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Wireless Cameras?
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Sorry, they are Canon HF G10’s with a Blackmagic HDMI to SDI Converter with SDI. I guess it would have to be a SDI run all the way to the switcher.
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Remember that HD-SDI has a cable length limit that changes depending on cable used, both cable gauge (RG59 or RG6) and by cable type/ballistics…
I’m sort of surprised Richard is getting signal integrity at 300 feet with CHEAP RG6… but RG6 IS more “forgiving” than RG59, at the cost of heavier, stiffer cable…
Belden 1505a, which my system will eventually be built around, has a theoretic limit at 1.5GHz of 300 feet and is considered a “premium” cable for HD-SDI use.
Big Dog – Technical Director – Switcher
Road Dog Media – Vancouver, BC Canada
roaddogmedia@gmail.com -
The cable I am referring to is cheap/inexpensive only because of the economy of scale. Miles of this cable are purchased and installed every day. Else it would cost several times more.
This cable is made for use at higher frequencies (satellite IF frequencies) than we need for HD-SDI. To be sure, it is quite stiff and not very practical for portable use. 300ft (100m) is the textbook limit for HD-SDI through RG6. One of these days I’m going to try even longer runs just to see where the threshold is.
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I understand completely Richard, as someone who used to fabricate all his own cables “back in the day”…
The “formulation” of a specific cable of course figures in shielding, capacitance and resistance and how it attenuates specific frequencies over a given length. The Belden 1505a (RG 59) and 1694 (RG6) are optimized for HD-SDI implementations.
Satellite cable is built for it’s specific properties and I’m pleasantly surprised to hear you have had such luck. Again, we are talking about THEORETICAL limits here… The point beyond which the signal is sufficiently attenuated so as to no longer meet “spec” and may fail to pass the required “peaks and valleys” adequately. There are also many factors into what the initial signal integrity is in the first place: at NAB, there was a matrix router manufacturer that was showcasing a LONG length of cable (post matrix router) which was showing proper burst on a scope even after approximately 450 METRES. (my dear American friends, 1 metre equals 39 inches) So well in excess of 3 times the theoretical limit of the cable, which I believe was 1694.
Big Dog – Technical Director – Switcher
Road Dog Media – Vancouver, BC Canada
roaddogmedia@gmail.com
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