Nilesat: Narrower Band LNB's and Gain.

**canofan** · 17-01-2008

Single band LNB's do increase gain compared to the wider band universal LNB's.
There are examples of such LNB's on the american market, where the use of the 11.7 to 12.2 gHZ band is standard. (Norsat 4000A)
Such LNB's, because of their narrower band, do display an increase in gain of 5db compared to the universal species we use in Europe.
If one accepts restricting the reception band of a particular satellite, like Nilesat, the use of such LNB, on a Channelmaster dish or equivalent, is certainly beneficial, and allows the use of a smaller fixed dish especially when used with a feedhorn of the same band characteristic (Channel Master 611-6060-10). Nilesat's Showtime and ADD (ART) are situated in this band.
The difficulty, though, is in finding the item which support voltage switching in order to receive vertical and horizontal transponders. Also in finding a solution to mate the feedhorn flange to such LNB's.
Please guys do come forward if you have solutions.

Prodelin · 17-01-2008

LNB gain doesn't have anything to do with how good signal quality you get.

If you have a normal gain you don't have any problems and +5dB doesn't improve anything except if you have very long cable runs to the receiver where cable loss is a major issue....

Only way is to buy a larger dish.

**canofan** · 17-01-2008

This thought is lingering after a post by a serious and experienced engineer

Originally Posted by Rd100

Right here it goes the circular option is for satellites the use left & right hand circular

............
And just to add the best way to get the most amount of gain out of your dish for nilesat is as follows, At home a have a 1.8m dish and get nilesat 24/7 and in the rain,

I also can receive nilesat on my 1.2m Andrew type 120 dish but the signal drops out in the rain this is with the 611-6060-07 linear feed and invacom but it does not drop out in the rain using a 611-6060-10 and a professional norsat 4000a lnb which covers 11.7 -12.2 and gives a better gain all around as the lnb covers the right band for the showtime transponders and the feedhorn 611-6060-10 gives better gain as it covers a narrower band of the ku-band

It makes a lot of sense. This means also that, in the band selected, a 1.2M CM equipped as Rd100 has done, would be equivalent to a 1.8M CM equipped normally.

Regarding gain, what you are referring to, Prodelin, is the IF gain generated by the amplifier of the LNB, but it is about the reception gain at the 11.2 to 12.2 ghz level. (This gain will also offset losses in cables as the overall signal will be higher). The limited band is responsible for the peaking which translates itself as a gain. It is not amplification gain but a sort of mechanical gain more related to the gain that the narrow band feedhorn displays. Of course the price to pay for this arrangement is forfeiting all other transponders on the satellite.

**canofan** · 17-01-2008

I still have to thank you for your intervention, Prodelin, you pointed that LNB gain is not reliable in the realm of determining peaking gain, because it combines amplifier gain and peaking gain.
Which brings me back to reevaluting the INVACOM QPF-31? which has both the correct flange and the voltage switching for selection of the V&H polarities.

bobon · 17-01-2008

The diagram that came with my channel master feedhorn shows a circular object called a 'transition' ,this appears to be what you need to align a square lnb to a round feedhorn. I tried to attach a picture of it but for some reason the post editor wont allow me to.

Prodelin · 17-01-2008

Originally Posted by canofan

It makes a lot of sense. This means also that, in the band selected, a 1.2M CM equipped as Rd100 has done, would be equivalent to a 1.8M CM equipped normally.

Impossible.

Please understand the difference between LNB gain and antenna gain.

It's not the same thing.

**Llew** · 17-01-2008

Now where have I seen this subject chewed over before?

Oh yes -

Evaluation of Invacom's QPF-31 LNB for use in Nilesat's fringe areas..

**canofan** · 17-01-2008

Originally Posted by Llew

Now where have I seen this subject chewed over before?

Oh yes -

Evaluation of Invacom's QPF-31 LNB for use in Nilesat's fringe areas..

yes Llew, chewed a lot but not swallowed nor digested.

I have all the elements I could possibly obtain.

I shall try the invacom qpf-31 plus the andrew 611-6060-10.

**Analoguesat** · 17-01-2008

If you are in belgium Id have thought a 1.2m dish would have been big enough for 7w anyway - there are reports of V&H polarity reception from *well set up dishes* in the south of England.

**canofan** · 17-01-2008

Originally Posted by Analoguesat

If you are in belgium Id have thought a 1.2m dish would have been big enough for 7w anyway - there are reports of V&H polarity reception from *well set up dishes* in the south of England.

Thank you for responding,
My Nilesat setup at the moment is CM1.2 plus QTH-31. I have all H&V on all Nilesat but nothing on AB4 7°2W. In bad weather, I lose some of the H transponders.
I have a QDF-31 which I am intending to try when I receive the andrew 611-6060-07 feedhorn; I know that this combination will improve the situation by 1.5db.
I was trying to prepare ahead for the cases of extreme bad weather.

