A partner is deploying AP300 located in heated enclosure into Freezers (-30°C). The Pipe bomp antennas are in use and placed out of the enclosure. they noticed a poor coverage when antennas are in the freezer. When pulling the set out of the fridge, the coverage is just fine. Would anyone have experience in coverage Freezer implementation? Any advice is welcome. Thanks, Guy
AP300 and coverage in Freezer// Expert user has replied. |
7 Replies
Thanks to you all for the wealth of your experiences and feedbacks ! I'll check tomorrow with the partner. Guy
Guy, in the passed we tend not to install the AP into the freezer but in the roof void with the Antennas inside the freezer box, we have had issues in the passed with multipath problems if the ceiling is very high and Omni drectional antennas are used, so to overcome this we have used directional patch antennas flat against the chiller or freezer ceiling facing the floor, however the holes for the coax need to be re-sealed to stop condensation into the Antennas. John.
After having done many freezer installations, the only reason we've seen RF signal degradation is because of: 1. Poor RF coverage survey. 2. Mounting the antennas in a location that doesn't maximize it's potential RF signal. 3. Mounting the AP/antennas in a location close to an EMI source. (ie, fans, lighting, etc.). 4. All frozen items contain water which absorbs the RF signal. Therefore the coverage area is less than average when compared to a standard warehouse. As far as the antennas go, I've never seen a substantial frost build up that would affect the RF performance.
Also to add, that the material make up of freezer walls and ceilings (usually flat) are different in that the RF signal doesn't reflect/propagate like it does in a standard warehouse.
Guy, Defintiely look at that last point. If its a standard freezer then you are probably getting a lot of reflections and mulitpaths due to the skin of the chamber so you may well just have too much RF in there. Try cranking the power down on the APs . Coverage may be affected if its an old freezer and has a lot of frost / ice build up on the walls etc, and check that the APs haven't been placed right next to the doors where you can often get a lot of moisture in the air when the doors open. Apart from that I've done plenty of freezer deployments and it normally works fine. IJ
Guy SuperValu (grocery distribution here in the US) has a lot of AP-300s in coolers and freezers. In the frozen environment, they use NEEMA boxes with the same external antenna as used in the dry goods section of the facility. As long as the heater is working in the enclosure it should perform fine. So I would swap the AP-300 and test. If no improvement is seen then check all antenna cable connectors from the AP, through the bulkhead connectors out to the antenna to ensure integrity. Also ensure no frost (and therefore water) got into the antennas located in the freezer. Z
Steve, I think your last comment hits the issue; frost build-up over time on the antenna surface affecting the antenna sensitivity dynamics & signal. Although Guy was vague per the issue, I would suspect they see a gradual degradation of signal sensitivity from these antenna over time, while frost starts to build up. I doubt the AP functionality degrades, unless they're not housed in a NEEMA. The box should prevent or minimize the frost build-up, assuming the antenna are within the box.