Electronic Circuits and Projects Forum

I found the following information in this datasheet:
http://www.electro-tech-online.com/c...2154_v1xAx.pdf

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XBee-PRO OEM RF Module

(@ 10 dBm Transmit Power, PL parameter value must equal 0)
The following antennas have been tested and approved for use with the embedded XBee-PRO RF Module:
• Dipole (2.1 dBi, Omni-directional, Articulated RPSMA, MaxStream part number A24-HABSM)
• Chip Antenna (-1.5 dBi)
• Attached Monopole Whip (1.5 dBi)
The RF modem encasement was designed to accommodate the RPSMA antenna option.
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So the chip antenna has a gain of -1.5dBi, and the whip antenna has a gain of +1.5dBi.

What this means is that there is a difference of 3dB beteween them, the whip antenna is superior by a factor of 2 in terms of transmitted and recieved signal power.

JimB

Most of them are linearly polarized in the plane of the pcb and working against the large pcb area as a counterpoise, so it would have the typical donut pattern that you might get from a typical monopole, only it is lying on its side and would be horizontally polarized. If you orient the module vertically, then it would come close to matching the pattern of the little whip antenna on the other version.

I never tried "chip antenna" and somehow missed the -1.5dbi vs 1.5dbi... actually - I have not seen it in original xbee doc's even after JimB's post. JimB THANKS for that link cleared up few things in my head.

Sceadwian, thx but no thx ... for this I am only interested in "ready made" solution .. no "adaptations" ..

diffy, thx for explanation .. never used chip antenna link is interesting but I'm going with whip

sceadwian, sorry when you said dipole I immediately imagined making my own ...

the modules come in 3 "ways"
- chip
- whip
- connector

there is a number of antennas you can connect to connector and they do offer more then chip/whip one .. but, then the whole thing becomes more complex (mounting the antenna etc)

I'm still deciding on how to proceed to the wireless realm .. the BT is too expensive, xbee loks like the right way to go .. with pro and non pro being interchangeable .. that might be the good option ... (pro use much more power but has longer range)... still considering the microchip solution ... the free time is limited now so I'm using it to get as much info as I can before I have free time to test .. (so I then spent right amount of money for testing and not too much as usual )

I am going to give the MRF24J40MA's a try. It uses a PCB antenna on the module but you need to supply a ground plane on your PCB.

They claim a range of up to 400 feet. I need half that.

3v0

3v0, I tought about it .. the 4layer pcb made me forget about the MRF24J40MA and go for "ready made stuff" .. the AC163027-4 (microchip daughter board with MRF24J40MA) is 39.00US$ locally, and zigbee (fully assembled with serial interface towards you) is 23.85US$ - 35.64US$ depending on the model (xbee, xbee series2, xbee pro) ... it is simple choice for me at the end ... it "just works" and it is cheaper to go with xbee modules.

I see here: http://www.electro-tech-online.com/c...ide_51524C.pdf the veri simple "MRF24J40MA PICDEMTM Z 2.4 GHz RF BOARD" 2 side pcb ... will have to investigate .. looks interesting