Signal Improvement: LNB vs. Dish Size

[esto]

I'm in Switzerland with a 80cm pointed at 4.8E (Astra 4A), and getting the "Europe Ku" beam at moderate strength/quality (about 80-90% str and 50-60% quality). I have some trees in the way that affect my reception.

I have been trying to get the "Nordic BSS" beam, also on Astra 4A, but Switzerland is just outside the coverage area, making that beam either not possible, or in the "fringe reception" realm. SO I tried different combinations of dishes and LNB's, but I still wasn't able to get the Nordic Beam. In any case, I thought it was interesting to see the difference between dish size and LNB.

I had a bucket of different LNB's, and was kind of surprised to see no real difference between them. I used a hand held "SAT-LINK" receiver connected directly to the LNB. I didn't move the dish, and after changing LNB, I would adjust the depth and skew to find the highest signal readings. I tested 2 different channels, "Espresso" and "Channel 5".

With a 80cm Schwaiger SPI996 (38.5db max gain) focused on 4.8E:

LNB (Telestar "SkyQUad", Grundig "GLS40", MTI "AP8-XTS2E")
Espresso: Quality 49-50% , Strength 80-90%
Channel 5: Quality 56% , Strength 92%

LNB Telefunken Quad "55724"
Espresso: Quality 50-51%, Strength 91%
Channel 5: Quality 57% , Strength 93%

LNB Inverto Black Ultra Quad
Espresso: Quality 53%, Strength 94%
Channel 5: Quality 59% , Strength 95%

Based on this, the bulk of LNB's were the same, with the Telefunken having maybe 1-2% better performance in quality, and the Inverto Black Ultra a 2-3%. So in all, I would say the difference in LNB performance is very minimal. Of course all these LNB's are relatively new and modern, I guess if you were to change out a really old LNB that was sitting outside for 10 years, the improvement would be more dramatic.

Moving on to the dish, I changed out the 80cm dish (measuring actually 82x72, and stating 38.5db max gain in spec sheet) with a 1m Triax dish (measuring 101x95, and stating ~40db gain max). Used the same Telestar LNB and pointed at Espresso channel:

80cm Schwaiger (38.5db): Quality 50%
100cm Triax (40db): Quality 63%

Changing the dish was obviously a much bigger improvement over changing the LNB. Moving from a 80cm to 1m dish gave about a 13% increase in quality, while changing LNB's (even the famous Black Ultra) only gave a 2-3% increase at best. Of course these are just my findings, I'm sure "your mileage may vary" ;)

 

[Lazarus]

No surprises, there!

Useful set of Tests, though. Some people get quite excited over the "best" LNB, but as you've more than adequately proven, for most purposes it's bunk and ensuring optimum alignment, skew and LNB axial position are the key factors for any given installation.

Mind you, LNBs like the Black Ultra can help optimisation owing to the long neck, giving more scope for finding the sweet spot.

 

[timo_w2s]

Yes very true, dish size will always win over LNB quality but when you've got the biggest dish you can possibly fit then the last thing left is to make sure you have a good LNB and sensitive receiver to squeeze the last bit of signal out of the dish. Sometimes with digital if you just don't quite have enough signal then an extra 3% may be enough for you to see something (although no rain margin).

 

[Archive4]

Yes very true, dish size will always win over LNB quality but when you've got the biggest dish you can possibly fit then the last thing left is to make sure you have a good LNB and sensitive receiver to squeeze the last bit of signal out of the dish. Sometimes with digital if you just don't quite have enough signal then an extra 3% may be enough for you to see something (although no rain margin).

Not sure I totally agree with the thoughts here. As a general rule I would agree "bigger dish is best" and also agree that even 1 or 2% can make a difference, however, a couple odd things I have noticed here in Spain.

I changed a less than 1 year old GI single for a BU single on a 1.4 dish for reception of Astra 2 spot beams and gained an extra 1.5dB c/n making an unwatchable, or non existant signal very watchable. I am also running tests of my own between a 1.4 Famaval offset and a 1.6 FTE Max and at the moment I think the 1.4 Fam will win. Won´t be sure until I have completed the tests.

The quality of the dish is at least, if not more important than the size in some respects.

Not knocking anyone here, just advising what I am finding in Spain

 

[RimaNTSS]

I am also running tests of my own between a 1.4 Famaval offset and a 1.6 FTE Max and at the moment I think the 1.4 Fam will win. Won´t be sure until I have completed the tests.

The quality of the dish is at least, if not more important than the size in some respects.

Not knocking anyone here, just advising what I am finding in Spain

I think, it does not really matter Spain, UK or another part of the world you test your antennas. I do not know what 1.6 FTE Max antenna is, but, if it is bigger than 1.4 Famaval offset, than it should perform better, maybe it is question of using proper LNB on it?

 

[satesco]

In the world of the antennas installers is a saying:"The best LNB is a large antenna"

 

[Terryl]

The over all quality of the dish can make a difference, lets say a 1.2 meter dish stamped out by some little company in the Far East, versus one from lets say Andrews Microwave, you could tell the performance difference, also what the dish is made of could also be a factor, some fiberglass dishes may have a difference in performance over a solid steel or aluminum dish of the same size.

But in my experience, when in doubt go bigger, if your in a fringe area, go bigger.

 

[solly]

i think incaom black pro litel better then red classic

 

[RimaNTSS]

In the world of the antennas installers is a saying:"The best LNB is a large antenna"

I am not installer, but agree with that; increasing of antenna's size influence reception dramatically. However, when you already increased size of your dish to the maximum you can afford, finding proper LNB still can improve reception.
Add: Especially when people are using LNBs designed for offset antennas on PFAs.

