Author Topic: WS-2902a sensor antenna and snow  (Read 186 times)

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Offline madkiwi

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WS-2902a sensor antenna and snow
« on: December 05, 2018, 02:23:29 PM »
Ambient Tech Support was nice enough to send me a new sensor array after I asked about the blackout when we had a snow event. Apparently that was before they talked to their engineers, because in a followup email they told me the array may be functioning perfectly but the snow/ice buildup will block transmissions and a new sensor array won't change that.

Talked with my brother (electrical engineer who works in the semiconductor fab industry) and he pointed out that water only a few thousandths of an inch will block 915 MHz radio waves.

He was visiting this week and on examining the array he figured the protuberance on top next to the UV sensor is the antenna (I didn't allow him to take it apart though) and if snow was to pile up on it that would be enough to disrupt the transmissions. In his opinion that was a poor design choice, he thinks modifying the antenna with the antenna extending downwards would be best for our climate.

Because I wasn't letting him dismantle the unit (or the new one) we have not figured out how easy this would be, although one thing was noted- a 1/4 wavelength antenna would be 78 mm long, that bump on the array is less than 1/2 of that. So our guess is that the antenna is the correct length but only part of it extended beyond the body of the array.

I have to decide if I want to make a modification, at least I have a "spare" array to tinker with. Could be as simple as drilling a small hole on the underside and reorienting the antenna downwards, then sealing around the hole with silicone.

Thoughts? Anyone done this already?

Offline DoctorKnow

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Re: WS-2902a sensor antenna and snow
« Reply #2 on: December 05, 2018, 03:59:46 PM »
The acurite 5 in 1 antenna is installed pointing down. I guess this is why...

Offline davefr

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Re: WS-2902a sensor antenna and snow
« Reply #3 on: December 06, 2018, 01:21:35 PM »
I thought someone here was experimenting with adding an external Yagi antenna to the sensor.  Curious if anything came of it?

Offline StephenR0

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Re: WS-2902a sensor antenna and snow
« Reply #4 on: December 07, 2018, 11:40:33 AM »
Here is the FCC site for the WS-2902a sensor array, the WH65B.

The internal pictures are here.

In the second picture, you can see the antenna.  It looks to me like a very common quarter wave antenna curled in a coil to minimize length.  I haven't taken mine apart either.  Like your brother, I had supposed that the thing on the top was where the antenna went, although I don't know for sure.