[chbot] OT: SDR

[Richard Jones]

Note I have changed the subject to OT: SDR to help archive browsing.

In response to ' talk with anyone about SDR in more detail'...

I bought the now obsolete dx.com rtl2832 + E4000 chips a while ago for
experimentation, I also have ordered some rtl2832+R820T receivers which
promise to be a little more sensitive, currently available, and cheaper at
$14.

Using the
https://www.cgran.org/browser/projects/multimode/trunk/multimode.grcreceiver
and gnu radio companion I cobbled together a nbfm digital mobile
radio receiver to receive DMR transissions which are 2 slot TDMA. Adding a
mixer to the front end I could simultaneously decode multiple transmit and
receive frequencies used in a wired trunked radio network site. All this
with exact relative timing, but limited dynamic range.

Over Christmas I finally got around to using the RTL2832 for DVB-T
reception, their original purpose. I can now record and replay digital TV
on my laptop using ubuntu 12.04 and keffeine, next stop mythtv. The delay
in getting around this was caused by needing a newer linux kernel and the
upgrade was finally prompted by a dying HDD in my laptop. Ubuntu 12.04
kaffeine requires an updated channel list for sugarloaf, I found this
useful info somewhere on the web :
# T freq bw fec_hi fec_lo mod transmission-mode guard-interval hierarchy
#
# Multiplex TVNZ, UHF channel 34
T 578000000 8MHz 3/4 NONE QAM64 8k 1/16 AUTO
#  Multiplex TVWorks, UHF Channel 32
T 562000000 8MHz 3/4 NONE QAM64 8k 1/16 AUTO
# Multiplex Kordia, UHF Channel 36
T 594000000 8MHz 3/4 NONE QAM64 8k 1/16 AUTO

The next application to try will be ADS-B aircraft transponder display that
Stuart Brown showed me, but I think the best apps are currently available
for Windows and my 4 year old Windows OS backup CDs don't read at the
moment, and I'm not exactly keen to pay again for something I already paid
for.

Anyone else have info to share on Software Defined Radio activities?

Richard

On Tue, Jan 1, 2013 at 2:04 PM, Dave Bracken <dave.bracken at gmail.com> wrote:

> Hi,
> I'm also interested in SDR and bought an RTL2832 based dongle recently
> and am considering buying a HF converter soon.
>
> http://www.ebay.co.uk/itm/Ham-It-Up-v1-0-RF-Upconverter-For-SDR-Funcube-RTLSDR-MF-HF-Converter-E4000-/150917110538?pt=UK_Computing_Other_Computing_Networking&hash=item23235c5b0a
> which is an opensource project the details of which can be found on
> http://code.google.com/p/opendous/wiki/Upconverter
>
> When I get it up and running, I'll let you know.
>
> Dave.
>
>
> On 19 December 2012 14:22, Solor Vox <solorvox at epic.geek.nz> wrote:
> > Hi all,
> >
> > Just wanted to post a follow up for those that wanted to talk more about
> > Laser cutting.
> >
> > My personal blog with some examples is at:
> > http://epic.geek.nz/
> >
> > Or you can see my shop with items for sale at
> > http://www.zebracraft.co.nz/
> >
> > I'm also keen to talk with anyone about SDR in more detail as I'm just
> > getting started with it.  Currently I'm planning on construction of a
> > quarter wave discone antenna with a low end of 80Mhz.
> >
> > Cheers
>
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