18v h power

Discussion about the MiniTiouner board and the MiniTiouner Digital ATV Receive Software. See also http://www.vivadatv.org/index.php
Post Reply
m1cdq
Posts: 7
Joined: Thu Feb 28, 2019 4:28 pm

18v h power

Post by m1cdq » Sat Mar 09, 2019 7:05 pm

Im thinking of fitting a small dc-dc buck convertor 12v to 18v
this is for the V/H on a lnb and make it switchable.. via a switch on the case

but Im thinking and i presume the output ground on the dc buck is isolated/floating from the input. and connecting this to the lnb power input on the board would bring the output group down to the min ground of the case. and this would defeat the upconvert to 18v

reason on thinking this route is i will be able to use it portable and not have to mess about with lnb all the time just switch it and be able to run from just a 12v supply

g8gtz
Posts: 1059
Joined: Wed Apr 07, 2010 6:26 pm

Re: 18v h power

Post by g8gtz » Sat Mar 09, 2019 7:20 pm

Hi

The typical ebay upconverters should common earth and can be used.

In fact, this is exactly what I have done to generate 12 or 18v from the 12v rail and switch it via a center off 3 position switch - center off makes sure there is no chance of shorting the 18v to 12v rail!

73
Noel - G8GTZ

m1cdq
Posts: 7
Joined: Thu Feb 28, 2019 4:28 pm

Re: 18v h power

Post by m1cdq » Sat Mar 09, 2019 8:29 pm

cheers for the reply noel
If found non isolated ones so Im going to give it a try. Same as you a centre off 3 switch

g0mjw
Posts: 707
Joined: Sat Sep 20, 2014 9:15 am

Re: 18v h power

Post by g0mjw » Sat Mar 09, 2019 10:44 pm

g8gtz wrote:
Sat Mar 09, 2019 7:20 pm
Hi

The typical ebay upconverters should common earth and can be used.

In fact, this is exactly what I have done to generate 12 or 18v from the 12v rail and switch it via a center off 3 position switch - center off makes sure there is no chance of shorting the 18v to 12v rail!

73
Noel - G8GTZ
Hopefully, but beware of things with capacitors in them that charge to 18V and you then connect then to your 12V rail.

Mike

F6DZP
Posts: 180
Joined: Fri May 27, 2011 9:59 am

Re: 18v h power

Post by F6DZP » Sun Mar 10, 2019 12:54 pm

Hi,

Someone in France has made a pcb for adding the same LNB chip as it is used in the MiniTiounerPro, for adding the possibility to give 13v, 18v and 22kHz/diseqc messages to the MiniTiounerV2_BATC.
This chip is protected and we can use 400mA continuously.
I am adding the use of this extension in the config.ini for Minitioune V0.9

Jean-Pierre F6DZP

YL3AKC
Posts: 12
Joined: Wed Aug 08, 2018 8:42 am

Re: 18v h power

Post by YL3AKC » Sun Mar 10, 2019 11:55 pm

I solve 18V problem cardinally. I have Twin LNB with Rafael Micro RT320M mixer inside. Similar to this LNB: http://www.pabr.org/radio/lnblineup/lnb ... LSO%201609

The idea is following: Each IF output have voltage sense pin connected to corresponding F connector. I found that there are 200K and 20K resistor dividers. So, when you apply +13V out get 0.9V on sense pin, and when apply 18V, you get 1.9V. What I want? I want that on one f-connector there is always H-pol and on second f-connector I want V-pol. Supply for mixer is made by two linear stabiliser ICs and then merged by 1n4148 diodes. So, I calculated divider and connected sense pins to diodes middle point (true VCC ~ 5.5V) 1st thing: find 220K (or 200K, I don't remember exact numbers) resistors and remove them. Then to get V-Pol (12V equivalent), connect between true VCC and sense pin ~91k resistor. To get H-pol (18V equivalent) use ~32k resistor. Now I have H and V outputs from LNB. And it desn't matter where you feed BIAS and doesn't what is bias voltage. I am using 12V BIAS voltage now, but considering to use as low as 7.5-8 V in future.

PS: Thinking to use CATV combiner to combine NB and WB signal in one coax cable and feed down to "radio corner" where are BIAS inserter (SPAUN and +12V), computers and transceiver.

Post Reply

Return to “The MiniTiouner and MiniTioune Digital Receive Software”