HDMI dropping signal

[telspar]

I'm having an issue in a classroom where the teacher reports that the projector drops the signal for a second or two several times a day. I have replaced the projector, HDMI cable and had her use a different computer for a while. I'm beginning to think it may have something to do with the electric in the classroom, but I have no idea where to start tracking something like that in our large and very old building. Any thoughts on the possibility of electric causing this issue or what could be done about it? Are there any small power line conditioner devices that could help?

[TwistedHelixis]

How long is the hdmi cable?

 

have you thought about changing the teacher :0P

[Bionic]

Does the HDMI cable run from the PC output to the projector via a wall mounted plate? Or does the PC output connect directly to the projector input? If the former, have you tried connecting the PC output directly to the projector input to rule out a problem with the cable run from the wall plate or the plate itself?

[telspar]

It is a 30 foot HDMI cable running directly from projector to PC. The previous setup was running HDMI over CAT, which I thought would be the problem, but after replacing that with this 30 foot cable the issue is still being reported.

[PD1279]

I would lean to some form of power saving on the PC

[Bionic]

Do you have the option of trying a VGA cable connection instead?

[jthompson]

In my experience (with VGA, mind) some computer/cabling/projector combos just do exhibit signal problems, even if each element works fine with all other hardware (even stuff of the same model). Manufacturing tolerances coming into play, I guess, especially if the cable is long.

 

If you have a suitable projector swap available, try that. Probably easier than swapping either the computer or the cabling. Try to avoid having the signal cable running right alongside any power cable, too.

[PotNoodleTech]

30foot is a bit on the long side for a HDMI cable, if it is also being run around/with power cables then it could quite feasibly be getting interference causing dropouts.

 

You could try buying a HDMI Active Booster / Amplifier to plug in at the PC end and give it a boost. Make sure it's active not passive though - I,e it should need a power cable.

[MatthewL]

Does it happen at the same time, get them to note the time when it does it. It could coincide with something happening at the same time every day, light switch, hand dryer, school bell.

[nathan3388]

We had this with 10m hdmi cables and apple TVs they were to long and needed get an active booster to push the signal down the cable more and pick up.

[SamanthaD]

Is your 10m cable an active cable? Passive cables have a length limit of 5m, though there are companies who will happily make longer cables even though they'll have problems.

 

We use Van Damme active cables up to 15m long and have no issues. Available from CPC here.

[PotNoodleTech]

We use Van Damme active cables up to 15m long and have no issues. Available from CPC here.

 

What is active bout that cable? It doesn't appear to have a power adaptor with it?

[SamanthaD]

HDMI has 5v available through the HDMI port.

[k-strider]

i've seen monitors blink on computers in our finance office when i hear the Fridge pump kick in

[dhicks]

It is a 30 foot HDMI cable running directly from projector to PC.

 

We used an HDMI signal booster to solve a similar issue:

 

https://www.amazon.co.uk/gp/product/B01EC2YEX0/ref=ppx_yo_dt_b_asin_title_o07__o00_s01?ie=UTF8&psc=1

 

Along with a USB-to-5v cable to plug in to a dedicated USB socket on a power strip:

 

https://www.amazon.co.uk/gp/product/B0763RXLS3/ref=ppx_yo_dt_b_asin_title_o07__o00_s00?ie=UTF8&psc=1

 

The previous setup was running HDMI over CAT, which I thought would be the problem

 

Hmm - if anything, we've tended to find replacing long-run HDMI cables with CAT5 cable tends to work better than HDMI.

[telspar]

Thanks for the thoughts everyone. It is not an active cable that is in there now. I observed class for an hour the other day an of course it didn't happen while I was there. I'm thinking I will try a signal booster. I have not removed the HDMI over CAT that was in place, just added. Would the signal booster have any effect if used in conjunction with the HDMI over CAT?