Re: LimeSDR with Debian
On Mon, May 22, 2017 at 10:54:26PM +0200, Daniel Pocock wrote:
>
>
> On 22/05/17 22:00, Andrew M.A. Cater wrote:
>
> > A bit expensive for a very low power rig. Filtering might be
> > "interesting" given that it is so wideband - intended as a
> > mobile phone network repeater in the GHz range, really.
> >
>
> Filtering on the RX side or the TX side?
>
100kHz - 3.8GHz - essentially no real filtering over a VERY wide
range. DSP filters in GNURadio might help - but there's not much
bandpass filtering.
10dBm power output at CW - so 10mw into 50 ohm?
> I'm using my ATU and up-converter to provide some RX filtering into my
> RTL-SDR. Will the ATU alone provide sufficient attenuation for RX on
> LimeSDR?
>
Wide open front end - potentially receiving all signals across 3.8GHz
bandwidth? Pretty much every radio we're used to has filter components
real inductors and capacitors. No is my guess :(
> > Ubuntu have produced snap packages.
> >
Looks like those are SoapySDR, Pothos and so on - nothing special.
> > It should work with gqrx - as ever, the problem is getting decent
> > transmit - see also HackRF which has similar problems, though the
> > LimeSDR is at least full duplex. Almost nobody is using GNURadio
> > for good quality transmit - it requires RF, DSP and (potentially)
> > FPGA expertise to get anywhere close at the moment - the number of
> > amateurs with good expertise is miniscule, the number of professionals
> > is probably the number of amateurs plus ten or twenty.
> >
>
> I had imagined using a QRP amplifier for about 30 dB gain, taking it
> from 10mW up to something in the range 5W - 10W. The amp would need to
> have some filtering (LPF?) for anything that goes to the antenna. Will
> a good choice of amp be enough, or what other problems would I possibly
> need to solve on the TX side?
>
Bear in mind that the LimeSDR is basically intended for FM/GSM etc. -
linearity in the amp? Not so good if you want to transmit SSB.
There's also the limitation of bandwidth to what will fit down a USB3 -
though there is the PCI card option at significantly higher cost.
>
> > To be honest, there may be more mileage in producing Linux drivers
> > for some of the more mainstream SDR e.g. the SunSDR QRP?
> >
>
> Do you know anything about the API, the price or where to get them?
>
SunSDR QRP is £799, ELAD is about the same price
> Would you consider any of the sound card SDR solutions to be more
> suitable for working the HF bands? One concern for me is to try and
> develop a highly portable setup that I can take to events.
Something like the SoftRock isn't that good. If you really want a
portable set up - KX2, KX3 or the Mountain Topper radios avaliable
from Kanga UK. Or, indeed, the canned WSPRlite from Sotabeams
covered in this month's RSGB RAdio Communications magazine, for example.
>
> Regards,
>
> Daniel
All the best - glad to see that the Albania demo went significantly
better than the Cambridge one :)
Andy C
G0EVX
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