I would go the 50 ohm route.  Also,  it might be best to skip the relays/switches.  Build separate boards for each attenuation factor.  You will have better repeatability and control of the attenuation. _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2

In message <BLU125-W52C2E2E83EF2C57D95E43CEC40@phx.gbl>, Mark Sims writes: >I would go the 50 ohm route. Also, it might be best to skip the relays/ >switches. Build separate boards for each attenuation factor. >You will have better repeatability and control of the attenuation. My assumption was that the relays would be more repeatable than the connectors and different boards etc. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.