Microwave Equipment
With the exception of the 1.3GHz band there are no ready built transceivers for the microwave bands. There are however sources of ready-made transverter modules that can be built into complete systems for bands up to 47GHz.
The other options are to use ex-commercial equipment re-aligned to operate on the amateur bands. For example 5GHz (6cm) band has seen adaptations of First Person Video (FPV) equipment that is used with drones.
With very simple equipment and making small modifications to support wideband FM operation, it is possible to make contacts of up to around 100km between suitable hilltops.
Some groups have repurposed commercial equipment to set up digital networks. These usually operate in our 2.4GHz allocation, and can provide reliable communication. A network covering the Firth of Forth (Feednet) was originally set up to support emergency communication. Similar can be achieved in 5GHz though care must be taken to fit data channels within the small size UK amateur allocations.
For the higher mm-wave bands the only option has been to build equipment, although even here 122GHz radar device based systems are being pressed into amateur service.
Although radio rallies often have large amounts of surplus equipment for sale, it can be hard to find what might be useful for the microwave bands. Fortunately there are a number of Microwave Round Tables around the UK where it is easier to find what you might need and listen to talks from fellow microwavers.