When using wifi analyzer in 5GHz to see what my W-DMX units were doing, I also had no results. I assumed that my gear was using frequencies other than standard ones while within the 5GHz band, and that was why I didn't see anything.
Might that be the case with the HMEs?
The analyzer correctly sees all my 2.4 & 5GHz router/wifi activity at home and on the gig, so I'd love to know if that is the case.
Wifi Analyzer only sees official wifi traffic, which makes sense. It would be great if it could see non-wifi RF in that band, but it just not be possible to get the chipset to do that. All of this stuff uses Spread Spectrum (aka frequency hopping) so the frequencies are constantly changing.