here you go, just opened a hub for you. As you can see the radio/wifi modules are one side, but the radio antenna has been set to the other side (other picture above)
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Yes, that is correct.
edits in brackets( This topic begins discussing Sensor to Hub then evolves into discussing the hub to the wifi which is why I am answering differently to the main topic)
There may be 2 ‘antennas’. It has the antenna for the long wave length (lower frequency) signal to the Tempest (915MHz or 868MHz depending on your region of the globe) and would expect to be the longer antenna such as that one we can see in the picture. The wifi (2.4GHz)may not have an antenna that you can see which is included on the circuit board.
The long wave length (lower frequency) signal to the Tempest will go through objects better than the wifi high frequency (shorter wave length). And because it is vertical and the Tempest antenna is vertical you should keep the hub vertical.
Then if you rotate the hub the wifi antenna may change its signal strength? In my limited wifi signal experiments I found the best improvement (apart from changing wifi channel, see below) is by placing reflectors to focus the signal.
If you have access to change the wifi router channel then I find very different results for the hub to wifi connection by using different channels on my wifi router. It depends on what other channels are being used in the area. To learn what channels are being used there are Apps you can load on your phone that displays all of the channels being used in the area. But those other routers will likely be changing their channels automatically and be getting loaded up with signal or turned on and off during the day which could be causing your random loss of signal due to interference. I experimented by selecting different channels on my router until I found the best one. I have had problems with neighbours wifi signals overlapping my wifi channel.
cheers Ian 
I moved my hub a little higher in the shed where it is located and now the RSSI values are in the -75 to -85 range, the Tempest RSSI values are now in the -65 to -70 range. Both of these are an improvement but the hub still went down for a few hours today.
also make sure it isn’t to close to a wall as this often also has impact on the radio signal
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Good tip, I will see if I can get it away from the wall.
Finally got Tempest permanently installed. Temporarily it was on the patio table outside the kitchen window on the deck. About 40’ away from the hub, through a wall of about 4" solid wood sheathed in aluminum bubble wrap. RSSI was -70. Hub is on a shelf about 4’ off the ground, facing the router 24’ away. Line of sight unimpeded. RSSI is -43. This surprises me, I would have expected much better. Now Tempest is installed on the mount, attached to the roof eave on the peak, so about 4’ higher than the ceiling of a second story at the end of the house. About 30’ to the hub just inside that wall (again 4" solid wood and aluminum bubble sheeting) on the first floor, with the antenna on the side the Tempest is on. The RSSI is -75. I didn’t expect there would be so little change in the RSSI given the change in location. Not complaining.
I realized I had an Apple Time Capsule sitting around doing nothing since we got fibre-optic and they provided a combined modem/router. We’re currently doing renovations and walls are open, so I was able to run an old 100’ ethernet cable from the main router to the attic and out to the second floor, about 15 feet from the Tempest on the peak of the roof fascia. I set up the TC as an extender and moved the hub to sit on the same shelf as the TC. Now the hub is a few feet away from a window directly under the Tempest. RSSI for the hub is now -23 and for the Tempest, -65. Very happy, and it’s a no-cost/no-waste solution! 
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I have about the same values at about 250 feet from the sensor - not sure the pic captures the distance but its line of sight and only glass between. I’m not an engineer but the antenna must be quite directional or very discrete beams because small degrees of rotation of the base cause (what i perceive to be) large changes in signal strength. Rotating maybe 5 degrees may change my signal strength from -70 (best i’ve seen) to somewhere between -90 and -98 or even intermittently offline.
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if you would open the hub you will find a very common antenna inside. vertical, cylindrical. Hardly directional. There is however also vertically mounted a pcb with lots of electronics. That will shield some of the signal. Try rotating the hub 180 degrees, so the antenna is on the opposite site, and see if it still is so sensitive to small rotations.
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Interesting. If i turn it 180 degrees i have about the same signal strength but at 90 either direction lose about 20db. I bet its more a function of the internal electronics as you described coupled with the obtuse (East facing windows with the Tempest to the North of the house) line of sight, placement on the window sill, siding, etc leading to better reception in certain directions in my specific installation.Thanks for the info and the response!
Rich
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