LNB's

[noxonstaff]

There exist LNB's with 0.1 dB up to 0.4 dB in the usual market.
What's the difference between them?
Which have the best quality?

[faccione]

Re: LNB's

0.1db S/N of course...
The right question should be: is a 0.1db S/N LNB real or just a fake label on a chinese LNB ???
It's almost impossible for a commercial cheap LNB to have such low figure....

[satman72]

Re: LNB's

Also noise figures depends by frequency and temperature. In fact you read ever on LNBs:typical noise figure , it means is a media into a range. If you'll buy an LNB Swedish microwave, it will arrive you with mesurament graphic of noise figure on all spectrum range, but it costs really much money. Real noise figure is ever around 0,7-0,8 all other numbers you see are not reals.

[tonybod]

Re: LNB's

When I bought my motorised dish recently, it came with a .2db LNB. I took some signal measurements, and then replaced it with an old quad LNB (.4db). Signal measurements were virtually identical, so I stuck with the quad LNB.

I wouldn't expect a lower noise LNB to give a better signal, the dish size (and installation/alignment) is the thing that makes the difference (strong signal in = strong signal out).

Tony.

[faccione]

Re: LNB's

of course a high quality dish makes the difference, but depends on what kind of dish.
A prime focus dish is much better than an offset dish, in the between the gregorian-style dish, but the LNB is the real core of the system.
A really expensive with high performance dish is a prime focus made by polycarbonate and stainless cage, but we are in the range of .000 price, depends on the diameter of the dish. The smallest one is 1.20mt.

[satman72]

Re: LNB's

I agree in part with you about prime focus dishes, Faccione. You're right because professional dish are all prime focus, but for sizes until 1,20 meters offset dishes have a vantage, the shadow made by LNB on the dish don't cover the dish center, so it gains something more then a prime focus. Other thing is if we spoke about 1,5 meters dish size or more, in this case the LNB shadow is negegible respect the dish gain. For this small dish sizes are all offsets.
For Tonybod, how did you've mesuread difference between the two LNBs? If you've checked the receiver meter it is not good instrument to comparate 2 LNB. Anyway a good LNB makes the difference like a good cable. Now with digital transmissions you can't see it watching the tv, but when there was just analogic signals it was visible also watching channels quality.
A good installation will let you receive also when is cloudly without freezes. But you can appreciate a good installation only on weak signals, you'll not see differences on strong signals.

[tonybod]

Re: LNB's

For Tonybod, how did you've mesuread difference between the two LNBs?

All I did was look at the measurements on the satellite box (Technomate TM600).

[satman72]

Re: LNB's

All I did was look at the measurements on the satellite box (Technomate TM600).

All satellite's box mesurements are not good to see LNB gain and noise. This indication is just to let you know if your dish is able to receive. If you try to connect 2 satellites box at same cable, each a time, you'll have two different values. You need field mesurament or spectrum analyzer to see how one LNB works, it is a measurement instruments that show you values in db also it show you crosspolarization.

[bong1]

Re: LNB's

if i upgrade to a hd reciever say dream 800 will i need a dual lnb or can i keep my single its got a rating of .3

[zoran89]

Re: LNB's

One LNB=one reciver, but you cant have one LNB and two recivers, so how many reciver that much LNB out.
Of course you can use one LNB with two exit

[bong1]

Re: LNB's

so not all hd boxes are the same as sky that use dual lnb for 1 reciever

[tonybod]

Re: LNB's

so not all hd boxes are the same as sky that use dual lnb for 1 reciever

No. Sky Plus/Plus HD need two inputs so that you can watch one channel and record another (it's the same as having two receivers built into the one box).

[Resident]

Re: LNB's

Well, i always tried to get the lowest lnb, got stuck with two globo goldens and an inverto. (and some old philips from a upc dish) Sometimes I feel like that old philips lnb is a lot better than the new globos... The other thing is that I can barely setup my dish so that every single transponder is watchable even in bad weather. For instance I recently set up the 90cm dish for 1W and some of the telenor channels are totally unwatchable, even at night... (when the sky is clear...)

[bong1]

Re: LNB's

i think its just the location as i can get 1west no problem its just 16e that has that effect with me

[galingo]

Re: LNB's

but probably will be a problem in the direction of the disc