Rain Hood

[Terryl]

I tried various bottles, but wanted something bigger as I may change the Ku LNB back to C Band, so need the extra space to accomodate the conical scalar.

Try a plastic coffee can, snip the thing down one side and cut the bottom off, trim to fit, a worm gear clamp will hold it on. (large 4 to 5 inch clamp for a dryer exhaust hose)

And "C" band should not need one, it is mostly weather resistant if your dish is big enough.

 

[Terryl]

You can always go with one of these puppies....(Puppie...an engineering terminology used for something that does not use any form of electricity or power)(if it uses power it's called a Hummer)

http://www.compositeradomes.com/Products/Radomes

 

[timo_w2s]

You can always go with one of these puppies....(Puppie...an engineering terminology used for something that does not use any form of electricity or power)(if it uses power it's called a Hummer)

http://www.compositeradomes.com/Products/Radomes

Could be handy if there is a satellite dish ban in your area, unless there is also a giant golf ball ban too of course.

 

[Terryl]

Check out the umbrella dish cover in this link.

http://www.dishcamo.com/dishcamo.htm

A bit pricy but it serves a purpose.

One could make one up if they have the skills.

 

[parkiepie420]

Pics as promised !!

 

[Journey]

nice job parkie !!

 

[parkiepie420]

ive tested this on many satellites when its raining with cover on and cover off and it makes quite a difference with it on ??

 

[Tony1A]

Simple and effective and cheap!

 

[RimaNTSS]

ive tested this on many satellites when its raining with cover on and cover off and it makes quite a difference with it on ??

Was that a question or a statement?

 

[parkiepie420]

a statement lol !!

 

[parkiepie420]

to be honest it was my other half that thought about me using the 3 litre bottle and cutting it down so really its just the cost of the bottle of pop ! lol

 

[excollier]

I can honestly say I have never had the need for a rainhood. Except on my raincoat. It rains a lot here in Donegal. I see a lot of incomers from Europe who insist on fitting one to their dish, can't see why.

 

[parkiepie420]

if you are going for the weaker satellites then I would advise one but again its up to you

 

[excollier]

Don't use them, and any of the continentals are using Hotbird or Astra 3, 16E so no real need.

 

[RimaNTSS]

Once I've made a hood, not for LNB but for Polar-mount. And it works great. Guess what I used to make this hood! ;)

 

[Fisty McB]

On my 80cm dish with multi lnb set up, I have a "narrow" lnb pointed at 9 east. When rain drops fall on the face of the lnb, it starts to weaken the incoming signal to the point of causing the multiplex containing the Swiss versions of some French TV channels to break up - presumably this is down to using 8PSK with a FEC of 3/4 whereas all other receivable transmissions here use more rugged parameters. When the rain stops I can go out and wipe the lnb face with a tissue or even just my bare hand and signal levels go back up on the Swiss French channels curing pictures breaking up. So from my experience there is definitely something to be gained in having some sort of shield or hood surrounding an lnb that keeps moisture off its face, particularly for "narrow" neck lnbs. It seems to be that without a bigger set of scalar rings behind the plastic face of the lnb, such lnbs seem to suffer more signal loss from rain drops.

 

[timo_w2s]

On my 80cm dish with multi lnb set up, I have a "narrow" lnb pointed at 9 east. When rain drops fall on the face of the lnb, it starts to weaken the incoming signal to the point of causing the multiplex containing the Swiss versions of some French TV channels to break up - presumably this is down to using 8PSK with a FEC of 3/4 whereas all other receivable transmissions here use more rugged parameters. When the rain stops I can go out and wipe the lnb face with a tissue or even just my bare hand and signal levels go back up on the Swiss French channels curing pictures breaking up. So from my experience there is definitely something to be gained in having some sort of shield or hood surrounding an lnb that keeps moisture off its face, particularly for "narrow" neck lnbs. It seems to be that without a bigger set of scalar rings behind the plastic face of the lnb, such lnbs seem to suffer more signal loss from rain drops.

Yep, this is exactly why my narrow LNBs are covered. I was finding some 23.5E on a 60cm where breaking up or disappearing if the LNB was wet and was fed up with going out to dry it. Now it's only heavy rain which causes issues but light rain and drizzle are not a problem any more.

 

[Fisty McB]

Just did a non-scientific test on an in-progress new multi-lnb set up I'm trying which currently has five different LNBs set up on a 97cm dish centred at 16E with LNBs at 13, 16, 19, 23.5 & 28.2E (additional LNBs to the west planned, rain continuously stopping play here!) About 30 mins after rain stopped, I dried the dish face - then with each satellite position I took a measurement of the SNR on a channel , then went outside wiped the rain drops off the face of the LNB and retook a measurement. Across the five satellites there was a difference between 0.4 to 1.0db in gain between a LNB with a "wet" face and when it dried. Seems that there could be more to this theory that I originally thought, and could mean the difference in some fringe areas in reducing break up of some services at least in certain weather conditions.

 

[Fisty McB]

Just as an example, around 15/20 minutes ago there was a fair northerly rain shower here. I was checking the SNR of Stars.TV on Hotbird (DVB-S2 8PSK 10911 V 27500 3/4) during the downpour and it registered an average of 11.2db.

Now it's stopped, it's averaging 11.3db SNR...

...going out to wipe the dish face... averaging 11.4db SNR. Not much of an increase.

Now wiping the LNB, which in this case is an Alps single LNB that is 3 degrees off prime focus... and the SNR is now averaging 12.2db!

Now this seems strange - surely rain drops on the LNB face itself can't be having that big of an impact. However in the previous test earlier I did a test on 16E (where the dish is pointed) from Magic TV Bulgaria (DVB-S2 8PSK 11595 V 30000 5/6) with an Inverto Black Ultra single in use and just wiping the face of that LNB gave a 1db SNR improvement!

Of course I'd need to test it more but so far I've came to two thoughts - DVB-S2 8PSK signals tend to lose more SNR strength compared to DVB-S QPSK signals (not a surprise, I tend to find that the 8PSK signals have more tighter margins to get the best skew angle) and that in rainy weather, even allowing for the massive amount of moisture falling from the sky it seems that if you can keep moisture off the face of the LNB you can significantly reduce the amount of rain fade you're subject to.

 

[4wd]

and could mean the difference in some fringe areas in reducing break up -\- if you can keep moisture off the face of the LNB you can significantly reduce the amount of rain fade

Subscribing to that. Tested by spraying a dry lnb = instant drop in levels.
Hood mandatory here for any marginal signal (28E). For strong sats it's only the seasonal matter of avoiding snow build-up.