 

[esto]

Mind you, LNBs like the Black Ultra can help optimisation owing to the long neck, giving more scope for finding the sweet spot.

I didn't find the neck on the Black Ultra to really be any longer than my other LNB's, altho yea, by adjusting the depth and skew I could improve the signal quite a bit, maybe 5-10% improvement in quality.

Yes very true, dish size will always win over LNB quality but when you've got the biggest dish you can possibly fit then the last thing left is to make sure you have a good LNB and sensitive receiver to squeeze the last bit of signal out of the dish. Sometimes with digital if you just don't quite have enough signal then an extra 3% may be enough for you to see something (although no rain margin).

I agree, if you are having reception problems then every little bit helps. But after reading the string of praises on the internet about the Black Ultra, I was somehow expecting more "magic", and was kind of let down by the marginal 2-3% improvement over other LNB's.

Actually, I now plan to return the Black Ultra, not because of the performance, but because of the build form. It's probably 30% larger than my Telestar (or most other LNB's), and I don't really like looking at it. My dishes are in my garden, so I have to look at them every day, maybe if my dish was on the roof and out of sight I wouldn't mind, but the Black Ultra is just big and ugly, and not worth looking at it for only a 2-3% boost. There's other ways I can tweak the signal. With my other dish pointed at 28.2° I moved it about 2 feet and my signal quality jumped about 10%. Granted I have an uneven tree line in the way, so a slight dish repositioning can have a big effect. If I slide my dish up a little I can probably get even more improvement. Maybe something small as changing the LNB holder can also give a boost of 2%.

The quality of the dish is at least, if not more important than the size in some respects.

Are the gains on the manufacturer spec sheets usually true? I'm looking at 1m Schwaiger and Grundig GSS dishes, are these known for good gain performance?

 

[RimaNTSS]

2 esto: 2-3% increase of performance sometimes is very good result achieved by only changing LNBs! Can you provide comparison tests taken at more or less same time by using IBU and "other LNBs"? What exactly you do mot like in the build form of IBU? I think it is very good LNB and outperforms majority if not all LNBs in the same price-range.
BTW, do you know that when you adjust depth of LNB you should also change elevation of the dish?
Concerning 1m Schwaiger and Grundig GSS dishes: If they are in the same size than you probably get same performance from them. If you have 10 Schwaiger and 10 Grundig dishes than not all of them will perform same. Try and compare different and pick the one which gives better results. Their performance will also depend on used LNB and tuning precision.

 

[RimaNTSS]

Continuing about IBU: Of course, some do not like it's "big face" (sometimes I do not like it also), but most importantly this LNb has very good electronics inside. Secondly, it is also possible to get IBU-based LNBs adopted to 70* or 908 opening angle (I do not know opening angle of original LN. I think it is also possible nowadays to get not original, I mean fake, LNB on the market .
I did not make comparison of performance of LNBs in attached picture, but can say for sure that modified ones perform about the same as original one. And, of course, depends on antenna they are installed on.

 

[esto]

2 esto: 2-3% increase of performance sometimes is very good result achieved by only changing LNBs! Can you provide comparison tests taken at more or less same time by using IBU and "other LNBs"? What exactly you do mot like in the build form of IBU? I think it is very good LNB and outperforms majority if not all LNBs in the same price-range.

Oh I forgot to mention, I was using the Quad version of the IBU. Comparing this to say the Telestar Quad, the Telestar is much smaller in size. I agree tho, the IBU performs better, but the difference of 2-3% really doesn't make much difference to me. If the IBU had the same form factor as the Telestar, I would definitely keep it.

 

[esto]

also what the dish is made of could also be a factor, some fiberglass dishes may have a difference in performance over a solid steel or aluminum dish of the same size.

I can't get any fibreglass, but both steel and alu are options, is there any performance difference between steel or alu?

 

[RimaNTSS]

is there any performance difference between steel or alu?

If steel and aluminum dishes are same in size and shape than they will perform exactly the same. Take both of them, install, compare and then remove one which performs worse.

 

[terryashbyash]

How about the best termites to fell trees

 

[timo_w2s]

Not sure I totally agree with the thoughts here. As a general rule I would agree "bigger dish is best" and also agree that even 1 or 2% can make a difference, however, a couple odd things I have noticed here in Spain.

Well obviously if you are going to substitute, say, a 1.8m Channel Master for a 2.4m Petal Fortecstar chances are you aren't going to get the results desired... (or at least not after the first heavy winds distort the dish)

 

[Archive4]

Well obviously if you are going to substitute, say, a 1.8m Channel Master for a 2.4m Petal Fortecstar chances are you aren't going to get the results desired... (or at least not after the first heavy winds distort the dish)

OK I give in, just a dog chasing a bone,after all

 

[Archive4]

Well obviously if you are going to substitute, say, a 1.8m Channel Master for a 2.4m Petal Fortecstar chances are you aren't going to get the results desired... (or at least not after the first heavy winds distort the dish)

OK did the LNB swap, same LNB on both dishes, and to my surprise the FTE 1.6 beat the Fam 1.4 by approx 0.5dBm c/n across most txps, although not all, also tried the BU quad on the 1.4 Fam at the same time for reference. Will post full results on "installing dishes in spain chit - chat" tomorrow, when I can see what i´m typing!