Hi all,
Just bear with me here,
My experience with some of the brandmeister guys has been less than
spectacular. There is no reason we cannot use "dmr framing" and use codec2
to transmit stuff, effectively splitting a dmr channel into 4 potential
codec2 slots.
I have revamped the adf7021 hotspot thing so it is more rf friendly, the
design is unfortunately in eagle 7.7, mail me for a copy.
This week I have been on holiday and struggling with the lora issue, but in
the back of my mind I have been thinking mmdvm, hotspot hardware adf7021,
sm1000 and 1296. I am about 90% finished with a mmdvm/sm1000/sdcard hybrid
using a stm32f405.
The code from mmdvm_hs uses bit banging to talk to the adf7021, I will add
an adf7021 to the mix and maybe a rda1846, a gps and esp8266. Another idea
is to break out the extra control lines and spi bus from the stm32f405 to a
connector so we can build a stacked system. I'll publish the pcbs, I have
no idea how we can use git or svn to share the pcb work.
There is issues with the adf7021 and harmonics, this is why the commercial
market uses R5000 (dedicated dmr framing) and the CML data pump devices.
Dual band matching seems to be an issue with this device as well, I am
trying to get the hotspot hardware to work on 145Mhz without harmonics on
290Mhz.
Please mail me if you need a copy of the files for a peer design review, I
will use dirtypcbs to do the dev run and give you guys the links and you
can order pcbs, shipping from South Africa is terribly expensive.
Look at the pine64 as an alternative to raspberries. The idea of doing a
sdr radio is excellent, but mixer bleed through is a massive issue for the
transmitting side. (most mixers gives 60db local suppression, but 60db down
on +5dbm local inject is still a very strong signal)
Regards,
Leon
Leon Lessing
雷立安
ZS6LMG/AC9GU
On Fri, Mar 9, 2018 at 1:31 AM, Adrian Musceac <kanto...@gmail.com> wrote:
> Hi Alan,
>
> >
> > I ask, how far are we in being able to completely replace the firmware
> > in the lowly MD-380 and clone radios? Or, could we beef up the power in
> > the 7021, already used in the project!!!!!!
> >
> That (as in running Codec2 2400A) will never happen for technical reasons.
>
> Using an SDR it's possible to have Codec2, C4FM, D-Star, DMR and
> whatever else on a single device.
>
> There exist handheld full SDR terminals with a price point of
> $800-$1000, capable of running almost everything you want up to high
> speed video. Documentation is close to zero, writing software for them
> would cost in the high 6 digits figures (not going to happen soon).
> Said terminals will go EOL in 4-5 years as public services transition
> to LTE.
>
> If you want to try some of the new digital modes without spending a
> fortune in equipment and DSP training, I suggest to invest some time
> in learning GNU radio. It's the only viable alternative. I managed to
> make for myself 4 types of Codec2 VHF modems using it. BPSK, QPSK,
> 2FSK and 4FSK. Enough to play with for a while. OP25 (a GNU radio
> project) has had P25, C4FM, D-Star and DMR for a while now. Combining
> them into a single, easy to use application is just a matter of time.
>
> Cheers,
> Adrian
>
> ------------------------------------------------------------
> ------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> Freetel-codec2 mailing list
> Freetel-codec2@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/freetel-codec2
>
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
