LNB Weather Protection

[AlphaOm]

Hi there,

Whilst browsing the internet, I came across an item called an "LNB rain/weather protection", which basically looks like a see-through cover that you clip onto the LNB arm. Apparently it's supposed to shelter the LNB and improve reception when it rains by protecting the feedhorn from rain drops. They sell for around £25 (am I allowed to name websites on this forum?).

I must say I had never heard of those things before, and am very suspicious. First, I would have thought that reception of weaker satellites is affected when it rains mainly because of the drops on the dish and because of the clouds' density, and not really because of the rain on the LNB cap... but then again, what do I know? Also, won't those covers act like a sail or a kite when it gets very windy and make the LNB arm even more wobbly and shaky than usual? (which can already be quite a lot when a 1m dish LNB arm is being assaulted by severe gales!!)

Even the protection against snow doesn't convince me, as it won't stop snow building up on the dish...

Has any got any thoughts on those covers? (I might be completely wrong, after all...)
Or has anyone tried them before, and if so, what are your impressions?

 

[Lazarus]

Post up a link ................ disable it by placing a dash at the front ie _http

 

[Analoguesat]

If you want to try it cheap just cut up a plastic 2 litre drinks bottle and tape a suitable sized chunk onto the edge of the lnb.

 

[sonnetpete]

On fringe satellites (such as Nilesat) raindrops on the LNB cap can definitely degrade your reception. In my experience it can knock your SNR down by 5 or 6 percentage points. I have no doubt that rain on the dish will have it's affect too but it seems less able to adhere to the dish surface.

I don't have an LNB cover, though I have seen a couple of designs for sale. I tend to use a 'Vileda' extendable floor mop to remove excess overnight rain on the LNB cap when it's good reception conditions the next morning. Other than that I just put up with it if it's raining!!

Edit : I think this is the sort of thing you've seen

_http://www.amazon.fr/Indipc-SAT-PARAPROT-Protection-pour-LNB/dp/B000R3P2YE/ref=sr_1_1?ie=UTF8&qid=1309332944&sr=8-1

 

[pgh13]

I remember years ago there seemed to be a trend for fitting what looked like soft fruit punnets over the old blue cap LNBs held in place with a tie wrap.

 

[timo_w2s]

From personal experience, the Inverto 23mm white slim LNBs are terrible when they get drops of water on the feedhorn so any kind of cover really helps for weaker signals:

http://www.satellites.co.uk/forums/...ms/191650-inverto-multiconnect-lnbs-rain.html

 

[Robbo]

Raindrops on the LNB cap affects the signal far far more than rain drops on the dish face, that is because the dish is a large area, but the lnb is small. In the past I have gone outside and dried the LNB face a few times when I've been in the middle of watching something. Have also taped a cut up fizzy drinks bottle above the lnb.

 

[Lazarus]

I spray furniture polish on mine (well, I spray a J-Cloth and use that to gently wipe the LNB face).

Works well, but needs repeating from time to time.

Good scheme for easily accessible dishes.

 

[AlphaOm]

Thanks very much for all your answers. Really really interesting.
And yes, SonnetPete, the link you gave is exactly the item I saw. This is the one I looked at:
_http//:shop.conrad-uk.com/multimedia/tv-reception/antennas/lnbs_1/accessories-for-lnbs/940116.html

Thanks for your explanations, Robbo – they make a lot of sense. And I find your suggestions really interesting, Tivù and Analoguesat. I might actually try both, as my dish is not out of reach (I do need the ladder, though). Does just any furniture polish work?

If your suggestions do prevent losing that 4 or 5 precious percent of signal quality when it rains, I might give one of those covers a go – I will then post my impressions on this forum, if it’s ok with you.
I am just a bit concerned about them making the LNB arm go beserk in the wind. But I am just at the limit of reception for Thor 6 (Thor 5 is fine), and the picture does break up if it starts raining as quality usually drops from 52% to 47 or 45% - which seems to bother the appalling tuner of my rubbish Canal Digital receiver a lot… So anything helping me secure even 3% is worth the try.

Cheers everyone.

 

[Lazarus]

Does just any furniture polish work?

I assume so - all you are doing is applying a thin layer of transparent wax.

 

[Terryl]

And all this does nothing for all the tons of water up there in those mean really dark clouds attenuating all the signals coming down through them, at the CATV head ends we would use bigger dishes for rain fade problems,(6 meters or larger) heated dishes and LNB's for snow/ice problems and dish covers for all the rest.

In my 50 + years of dealing with this stuff I have seen everything known to man to try and get the signal back, most is just temporary, the coatings/wax/sprays collect dirt or gum up the dish, the plastic covers blow away or crack to pieces, up north at the dew line we built radomes around the dishes, big problem was that the snow would pile up on one side and you would loose signal in that direction.

