[linux-dvb] [OT] UHF masthead amp power supply location

[linux-dvb] [OT] UHF masthead amp power supply location

[Nicolas Will]

This this OT, but I don't really know where to ask. And after all, the
odds are that I will find a person with that sort of knowledge here.

I currently have a masthead amp for my DVB-T antenna. It uses a power
supply in the house that inject current through the antenna cable.

I am now installing my Sat DVB-S system properly (i.e. not with a cable
going through an open window), and I'd like to use a combiner/splitter
system as I cannot lay a new cable from the dish to the tuner for the
satellite signal (very old granite house), and I would like the existing
cable going under the floor.

I am afraid that the masthead amp power supply will be bothering the
whole deal. I cannot get rid of the amp, my DVB-T reception is too weak
without it.

Here are diagrams of my 2 options:

http://www.youplala.net/~will/htpc/Satellite/masthead_amp-where.png

Option A - This is the easiest for me to achieve, but the position of
the power supply worries me.

Option B - I'm confident that this is technically sound, except that the
necessary physical location of the power supply in this case has no
power plug nearby...

My question is: can Option A fly?

Thanks for your help.

Nico



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Re: [linux-dvb] [OT] UHF masthead amp power supply location

[Adam Nielsen]

> This this OT, but I don't really know where to ask. And after all, the
> odds are that I will find a person with that sort of knowledge here.

Perhaps a satellite TV forum, if you don't get any good replies here.

> Option A - This is the easiest for me to achieve, but the position of
> the power supply worries me.
> 
> Option B - I'm confident that this is technically sound, except that the
> necessary physical location of the power supply in this case has no
> power plug nearby...
> 
> My question is: can Option A fly?

I'm no expert, but I think with Option A you'd have problems trying to
send 12V and 13/18V over the same line.  I don't know how the power
distributed, but is it possible to run the masthead amp from the 13V
supplied by the sat tuner?  As long as it doesn't choke on 18V (and the
sat combiner doesn't block the voltage) that might be an option.

Of course if each power supply increases the voltage (so putting in 12V
and 13V means you actually have 25V on the cable for a while) then it
might work, but I don't think that's how it's done (or if it is, I don't
think the sat combiner would strip out the 13/18V and leave 12V on the
line for the masthead amp to use.)

I don't know whether the power is sent as DC or AC, but if your masthead
amp runs on roughly the same power as the sat tuner puts out, you might
be able to do away with the masthead amp altogether, assuming the sat
tuner still puts out power when you're not watching a sat channel.

Again - I'm no expert!

Cheers,
Adam.

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Re: [linux-dvb] [OT] UHF masthead amp power supply location

[Olaf Titz]

> http://www.youplala.net/~will/htpc/Satellite/masthead_amp-where.png

Option A is not possible, because the LNB is powered by the tuner too.
You can't have two power supplies in parallel on the same wire.

(The only solution would be to draw the power for the amp from the LNB
supply too, so you would need a suitable combiner and perhaps a
suitable amp which runs on 13-17V [AC or DC?], and you would need a
sat tuner which can deliver enough power for LNB plus amp, and never
turn it off. Unlikely that such components exist.)

Olaf

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Re: [linux-dvb] [OT] UHF masthead amp power supply location

[Martin Thompson]

years ago i had a sat installed
because of the wall they used a combiner/decoder with power pass
like these

http://www.hillsantenna.com.au/cattleprod/products/D3101DIP

so the power goes via the cable but not onto the fta side
put your amp power supply up in the roof after teh combiner

----- Original Message ----- 
From: "Nicolas Will" <nico@youplala.net>
To: <linux-dvb@linuxtv.org>
Sent: Friday, February 29, 2008 8:25 AM
Subject: [linux-dvb] [OT] UHF masthead amp power supply location


> This this OT, but I don't really know where to ask. And after all, the
> odds are that I will find a person with that sort of knowledge here.
> 
> I currently have a masthead amp for my DVB-T antenna. It uses a power
> supply in the house that inject current through the antenna cable.
> 
> I am now installing my Sat DVB-S system properly (i.e. not with a cable
> going through an open window), and I'd like to use a combiner/splitter
> system as I cannot lay a new cable from the dish to the tuner for the
> satellite signal (very old granite house), and I would like the existing
> cable going under the floor.
> 
> I am afraid that the masthead amp power supply will be bothering the
> whole deal. I cannot get rid of the amp, my DVB-T reception is too weak
> without it.
> 
> Here are diagrams of my 2 options:
> 
> http://www.youplala.net/~will/htpc/Satellite/masthead_amp-where.png
> 
> Option A - This is the easiest for me to achieve, but the position of
> the power supply worries me.
> 
> Option B - I'm confident that this is technically sound, except that the
> necessary physical location of the power supply in this case has no
> power plug nearby...
> 
> My question is: can Option A fly?
> 
> Thanks for your help.
> 
> Nico
> 
> 
> 
> _______________________________________________
> linux-dvb mailing list
> linux-dvb@linuxtv.org
> http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb

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Re: [linux-dvb] [OT] UHF masthead amp power supply location

[Nicolas Will]

Thanks all for the comments, here or in private.

Option B it will be.

I have to bite the bullet and manage to get a power point where I need
it now...

Nico


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