maximum range for ez430-rf2500?

[pine 140]

Given line of sight communication, how far away can these modules communicate?

 

Thanks in advance.

[bluehash 1,581]

From E2E thread. 2nd post.

 

1.This sound a little les than what's expected. From the eZ430-RF2500 user guide:

 

"Based on practical rage testing with one node connected to a PC and the other node connected to the battery board, we have measured indoor line-of-sight range of more than 50 meters. This range can be significantly affected by the orientation of the boards and the environment. Note that the eZ430-RF2500 target board was designed to optimize for factor and does not focus on maximizing RF range."

[jpnorair 340]

Years ago I used a CC2510 with Smart RF Studio and a larger antenna to achieve ~150m outdoor line-of-sight. I don't actually remember what modulation I was using, but a good guess is 28kbps FSK +/- 50kHz, given some of the things I work with.

 

If you want range, you can develop your software on the 2500 and then switch to the CC430, CC11xx, or another sub-1GHz transceiver. If you can build a decent antenna, you can get insane range from the 433 MHz band. I have achieved reliable 1km outdoor NLOS with a CC1101 using 28 kbps GFSK +/- 50kHz @ 433 MHz, -3dBm. In the USA you can use the 900 MHz band with greater power, but it also falls-off faster. In most other places in the world, the 862/866/868 bands are regulated more strictly. In any case, there's basically no good reason to use 2.4 GHz unless you're doing something high-throughput.

[antennahead 13]

OK, I really do hate to brag here, but see attached snap shot of an ultra-long range xcvr based on the CC2500+CC2591+Yagi antenna, (+7 dBi Gain).

 

This xcvr design was based on the ez430-rf2500, and then I added the 2591 and the antenna.

 

This design was the basis for TI app Note DN034, "2.4 GHz Yagi Antenna Design" http://www.ti.com/lit/an/swra350/swra350.pdf

 

With low data rate, and +28 dBm EIRP, this thing had a range of ... 60 miles.

 

We tested it by placing the transmiter on top of Pikes Peak (14,110 ft) west of Colorado Springs, and started driving to Kansas.

 

[Lgbeno 189]

@antennahead

 

That's really awesome range! Is the design open source at all, it would be cool to see what you did. I assume that you are using a external LNA & PA is this the one from TI as well? Did you have access to a VNA or what was you strategy for getting all of the components matched on a budget?

[bluehash 1,581]

We tested it by placing the transmiter on top of Pikes Peak (14,110 ft) west of Colorado Springs, and started driving to Kansas.

Wow! Doesn't look like LOS(Line of Sight) 

[antennahead 13]

Please see attached schematic, board photo, and paper we had submitted to RWS 2011/2012. 

 

At any rate, we spun the antenna out of this as I previously mentioned and made DN034, previously cited in this thread.

 

Ultimately the Chipcon team in Oslo decided not to pursue and App Note based on the combination CC2500+CC2591 for a few reasons.

 

Beware, the way we were operating this thing was breaking all sorts of FCC rules... but we wanted to see how far we could push this chipset.

 

The zip file has the gerber files- for proper transmission lines you MUST use the PCB stackup outlined in silkscreen.

This stack-up is the Advanced Circuits "$66 Each" 4 layer prototype stackup.

paperF.pdf

schematic.pdf

xcvr4.zip

[antennahead 13]

@antennahead That's really awesome range! Is the design open source at all, it would be cool to see what you did. I assume that you are using a external LNA & PA is this the one from TI as well? Did you have access to a VNA or what was you strategy for getting all of the components matched on a budget?

 

Yes, using CC2591 PA/LNA. 

 

I do have an VNA, but we actually matched this using load pull characterization, see paper.  Wasn't much better than what was in the CC2591 data sheet for a 50 Ohm match though.

[bluehash 1,581]

Beware, the way we were operating this thing was breaking all sorts of FCC rules... but we wanted to see how far we could push this chipset

You got a badge! , so do gwdeveloper and spirilis.

[spirilis 1,265]

60 miles!  That is amazing.  You guys do exciting work

[jpnorair 340]

You could improve that antenna by adding a reflector behind the driven element.  I suspect the ground plane is acting as something of a reflector, but if it were sized to half-lambda and moved a bit closer to the driven element (typ 1/10-lambda IIRC), you would have a textbook Yagi-Uda array that should work even better.

[antennahead 13]

You could improve that antenna by adding a reflector behind the driven element.  I suspect the ground plane is acting as something of a reflector, but if it were sized to half-lambda and moved a bit closer to the driven element (typ 1/10-lambda IIRC), you would have a textbook Yagi-Uda array that should work even better.

 

Actually, it is already a Yagi-Uda design.  Indeed the ground plane is the reflector element, and you can see the 3 director elements.

[jpnorair 340]

Actually, it is already a Yagi-Uda design.

 

Yes, just not a *textbook* one.  Maybe this one works better, I don't have one of these boards so I can't say, nor have I modeled anything like it with an oversized ground plane as a reflector.  Numerical optimization usually specifies a reflector that's slightly shorter than the driven element.