*Hi Leon and all,*
*
*
*I'm looking at the **
*Si4464/63/61/60 data sheet *
*
*
*
*
*
*
*https://www.silabs.com/documents/public/data-sheets/Si4464-63-61-60.pdf*
*
*
*On Page 8 we have "Image Rejection" at only 35db and 55db corrected.*
*
*
*Since their IF is only 468KHz, it's not possible to filter it our with
the RF front end.*
*
*
*Would better Rx performance be had using a Superhet design. A 45MHz,
21.4MHz or 10.7MHz IF*
*where we use a crystal filter and 'completely' loose that image?*
*
*
*Alan VK2ZIW*
*
*
On Fri, 9 Mar 2018 18:06:30 +0200, Leon Lessing wrote*
Hi all,
I have about 90 pieces of stm32f405rgt which is the 64 pin device, I
see it is "compatible" with the stm32f722
Having worked a lot in the low volume/cost arm world, I have a pcb
carrier roughly 1x3 inches, it has the usb plug on it and the xtal, swd
etc.
It helps you do extreme speed hardware development with minimal
effort, so porting the design to another cpu it not a big issue.
Yea I know it is an ugly shortcut, but it works well when your product
must pass emc tests, well sometimes.
Them RT1050 silicon looks damn cheap compared to the stm devices, a
good reason not to use cubex :)
Leon
Leon Lessing
雷立安
ZS6LMG/AC9GU
On Fri, Mar 9, 2018 at 10:44 AM, glen english <g...@cortexrf.com.au
<mailto:g...@cortexrf.com.au>> wrote:
Agreed.
>
> skip the F4 and go straight to the F7 , unless cost is an issue.
>
> CODEC2 was almost 1.7x the speed on the F7 compared to F4 for same
clock .
>
> The H7s are expensive, don't you think Danilo ? I am going RT1050
for next design.. $5. k
>
> On 9/03/2018 7:05 PM, Danilo Beuche wrote:
>
> Hi Leon,
>
> if you design with a STM32F4xx and 100 pin, I would recommend to
choose one of the newer types (read STM32F469/STM32F479). They
have a pinout compatible to the 100 pin STM32F7xx line (and it
is only slightly different compared to the STM32F40x so a
relayout shouldn't be hard). With this it would be trivial to
drop in a much higher performance STM32F7xx without PCB
redesign. The F7xx gives about twice as much performance as the
F4xx with about the same amount of power used (that is our
experience with the signal processing in the UHSDR/mcHF vs.
UHSDR/OVI40 firmware builds). This restriction does apply for
100pin devices only. So if you used a 144 pin variant of the
STM32F405, nothing to worry about.
>
> BTW, once the STM32H7 is really readily available, you get
either even more processing power at 400 Mhz clock for about the
same power usage or at the same clock rate similar performance
but less power consumption due to shrinked MCU design (90 ->
40nm AFAIR).
>
> Danilo
>
> On 09.03.2018 07 <tel:09.03.2018%2007>:00, Leon Lessing wrote:
>
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 <mailto:kanto...@gmail.com>
<mailto:kanto...@gmail.com <mailto: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
>
>
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