ADALM-PLUTO (new DATV SDR)

[radiogareth]

As an experiment I tried running both MT V0.8 and DATV Express on my tablet PC a linx 12x64 Intel Atom x5-Z8350 CPU at 1.44GHz. It works fine, using just under 90% cpu when transmitting and receiving 2000Ks/s on 437 MHz. It included using the internal camera. I bought this unit specifically as it had USB3 (via a USB3 hub for the two devices.
Makes lightweight portable a reality. The tablet has good battery life too and a mini USB to keep it charged.

£200 from AO.com.

Gareth

[G4FRE]

Mine has had the devices labelling scratched off!

Interesting. It's supposed to produce a lot more power than that! What are the devices in that amplifier ? Surprised it's linear at a half watt or so needed to drive the LDMOS.

[g7jfi]

Mouser have some Pluto's in stock, ordered one yesterday, just received email that it has dispatched

[radiogareth]

Wondering if one of these https://www.ebay.co.uk/itm/LNA-0-05-4G- ... Swor1aT0Vy would go well on the output of my Pluto. Spec says:Voltage: 5V
Current: 90mA
Gain:18dB@0.9G
Input/Output Impedance: 50Ω
Max. Output Power: P1db 22dBm(@2GHz)
Input Signal: <+10dBm(as low as -110dBm. If input >+10dBm, output is distorted)
Bandwidth 0.05-4GHZ(differs at different frequency, refers to S21 curve)
Noise Factor:0.6dB@0.9GHz
Size:6x2.4cm/2.36x0.94inchh
10Dbm translates to 100mW so on paper it looks ideal. I'm going to my club this evening where I can access a spectrum analyser up to 1.3 GHz We shall see....

[radiogareth]

Power to the Pluto
I was able to test it on a calibrated SA from 50MHz up to 1300 MHz. At the lower frequencies it was drivable to distortion (shoulders above -35dB) but at 1296 it was OK on full Pluto power. As a rough indication we were getting about 22dBm (150mW +/-) so a useful increase in terms of driving other things. Linearity can be maintained on the lower frequencies by limiting the Pluto drive level in Express DVB. As the amp runs from 5 volts that should be available inside the Pluto case, yet to be investigated. A neat solution.
Link again: https://www.ebay.co.uk/itm/LNA-0-05-4G- ... Swor1aT0Vy or this one in a posh metal box https://www.ebay.co.uk/itm/Low-Noise-LN ... 0005.m1851
Onwards to finish my Portsdown properly now

[g7jfi]

Hi,

That's good info about the amp Gareth, thanks. What is the active device in there, I would like to look at the datasheet.

Cheers
Terry G7JFI

[radiogareth]

So small I had to dig out extra magnification - I assumed it had been scrubbed off! Its a SPF5189Z. https://www.qorvo.com/products/p/SPF5189Z Not bad for a £5 with SMA's and board!!
Spectrum as shown....

2018-09-17 20.16.34.jpg (608.16 KiB) Viewed 8337 times

2018-09-17 20.16.34.jpg (608.16 KiB) Viewed 8337 times

Looks like its good to 13cm too, unlike my colleagues SA!
Driven by 2000KBs/pluto/webcam
Gareth

[g7jfi]

Hi

Started to play with my new Pluto last night. Setup to use my webcam as a video source. The Pluto was plugged into the USB 2.0 port on my PC as was the webcam, I assume on the same USB hub inside the PC. I could only get as high as 3MS/s on DVB-S, 4MS/s and there was break up of the picture received. Interestingly though, I have a USB 3.0 card fitted in the PC too, and when the Pluto is plugged into that, I can achieve a stable 4MS/s which is nice!

As I am led to believe that the Pluto is a USB2.0 device, I can only assume the webcam was taking just enough USB bandwidth on the PC's USB2.0 hub to throttle the data out to the Pluto, until the Pluto effectively got a USB hub to itself.

Anyone have any thoughts on whether that is plausible or not? Anyway I'm well chuffed I can get 4MS/s, makes it use-able to access GB3VL for me.

I also have the maxcpu mod done and cat /proc/cpuinfo shows 2 cores in the Pluto.

Terry G7JFI

[G4GUO]

Yes it is supposed to be a USB2 device. Interesting to hear it seems to work better
plugged into USB3. USB3 is actually a bit of a kludge as it has USB3 data lines in it but also
a set of USB2 data lines as well so it is basically 2 USB types in 1 socket.

- Charles

[VK5YYY]

Hi Terry

I found the same 3msym worked but 4msym didn't, bombed out around 3.2msym in my testing, USB 3 didn't help
Charles said you could expect around 2msym
Portsdown with the Logitech C920 is stable at 5msym
With older versions of DATV express Lime ran at 5msym too, but the bandwidth is higher with USB 3
My older PC managed only 2msym recently with Lime mini and current DATV express software
If Pluto can achieve 4msym sounds like you are breaking new ground

Cheers Roger VK5YYY