Would snow affect analogue reception?

redalicat

Since I've never lived in snow before, wondered if snow affects analogue reception? All of a sudden, RTÉ One, TV3 and TG4 seem to be coming in even clearer than before, but RTÉ Two has gone really bad. Aerial appears to be unmoved, and I haven't changed anything on the tuning of the receiver.

slegs

redalicat wrote: »

Since I've never lived in snow before, wondered if snow affects analogue reception? All of a sudden, RTÉ One, TV3 and TG4 seem to be coming in even clearer than before, but RTÉ Two has gone really bad. Aerial appears to be unmoved, and I haven't changed anything on the tuning of the receiver.

Air pressure has a lift effect in some scenarios.

watty

you can get temperature inversions
* Warm air above cold air
* Or Dry air above very damp air

Both may cause drop or rise in signal level depending on terrain and distance.

Very heavy snow in the air can seriously attenuate or scatter the signal depending on size of flakes, density, wind, damp/dryness of air and frequency.

Very thick snow caked on aerial or icing of aerial can dramatically reduce gain or matching.

Occasionally if the guys or chains get too much ice build up in bad weather the Transmitter mast can fall down (Emley Moor, not Emily Moore)

Sam the Aerialman

As Watty rightly says snow can seriously attenuate the signal, extra moisture in the air can be the enemy of RF.

Another problem caused by snow, that caused the infamous Durris incident was because the feeders normally run hot, around 90 degrees Celsius. The snow cooled the feeders and ice began to accumulate, a secondary effect was the PTFE strips that connect the aerial panels to the 7/8 connectors began to scorch and burn. This started a fire that engulfed the entire array.

Guy lines sagging - Is a sight to behold infact i was Holme Moss many years ago and witnessed it first hand. Because the mast is pivoting on a large bearing its in constant movement, the weight of the ice forces the structure to move in different directions and dramatically shifts the wind loading. The structures are designed to move to great tolerances, listening to a broadcast mast creek under it's own weight is an eerie sound.

radioredcat

Here is a video of the durris incident.

http://www.youtube.com/user/radioredcat#p/u/8/4qqva2pB63c


Andy

redalicat

radioredcat wrote: »

Here is a video of the durris incident.

http://www.youtube.com/user/radioredcat#p/u/8/4qqva2pB63c


Andy

Had no idea.

watty

watty wrote: »

y

Very thick snow caked on aerial or icing of aerial can dramatically reduce gain or matching.

Ah yes... rather more dramatic having mismatch on 100kW Transmission than on a domestic receiving aerial.