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Old June 13th, 2002, 04:14 PM   #1
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wireless v-tap?

Ran across this wireless video tap, and am wondering if anyone has had any experieinces using these?

goto:

http://www.shotwatcher.com/


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Old June 13th, 2002, 10:11 PM   #2
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Ford:

Yes, I use this type of transmitter, and they give a lot of bang for the buck...but this particular unit is overpriced. Check out:

http://www.supercircuits.com/STORE/prodinfo.asp?number=AVX434MINI&variation=&aitem=1&mitem=5

This is a similar transmitter for only $139.95, plus it's a fraction of the size. It's essentially a shrinkwrapped board, definitely better sized for DV use.

It's important to note that to receive the signal, the TV you use must have sliderule tuning as opposed to the type that allow you to punch in the exact channel number. The signal appears just below channel 14 at the bottom of the UHF band.

It is important to check your audio playback as the transmitter can occasionally create a hum. Placement of the unit on the camera is critical.

I had to direct a shoot with two handheld XL1's equipped with transmitters a few months back, and mounted two little Casio LCD TV's side by side on a small aluminum plate. I was free to move around the room (getting out of the way of the cameras) and whisper directions to the operators as needed. Once you've worked that way, it's hard to go back to cables!
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Old June 14th, 2002, 06:44 AM   #3
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ATV

Guys don't consider this as someone telling you how to live your lives and Chris feel free to delete this if you desire because it really does not have much to do with this thread.

First off, as background, I am a video geek who happens to also be an amateur radio licensee (both expensive hobbies)

As pointed on the shotwatcher web page, you MUST have an amateur license and abide by the FCC rules governing amateur radio operators. What will happen if you do not? I would like to direct you to the Amateur Radio Relay League web page (www.arrl.org) and to take a look at 'Recent FCC Enforcement Actions'. Usually you will find one or two cases of unlicensed operation. The most recent one involved a $7000 fine which the individual neglected to pay and is now in a Federal Court in Florida. Actually he is getting off easy as FCC regs state 'up to $10K per occurance' so if you fire that little guy off 3 times in one day you can be looking at $30K at sunset.

Interference? If you interfere with a licensed operation (makes no difference if it is Amateur or Commercial) you are in a whole different league. Not only will the government get you but the individual licensee who you interfered with can apply for redress through the courts.

So do what you want but items like the shotwatcher and ATV434 will get you in trouble without a license. (434 Mhz is a heavily used TV frequency in the Amateur bands and bound to be noticed in a metropolitan area and most areas have what is called an 'Intruder Watch' which looks for unlicensed operation)

'nuff said about that. If you really like doing this kind of thing with wireless transmitters then get the license. You can get away from those little commercial grade transmitters and into higher power, longer range equipment. The license is basically free (taking the test costs around $7), lasts for ten years, renewable, and not that hard. Again, I will refer you to the ARRL web page for licensing info and ATV groups in your area.
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Old June 14th, 2002, 11:50 AM   #4
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Actually that has everything to do with this thread, thank you for posting that. It's good to be reminded of the things that we do that cross over the line as far as the law is concerned--that includes using and distributing pirated software and materials (everyone here pay for every piece of copyrighted software on their hard drive? Really?)

I'm probably more cavalier than I should be about the transmitter issue because virtually every film set I've worked on uses a TV band transmitter, they are industry standard and no-one seems to get busted. There have been some vague shadowy stories but largely unsubstantiated.

The range of these little 434 mhz transmitters is really not all that great, so in reality it's unlikely they will be noticed (most people seem to have cable or satellite these days anyway). I would think twice about using them if you are shooting material that is less than family oriented!

But thanks again for pointing out how to make this a legitimately-operated accessory. I will look into it.
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Old June 17th, 2002, 01:42 AM   #5
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RF transmitters

I guess what scares me the most is that we are discussing this stuff in an open forum that anyone could get to... and maybe I have seen too many of those shots on the news of people in dark suits carting out hard drives and computer systems to be used as evidence.

Alot of that 'TV channel transmitter' stuff that you see is completly legal. What they actually do is take the video and audio off camera and transmit it on an experimental band such as 2.5Ghz. The receiver then converts it down to a TV channel, say at 62 Mhz for channel two and outputs it directly to a monitor. Bottom line is that there are no transmissions on a band that requires a liense.

You mention about maximum distance of the signals. There are many things that effect transmissions. Primarily they are transmitter power, transmitter antenna and receiver antenna, receiver sensitivity. If I put together a more sensitive receiver and a high gain antenna I assure you that I can receive you transmitted signal at 10 times the distance that you are able to do so.

The Amateur community likes to put together what is known as 'repeaters' for ATV work. Usually it is a sensitive receiver system with a high gain antenna stuck on to of a local hill so that it has a clean, clear, line-of-sight view of the sourounding area. Your signal that you may not be able to receive on your receiver at 500 feet may be being broadcast all over the county. Unless you are taking close ups of flowers or something they know exactly were you are located because they have the point of view of your camera!

Again, this is just a word of warning. Just be very gently if you feel you must use any of these devices that say that they require a license. All it takes is one irate person and you now have a problem with which you prefer not to deal.
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Old June 18th, 2002, 09:10 PM   #6
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I bought a 2.4 gigahertz transmitter/receiver from a website in the U.S. and had it shipped to me in Japan(actually I had it sent to my sister in the states and SHE sent it to me, they don't export that stuff), been using it a couple of times at some clubs, works great, except the transmitter is sensitive to movement. I was worried if the video I transmit can be picked up by a tv but isn't 2.4 gigahertz and the tv signal pretty far apart.

