Signal Strength To LNB's Using C120 Y Splitter ?

[moonbase]

Hi,

I would like to increase the number of direct cable runs to my receivers from a 1.5m prime focus dish with C120 flange. Currently, I have one quad output C120 invacom LNB attached to the C120 feedhorn serving 4 receivers, each with a dedicated coaxial feed from the LNB.

Would anyone know if using a "Y Splitter" between the feedhorn and the LNB's will cause any loss of output signal or will the LNB's attached to the "Y Splitter" function as normal with no loss of output signal?

The "Y-Splitter" will split the signal from the dish just after the feedhorn but before it is received by the LNB's.

I have attached a couple of pictures of the "Y-Splitter".



Regards
moonbase

 

[ralphmagno]

hello,
there is about 3 bd loss.
if you need more lines there is a quatro lnb with a c120 flange.
this can run a 10 to 16 output mulitswitch.
the output are seperate hor low, vert.low, hor high,vert high.
no loss here at all.
ralph

 

[moonbase]

Ralph,

I would like each coaxial cable connection from the LNB to have the full frequency range. The current quad output LNB gives 4 coaxial outputs, each one with the full frequency range (H-L, H-H, V-L and V-H). I wish to avoid using LNB's where the outputs are restricted to a specific range such as H-L (horizontal - low).

If the loss from using the "Y Splitter" is about 3db will that cause me any loss of channels considering the specified gain of the dish is about 43db?


Regards
moonbase

 

[ralphmagno]

hello,
what are you trying to receive?
the range is 10.7 ghz to 12.7 ghz
cross over at 11.7 ghz.
ver or horz low runs from 10.7 to 11.7 ghz
high band from 11.701 to 12.7 ghz.
but the dish is 43 and lnb is another 55 db gain as well
if you get it set up right it should be ok
ralph

 

[moonbase]

Ralph,

I am getting confused by your references to different bands etc. I do not wish to use an LNB where each output from the LNB only covers part of the 10.7 to 12.7 range. I am using an LNB that outputs the full range of 10.7 to 12.7 on each one of its 4 outputs. That is what I wish to continue using, possibly connected to a "Y Splitter"

What I want to know is will I suffer loss of channels by using a Y splitter located between the feedhorn and the LNB's. The LNB will be quad output LNB's with each output covering the full 10.7 to 12.7 range.



Regards
moonbase

 

[Huevos]

I am getting confused by your references to different bands etc. I do not wish to use an LNB where each output from the LNB only covers part of the 10.7 to 12.7 range. I am using an LNB that outputs the full range of 10.7 to 12.7 on each one of its 4 outputs. That is what I wish to continue using, possibly connected to a "Y Splitter"

Yes the quattro splits the bands but that doesn't matter. Each receiver is connected to the multiswitch and that connects the receiver to the port on the LNB that corresponds with the control signals the receiver is sending up the co-ax. This means more than 4 receivers can share the same LNB without any conflicts and all have access to the complete Ku spectrum. This is much better than trying to split the signal before it arrives at the LNB.

 

[ralphmagno]

hello,
if you use 2 c120 should be no problem but you have to be aware of seting it up with the proper polarization with respect to the dish.
think of if the c120 was on the front of the dish feed and it was brought to the side without twisting it in phase.
other wise it will be out of phase and horz will be vert or somewhere in between.
ralph

 

[Terryl]

The “Y” yoke is going to split the RF signal from the dish, the dish has 43 dB of gain (as quoted) the “Y” yoke is going to deduct 3 dB from that giving only 40 from the dish, 3 dB may not seem like much but in the RF world it is ½ of your total RF RMS voltage, if you have 100 Pico volts of RF now, after the split you will have 50 Pico volts to each LNB. (The signal from the satellite is very very weak)

If you have any problems with weather affecting your satellite reception you will have more after installing the “Y” yoke.

It would be better to get the proper switch with the required outputs you need to run more receivers.

 

[ralphmagno]

hello huevos
on this 1.5 meter dish what are you going to receive?
and where are you?
you have the following.
dish gain 43 db
lnb gain fron 55 to 60 db
spliter loss 3 db
cable loss unknown depends on type and length.
signal path loss about 120 db.
so if you are receiving astra at 28 east there should be no problems.
if you are receiving bbc1 and bbc 2 on astra 2d and it is not comming in well then it will get a little worse.

its good to know where you are and what you are receiving
ralph

 

[moonbase]

Yes the quattro splits the bands but that doesn't matter. Each receiver is connected to the multiswitch and that connects the receiver to the port on the LNB that corresponds with the control signals the receiver is sending up the co-ax. This means more than 4 receivers can share the same LNB without any conflicts and all have access to the complete Ku spectrum. This is much better than trying to split the signal before it arrives at the LNB.

Hmmm, OK, I can see what you are getting at, use a quattro LNB to a multiswitch then have 8 receivers all connected to the multiswitch with each one having full access to the entire Ku Band spectrum.

