Try telemakus for variable attenuators and variable phase shifters. Aeroflex works well to though are a bit more expensive, e.g. the 8331 is an example

Power dividers, splitter/combiners and butler matrix devices are sold by multiple vendors. Prices will vary. Unfortunately, prices aren't super low. But usually it's worth the extra money to get a reliable and controllable test bed, particularly when one values their time into the equation.

Bob

On Sat, Nov 4, 2017 at 2:48 PM, Toke Høiland-Jørgensen <toke@toke.dk> wrote:

Bob McMahon <bob.mcmahon@broadcom.com> writes:

> A way I think about is to emulate the "system" in both range/power
> (attenuation) and in mixing (phase shifts) It's a diagonal matrix for
> range feeding into an h-matrix for the mixing. A butler matrix can be used
> for the latter if variable phase control isn't required, e.g. you don't
> care about spatial stream relative powers.
>
> On adding energy for "random" noise, some knobs of concern are the energy
> detect on the tx and signal floor for the rx. These sources can be fed
> into the same h-matrix through their own d-matrices. This won't replace
> field tests but helps get closer towards that while providing for repeat
> ability.

What equipment would it take to do something like that?

> Also, equally important by my judgment, though not related to wireless, is
> to synchronize the clocks on the PCs. An oven controlled oscillator and
> PTP works well towards that goal.

Yeah, already using PTP in my testbed; quite essential for measuring
one-way delay.

-Toke