BATC Forum

GB3NQ input is 2000kSR so I thought that the Lime Mini was the only way to access it using a Portsdown 4. However I had a long QSO with M0BFB through the repeater and he was using a Portsdown 4 and a Pluto. He said he had quite a job trying to get his setup to work and nearly gave up. The QSO showed it worked.
I experimented with my Portsdown 4 and Pluto and found there were two modes that worked.
Modulation S2QPSK H264 CompVid FEC 1/2 4:3 (or 16/9)
or
Modulation S2QPSK Encoder IPTS in FEC 1/2 with an external H264 encoder (AMX NMX-ENC-1100 running at 1360 * 768)

As the Limemini seems to be in short supply and the Pluto can be bought for around £130 it may be way for people to get into DATV repeaters that require larger SR.
You will need some sort of video input as the webcam and Pi cam did not seem to work at this 2MSR

I was using the Pluto on the network connection via a 1Gb LAN (just to make it more difficult!) This showed when the Portsdown was working the Pluto as the LAN 'busy' lights flashed faster. The Portsdown might not always start to transmit through the Pluto (as G0BFB was finding ) but seemed to work most of the time.

The Pluto can also be used using Langstone and also for 10GHz TX using 5th harmonic into a waveguide.


Martin G8LCE

Other ways of feeding the Portsdown 4 and Pluto for 2000kSR would be from vMix or OBS from this post
viewtopic.php?f=15&t=7207
or from another Portsdown using the IPTS out.

Martin G8LCE

Martin,

my Ethernet-USB adapter seems to have packed up so I tested my Pluto (PWR set to 0) on a USB cable straight into the Pi4's USB3 port. On the o/p I used the Pluto's rubber duck.

I transmitted the testcard across the bench on 2407.250 MHz to Minitiouner/Minitioune with SR333, FEC 9/10.

In spite of a lovely constellation sending DVB-S, MT didn't decode it, but S2QSK, 8QSK and 16PSK all decoded fine and looked very good.

I'm using Portsdown version 202102250.

73 Graham - G3YJR

Graham

As stated on the Wiki, https://wiki.batc.org.uk/Portsdown_4_Pl ... ctionality the Pluto only works well up to 1 MS. Somthing internal to the Pluto (not Portsdown) won't handle DVB-S at higher SRs than that.

If you want high SR DVB-S, the LimeSDR Mini driven by Portsdown can manage over 4 MS.

Dave