RFXtrx433 and OS Sensors

Posted on
Mon May 21, 2012 12:49 pm
Dewster35 offline
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Location: Petoskey, MI

Re: RFXtrx433 and OS Sensors

For what it's worth, I have three 3 channel sensors running correctly and I just ordered two 10 channel sensors that should arrive by wednesday if you want to hold off that long for a definitive answer from me.

Posted on
Mon May 21, 2012 2:42 pm
b_weijenberg offline
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Joined: Jun 14, 2006

Re: RFXtrx433 and OS Sensors

About number of oregon sensors see: http://www.rfxcom.com/oregon.htm#Oregon

Posted on
Mon May 21, 2012 7:30 pm
hamw offline
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Joined: Mar 31, 2008

Re: RFXtrx433 and OS Sensors

Does anyone know the range of these sensors? I'm looking into monitoring my crawl space with either 1-wire or perhaps this solution. The signal would have to travel probably 75 ft and pass through walls etc. I currently have some wireless sensors down there from a cheap AcuRite weather station and it works, but it is very location dependent.

Also, I was thinking I might clip the terminals to a 3v wall wart to eliminate the batteries - thoughts?

Posted on
Tue May 22, 2012 6:14 am
johnpolasek offline
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Joined: Aug 05, 2011
Location: Aggieland, Texas

Re: RFXtrx433 and OS Sensors

hamw wrote:
Does anyone know the range of these sensors? I'm looking into monitoring my crawl space with either 1-wire or perhaps this solution. The signal would have to travel probably 75 ft and pass through walls etc. I currently have some wireless sensors down there from a cheap AcuRite weather station and it works, but it is very location dependent.

Also, I was thinking I might clip the terminals to a 3v wall wart to eliminate the batteries - thoughts?


I don't think that walls are a problem unless they have metal in them; my experience with the Radio Shack temperature sensors (apparently rebranded OSIs, listed by the RFX plugin as type 2s, the same as the OSI sensor that came with the WGR80a weather station) is that the OSI outside temperature sensor which is 40 ft from the RFX and needs to get through an outside (brick) wall and two interior walls shows a signal strength 6, while the one in the freezer (steel walls) cannot reach it's display if I move it more than 10 ft from the freezer, although the RFX about 30 ft away grabs a reading from it a couple of times a day. We also had to stick the sensors I'm using on the AC ductwork on the outside of the vents rather than inside the ducts like I originally planned in order to get a reliable signal back. Since the RFX has detachable antenna, I was going to ask some Ham operators I know if there might be some kind of fairly cheap higher gain antenna I could use instead, kind of like the "pancake" WIFI ones we used back in the old "g" days before n and MIMO took over. And the RFX is also reliably (signal strength 5) picking up a rain sensor apparently from one of my neighbors that must be at least 60 feet away, since that's the nearest property line...

Posted on
Tue May 22, 2012 7:14 am
b_weijenberg offline
Posts: 172
Joined: Jun 14, 2006

Re: RFXtrx433 and OS Sensors

To increase the receiving range you can connect for example a 190073 www.conrad.com 433MHz ground plane to the RFXrec433 receiver. Or any other 70cm HAM radio antenna can be used.
This adapter can be used for SMA- to BNC http://www.ebay.com/itm/BNC-female-SMA- ... 2a03ea8391

For RFXtrx433 transceiver users: another antenna will also increase the radiated transmit power of the RFXtrx433 transceiver which is illegal!

Posted on
Sun Jun 03, 2012 8:09 pm
hamw offline
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Joined: Mar 31, 2008

Re: RFXtrx433 and OS Sensors

Got the RFXrec from Norm the other day along with 4 Oregon Scientific 3-channel sensors. The first thing I noted is that the sensors are calibrated within 1 degree and 1 percent humidity of each other, and are actually very close to the Venstar thermostat temp/humidity readings. This is in contrast to the Acu-Rite temp/humidity sensors I have had for the last couple of years, so that is a real plus.

The RFXrec installed without a hitch, and the sensors all came up without a problem. The only issue is that I duplicated devices to create the new devices, and in doing so had to reconfigure the prior device as it fell off the RFX list. No worry about that.

The OS sensors actually transmit in the crawl spaces, I guess b/c they are shielded only by wood floors and weren't passing thru the plaster walls. The signal strength, even on the weakest, is a 4, which is adequate, and the "last update" time stamp lets me know they are communicating regularly. Finally, even though these are "3-channel" sensors, all 4 work fine. It was explained to me that while duplicate channels may occasionally step on one another, in general they are all received and tracked independently as separate devices, and this seems to be the case.

In regard to the Acu-Rite sensors, it appears the one I had under my game room was really out of whack. The Acu-Rite was reading 40% humidity but the new OS sensors read 63% humidity -- what a huge error! So it's a good thing this device came along!

Kudos to the RFX crew for making this great plugin available!

Posted on
Tue Jun 05, 2012 12:28 am
AlaskaDave offline
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Posts: 293
Joined: Oct 16, 2008
Location: Juneau, Alaksa

Re: RFXtrx433 and OS Sensors

So my RFXtrx433 arrived today from the MacHomeStore and it's running great. Took only a few minutes to get up and running. I do have a couple of questions from items I noticed:

1. When configuring the RFXCOM plug-in I was presented with two serial port options. USBSERIAL-03VGC637 (chose) and USBSERIAL-A700ahVc. Whey two serial port options and did I select the right one? Does it matter?

