What do HopeRF modules cost?

Joachim Steiger roh at hyte.de
Mon May 10 20:50:36 EDT 2010


Wolfgang Spraul wrote:
> JDH,
> 
>> Are you sure about the modules having a built-in antenna?
>> All the devices I've found that use them have an external antenna.
> 
> No not sure. I think I was told they work without an antenna as well,
> but I didn't look into it further. I assumed 'without antenna' means
> there is some antenna on the module, but that's just a guess. Maybe
> they don't even work 'without antenna'.

they work, but bad (no real antenna => not much distance)
all rfm12 modules ive seen have no internal antenna.
are there even chip-antennas for uhf? (3xx-9xx mhz)

>> https://fjallfoss.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=546270&fcc_id='NS634727-1-900'

hm.. weird toy... check out the 'wire antenna' in the case internal pics.

it also uses a rfm12 module, still they call it rf12

>> It's called an ETEK's RF12, but looks like it's based on the same
>> Integration/Silicon Labs IP as HopeRF's RFM12
>>
>> The datasheet is an appendex to the 'Technical Description'
> 

its just a copypaste from http://www.hoperf.com/upfile/RF12.pdf afaik

i dunno if hoperf licensed it from etek or what, but there are 2 things
to differentiate:
- the chip RF12 http://www.hoperf.com/rf_fsk/rf12.htm able to be used
for 4 bands
- the module(s) RFM12 http://www.hoperf.com/rf_fsk/rfm12.htm having the
RF12 chip, a crystal and some more passives and known to be working
layout for one band of the possible 4.

> You mean the Radica IM Me device?
> http://www.amazon.com/Radica-IM-Wireless-Handheld-Device/dp/B000NX1LUM

eheh.. yet another toy which could be using the same chip

> You are saying HopeRF's RFM12 is based on Integration/Silican Labs IP.
> Can you tell us more about this? Is this good or bad? :-)

why should it be bad?
does it matter?

ps: there seem to be different revisions of the modules around.
http://news.jeelabs.org/2009/05/06/rfm12-vs-rfm12b-revisited/


kind regards

--

roh




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