Advice Needed Norsat 4108CF Ku band LNB

[Archived-1]

My main dilemma at the moment do i put C band on the 1.8 are the 1.5, i am thinking 1.5 to start with until i get my head round it better, what's my options for an average setup on C band please ? not two cheap things side by side i would also like auto switching polarity.

 

[beavs2112]

The mobile phone operators want to snaffle part of the C band spectrum for mobile broadband and other such guff that they want to use it for. The satellite operators are not happy about it so it could develop into a drawn out process before it is resolved.

Martin some other info here:
The importance of C-band satellite services | Intelsat S.A.
I donèt want to lose my c-band so hands off mobile phone system operators.

 

[moonbase]

My main dilemma at the moment do i put C band on the 1.8 are the 1.5, i am thinking 1.5 to start with until i get my head round it better, what's my options for an average setup on C band please ? not two cheap things side by side i would also like auto switching polarity.

Martin,

For auto switching polarity then the options as I see it are:

1. Dual C band feed with orthomode and two LNB's, in line power inserter or unit to send 18v to the LNB's, switch to auto select desired polarity from correct LNB.

2. Single C band LNBF such as Titanium C2W-PLL.

Option 2. is simpler, a low cost introduction and provides auto polarity switching from your satellite receiver. It can be setup directly on your 1.5m dish without the need for power inserters or polarity switches whereas Option 1 is higher cost and a more complex setup.

To put C band on your 1.8m offset focus dish gets tricky with Option 1, I am not sure how a CM 1.8m dish would perform with a cone fitted to a dual C band feed. The scalar ring would need to be removed from the feed and replaced with a cone type hood.

Decisions decisions.....

 

[Archived-1]

Martin some other info here:
The importance of C-band satellite services | Intelsat S.A.
I donèt want to lose my c-band so hands off mobile phone system operators.

Thanks for the link Kevin I will have a read through it.

Martin,

For auto switching polarity then the options as I see it are:

1. Dual C band feed with orthomode and two LNB's, in line power inserter or unit to send 18v to the LNB's, switch to auto select desired polarity from correct LNB.

2. Single C band LNBF such as Titanium C2W-PLL.

Option 2. is simpler, a low cost introduction and provides auto polarity switching from your satellite receiver. It can be setup directly on your 1.5m dish without the need for power inserters or polarity switches whereas Option 1 is higher cost and a more complex setup.

To put C band on your 1.8m offset focus dish gets tricky with Option 1, I am not sure how a CM 1.8m dish would perform with a cone fitted to a dual C band feed. The scalar ring would need to be removed from the feed and replaced with a cone type hood.

Decisions decisions.....

Thanks Dave, I will have a read up and go with option 1, I am defiantly going with the 1.5 to start with, the 1.8 needs to come back down now I have actuators,

So the plan is get the 1.5 up and running on C band using option 1, take the 1.8 down and put the 1224 on the 1.2 while the 1.8 is down mod the dish arms and make dual axis mount, then at a later date introduce C band to the 1.8 and mix a few KA band lnd around all 3 dishes

 

[moonbase]

Thanks Dave, I will have a read up and go with option 1, I am defiantly going with the 1.5 to start with, the 1.8 needs to come back down now I have actuators,

So the plan is get the 1.5 up and running on C band using option 1, take the 1.8 down and put the 1224 on the 1.2 while the 1.8 is down mod the dish arms and make dual axis mount, then at a later date introduce C band to the 1.8 and mix a few KA band lnd around all 3 dishes

Martin,

I thought you might go with option 1, its getting close to a corporate setup and is high quality. However, it should still be within your £500 budget. There is a slight variation possible for option 1, you could use two receivers, one for H and one for V instead of an auto switch for polarity.

 

[Archived-1]

Martin,

I thought you might go with option 1, its getting close to a corporate setup and is high quality. However, it should still be within your £500 budget. There is a slight variation possible for option 1, you could use two receivers, one for H and one for V instead of an auto switch for polarity.

Thanks again Dave, I will more than likely go with the auto switch, I guess there might be a very slight loss using a polarity switch ?, I will be running a few STB to start with and can do without an extra one.

 

[Archived-1]

Thanks again Dave, I will more than likely go with the auto switch, I guess there might be a very slight loss using a polarity switch ?, I will be running a few STB to start with and can do without an extra one.

Ok looking more into this a twin tuner maybe the way to go ?, what's your thought on this connected to a twin tuner please ?.


Primesat Dual Polarity C Band feedhorn.

http://www.satellitesuperstore.com/cband.htm#cbanddualfeedhorn

If the above is ok do i need anything else to go with it to make it work ?.

 

[moonbase]

Ok looking more into this a twin tuner maybe the way to go ?, what's your thought on this connected to a twin tuner please ?.