But if for some reason it could be picked up by someone else, the Gothic event's VJ's stuff(devil/vampire images) and the S/M show I film would probably fit right in with late night japanese tv so people probably wouldn't mind it.

But using wireless it great, I can set up a monitor or projector on the other side of the club or out in lobby and not worry about cables, i definitely plan to get some more. I orginally wanted to use it to send my camera(XL-1) signal wireless but the transmitter isn't battery powered, anyone know of a good trans/rec out there that has a battery powered transmitter and small enough to attach to the XL-1. I'm not worried about the audio, I only need to send the video signal.
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Old June 18th, 2002, 11:26 PM   #7
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I have a catalog from www.supercircuits.com which lists several wireless video links in 434mhz, 900mhz and 2.4ghz flavors. I was considering using some of their equipment to send the output of a VCR to several TVs in a bar. After talking to a supercircuits.com rep, I decided against this solution. He said they were often subject to interference from many different sources and would likely not be suitable for my intended purpose.
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Old June 18th, 2002, 11:56 PM   #8
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Ed,
this is the one I have:
http://eye-witness.com/cgi-bin/quikstore.cgi?product=Mini24VT&category=Video_Transmitters

so far it's been pretty good, only thing is it doesn't like to be moved so I can't use it on my camera, plus it's not battery powered. maybe because I use it outside of the states I don't much interference. it's also got 4 channels to choose from, so I can switch channels if one isn't looking good.

in the bars I've set up video systems for I just run a bunch of cables and hook them up the old fashioned way. same for club events that are a one night thing, I only use the wireless on monitors that are on the floor above the main floor or out in the lobby, too far and too much hassle to run a cable all the way out there, plus at 5am when I'm packing up to go home, the less cable I have to roll up the better.

if you can order one that has a money back if not satisfied kind of deal, pick one up and try it out, then you can return it if it looks bad. wireless stuff is great, once you try it you won't want to go back to the cables.

now if I could only get a good wireless for my video camera signal, then I could run around transmitting the video from anywhere in the club, very cool.
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Old June 19th, 2002, 12:49 AM   #9
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Hi Rik,

You might try www.markertek.com. Do a search on "wireless video" or "be-320". The BE-320 isn't cheap, but then not alot is at markertek. Might be what you're looking for if you have the budget.

Thanks for the info on the one you are using. I'll take a look.
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Old June 19th, 2002, 07:01 PM   #10
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Hi everyone.

Ottotune is correct. 434, 900, and 1200 Mhz are shared exclusively by Ham radio operators and the Govt.-Military.

Itís cute how these companies list their disclaimers and then go ahead and advertise their products to the Non-Amateur radio public.

What Ottotune did not mention is that there is up to one year in jail that can be added to these fines.

IMHO itís not worth it.

All the best Jim.
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Old June 21st, 2002, 03:12 AM   #11
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video signals

Part of the problem with video signals is the 'amount of signal' you must have for clean copy at the receiver.

The basic reference is called MDS (minimum descernible signal). At MDS you can just tell that the signal is there and it doesn't mean that you will like it.

For audio you need an MDS of about 3 micro-volts at the receiver. For clean copy you should really have about 10 mv (or more) to have a clean signal.

For video you need an MDS of 300 micro-volts and around 900mv to have good, clean crisp signals.

These values are rather large and suck down quite a bit of power, battery-wise so video transmitters are usually short lived devices on small batteries. Most manufacturers love for YOU to supply the power from some other device so that the miniture package stays miniture. Kinda hard to call it 'small' when it has a big, honkin' battery attached to it.
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Old June 21st, 2002, 03:14 AM   #12
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off topic

Supersparks, does the following series of letters mean anything to you?

DA1TE/KV7J/HP1XNE
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Old June 21st, 2002, 10:37 AM   #13
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Sure does 'ED'. (ae) As a fellow ham operator for 40+ years,
My old calls included wa2ghm, wb4diu, now kd4lav.

I really got interested in video while readind trade magazines and found this wonderfull site. Look foward to my new hobby-pastime-work being just as much fun and cost $$$$ as ham radio has been
73's jim
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Old June 21st, 2002, 03:21 PM   #14
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<<<-- Originally posted by Jim S. "supersparks" : Sure does 'ED'. (ae) As a fellow ham operator for 40+ years,
My old calls included wa2ghm, wb4diu, now kd4lav.

-->>>

Hmm.. I know a kd4pbs. How do those callsigns originate anyway? What do they mean?
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Old June 21st, 2002, 06:37 PM   #15
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Hi Dylan
Sorry if it came across as cryptic. When Otto (ED) posted his amateur radio call sign, I could not resist sending mine. These call signs are issued by the FCC after passing a test.

As a ďhamĒ You can send these videos from point to point using a transmitter
I once saw a model train with a tiny video transmitter hooked up to the front of the train engine, and what great video it fed into the big screen tv located 10 miles away. If any one is interested in getting a license I would be glad to help.

Sorry if this post is not on topic, but, imagine the possibilities of recording our videos sometimes this way. You never know
Jim
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