R&S FSH3 VSWR bridges

[Grubi]

Hello,
I was wonder - have you seen FSH-Z3 and FSH-Z2 bridges teardown somewhere?
If one have FSH3 with tracking generator, but missing those bridges - is it possible to make own, external bridge and
still have correct measurement? Spare ones are available from R&S, and from ebay, but on crazy prices.
Even calibration set cost like 700-1000Euro.
I guess for pre-amplifier it will be easier, but for bridges I don't know...

[Robert763]

Hi,
There s nothing "special" about the R&S bridges. You can use a directional coupler, return loss bridge or even a hybrid power splitter / coupler. They just have to be 50R and cover the frequency range you are working with. You do of course have to normalise it with a short and 50R load.  I no longer have a FSH3 but when I did I just used a Mini-circuits hybrid for lower frequencies and a HP directional coupler for V/UHF.
Even one of the cheap RLBs on ebay work well. You can put one in a diecast box with N sockets at te righ spacing and use a pair of M-M N couplers to connect it directly to the FSH3.
Even better use a pair of these
https://www.ebay.co.uk/itm/303209389457?
and semi rigid coax inside the box to one of these
www.ebay.co.uk/itm/332052527822?

[chick0n]

Sorry for digging up this old thread. But here is Service Manual for FSH-Z2.

http://manuals.repeater-builder.com/te-files/R&S%20FSH%20CD-ROM/FSH7.10%20(D)/Manuals/Service_Manual_Z2.pdf