My Portsdown Conundrum - Actually a MiniTiouner Issue!

[g4eml]

There have been several reports recently about faulty buck converters. It might be worth replacing it with one from another source.

Alternatively you can disconnect the output from the buck converter and instead feed the regulators from 5V with a wire link from the USB module. The minitiouner will then run from USB power and the external power will run the LNB. That’s how I have always run my minitiouner.

[M0SKM]

How do others power the LNBs - separate PSUs for the MiniTiouner and the LNBs?

Mark
G0MGX

Hi Mark,

I'm using a Global splitter with a domestic satellite receiver on one output. Most days I just leave it tuned to Euronews and that sends the 18 volts to the LNB.

https://cpc.farnell.com/global-communic ... dp/SE00009

73 Steve

[g8vpg]

I built a separate power supply for my satellite monitoring system. I bought a general purpose 18V 3A switch mode psu in a ventilated metal case from Ebay for just over £15. I adjusted the output voltage to 17V, which is enough to select horizontal polarisation. I added a couple of line inductors and decoupling capacitors across the output, although it seems quite clean anyway. I then provided three outputs, two at 17V and one at 12V via a 7812 linear regulator. Each output has its own 500mA quick blow wire fuse, so if the LNB output is shorted, it won't take out the inductor in the NIM. Minitioune runs quite happily on 17V because the switch mode board on the input takes the input voltage down to 3.7V. This arrangement allows me to run Mintioune and an SDR for the NB transponder from the same psu.
73 Shaun.

[G8GKQ]

This is all connected to the PSU for the MiniTiouner.

I have a buck-boost on the board to drop the supply DC down to 4V which then feeds the on-board regulators.

Mark
G0MGX

Hi Mark

So, does this seem to be a MiniTiouner buck converter issue, rather than a Portsdown or LimeSDR Issue? Please let me know and then I can move the discussion to the MiniTiouner thread.

Dave, G8GKQ

[g0mgx]

Yes, most definitely - please move the thread.

Mark