma separates the two linked parts of the comparative construction.

In practice, if you use jo ..., desto ..., you should expect a comma between the two clauses.

Yes. A more straightforward version could be something like:

• Hvis dækningen er bedre hos udbyderen, er mobilsignalet stærkere.

That means roughly:

• If the coverage is better with the provider, the mobile signal is stronger.

But this is not exactly the same nuance. The original jo ..., desto ... construction expresses a proportional relationship more clearly:

• the better X, the stronger Y

So the original version is more elegant and more precise for that meaning.

It is mostly neutral, with a slightly polished feel because of desto.

The vocabulary is standard and natural. In everyday speech, many people might also say:

• Jo bedre dækning der er hos udbyderen, jo stærkere er mobilsignalet.

or even phrase it more loosely in conversation.

But the original sentence is perfectly normal written Danish and would fit well in an explanation, article, advertisement, or informational text.