Not exactly certain about purchases. I -believe- the system is only available right now for rentals, but as with everything I'm sure that could be negotiated.
There are currently 2 systems that I would look into;
The system originally built for the WFFC was less than $5000. There was actually more invested in parts/configurations that did not work well. The final configuration was good for very clear video and good audio (audio was secondary, of course). If you are looking for broadcast quality, the camera used would have to be upgraded, but the transmitter/reciever would work just fine.
The system was lost in a house fire, and I haven't had the capital to rebuild it. Certainly not something you'd want to build for a one-off production, but if the demand was there, I'd consider building another.
quade (D 22635)
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Dec 12, 2002, 10:59 AM
Post #9 of 26
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I'm not saying it -couldn't- be done for less cash.
No. What I'm saying is that if you wanted broadcast quality air-to-ground video suitable for covering say, a demo squad jumping into the Olympics or something of equal criticality, there is currently some amazing off-the-shelf stuff you can rent.
Of course, you could ask ANDREVIDEO, since he invented it - literally - and built the first unit from scratch. Not many know this, but he was doing it live in the mid 1980's with awesome quality - but never patented it.
Yeah, but I believe that was an older analog system much like the one that the Wagner's still occasionally use.
The issue I have with these older systems a problem called multi-path. Bascially, the signal gets reflected by objects along the way and can cause some significant interference in certain circumstances -- requires a bit of skill and luck to get it running right. Obviously the systems were great for their time, but the current state of the art is so much better and darn near fool-proof. If you need something you can count on actually working, the newer COFDM systems are definately the way to go.
Quade - you're spot on with the analog/dig microwave comparison. I had a live shot today with a conventional microwave ENG truck that should have been really easy to get a good signal. I was within a stone's throw of the tower I was trying to hit, but ended up with a very marginal signal b/c of "multi-path" reflections/bounces... It can be a royal pain some days. I'm not an engineer, but how does the newer system get rid of the multipath so well? matt
quade (D 22635)
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Dec 13, 2002, 9:47 AM
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The key technologies behind the COFDM stuff are Mpeg compression and transmission algorithms that actually take advantage of multi-path.
In other words . . . multi-path actually helps rather than hurts. So, you don't have to have line-of-sight and being in a concrete canyon is no obstacle. Go ahead and shoot around the corners of a building back to the microwave truck, no big deal. Further, because it's all digital, there's no signal fade really -- it's either working or it isn't. This can be an advantage and also a disadvantage depending on the way you look at it, but generally speaking it looks better with a weaker signal right up until the time it craps out.
The only drawback with the newer systems is there is a slight delay because of the Mpeg compression and transmission of about 1/10th to 1/3rd of a second depending on how robust you want the error correction. This is damn near trasnparent at the 1/10th of a second delay, but is roughly the same as a standard satellite delay at the 1/3rd of a second end of things. Makes IFB & cueing interesting.
Is it possible to transmit live video air-to-ground via 3G/4G cellular network? I am sure it’s technologically possible, but has anybody done it? I am a cell phone dealer and am very interested, because it would be cheap with unlimited data plan.
Is it possible to transmit live video air-to-ground via 3G/4G cellular network? I am sure it’s technologically possible, but has anybody done it? I am a cell phone dealer and am very interested, because it would be cheap with unlimited data plan.
Once you're in the range of the cell phone, sure... why not?
This is something that I wanted to test out but never got around to it. Might be an inexpensive consideration. Don't know if it would have the quality that you were looking for.
Some people brought their Iphones on the plane to test the GPS. They normally lost signal less than half-way up to jump altitude (cell navigation requires reception from the tower too). We have concluded the cell towers are transmitting in a super flat angle; the antennas don’t beam “up ward” at all. Engineers designed the cell tower system to beam in a flat radial angle rather than every (spherical) direction .
There’s another thread about this somewhere on DZ.com…. We agreed the digital signal would be the best. I think the easiest would be if a 1-2watts of UHF transmitter would be directly modulated from the fire wire port. Now days a size of such a transmitter is very small and light, the 2watts of power in that frequency is strong enough even with a ¼ wave antenna to transmit in a few miles radius. And of course the digital signal would allow transmitting without the loss of the quality.
(This post was edited by Laszloimage on Jan 29, 2010, 4:22 PM)
I found this on ebay: http://cgi.ebay.com/...?hash=item35a6a688f1 ...and it's only $375! 4 Watts on the UHF band is pretty good. This only for analog SD signal though. But I'm sure it would do the job pretty good.
I would love to combine somehow this: http://www.arcade-electronics.com/...roduct%20Sheet-2.pdf with that 4 watts TV transmitter. This device basically is an HDMI RF modulator (I assume somewhere in the UHF range). That would create a UHF DTV transmitter.
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