VK1 Output Attenuator Question

Hello Group!

I build a VK1 right now and like to have smaller steps at the output attenuator. Knows someone how to calculate it for 1db steps?
And by the way... i don´t get what happens here. Normaly i would believe a t-pad should be there, but this dosn´t looks like one to me. Can someone please explain how it works, i like to understand it...  ??? Is it possible to just work with a h-pad here?

Here is the schematic:

https://www.docdroid.net/PXaWvs9/vk1-schematic.pdf.html

Thank you!

I am going to answer my own question: it´s a bridged t-pad. I found the calcualtion and can do my own attenuator now.

But still don´t know the benfit of using a bridged here and not a h-pad...  ???