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Problem with HDMi over cat5


Standard Member
Hello all,

Would be grateful if anyone has insights that might help me with my problem.

In my setup, the sky hd box and home cinema are in the lounge, with the hdmi from the sky box being sent to the tv in the kitchen via cat5e.

The Sky hdmi output goes into a gefen 2x2 hdmi switch, with one output to the TV in the lounge and the second hdmi putput going into an hdmi-->2xcat5e balun. the cat5e cables are armoured for external service, and they run round the outside of the house to the kitchen, where they go into a second cat5e-->hdmi balun, and from there into the tv via hdmi cable.

Last night this worked fine (and has done for two years). This morning, with a frost outside (might be relevant), the TV in the kitchen has a snowy picture and no sound. TV in the lounge still works fine.

I did the following:
reseated all cables - no impact. Unplugged and replugged all powered equipment - no impact.
Switched hdmi outputs at the gefen switch - TV in lounge continued to work fine, tv in kitchen lost signal during the switch, snowy again once switched back.
Switched HDMi cables in the kitchen - still snowy so not the TV at fault or the hdmi cable.

Beginning to think there is a problem with the ethernet cables outside the house. Despite weather armouring, maybe a mouse has had a nibble and the frost has caused a problem - moisture got in etc. It might be the hdmi switch though the fact the tv continues to work in the lounge on both outputs suggests not. HDMI - cat5 baluns? Hard to believe and hard to test without replacing.

What's the cheapest way to resovle this problem? Buy a £15 cable tester and test the cat5e cables? if they are good, replace baluns? If they aren't the problem, replace hdmi switch? failing that, panic?

Appreciative of any advice.



Active Member
Hmm, it does sound like a temp related issue, if you have any spare cat 5 you could try making up a couple of leads and trying the baluns that way, then you'd know one way or another if the baluns are ok or there's a problem.

I wouldn't think its the baluns, sounds like your cat 5 is showing its age.

I hope you can solve your problem without to much extra expense.

Kind regards,



Active Member
I had an intermittant problem with a cat5e balun run when I first installed. Every now and then the TV would lose signal and it was impossible to get it back without simply waiting for it to sort itself out. It turned out to be the length of the cat5e cable run. I had excess cat5e cable which was coiled in the loft. I shortened the cable down to the correct length and have never seen the issue since. I reckon the cat5e was right on the upper limit of the balun's range.

Just a thought.


Active Member
Plug in the sky hd into your TV to make sure the tv and hdmi lead in use are working.
Take the output from the splitter going to your kitchen and send it to the living room to check that part of the splitter is working.
Finally go nick a 15m network cable from work and plug it in directly to eliminate the outside net cable.
Process or elimination really.

Remember to put in Cat 6 as its fully twisted pair as a replacement if that is the cause.

[email protected]

Active Member
remember, just because the cat5e is shielded does not mean its an external cable. its shielded from interference from other cables and low voltage lighting. if it is external cat5e the cable will be black and much more stiffer. purple (low smoke) or grey are internal cables. any sharp kinks in the cable also affect its performance as does the length. hope this helps.


Standard Member
The External cat5e cable has been chewed, probably by mice. god knows what attracts them to climb up 2 feet of brick wall to eat plastic but there you go. Only the green cable is exposed to the metal, and though it still looks intact, no signal. Cable tester is showing strand 3 is shorted. I guess this is the green one.

Most likely there is no obvious repair, so am into replacement.... Think that will be expensive.



Active Member
Cut at the point of damage, trim the mangled bit off, fit 2 RJ45s, plug into a coupler, tape up, job jobbbed :)

I would personally recommend that the cable is replaced. However, if the time/cost is too great to allow this and an idea such as above is used - then self amalgamating tape would be a better bet.


Active Member
Agreed - in an ideal world it would be replaced. However, if replacement is a significant investment in time and causes lots of disruption to wall/floor/ceiling finishes, then a repair is worth trying first.



Active Member
I agree that a repair would do the job, but what's to stop the mice chewing it again? I think you either need to protect the repaired cable or run a new cable higher up the wall or possibly through trunking.

Alternatively, you could just shoot the mice... ;-)

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