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#1 midway199

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Posted 27 December 2007 - 02:16 PM

On the "Dual Purpose: Mallincam AND Wireless - HOW?" thread the concept of attaching two devices to the Mallincam is being discussed. The Mallincam has two outputs (S-Video and composite), and we are learning that using both at the same time is not recommended.

What about a daisy chain? For instance, camera to monitor to PC capture card. My monitor has an input and an output. Does that cause problems for the camera as well?

#2 Chris Schroeder

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Posted 27 December 2007 - 02:21 PM

I believe what is not recommended is to not split the signal of one output. Rock has mentioned in the past that it is okay to use both the the Composite and S-video at the same time.

#3 midway199

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Posted 27 December 2007 - 02:49 PM

Whoops! Did I read it wrong on the other thread?

#4 Jack Huerkamp

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Posted 27 December 2007 - 02:49 PM

Chris,

You are correct. It is perfectly okay to use both the BNC composite video and the S-video concurrently. What is not recommended is splitting either of the outputs to service two different devices at once without taking the precautions previously posted.

jack

#5 midway199

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Posted 27 December 2007 - 03:52 PM

Sorry about that. I went back and re-read the posts and see where I got mixed up. Thanks for the correction.

So, does that mean no daisy chain? You see, I'm thinking that going into and back out of a powered device (in this case my b/w security monitor) is different than just going into a non-powered splitter.

Or is going into and out of a powered device just as detrimental?

#6 CarolG

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Posted 27 December 2007 - 05:58 PM

I would also like to know if using a daisy chain is ok. Seems I read somewhere that someone ran the composite cable to their monitor then out of their monitor to another device. I used a splitter once, but after reading these posts I will not do that again. I would like to run the composite from the camera to my Sanyo monitor to my Watec. I run the s video to my laptop capture device. Are we wanting to do more than is possible with all the cables?

#7 ccs_hello

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Posted 27 December 2007 - 06:38 PM

Not an endorsement nor not the cheapest, after 5 minutes Google search, I found these two examples of video Distribution Amplifier:

http://www.cablestog...=2402&sku=41066
http://www.studio1pr...bution_amps.htm


They are talking about 150' cable.

I don't know how long a RG59 22AWG (always shielded) 50 ohms coaxial cable can do even further.
Will longer cable not be having too much DP/DG issues?
Will attenuation be too much thus "hotter" D.A. (e.g., 12dB type) is required?

Clear Skies!

ccs_hello

#8 skyguy88

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Posted 27 December 2007 - 07:09 PM

I sometimes run the s video signal to my laptop and then use the dual monitor mode in the laptop to run a monitor out of the laptop. That gets me a bigger display with better color than I can get on my old toshiba laptop. But it still is inferior to the crt TV which I can run on the composite output. The dual display configuration is handy for outreach programs where I can switch between the live image and a data page for objects being displayed or run.

Bill

#9 Jack Huerkamp

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Posted 27 December 2007 - 08:40 PM

I routinely run the S-video output to a DVD recorder and then connect the composite output from the DVD recorder to a 10.2" DVD player used as a monitor. I run the BNC composite video output to the Watec-35 monitor mounted next to my FeatherTouch focuser.

Also many hi resolution monitors allow you to run the signal into them and then run them out to another device. All this is allowable.

Jack

#10 CarolG

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Posted 27 December 2007 - 08:41 PM

That's a great idea, Bill! I never would have of thought of that. Thanks for the tip! I'll give your idea a try the next time I'm out. Would doing it your way qualify as a 'daisy chain' of sorts?

#11 skyguy88

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Posted 27 December 2007 - 10:25 PM

Hi Carol,
I'm not sure what qualifies as a daisy chain, but since the windows software is set up for dual display mode, I'm sure that it's OK. Just in case you don't use it regularly, to get to the dual modee setting, right click on the desktop to get to the dual sequence. Same setup that you would use to run a projector.

Bill

#12 Bowmoreman

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Posted 31 December 2007 - 12:02 PM

Carol, Daisy Chain should be fine. the input video circuit on your monitor presents a fixed "load" back to the camera, which is all the camera needs/cares about.

When you take two outputs (split) from the single camera ourput is the problem scenario, because via Ohms Law you will significantly REDUCE the output "load" that the camera sees. This reduced load causes it to try and drive more current, and *can* (doesn't always) lead to buring out the video amplifier for the output circuit.

But, again, with the output to a SINGLE monitor, and then having the MONITOR output video circuit, in turn, send the signal on to another device should work.

But, not recommended, because what you are doing with each step in the daisy chain is adding an additional "layer" of electronics... which degrades the signal... if you do it more than once, you should go the OTHER route: an amplified Video distribution device... (there are many)...

Hope this helps to clarify!

Clear skies

#13 ccs_hello

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Posted 31 December 2007 - 12:20 PM

IMHO, passive daisy chain has the potential introducing many underesirable artifacts. This is not a super-technical forum nor poeple have trained eyes to spot the problems. So under the best circumstances, none of the potential issues will be noticed. YMMV.
What are the potential issues:
problem sources: not well designed monitors (RFI, color subCarrier leaks, AC 60 Hz humming due to grounding, improperly implemented DC restoration, etc.), cable related (noise immunity, grounding, etc.)
Potential artifacts: AC 60 Hz interference pattern, color subCarrier beating pattern, incorrect black level, etc.

As I said, I've seen all of them in the past.

But if you do not notice any issues and feel comfortable about it, then why bother :) :).

One single input, multiple output video D.A. driving multiple video devices (not that active- driven daisy chain method) would be nice, since it effectively isolates (potential) problems back-flow and crossover from one video device to the other.

