Hi Tom,
thanks for answer. I will make device for data-transfer on 900 MHz with
nRF905 from Nordic. I have no experience in so high frequency. This
device is low power transmitter. I am not sure what happen wenn I use
standard (non-RF) circuit board. Probably output power will be low or
cann I waiting another problems ?

Cheers,

Fero

Hi Fero,

Since I'm not familiar with the nRF905, I can't really anticipate what
problems you might run into. I do expect that at 900MHz, if you can
come up with a proper layout and execute it correctly, standard FR-4
(modern fiberglass-epoxy) dielectric shouldn't be a significant
problem. I'm assuming that the whole board is small and you don't have
more than a couple cm trace length. Obviously, if you ran a few meters
of microstrip, you'd have noticable loss. Perhaps someone with some
nRF905 experience can give you more help. I did bring up the Nordic
website, but the ap note files for the demo boards were in some format
my 'puter doesn't understand. (Why doesn't eveyone include a PDF
version??) Since Nordic seems to try to provide lots of info on their
web site, perhaps they would answer an email about your concerns.

Cheers,
Tom

The application note for the NRF905 does specify FR4 board with 1.54mm
substrate thickness. FR4 is the board material used for almost all printed
circuit boards, so you can use a regular board and just make sure the
thickness is 1.544mm.

http://www.nordicsemi.no/files/Produ...out_rev2_0.pdf


here is the link for most od the documents related to the NRF905.


http://www.nvlsi.no/index.cfm?obj=se...t=searchResult



Jim
N6BIU

--

14:04 Pacific Time Zone
Sep 5 2005

International Time
21:04 UTC
05.09.2005

1.5mm just happens to be 0.062" (1 / 16 ") which is the industry standard
board thickness.

Jim


"Jim" wrote in message
...
The application note for the NRF905 does specify FR4 board with 1.54mm
substrate thickness. FR4 is the board material used for almost all
printed
circuit boards, so you can use a regular board and just make sure the
thickness is 1.544mm.

Hi Tom,

I have got one more question : could this RF-4 material be used for
frequency up to 2,4 GHz too ? ( blue toot )
Namely, Nordic offers chips for this frequency, too.

Thanks a lot.

Fero

Fero wrote:
Hi Tom,

I have got one more question : could this RF-4 material be used for
frequency up to 2,4 GHz too ? ( blue toot )
Namely, Nordic offers chips for this frequency, too.

Thanks a lot.

Fero

I used ordinary FR-4 for a 6 GHz pulsed oscillator in a commercial
product, and the last I heard it was working fine in mass production.
But it's used only in a dry environment, and doesn't have any high Q
networks or filters. If your design can tolerate relatively high loss
and a moderate dielectric constant (about 5) that varies with
temperature and humidity, FR-4 is fine. If it can't, you should consider
Rogers PTFE board products or something similar.

Roy Lewallen, W7EL

I used it at 2.3 Gig in a 5 watt transmitter and it worked just fine.

Jim



"Fero" wrote in message
oups.com...
Hi Tom,

I have got one more question : could this RF-4 material be used for
frequency up to 2,4 GHz too ? ( blue toot )
Namely, Nordic offers chips for this frequency, too.

Thanks a lot.

Fero