Pluto downconverter for Mini-tiouner?

[radiogareth]

Whilst software does exist for DVBS/S2 reception using the hacked Pluto, (DVBS2-GUI and SDRAngel) it crossed my mind that people might prefer to use the comprehensive facilities of MiniTiouner or indeed Longmynd (which works very well for me) to receive their video. But there are limits to the tuning range of the Serit NIM, missing out on 70MHz, 9cm and 6cm. It seems a lot of 'experienced operators' have over the years built up NB transverters which I am now reading about being used for DATV conversion. Other than the IF generally being targeted at 144-146, (which can compromise the received TX frequency as designed for the NB part) this seems a sensible solution.

I have at best an 'awareness' of GNU Radio and the fact that the Pluto has a LINUX SBC lurking within it.
Would it be feasible for the Pluto to receive on one frequency and 'transvert' it on another to the TX port? Access to the GPIO (top two bits so as not to get in the way of the GPIO 0 & 1 bits used for PTT switching in other Pluto modes) could provide band select (4m, 9cm and 6cm).
Some front end filtering and gain (MODAMP and pipe-cap filters would seem simplest, except on 4m!) should clean things up for the MT front end.
ALso gleaned from other posts is the ability of the Pluto to boot from an external drive if one is found on power-up.

At this point I'm well beyond my 'pay grade' but with projects like Portsdown and Langstone, the Lime Mini/USB and the Pluto this sort of thing brings what was previously the almost exclusive area of microwaves into the realms of people like me who can follow instructions and connect things together......

Thoughts.....

Gareth G4XAT

[g0mjw]

Hi Gareth,

It is possible. I did this on 4m a while back. You use the Pluto as a transponder converting one band to another. I found it didn't work as well as a simple mixer, filter with 400MHz LO so I designed that conversion module instead.

In Gnuradio Companion on a PC this is very simple to implement with the Pluto source and sink modules and some filter modules. It makes an interesting learning experiment, so try it. Then you can think on improvements like AGC.

What I do not know is can this be done by the Pluto SBC all on it's own. Quite possibly.

Mike

[g4eml]

The analogue devices wiki does have an example of running GNU radio directly on the Pluto from a USB stick. I have never tried it though.

Colin.

[G4FKK]

Hi Mike,

I've been stumbling around, playing with Gnuradio companion on my PC but with some encouraging results. At the risk of asking a stupid question; how do I install the Pluto source and sink modules? So far Googling seems to think this is far from easy and is better done on Linux and by someone cleverer than me

At the moment this SDRery is like some sort of wizardry to me and I sometimes get reminded how I felt as an 8 year old trying to get my head around how a crystal set works

73, Martin - G4FKK

In Gnuradio Companion on a PC this is very simple to implement with the Pluto source and sink modules and some filter modules. It makes an interesting learning experiment, so try it. Then you can think on improvements like AGC.

[g0mjw]

I have not used it for some time but I think the Pluto source and sink is installed as standard. You can't RTFM as there isn't one. So, I fired up GRC for the first time in a long time on Windows and found a flowgraph I used to show this to Jules G0NZO came up. That should get you going.

Mike

[G4FKK]

Thanks for the quick reply Mike,

Unfortunately it's not installed on my version (v3.8.0.0). I'll do some more Googling - clearly it's possible

73, Martin - G4FKK

[g4eml]

The analogue devices wiki has a Windows GNU radio installation that includes the Pluto.

Even when it is installed it is not easy to find because it is hidden in under the IIO devices branch in the module tree.

Colin.