But what ever works for you keep doing it, but in my professional opinion the best permanent solution for weather fade is a bigger dish.

 

[Lazarus]

True enough, Terry - But in England (similar rules in other parts of UK) we are limited to 1m Dishes unless we gain Planning Permission for something bigger. Clearly a lot of people manage, with or without Permission, but it is particularly difficult for town and city dwellers.

 

[Analoguesat]

I assume so - all you are doing is applying a thin layer of transparent wax.

WD40 / GT85 is just as good.

 

[Lazarus]

Yup. There's nothing like the occasional little squirt.

 

[Terryl]

True enough, Terry - But in England (similar rules in other parts of UK) we are limited to 1m Dishes unless we gain Planning Permission for something bigger. Clearly a lot of people manage, with or without Permission, but it is particularly difficult for town and city dwellers.

Aww that's a big bummer, I live out in the boonies, no one to tell my my dishes are too big.

Then the best thing is to make sure the dish surface is flat and a good coat every two weeks or so with a top quality paste wax, (it does evaporate, just like on your car) the other stuff may wash off and may affect your spouses flower bed, then you wont be able to watch TV, not with two black eyes that is.

 

[sonnetpete]

Yup. There's nothing like the occasional little squirt.

That'll be Mr Sheen then.

 

[Terryl]

And the best and cheapest way to keep the snow off the dish/LNB is a heavy duty black lawn/leaf/garbage bag big enough to fit over the dish and LNB and duct taped down, it wount affect the signal and if there are iceing problems then put a 25 to 40 watt light bulb in a drop light and stick it up inside the bag, works wonders, also the pipe heating tape and thermostat works good, it can be glued or taped to the back side of the dish and wrapped around the LNB to keep the ice off.

The pipe heating tape should be found at most plumbing supply houses (I dont know if you all have this stuff on that side of the pond) they also have thermostats for it, you could use it for the drop light, it comes on at 0 degrees C and off when it gets above freezing.

I know a place in Montana that sells electrically heated linear LNB's and stick on heat panels for the dish.

 

[AlphaOm]

Thanks for all your answers everyone. I truly love this forum. The amount of stuff and knowledge that you gain just out of a relatively simple question is astonishing. I think I want to live in the Boonies where I can have as many dishes as I want and the size I want. And indeed I'll need a biiiiig dish to be able to get Astra and Thor from over there!!!!

 

[Terryl]

It wouldnt be a big dish to get those satellites over here in the boonies but a very BIG and LONG tunnel, the furthest East satellite I can get from here is 58W, after that then Mammoth Mountain gets in the way, I could get some a bit lower if the volcano blew its top, but then I would have to contend with the lava.

 

[archive10]

Raindrops on the LNB cap affects the signal far far more than rain drops on the dish face, that is because the dish is a large area, but the lnb is small. In the past I have gone outside and dried the LNB face a few times when I've been in the middle of watching something. Have also taped a cut up fizzy drinks bottle above the lnb.

We just had two waves of rain run through the Copenhagen area, one early in the morning, one tonight.

This morning we saw some "normal" rain, I think it was a warmfront passing.
When I turned on the telly, "no or bad signal" in the BBC transponders made me worried (the CM180 should if not eliminate the rain fade even with 2D).
The 2A and 2B came through fine, though.
As it actually just stopped raining, I remembered Robbos quote, and I went and wiped the front of the LNB (very little wetness felt so I wasn't expecting much).
Everything went back to normal!

Then this evening, we had a super-cell wander across from Sweden (Hakon must've enjoyed this too).
It passed right over us, and covered the sat arc to the south, with flooding in the city and what have you.
(Sheets of rain, hail, lots of thunder etc.)
Of course no 2D.
Even the Viasat signals on the small dish were gone.
Massive rain-fade was the first thing that came to mind. But then again, I though I have a large dish, so something should come through.
So lo and behold - the 2A and 2B signales as well as the Eurobird 1 transponders (that I don't already have reception problems with) came in load and clear, even with a very large thunderstorm right on top of us.
Many (BBC News, CNN etc) at 100% signal level and 100% quality. the others (e.g. C4 HD) at 100% signal and 80-90% quality.
All figures from the FoxSat.

These experiences shows me two things:
1) Water/raindrops on the LNB will make the difference between 2D and not 2D in fringe-reception situations.
2) Even with supercells, rain fade can be compensated with large dishes.

This echoes and confirms the comments in this thread, and leads me to consider the following actions:

a) Put a rain-cover on the LNB on the CM180. Need to consider the options.
b) Get a bigger dish for normal TV (Viasat) to eliminate rain-fades.

Seems like fringe reception is many more things than the right dish and LNB combo...