Your kit looks very cool! I was inspired by your AC current probe. I planed to design a DC current front end using the hall effect sensor for the oscilloscope, but I never realized that the coil which usually used as AC current probe for DMM, it can also be used by oscilloscope and spectrum analyzer. I am bounded set thinking
I added the current probe to my to do list.
For the power limiter for RF explorer, I do not want to buy it right now, since it's frequency range is DC ~ 3.0 GHz. I am waiting for the 5.8G edition
I have a set of attenuators form mini circuit which could cover the frequency range DC ~ 6.0 GHz. I think, to a certain extent, using attenuators is enough for measurement after carefully calculation
Ps. The attachment is the RG405 cable I used. It also contains a SMA male connector. Theoretically, I think all semi-rigid coax cables should work.