Yes, it would work, however, are you sure there is no loss of signal caused by the introduction of the multiswitch process. For example, if you measured the signal strength for test transponders with a direct coaxial cable connection to the LNB and compared this with the output from the multiswitch for the same test transponders, are you saying there is no signal loss?

Would you please be able to recommend a multiswitch that can be used for this purpose, preferably one with a minimum of at least 6 outputs?



Regards
moonbase

 

[moonbase]

hello huevos
on this 1.5 meter dish what are you going to receive?
and where are you?
you have the following.
dish gain 43 db
lnb gain fron 55 to 60 db
spliter loss 3 db
cable loss unknown depends on type and length.
signal path loss about 120 db.
so if you are receiving astra at 28 east there should be no problems.
if you are receiving bbc1 and bbc 2 on astra 2d and it is not comming in well then it will get a little worse.

its good to know where you are and what you are receiving
ralph

Ralph,

I am located in the UK and the dish is a motorised dish which is used on signals from 36E to 25W including feeds and inclined orbit satellites. I am not using the dish for a specific satellite such as 28E but I am using it for a 60 degree span of the arc.

The maximum cable length run to any of the receivers will be approximately 30 metres.


Regards
moonbase

 

[ralphmagno]

hello,
most multiswitches have small amps to compensate for loss
if you need 8 outputs you will need a 10 out multiswitch
a quatro lnb with a c120.
and 4 lines from the quatro to the switch.
do not cross the lines where as mark all the lines.
if you put the horz line on the vert or upper on the lower it will not work at all.
horz low line goes to the horz low in on the multiswitch
vert low to the vert low etc.
then you could run 10 receivers in the house and they will all work without affecting the others.

what satellite are you trying to pick up ??
ralph

 

[moonbase]

.......If you have any problems with weather affecting your satellite reception you will have more after installing the “Y” yoke.......

The Y yoke is for the trash can then, wait, there is always the flea bay.....



Regards
moonbase

 

[moonbase]

what satellite are you trying to pick up ??
ralph

Ralph,

Our replies crossed in posting, I answered the question in an earlier post, however, here is the answer again:

I am located in the UK and the dish is a motorised dish which is used on signals from 36E to 25W including feeds and inclined orbit satellites. I am not using the dish for a specific satellite such as 28E but I am using it for a 60 degree span of the arc.

The maximum cable length run to any of the receivers will be approximately 30 metres



Regards
moonbase

 

[moonbase]

......if you need 8 outputs you will need a 10 out multiswitch....

Ralph,

Have you any recommendations for a good quality "10 out multiswitch" that is a proven performer ?


Regards
moonbase

 

[Terryl]

EMP-Centauri are good, and some have very good low noise amp's.

 

[Huevos]

are you sure there is no loss of signal caused by the introduction of the multiswitch process. For example, if you measured the signal strength for test transponders with a direct coaxial cable connection to the LNB and compared this with the output from the multiswitch for the same test transponders, are you saying there is no signal loss?

With good quality components MER will be identical for both systems. Signal loss through the multiswitch is similar to a DiSEqC switch, but this is irrelevant as the noise floor is attenuated by the same amount. Also a 3dB loss due to a smaller dish, and a 3 dB loss due to a long coax run are completely different things and not interchangeable.

 

[moonbase]

..... Signal loss through the multiswitch is similar to a DiSEqC switch...... Also a 3dB loss due to a smaller dish........

Huevos,

I do not use DiSEqC switches, I use a 36v external positioner to move the dish so I do not get loss from DiSEqC switches with my current setup. Moving to a quattro band LNB with a multiswitch will introduce a signal loss in comparison with my current setup unless the multiswitch is high quality with some type of inbuilt amplification to counteract signal loss.


Terryl,

Thank you for the recommendation for the EMP-Centauri multiswitch. Could you please confirm if I am reading your post correctly, are you saying that some of the EMP-Centauri multiswitch models have very good low noise amplification?

Or, are you indicating that there are other makes of multiswitch that have good low noise amplification?



Regards
moonbase

 

[satelliteman]

Ralph,

Have you any recommendations for a good quality "10 out multiswitch" that is a proven performer ?


Regards
moonbase

If you only need 8 receivers, you can get an 8 way multiswitch. An active Rx powered would suit; Triax TMPR 5x8 or Fracarro SWI508DC.

 

[Huevos]

I do not use DiSEqC switches, I use a 36v external positioner to move the dish so I do not get loss from DiSEqC switches with my current setup. Moving to a quattro band LNB with a multiswitch will introduce a signal loss in comparison with my current setup unless the multiswitch is high quality

You are quoting me out of context. MER will be the same with or without the multiswitch in-line. This is all that counts. If you lose a couple of dB on transmission between the dish and the receiver that has got nothing to do with the dishes ability to capture signal in the first place. These two gain figures are not interchangeable. A low loss transmission line cannot be used to compensate for a dish that does not have sufficient gain, and vice versa. These gain figures are completely unrelated.