Portsdown 4 Changing from DVBT to DVBS-2

[G3XPY]

Having successfully used Portdown 4 and Pluto for DVBS-2 for some time I am trying out the potential benefits of using DVBT.

I have noticed a problem with the Portdown 4 / Pluto when selecting DVBS-2 after using DVBT because the Pluto produces the wrong output.
In addition this wrong output is maintained for some 2 minutes after switching off TX.
A system reset of both Portsdown and Pluto is required to get back to normal working.

Two other local stations using the same setup and up to date software confirm that they have the same problem.

A video demonstration is available at https://1drv.ms/v/s!AgkBtYQMyUfVgZg5gC1 ... A?e=jxkdHy

[VK3IE]

G,day
Recall you need to reload the firmware for lime. via PD4
Remembering to reload DVB when you need to go back to DVBS

[g8lce]

Hi VK3IE,

It is not the Lime we are using, it is the Pluto. In Cornwall we are trying the DVB-T for 146.5MHz as it may offer a way for more remote stations to use GB3NQ. Therefore we are doing lots of experimenting with it and also DVBS-2. It could be a quirk in the Pluto firmware or a bug of the Portsdown 4 software. However if you do switch between the two systems you may end up with a transmission that does not conform to the standard and last for a longer time than you expect. It is also higher power than you might have expected. It transmits correctly the first time but after switching back and forth between the standards, it may not be correct the second time. Resetting the Pluto may get you back to normality for the next transmission. See Alan's video for a good explaination. (and see his high quality video!).

Martin G8LCE

[g8lce]

This issue can be got around if you reboot the Pluto each time you switch between DVB-S and DVB-T by going to menu 3, Pluto Config, Reboot Pluto.
Maybe this could be included in the software?

Martin G8LCE