High floating voltage on RF TV distribution on house

Is there something wrong with the grounding of the AC line in your house?

snipped-for-privacy@gmail.com schrieb:

So there is no direct earth connection...

The ground/shield potential therefore is floating but is slightly coupled to the line voltage (switching supply with transformer). You could connect the RF shield or the housing of the video machine to earth (but only at _one specific point of the net) to avoid these effects.

- Udo

If your video records OK from the TV, then it is almost certainly working correctly and the voltage you are reading is pickup from the TV scan coils. (BTW you didn't say what meter and range you were using , analogue or digi, AC or DC).

You are not getting very good results because when you split a TV signal you reduce its signal strength. You should use a splitter with built-in pre-amplifier. Then you will get the same level signal from each of the outputs as you are putting in to it.

You are most likely (and hopefully) seeing "normal" very low current leakage voltage.... because you are undoubtably using a very high sensitivity digital meter. If you truely had 100 volts due to a direct short or other fault you would be drawing sparks and making fires. Try reading the voltage again, this time with a 1 K resistor shunt across the meter leads..... that should give you a "real" measurement of things. Best Regards, Daniel Sofie Electronics Supply & Repair

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Hi Pebe,

The meter is a Tektronix digital, on an autorange AC and DC range, so as Daniel Sofie mentioned, I am no doubt not getting a true reading. I noticed that I wasn't getting any sparking if I earthed the splitter.

Regarding the splitter and the preamplifier, I must confess that I don't know too much about RF signal distribution. The problem I have is that I am on a hill just below the TV mast. When I first connected up the system, the TV parts salesman told me I should have an amplied splitter, which I duly installed. I got terrible results because the signal was too strong. I found that I had to remove the amplifier, and put an attenuator inline to get anything like decent results. I may still have too high a signal, but I don't know what meter I can use to measure it. (I only have digital multimeters and an oscilloscope.)

Thanks and regards, Nick

Hi Daniel,

I will try with the resistor; it is a Tektr> You are most likely (and hopefully) seeing "normal" very low current

nic.alexander: Do as the Sofie reply post suggests and I will bet that your new voltage reading will be close to Zero. The tingle you felt with your fingers is probably the leakage current from one or more pieces of equipment that are plugged into the cable hookup. Some leakage is normal and to be expected... if your reading is still abnormally high even with the shunt resistor then post back with your results.... otherwise... no problem. electricitym snipped-for-privacy@gmail.com wrote:

On 5 Sep 2006 19:38:51 -0700, snipped-for-privacy@gmail.com put finger to keyboard and composed:

You seem to be posting from NZ where the mains voltage is 240V. I'd expect that all your appliances are 2-pin (no earth). My Sanyo TV, for example, has a series R and C between the "ground" point on the mains side and the circuit ground on the secondary side. If the AV and RF sockets are unloaded, then the circuit ground floats to about half the mains voltage. This is normal behaviour.

- Franc Zabkar