My Portsdown Conundrum - Actually a MiniTiouner Issue!

Discussion about the MiniTiouner board and the MiniTiouner Digital ATV Receive Software. See also http://www.vivadatv.org/index.php
g4eml
Posts: 34
Joined: Thu Apr 26, 2018 9:36 am

Re: My Portsdown Conundrum

Post by g4eml » Sat Apr 20, 2019 7:23 pm

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
Posts: 253
Joined: Sun Jul 13, 2014 3:15 pm

Re: My Portsdown Conundrum

Post by M0SKM » Sat Apr 20, 2019 10:43 pm

g0mgx wrote:
Sat Apr 20, 2019 7:15 pm
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
Posts: 311
Joined: Fri Oct 11, 2013 9:35 am

Re: My Portsdown Conundrum

Post by g8vpg » Sun Apr 21, 2019 9:47 am

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
Site Admin
Posts: 1268
Joined: Sun Mar 22, 2009 1:21 pm

Re: My Portsdown Conundrum

Post by G8GKQ » Sun Apr 21, 2019 1:59 pm

g0mgx wrote:
Sat Apr 20, 2019 7:15 pm
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
Posts: 31
Joined: Sat Dec 31, 2016 7:57 pm

Re: My Portsdown Conundrum

Post by g0mgx » Sun Apr 21, 2019 2:23 pm

Yes, most definitely - please move the thread.

Mark

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