Clear Skies!

ccs_hello

#14 Bowmoreman

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Posted 31 December 2007 - 12:38 PM

All excellent points, CCS! My specific thoughts were for ACTIVE daisy-chaining (i.e. where the output from the monitor is a driven/active circuit...). In those cases all the signal errors are ADDITIVE... I wasn't aware there were any passive monitor video outputs - that would really be a truly cheap/awful design, and which would really degrade the signal very rapidly to boot! :ohgeeze:

Best solution, as we've both stated, is a amplified/driven video switcher/splitter - only ONE generation of signal degradation, instead of cumulative, and since it's active, the input side is buffered and thus presents an appropriate (and more importantly non-changing!) load on the source component, in this case the Mallincam output circuit!

clear skies

#15 ccs_hello

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Posted 31 December 2007 - 12:40 PM

Dave,

:waytogo:

Happy Holidays!

ccs_hello

#16 midway199

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Posted 31 December 2007 - 12:49 PM

Thanks for the advice guys!

#17 CarolG

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Posted 31 December 2007 - 02:39 PM

Thanks, for your explanation. I was going to run the composite cable from the camera to my Sanyo monitor input connection and then run another cable from that, via the monitor's output connector, to my Watec. Since that is only rerouting the signal once, it looks like that setup will be OK. This thread has probably saved some of us from frying our cameras. Thanks to all for your advice and words of caution!!

#18 Bowmoreman

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Posted 31 December 2007 - 04:00 PM

Hi Carol... that approach will work... my only additional thought is this:

The WATEC is most likely HIGHER resolution than your Sanyo monitor... so effectively you are degrading the signal by passing it in and then back out of the Sanyo, to then go on to a higher resolution device...

Conceptually, this is backwards...

On the other hand, the WATEC doesn't have a "video out"... so you can't go the OTHER way...

You should, therefore and IMO - and no doubt worth every :penny: consider using both outputs of your MCHP one for the sanyo, and one for the WATEC. Since the WATEC is so small, you could mount it right on/near your scope, and run very short length of Svideo/RCA cabling (nothing to tangle/trip over and/or be subject to cable wrap).

I just came in from WSO where I finally lashed everything up in preparation for anticipated clear skies tonight.

I take S-video out, through an inline adapter (from Radio Shack) that converts S-video to RCA, then to an RCA to BNC adapter to fit the WATEC input. I then take the BNC output (composite) from the MCHP via the supplied LONG cord over to my 19" monitor Video In... Then I take another RCA from the 19" monitor Video OUT, and have connected it to my wireless transmitter... (which I may just try tonight, or may not)...

I'll take some pictures later tonight if I can remember to take the DSLR outside :lol:

That way the only "degradation" of an extra step in the chain, is hooked into mywireless, which would then go into my interior HDTV (through yet more conversions anyways!)... so that end of my chain was destined to be my least "high quality"... (it would always have the "to wireless", the wireless transmission, the "from wireless" and the "from RCA composite to HDTV" conversions all to go through anyways!)

It may help to envision that every time you take a signal, and convert it, the conversion loses information that can never be recovered. So you want the least number of conversions between your source and your highest quality need... and the most number of conversions before your LOWEST quality need...

Note: I am not yet certain the wireless (VFM 1.2Ghz) will be a long term component of my setup; I have to investigate further other users of that spectrum in my vicinity and look into making it as highly directional as possible...

Clear enough skies

#19 CarolG

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Posted 31 December 2007 - 05:10 PM

Thanks for your input! Is this the converter you are talking about? I hope so, because that is what I have. I've already got the Watec ready to mount above my focuser, so if this is the connector, then I have everything needed for your suggested setup. The only reason for running the s video to my laptop, though, is to get the best possible picture for capturing images. Of course, I could disconnect the s video from the Watec when I'm ready to get the images on my laptop. Good luck tonight getting everything set up! If you get some pictures, we would sure like to see them.

#20 Bowmoreman

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Posted 31 December 2007 - 05:31 PM

yep works great and is small... $21 seemed too much to me, but whatever...

first total light tonight for me - hopefully for you as well!

clear enough skies

#21 Bowmoreman

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Posted 31 December 2007 - 10:28 PM

Heres the setup photo; used it tonight, as described. it all works quite nicely! the wireless! the monitor! the Watec!

Loving it!

clear enough skies

Attached Thumbnails

  • 2086573-equip1sml.jpg


#22 CarolG

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Posted 31 December 2007 - 11:43 PM

Nice Setup, Dave!! :bow:

#23 Pat G.

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Posted 01 January 2008 - 03:31 PM

flip mirror kinda thingie between the camera and scope :question:

#24 Bowmoreman

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Posted 01 January 2008 - 05:01 PM

yes, indeed! I am a HUGE fan of flip mirrors... makes finding and centering objects MUCH easier...

I have par-focalized my Ethos in the flip mirror with the MCHP... the REAL challenge is in observing where the CENTER of that 100 degree FOV actuall *is*...

sometimes I "cheat" - and use my 5mm illuminated reticle to NAIL things...

My hearts desire is to have a full, true 2" flip mirror that will work in this setup (so I can also use my 31T5 and 22T4 in the Vixen...) but, the Van Slyke Slider I bought used is too "deep" to leave enough in/back focus to come to focus with the MCHP

I'm still looking for a solution to THAT problem..

BTW: in the picture that red/black braided wire is the custom power harness I made to go from a Radio Shack 3A AC/DC power supply to the Watec... once I confirm with Rock that it will also be safe to use for the MCHP, I'll use it to power that as well... I'm all about losing too many wires :lol:

I wish that the makers of flip mirrors would publish full dimensional specifications, etc...

I'm currently researching if there are alternatives that would allow me to use the Van Slyke (cause it is really well built and very nice!)... else it'll be up for sale...

clear enough skies!


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