emonTx V3 Transmission Range



I am new to this board. I would like to know what is the Transmission Range that I can expect out of emonTx V3?

Also if there are more technical info in terms of Radio Transmission Power in dB, it would be great.





Robert Wall's picture

Re: emonTx V3 Transmission Range

At present, the V3.2 & V3.4 use the RFM12B radio module. It's said that in good conditions, a range of 100 m is possible. Generally, users seem to have trouble when there are more than two or three walls (depending on the thickness and materials used in their construction) blocking the signal.

The HopeRF Electronic data sheet for the FM12B should help you with output power, etc.

You might also find some useful information over at JeeLabs.

JD's picture

Re: emonTx V3 Transmission Range

RFM12b specs:

Transmit: 7dbm (about 0.005 watts)

Receive makes up for the low power with really good sensitivity:  -110dbm

I've tested a half dozen antennas, and although the stock wire is tough to beat you can get better range with a directional antenna like a yagi.  

JD's picture

Re: emonTx V3 Transmission Range

The switch to the RFM69 in the new EmonTX V3.4 is good news for range:

Transmit: 13dbm (about 0.020 watts)

Receive: -120dbm

Here is a nicely done test that shows the difference between the old RFM12b and a RFM69HW (the 'HW' variant is a higher power version of the RFM69 - 20dbm instead of 13dbm output.  The EmonTX V3.4 uses the RFM69 version.  Both modules use the same receiver).  





techupin's picture

Re: emonTx V3 Transmission Range

thank you guys for this information!!!

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