2. One of my sensors indicated a low battery (level 1) so I replaced the batteries. When I did the channel changed. When you replace batteries can I expect the channels to change (random process?).

Thanks. So far really nice.

Posted on
Tue Jun 05, 2012 2:19 am
b_weijenberg offline
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Joined: Jun 14, 2006

Re: RFXtrx433 and OS Sensors

The sensor ID is changed with a sensor reset or battery exchange.

Posted on
Tue Jun 05, 2012 5:54 am
Dewster35 offline
Posts: 1030
Joined: Jul 06, 2010
Location: Petoskey, MI

Re: RFXtrx433 and OS Sensors

Can the existing device in indigo simply have it's ID changed if there is a battery change? I ran into problems duplicating devices and changing the ID's... would be a real pain if you have to create a new device each time... that means I've got to go into my control pages and change those each time, change my triggers...etc, etc.

Posted on
Tue Jun 05, 2012 6:14 am
johnpolasek offline
Posts: 911
Joined: Aug 05, 2011
Location: Aggieland, Texas

Re: RFXtrx433 and OS Sensors

Dewster35 wrote:
Can the existing device in indigo simply have it's ID changed if there is a battery change? I ran into problems duplicating devices and changing the ID's... would be a real pain if you have to create a new device each time... that means I've got to go into my control pages and change those each time, change my triggers...etc, etc.


I just changed the ID on the rain sensor when I had to do a HARD reset, and everything ran fine. It wasn't a problem in the RFX, but when I first set up the rain bucket it was sending really weird messages both to the RFX as well as the OSI monitor, and OSI told me to pull the battery for 10 minutes then do a reset. The ID changed, but I just went into the existing device and changed it there, and Indigo never noticed the difference (except now the rain doesn't jump from 2 inches back to 0 then back to 1 inch over a 6 hour stretch).

Posted on
Tue Jun 05, 2012 10:40 am
AlaskaDave offline
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Location: Juneau, Alaksa

Re: RFXtrx433 and OS Sensors

AlaskaDave wrote:
1. When configuring the RFXCOM plug-in I was presented with two serial port options. USBSERIAL-03VGC637 (chose) and USBSERIAL-A700ahVc. Whey two serial port options and did I select the right one? Does it matter?


I switched it to USBSERIAL-A700ahVc and everything went red in the log so switched back. I've found that my reception strength is about the same. I still can not reach the sensor in my freezer (internal) or the sensor in my workshop. I've located the RFXtrx433 up high on the ceiling but that does not seem to effect things. Just to test I'm going to try to connect a longer USB cable and place it closer to those sensors. The freezer should really be replaced but getting a signal from the sensor in my workshop sure would be nice. Anyone using a ground plane antenna in order to boost reception?

Posted on
Tue Jun 05, 2012 1:38 pm
RJdeKok offline
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Joined: Mar 27, 2012

Re: RFXtrx433 and OS Sensors

I had the same problem with the sensor in my freezer, but with a better and a little bigger rubber antenne it goes great.

Posted on
Tue Jun 05, 2012 3:28 pm
AlaskaDave offline
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Location: Juneau, Alaksa

Re: RFXtrx433 and OS Sensors

Antenna on the RFXtrx433? If so, which one?

Posted on
Wed Jun 06, 2012 10:53 am
AlaskaDave offline
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Location: Juneau, Alaksa

Re: RFXtrx433 and OS Sensors

During testing to see if I could increase the range of my RFXtrx433 I placed a USB 2.0 Active Extension (10m/32ft.) between the receiver and my MacMini so I could place the receiver closer to most of my sensors... success. I can now pick up both the freezer sensor and the sensor that is furthest away in my workshop, which I was never able to pick up with my WMR100 weather station or the RFTtrx433 with the supplied antenna. The cord is a bit unsightly but having the extended range is great. The USB extension that I'm using is: http://www.amazon.com/gp/product/B002VG39BI/ref=oh_details_o03_s01_i00.

Other than the ground fault antenna that RFXCOM recommends (not available in US) I'd be curious if others have added an extended antenna to the RFXtrx433 as indicated above. The RFXCOM site shows some extendible antennas but it appears they are now for this device.

Posted on
Wed Jun 06, 2012 2:57 pm
b_weijenberg offline
Posts: 172
Joined: Jun 14, 2006

Re: RFXtrx433 and OS Sensors

To increase the receiving range you can connect for example a www.conrad.com order nr 190073 433MHz ground plane antenna with coax cable,

Or a http://www.radioshack.com/product/index ... PerPage=60 scanner antenna. This antenna needs a coax cable with PL-259 and SMA-male or BNC connector.

This adapter can be used for SMA- to BNC:
http://www.ebay.com/itm/BNC-female-SMA- ... 2a03ea8391

Note that another antenna on the RFXrec433 is possible but on the RFXtrx433 it is not allowed because the transmitter is certified with the delivered antenna and with the ground plane the antenna output will also be increased.

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