For this project I’ll be using two pe4302 boards sourced from eBay. They come with the pe4302 chips pre-soldered along with pin header and pulldown resistors.
DuWayne KV4QB, has done a Step Attenuator project and was kind enough to give me a board he had designed when I met up with him at FDIM this year. I’ll use DuWayne’s board and won’t develop my own pcb for this project. I’ll follow his design and possibly make changes at a later date. Here is a link to his blog where you can read in more detail about his attenuator project. http://kv4qb.blogspot.com/
As with DuWayne’s project, I’ll use 2 pe4302 boards connected in series with the control lines in parallel. This will mean that the attenuator steps will be in 1dB increments and not .5dB steps that the pe4302 chip is capable of. Max power input is +24dbm. Total attenuation will be 63dB. There will however be an insertion loss of about 3dB, 1.5dB per board. I’ll likely measure the exact loss and add it in to the selected amount of attenuation so the display will show the actual level of attenuation.
Download a PDF of this article HERE.