First test of RFXCOM: dissapointing

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J.S.
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First test of RFXCOM: dissapointing

Post by J.S. » Sat Aug 02, 2008 10:18 pm

I have bought an Oregeon BAR 898 just a test unit as it receives at 100 m and I get my money back when it doesn't work like I want it to.

It is is supposed to reach 100 m with the sensors. And it clearly does reach it, even more. I had a straight line of sight.
On exactly the same possition, next the the BAR 898 I have an RFXCOM 80003. It could not even reach the sensor at 50 m. No matter what, it doesn't pick up the sensor at all. Only when I get to about 20-30 m it does. The only thing between it is the glass of a window...

I was almost sure that RFXCOM would receive better, but it does not.

The sensor is a THGR 228N BTW.

It is a first impression, I do not know of anyone elses experiences comparing Oregon receivers to this RFXCOM receiver. Any tips?

Thanks in advance!

skyewright
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Re:First test of RFXCOM: dissapointing

Post by skyewright » Sat Aug 02, 2008 10:39 pm

J.S. wrote:The sensor is a THGR 228N BTW.
The THGR 228N is what I'd call an 'extra' sensor, like the TCH 238.

The design spec. for the 228 is only 30m.
RF Transmission Range : Maximum 30 meters
The main WMR928 sensors are quite different in design.

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Re:First test of RFXCOM: dissapointing

Post by admin » Sat Aug 02, 2008 11:24 pm

some ideas from my past times as radio amateur DD4OS :laugh:

1) try to vary postion a bit. If the antenna is close to walls or other massiv material this can have major drawbacks on how good it receives (even if it is not in the line of sight).

2) higher positions of the antenna are always better. having it close to ground reduces received signal strength significantly

3) I don't know of the quality of the included antenna. I have an older RFXCOM model with a ground plane antenna that works quite well but looks very akward ;) as you are in 70cm band, you could even think of putting a standard 70cm yagi or hb9cv to it (direction anetennas) which will bring significant improvements. As far as I know the new RFXCOM units have standard BNC connectors, so changing antennas should be easy.

4) If situation does not improve ask Bert at RFXCOM. He is very helpful in general.

73

J.S.
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Re:First test of RFXCOM: dissapointing

Post by J.S. » Sun Aug 03, 2008 9:58 am

I knew that it was specified fot 30 metres. When I bought the system, I immediately checked which sensor was added. As it was specified for 100m, I hoped it would be a 800 or 810 series.
How come the BAR 898, which is combined with this sensor, still picks it up easily at 100m and RFXCOM seems to be in line with the sensors 30 m spec?

J.S.
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Re:First test of RFXCOM: dissapointing

Post by J.S. » Sun Aug 03, 2008 10:37 am

First of all thanks for the great idea of the Yagi antenna. RFXCOM 80003 uses a BNC connector, so I will check it out.

I put it 4 m above ground 5 cm from the window and had a line of sight. I myself went out with the sensor in my hand. I had all wireless things in my house turned of, so also USB 802.11g receiver and my wireless router etc. To no avail.

This morning, it does not even receive the sensor 7 metres away with a cupboard and a 20 cm wide iron fireplace (very small one) between it (at 3 m).
When I put the RFXCOM on my desk so he signal could pass the fireplace, it did receive the sensor...

It is specified for 30 m. I think the yagi is just a great idea.

Í'll await my Oregon 968 and additional UV and 800 and 810 series sensors and then test again. I guy from the States brings the sensors over on 17 august, just when my holidays start. Time enough to test.

BTW: the sensor already broke down. It now constantly reads 98% RH, even when I reset it, take the batteries out etc...I m not bothered by it anyway. Will give this unit back anyhow.

Final thing: the sensor is very accurate. Compared to a calibrated sensor at a constant temp of 22,7 to 22,8 C it reads 0,1 to 0,2 K lower. But that, we knew of oregon scientific.

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