ربما يختبر الفني الإشارة اللاسلكية الآن.

ربما means perhaps / maybe / possibly. In this sentence, it adds uncertainty to the whole idea: the action is not stated as a fact, only as a possibility.

With a present-tense verb like يختبر, it often corresponds well to English may or might, as in might be testing. In other contexts, especially in formal Arabic, ربما can sometimes feel closer to perhaps or even probably, depending on tone and context.

Arabic does not usually need a separate word for is in the present. The imperfect verb يختبر can cover several English meanings, such as:

tests is testing will test

Context tells you which one is meant. Here, الآن (now) makes it clearly ongoing, so يختبر الآن means is testing now. Because of ربما, the whole phrase becomes something like might be testing now.

This is a very common Arabic word order: verb + subject + object.

So in: ربما يختبر الفني الإشارة اللاسلكية الآن

the order is:

• يختبر = verb
• الفني = subject
• الإشارة اللاسلكية = object

This verb-first order is very normal in Modern Standard Arabic. Arabic can also use a subject-first order, but the version here is natural and standard.

Here, الفني is a noun, meaning the technician.

That can confuse learners because فنيّ can also be an adjective in other contexts, meaning something like technical or artistic, depending on context. But in this sentence, it stands alone after the verb and functions as the subject, so it is clearly the technician.

الـ is the Arabic definite article, equivalent to English the.

So:

• الفني = the technician
• الإشارة = the signal
• اللاسلكية = the wireless

In Arabic, if a noun is definite and it has an adjective, the adjective must also be definite. So:

• إشارة لاسلكية = a wireless signal
• الإشارة اللاسلكية = the wireless signal

That is why both words in الإشارة اللاسلكية have الـ.

In Arabic, adjectives normally come after the noun they describe.

So:

• الإشارة = the signal
• اللاسلكية = wireless

Together: الإشارة اللاسلكية = the wireless signal

The adjective is feminine because إشارة is a feminine noun. Arabic adjectives must agree with the noun they describe in:

• gender
• number
• definiteness
• case

So because إشارة is feminine singular and definite, the adjective must also be feminine singular and definite: اللاسلكية.

If fully vowelled, the sentence would be:

رُبَّما يَختَبِرُ الفَنِّيُّ الإشارةَ اللاسلكيةَ الآنَ

The important endings are:

• يختبرُ: the verb in the indicative mood
• الفنيُّ: nominative, because it is the subject
• الإشارةَ: accusative, because it is the direct object
• اللاسلكيةَ: accusative too, because it is the adjective describing the direct object
• الآنَ: an adverb of time, usually in the accusative form

In normal unvowelled writing, these endings are usually not written, but they are still understood grammatically.

الآن means now, and placing it at the end is very natural in Arabic. It works a lot like English sentence-final now.

Yes, it can move, depending on emphasis. For example, different placements can sound more marked or emphasize time more strongly. But the version here is a very neutral, natural way to say it.

So ربما يختبر الفني الإشارة اللاسلكية الآن is a perfectly normal sentence.

Yes. You could also say:

الفني ربما يختبر الإشارة اللاسلكية الآن

That puts more focus on the technician. Both patterns are possible, but the original sentence uses the common verb-first style of formal Arabic, which often sounds more neutral and standard in MSA.