Joseph H Allen wrote:
Analog devices makes RF-log amp/detector chips which are good to microwave
frequencies (basically RF in, 10mv per dBm out, from -80dBm to 0dBm).
Replace the SWR meter's detector with one of these.

--
Andy writes:
I built one of those up -- the version that goes to 500 Mhz -- and
I use
it with a Mini-Ckts Fwd/Ref bridge and a Measurements 202, which only
puts out around 0 dbm. It works like a charm. I use the 202 to get
reference
measurements and use that system to tune antennae and transmission
lines.
It's a very very sensitive RF power meter and, while the absolute
accuracy may not be the best, it's very good for using low power signal

sources and taking relative measurement.

Andy W4OAH