No Noise Is Good Noise

To most DXers, installing a higher gain, more directional antenna would be something to get excited about. I though this naively, but it has highlighted a problem in my case, not because the antenna is poor. Quite the opposite in fact. The extra gain and directivity has been very noticeable, providing I beam in certain directions. If I beam anywhere between south-east and north-east I have S9 noise across the entire of band 2 and this starts to encroach even from the south. These are my my main directions too.

This noise has been plaguing me for more than a year, though I wasn't initially aware of it because it doesn't register as you would expect it to on my Sony XDR-F1HD tuner. It is almost invisible, producing one bar of 'nothing' on the tuner's display. While I have always been aware of an increase in noise when I beam towards the east, it only became apparent recently when I connected my new 9.2 antenna directly to my Icom IC7000 and tuned between 88 - 108 MHz. Quite simply, it's a DX killer!

As things stand, the noise is intermittent, tending to go off at night and occasionally during the daytime. There are no set patterns so I suspect it might be a plasma TV or power supply operating in the neighbourhood. It is capable of masking weak signals such as tropo and scatter. Sporadic E is getting over it easily though. The noise sounds like traditional FM white noise, the sort you hear when not tuned to a station. But there are also ticking sounds, buzzes and even the occasional drifting blank carrier, which can register two or three bars.

When my Körner 9.2 antenna arrived, I tried it out on the garden on a small mast, roughly three metres above the ground. Even down at this low level it knocked spots of the rooftop Triax FM5. I was immediately aware of how quiet band 2 was and it reminded me of DX camps where you're in the middle of a field, far away from electrical interference. Even with the antenna three metres above the ground, I was able to hear excellent aircraft scatter from as far away as Brocken at 713 km, Torfhaus at 707 km and a new one - Sonneburg, increasing my scatter distance to 793 km!

Naturally, I was concerned that the noise would be present once the 9.2 had gone on the roof. It was. Worse still, it was worse! The extra gain of the 9.2 dragged the noise in as if it was a regular signal, but since the directivity of the 9.2 was better I could beam away to the south or west. These were not my main directions of interest though.

As far as I know, none of this noise is being radiated through the mains electricity supply. I have conducted fairly rigourous tests to determine this, disconnecting the main supply to the property and running the XDR-F1HD on a leisure battery and mains inverter. I have checked the mains earth supply and gone all around the property, inside and out, around the loft and out on the street, checking lighting, etc. The noise is definitely coming in through the antenna. There is a large OAP home in the general direction of the noise and I wonder if some of my noise is coming from there.