DC interfering with high-frequency digital signal?

I need to run 250 ft. of 2 cables, and they have to be right next to each other. I'm trying to figure out if low-voltage DC electric
interference will be an issue. Hopefully the following data is sufficient:
Cable 1: twisted pair 15VDC at 13W 2 conductors, 16AWG: stranded bare copper, radius=0.645mm, resistance 4ohm/1000ft.
Cable 2: Coaxial 18AWG conductor: solid bare cooper, radius=0.51mm, resistance 6.4ohm/ 1000ft. Full copper braid and foil Shield: see full specs for VSD2001 in http://www.gepco.com/products/proav_cable/video/coax_hd_sdi_F.htm
The signal is SMPTE 292M, a.k.a. HD-SDI, carrying 70mA of 800mV peak- to-peak, at 1.5Ghz. More detail in http://en.wikipedia.org/wiki/HD-SDI . I know the coax alone is fine, since the manufacturer certifies it for 300-560ft. of HD-SDI.
I'm not expecting anyone to delve into the HD-SDI specs to figure out exact error tolerance, I just hope to get an idea of whether I should be worried or not. Should I go to lengths to get a shielded version of cable 1?
Any insight is appreciated.
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DrewL wrote:

You don't need to twist them and solid 14AWG solid might be cheaper. (With the price of copper going up, the #16 might be cheaper, but it's not a standard gauge for power wiring.)

DC doesn't radiate! No problem. Even if the DC is "noisy" the co-ax shielding should be adequate.
--
Virg Wall

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That sure makes it all sound easy :-) I do plan to use the most expensive DC power supplies I can find - ones for laptops - so for the sake of my signals and the expensive equipment they'll feed, I hope they will behave.

I have plenty of twisted & stranded 16 AWG in stock (speaker wire), so costing an extra $0 makes it the cheapest and preferred choice...
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DrewL wrote:

These may be expensive for other reasons than quality. There are many excellent 15V power supplies on the market.

Free is always cheaper than anything else! My point was you don't need the twist or the stranded and 14AWG is availably extensively.
Don't let monster Cables know you're using #16 for speakers! :-)
--
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Even if he was using #10 it would be cheaper than monster cable;-)
--
Tzortzakakis Dimitrios
major in electrical engineering
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wrote:

And sound at least as good !

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sparky wrote:
??????

But it wouldn't be OFHC Copper! :-)

Some interesting observations:
From: http://www.roger-russell.com/wire/wire.htm#oxygenfree
"...So what do our fifty hours of testing, scoring and listening to speaker cables amount to? Only that 16-gauge lamp cord and Monster cable are indistinguishable from each other with music and seem to be superior to the 24 gauge wire commonly sold or given away as 'speaker cable.' Remember, however, that it was a measurable characteristic--higher resistance per foot--that made 24 gauge sound different from the other cables. If the cable runs were only 6 instead of 30 feet, the overall cable resistances would have been lower and our tests would probably have found no audible differences between the three cables. This project was unable to validate the sonic benefits claimed for exotic speaker cables over common 16-gauge zip cord. We can only conclude, therefore, that there is little advantage besides pride of ownership in using these thick, expensive wires"
--
Virg Wall, P.E.

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??????
Ah. But they weren't using one of these power leads ;-)
http://www.psaudio.com/products/xstream_ultimate_overview.asp
Tim.
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wrote:
??????

Or perhaps one of these: http://www.needledoctor.com/Tara-Labs-ISM-The-ONE-AC-Power-Cable
I can't believe there's more than one company doing things like this (or is it all an elaborate April fool?)
Tim.
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snipped-for-privacy@woodall.me.uk wrote:

??????
The audiophile community seems to have a adequate supply of fools, regardless of the month! There's a more than adequate supply of those ready to fool them, if only most of the time.
Where else is a complex signal transmitted and replicated many times through non-linear systems, accessed by a non-linear human ear, and evaluated by the most complex element of all, the human brain?
No wonder there's room for fools! "Send in the clowns."
--
Virg Wall

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$140 a foot? For $2bn you have a custom nuclear power plant, (1.3 GW, impulse current 100 kA at 400 kV)with enough wattage to satisfy even the more power hungry stereo maniac! Complete with OFC wiring right to your receptacle. I thought that somebody would think of special plug cables! (PS see in this videoclip in you tube an interesting song by OMD with some disconnect switches closing
http://youtube.com/watch?v=Sq2vl99iIEc&amp
;feature=related )
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