Primesat Dual Polarity C Band feedhorn.

http://www.satellitesuperstore.com/cband.htm#cbanddualfeedhorn

If the above is ok do i need anything else to go with it to make it work ?.

Martin,

The Primesat feedhorn looks very similar to a Chaparral orthomode dual C band feed and looks to be OK.

Were you considering buying the unit with the 2 C band LNB's included (£199.85p) or without the two C band LNB's (£79.95p)? Reading the SSS description, they do not provide detailed specification figures for the LNB's that are supplied in the inclusive package. However, the LNB's are listed at £69.95p each elsewhere on the SSS website but it still does not state if they are DRO or PLL.

You need to check if the LNB's require 18 volts, if they do then you will need a power inserter to get 18 volts to the LNB for Vertical polarity as the receiver will be sending 13 volts. If the LNB's do not require 18 volts then you do not need the power inserter.

If you only buy the feedhorn without the LNB's and purchase Norsat PLL LNB's separately then you will need a power inserter to send 18 volts to the Norsat LNB's.

Finally, for circular polarisation you will need to insert an appropriately sized dielectric plate into the throat of the feed. A high proportion of the C band arc visible to a UK location is circular polarity although there are some linear polarised signals. It might be best to check with SSS if a dielectric plate is included, or talk them into chucking a few in as freebies.

Rgds

 

[Archived-1]

Finally, for circular polarisation you will need to insert an appropriately sized dielectric plate into the throat of the feed

Thanks Dave, having the plate inserted all the time will I get loss in signal ?, from what ive read in the past I will ?, or does the loss only apply to a normal cheap lnb ?,

Yes I was considering buying it as a full unit does this unit need a plate?

 

[moonbase]

Thanks Dave, having the plate inserted all the time will I get loss in signal ?, from what ive read in the past I will ?, or does the loss only apply to a normal cheap lnb ?,

Yes I was considering buying it as a full unit does this unit need a plate?

You will need to ask SSS if the feed/LNB unit is supplied with a plate, it does not say either way on their website. For linear polarities I would remove the plate, however as most of the visible are is circular polarity the plate would be in more than out. For fringe reception where the last drop of signal can be important it may be best to remove the plate for linear polarities.

 

[Archived-1]

You will need to ask SSS if the feed/LNB unit is supplied with a plate, it does not say either way on their website. For linear polarities I would remove the plate, however as most of the visible are is circular polarity the plate would be in more than out. For fringe reception where the last drop of signal can be important it may be best to remove the plate for linear polarities.

Well that's no good then Dave, I might as well just use two lnd I don't want to be climbing up and down installing and removing plates .

My main reason for wanting this setup was for a all in one lnb with no messing about with plates and moving to a different position to get L/R and no loss in signal with the plate in,

Does the above options exists ?

 

[moonbase]

Well that's no good then Dave, I might as well just use two lnd I don't want to be climbing up and down installing and removing plates .

My main reason for wanting this setup was for a all in one lnb with no messing about with plates and moving to a different position to get L/R and no loss in signal with the plate in,

Does the above options exists ?

No, I think not, I just checked out the Chaparral feed with polarotor and it also needs a plate.

Polarotor I E/A | Chaparral Satellite Components

 

[Archived-1]

No, I think not, I just checked out the Chaparral feed with polarotor and it also needs a plate.

Polarotor I E/A | Chaparral Satellite Components

Thanks Dave, the only way I could do it this way then is to use 2 single ones side by side one with a plate in one without, the same way as the cheap lnbs are done, what I did not want to do but its what will produce the best signal wins at the end of the day.

I think ive asked this before ? how will this type of dish perform with off set lnbs I wonder please.

 

[moonbase]

I think ive asked this before ? how will this type of dish perform with off set lnbs I wonder please.

Martin,

I don't know is the honest answer, I have never used a prime focus dish with an LNB offset from the centre. I think that there are a few forum members who have a prime focus dish with an LNB offset from the centre point.

As it is going to be used for C band, the scalar ring assembly is quite wide. If you have one LNB at its correct position and the centre focus point, the other C band LNB is going to be pushed out a fair bit from the centre in order to accommodate the two scalar ring assemblies. You would be getting the offset LNB illuminated with a signal from a satellite a good few degrees away from where the dish was actually pointing.

As you plan to use it for motorised reception on an arc, the dish may need a lot of "peaking" to maximise the signal from the offset LNB? Your centre focus LNB would be correctly sighted to a satellite at its correct arc point. The offset LNB if gathering signal from a satellite 5 degrees away would be aiming too high or too low depending on where you were on the arc. If you have a dual axis system on the dish then you could "peak" easily, even if quite regular.