Where are instructions to assemble a new expansion module?

Please check this online article.

Can I fit any Expansion Module in any RF Explorer model?

Yes, both firmware and hardware are ready to work with any combination.

For instance, you can enhance a wideband RF Explorer WSUB1G with a RFEM24G module to get access to 2.4GHz band as well as 240-960 MHz band. The exact same functionality is available if you enhance a RF Explorer 2.4GHz with a REFMWSub1G module. So both combinations work the same.

How many Expansion Modules can fit in RF Explorer?

Due to size constraints, there is room for 1 single Expansion Module at a time.

Can you give more details on future frequency band options?

Not yet. We prototype a lot with solutions available from different vendors (Silabs, ADI, TI, Microchip, RFMD, MiniCircuits, Skyworks, Hittite, Maxim... to name a few) to get the most affordable and powerful combination that can fit into RF Explorer.

In our experience, unfortunately the more specific a RF product is, the more restrictive vendors are offering samples for prototyping. In some cases we had to wait for 2 months and pay more than $500 for a sample order...

It takes months before we can really go for a pre-production Beta batch. That means we are not able to provide any reliable details before we are certain a given solution will be feasible.