Antenna Amp Blows When Lightning Is Around

[Felix1503559512]

Hi guys im going crazy here trying to work out how to fix my promblem. I have a hills home hub which has a distribution amplifier for the arial feeds,

ive had it for a year and in that time on 3 occasions when there is lightning around it just blows im assuming the power surge from the lightning is doing

this because its intantaneouse when a strike happens near by it stops working. Suggestions please.

Regards Felix

[digitalj]

Does the powered amplifier have a surge protector on the power point that it's connected to?

If not, I'd recommend you get a surge protector for that outlet.

[alanh]

Felix,

A couple of things,

Firstly the most likely place that will cause failure is the antenna input. Please ensure that the mast is effectively earthed. The antenna should be of a Yagi or phased array type and not a Log periodic array. This will minimise the amount of metal work which is not connected to ground.

To identify your antenna type look at all 4 pages of Scaled drawing including dimensions on page 1

Do not earth the shield of the antenna cable as this can worsen noise pickup.

You can get failures from power surges, but surge suppressors will not protect from strikes close by.

The best thing to do is to disconnect the antenna from the distribution amplifier and the power when the lightning and thunder are close together. If the lightning preceeds the thunder by 3 seconds it is about 1 km away.

AlanH

[bellotv]

Australian Standards recommend approx 3-4 turns of coax approx 200mm diameter where coax leaves antenna/mast and earth mast.

Logic is high impedance of loop will deture lightning from travelling down coax to your equipment and take easier path via earth conductor to ground.

Good in theory ,it may even work.The practical realization is a direct path to ground for the earth lead which is fine if its a facia mounted antenna but hard if its anywhere else on the roof .Sods law indicates that the best reception will be found in the least easy to earth position

A direct strike to the antenna (like what we get around here ) is likely to melt the earth conductor lead like a piece of fuse wire and blow the rod out of the ground

[I am not a duck]

I have a hills home hub which has a distribution amplifier for the arial feeds,

ive had it for a year and in that time on 3 occasions when there is lightning around it just blows im assuming the power surge from the lightning is doing

this because its instantaneouse when a strike happens near by it stops working. Suggestions please.

Fit an F grounding block at the input to the home hub. I am assuming here the antenna feeds directly to the input of the hub.

Ground this to a separate earth stake via the most direct route possible.

Earth the inner of the coax to ground via a rf choke which may enable induced voltages to bleed away safely before rising sufficiently to cause damage.

This will not protect against close by or direct strikes as noted, but may give some leeway against induced ESD.

A gas arrestor from inner of coax to earth may also offer some protection, however these usually strike at 70 volts which may be too high for the input of the home hub.

edit: Use a multimeter on the diode position and look at the "ANTENNA RF IN" port of a known good hub to see if there is already a DC shunt or back to back diodes - this is what Hills use on their amplified splitters I just replaced one after lightning here last night.

FMA showed these diodes had gone short circuit sucking most of the input signal to ground that was the only fault.

[Felix1503559512]

Thanks guys for your input, i will look at these now. I had an urgent O/S trip since my original post.

Regards Felix

[DOCK]

Thanks guys for your input, i will look at these now. I had an urgent O/S trip since my original post.

Regards Felix

I Live in the Hills District north of Sydney and we have continual problems with power supply and plenty of lightening.

Call me "Paranoid" but I have a back up generator for power, and UPS's (Uninteruptable Power Supplies) on any

equipment likely to be affected including all entertainment Equipment, including the power supply to the Dist Amp.

Between the Kingray Dist' Amp and antenna I have a Lightening Protector Cat No AR3278 from Jaycar.

The UPS's protect the equipment from surges and lightening strikes on the power side while the Lightening Protector

protects, the antenna input from spikes. (yes I know the Lightening Protector is the wrong frequency but appears to work.)

Foot note: It is probably a pain in the "but" having to continually change the Amp, but look at it this way, It's cheaper than changing the TV. I also find the displayed signal is much better for having the UPS smoothing out the power supply also.