Melted LNB

[G0RBG]

I wondered if anyone had come across a LNB melting. (Bullseye mounted on a 90cm offset dish)
I found this early this morning, Its not as if the UK is a hot sunny climate at present.

If you look carefully you can see the LNB mounting has melted.
Your thoughts would be appreciated.
- Russell

[Basil]

I suppose the air temperature need not be that high if the sun's strength is strong enough for a short duration and here in Shropshire we have had strong sunshine for two days.

The horizontal burn on the LNB mount may be associable with the sun's path? Or maybe you have an upset neighbour with a blowtorch but not enough determination to start a proper conflagration

Fascinating though, I await opinions from others more qualified.

[G4EWJ]

Today and tomorrow, the sun passes directly behind QO-100, so the LNB would have been receiving lots of energy for a few minutes. I haven't heard of a Bullseye melting before though.

If you watch the WB spectrum between 10:45 and 10:55 local tomorrow (Saturday) you should see the effect. It will happen again around the beginning of March.

Brian

https://www.satellite-calculations.com/ ... erence.php

[g8lce]

It is a good time to check your dish alignment!

Martin G8LCE

[PA3CRX]

Video about this: https://youtu.be/6G4nREMqU2E

[G0RBG]

Thank you.
I found that fascinating, and clearly not something I was prepared for.

[G0ATW]

I had similar problems with a friends narrow band QO100 setup, spraying it white seems to have helped.

[PA3CRX]

Or make the surface of the dish less reflective by spraying it matt black/dark gray?
Just an idea...

[G4EWJ]

It's solar outage time again, when the sun passes directly behind Es'hail 2 and reduces the S/N ratio and heats up the LNB.

Peak time for me near Liverpool is this Saturday 1.3.2025 at 10:18:13z. It's quite high a couple of days either side.

Brian


https://www.satellite-calculations.com/ ... erence.php (dates in US format)

https://gml.noaa.gov/grad/solcalc/index.html

[Basil]

Cue neighbours saying "Just look at him now staring at that bloody dish, he's not right in the head".