**Analoguesat** · 17-01-2008

Im not surprised you dont get anything off AB4 - its firing into the mediterranean basin not northern Europe. The downlink powers in Belgium are very poor.
You can forget anything on the steerable beam - its firing into the Middle East.

**canofan** · 17-01-2008

keano does get them in Manchester, but he has a CM 2.4M.
I just mentioned AB4 for yr information. I am not interested in this satellite.
I would like to know your opinion concerning the peaking gains of the narrow band LNB's and Feedhorns. I may have to return to the UK. Hertford Area.

**Analoguesat** · 17-01-2008

Sorry canofan havent a clue about peaking gains. I shove whatever lnb's I have lying around onto my dishes - if they work for the main European sats thats good enough for me.

Good luck with your project though, I shall follow it with interest

**Channel Hopper** · 18-01-2008

Originally Posted by canofan

This thought is lingering after a post by a serious and experienced engineer

And there were others that are just as serious, and probably more experienced on this forum.

Some have replied to your questions, why not give them the benefit of the doubt before you waste more time on a frivolous exercise?

**canofan** · 18-01-2008

Originally Posted by Channel Hopper

And there were others that are just as serious, and probably more experienced on this forum.

Some have replied to your questions, why not give them the benefit of the doubt before you waste more time on a frivolous exercise?

I seem to have offended you Channel Hopper. I never intended that, so please accept my apologies.

Facts are important. RD100 did try the combination and it worked, he reported on it. I cannot ignore this.

Theory on the other hand is very important in the development process. It leads the way when facts are not there yet.

To be convinced of a theoretical statement I need all the underlying elements of that thought.

Unfortunately, this has been missing. Perhaps this sort of total approach does not belong in a forum.

So please forgive me if I tend to follow the facts.

**Channel Hopper** · 18-01-2008

No offence taken, but to ask the same question more than once without looking at the alternatives that have been suggested

I would still advise a bigger dish unless you really are determined to purchase the LNB that has been recommended, but I fear this will be an exercise which doesnt give you what you want.

**canofan** · 24-01-2008

@ Channel Hopper

Invacom QPF-31: I abandon the idea. You convinced me.

But a pair of Norsat4206A or equivalent with the proper two flange andrews 611-6062-10 feedhorn is still an option for me.

**canofan** · 29-01-2008

I am going to use single band LNB's.
Is there any advantage in choosing a higher stability Local Oscillator ?
Invacom, considered good for general purpose, specs at 1mhz while Norsat makes theirs more stable in a variety of values.
They have also a very expensive PLL species.
Would a NORSAT 7707A be enough at 750Khz? or should I stick to the 4106A at 100Khz or better?

**Llew** · 29-01-2008

LO stability is a function of temperature. Changes in temperature sometimes had an effect on my SMW XLNB (+/- 3MHZ LO stabiity) in the old analogue days on some narrow band signals, but nowadays LNBs have pretty a pretty tight spec. Receiver tuners too now have good AFC pull-in, so I doubt that you will have any problem using any of the Norsats.

Llew

Prodelin · 18-02-2008

If you want the best performance and got the budget forget Norsat and buy SMW PLL LNA's as seen in the picture.

It will cost you around £1500

**Channel Hopper** · 18-02-2008

Originally Posted by Prodelin

....
It will cost you around £1500

Which would secure a rather good 2.4m dish from most outlets.

adnan20 · 28-10-2008

i just wonna ask u if u get all the TRANSPONDERS on Nilesat in brussels??

**canofan** · 29-10-2008

Originally Posted by adnan20

i just wonna ask u if u get all the TRANSPONDERS on Nilesat in brussels??

If you mean Nilesat 7°W and not Atlantic Bird4 at 7.2°W.
I get them all on a Channelmaster 120 with round throat long channelmaster feedhorn and inverto c120 quattro most of the time.
I get all horizontals on a Channelmaster 120 with round throat long channelmaster feedhorn with transition and Norsat 7706A lnb all the time.

**GreenmanBelg** · 10-11-2008

Just checking Canofan but when lining out my CM1.2m do I use Sirius 5 degrees east as my mid point on my CM polar mount?

Very windy here so it looks like a next weekend job.

**canofan** · 11-11-2008

Your longitude is 5.149 East so it is very close to Sirius at 4.8 East.
It is very close. you just go ahead JD.
Seems like the wind has calmed down. As it is holiday, you may be able to set it up to day.
Cheers

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Nilesat: Narrower Band LNB's and Gain. If you live outside the reception footprint of a satellite and would like to, or can already receive services, post your questions or information here.

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