Comments on: Strobit Final Shots

By: Stephen Eaton

Stephen Eaton — Fri, 17 Dec 2010 06:57:30 +0000

I would look at using a bit of wire at the correct length for 433 this are:

433 1/4 wave = 164.7mm
433 1/2 wave = 329.4mm
433 full wave = 692.7mm

so using a 1/4 wave is your best bet, as it’s the smallest.

I think that using the 915 antenna will limit your range. It will should still work though

By: Deanna

Deanna — Thu, 16 Dec 2010 04:48:39 +0000

Thank you for that, Stephen – I pried the chip out and it had the boxes ticked.. doh!

I have found the 900MHz stubby antenna from DealExtreme that you used but my modules are 434s – I was just interested if this is the antenna that you use for the 434s too (I imagine perhaps just with less range.. but I doubt it could be worse than my whips )

Thanks again for your help!

By: Stephen Eaton

Stephen Eaton — Wed, 15 Dec 2010 04:32:52 +0000

Hi Deanna,

I was using whip antennas at the appropriate length for 915Mhz as I was using a 915Mhz Module. The modules I initially used for the prototypes were the DIP Version, these have a check-box ticked of which band the module is for, i.e 433, 888 or 915 Mhz. I’m pretty sure the SMD version also has this, but I don’t have one hand at the moment so I can’t check, I’m pretty sure the SMD has it on the underside of the module, so if its soldered in you won’t see it.

Stephen…

By: Deanna

Deanna — Wed, 15 Dec 2010 04:05:51 +0000

Hi,
I’ve been looking around for a while but haven’t figured it out yet:

Are you able to tell me please if you use the 900MHz antenna for all three rfm12b modules?

And do you know of a way to determine the frequency band of a 12b by looking at the module, please?

Thanks!!