Need prime focus LNB replacement (Costa Blanca)

[Pride Of Cucamonga]

Hi, trying to find a replacement LNB for this very old dish on the Costa Blanca. Think it's about 2.2 or 2.3m (I had to use an app to measure it as don't have a tape measure!). You can see the old LNB underneath. As an interim I'm currently using an offset LNB and it's not picking up the higher frequency channels on the UK spot beam, e.g. CNBC

Second hand will do. Any advice much appreciated.

 

[ymttt]

Hi, trying to find a replacement LNB for this very old dish on the Costa Blanca. Think it's about 2.2 or 2.3m (I had to use an app to measure it as don't have a tape measure!). You can see the old LNB underneath. As an interim I'm currently using an offset LNB and it's not picking up the higher frequency channels on the UK spot beam, e.g. CNBC

Second hand will do. Any advice much appreciated.


View attachment 161599

I will provide some suggestions but I want to find out if this is a comtech dish.

 

[ymttt]

On the lnb, my suggestion is you find an invacom feedhorn or something similar, you cut the head off the offset lnb and also cut off the base of the feedhorn. Glue the two pieces together. You will be good to go.

 

[Miika]

You can see the old LNB underneath.

Do NOT throw this old LNB away! You can/need to use the old feedhorn, as new prime focus LNBs are provided usually without feedhorn.

Or as previous member said, from offset LNB saw the cup and feed off and put old feedhorn and new LNB together. Try not to touch small antennaes inside the tube.

 

[woborny]

The dish is a 2.4m Famaval (needed prior to 2012 in the Valencia area)
Your location says "Valencia CIty" (is that where the dish is?), so even with an offset lnb on, the dish should be easily picking up all the signals. Even a dish half the size gets all the signals in the Valencia area!
(I went to the same dish with a quad offset LNB in the Lliria area yesterday, and all channels coming through fine, even without a feedhorn.)

I have a stack of inverto prime focus twin c120 LNBs.
Drop me a PM with your details and I shall see what I can do for you.

 

[Pride Of Cucamonga]

Thanks for the help guys

On the lnb, my suggestion is you find an invacom feedhorn or something similar, you cut the head off the offset lnb and also cut off the base of the feedhorn. Glue the two pieces together. You will be good to go.

Do NOT throw this old LNB away! You can/need to use the old feedhorn, as new prime focus LNBs are provided usually without feedhorn.

Or as previous member said, from offset LNB saw the cup and feed off and put old feedhorn and new LNB together. Try not to touch small antennaes inside the tube.

cheers. I would prefer to buy one outright but good to know this is an option. out of interest, why isn't the feedhorn provided with prime focus lnbs anymore?

The dish is a 2.4m Famaval (needed prior to 2012 in the Valencia area)
Your location says "Valencia CIty" (is that where the dish is?), so even with an offset lnb on, the dish should be easily picking up all the signals. Even a dish half the size gets all the signals in the Valencia area!
(I went to the same dish with a quad offset LNB in the Lliria area yesterday, and all channels coming through fine, even without a feedhorn.)

I have a stack of inverto prime focus twin c120 LNBs.
Drop me a PM with your details and I shall see what I can do for you.

I'm now in Genoves, near Xativa. Yeah, I thought it would be good enough to pick up everything. Am i positioning the offset LNB wrongly?

Are the higher frequency UK spot beams harder to receive here?

 

[scopus]

I will provide some suggestions but I want to find out if this is a comtech dish.

Looks like a Famaval dish to me. I have a 1.8m version

 

[woborny]

I'm now in Genoves, near Xativa. Yeah, I thought it would be good enough to pick up everything. Am i positioning the offset LNB wrongly?

Are the higher frequency UK spot beams harder to receive here?

Genoves, a 2.4m dish should pick up everything, as a 125x135cm dish does fine there...
(was working over the hill in Beniganim this morning!)

But the higher frequency UK beams require 100% dish alignment and LNB skew... and a good LNB.
A fraction of a degree out can make all the difference with those 12000+ uk beam frequencies...

 

[Pride Of Cucamonga]

Genoves, a 2.4m dish should pick up everything, as a 125x135cm dish does fine there...
(was working over the hill in Beniganim this morning!)

But the higher frequency UK beams require 100% dish alignment and LNB skew... and a good LNB.
A fraction of a degree out can make all the difference with those 12000+ uk beam frequencies...

I think there is some alignment issue, probably with the lnb rather than the dish. the offset LNB is giving very poor results

are the 12k+ frequencies still weaker on a theoretically perfectly aligned dish? I'm also finding that H is worse than V

 

[woborny]

"weak" is probably the wrong term
once you have them they are strong.
But they need 100% dish and LNB alignment to lock onto fully.

HAve found most famaval 2.4s I go to see are slighly out of alignment, usually as the back bracket "holders" are never straight, and a few washers placed strategically move the dish back into shape and get the signals nice and strong.

In this area, i find 12382 H slightly easier to locate and "stronger" than 12363 V which in turn is slightly easier to locate and "stronger" than 12168 V , which in turn is slightly easier to locate and "stronger" than 12226 H., no matter if I am using a 125x135cm dish, 1.8m dish, or 2.4m dish.

 

[ymttt]

Looks like a Famaval dish to me. I have a 1.8m version

Thanks. I asked because, I have a 5 meter comtech dish which I found without all 3 lnb arms. It hasn't given good signal and the information I have been trying to find is whether or not all 3 lnb arms measure same length? Anyone with the info may assist.

 

[Pride Of Cucamonga]

"weak" is probably the wrong term
once you have them they are strong.
But they need 100% dish and LNB alignment to lock onto fully.

HAve found most famaval 2.4s I go to see are slighly out of alignment, usually as the back bracket "holders" are never straight, and a few washers placed strategically move the dish back into shape and get the signals nice and strong.

In this area, i find 12382 H slightly easier to locate and "stronger" than 12363 V which in turn is slightly easier to locate and "stronger" than 12168 V , which in turn is slightly easier to locate and "stronger" than 12226 H., no matter if I am using a 125x135cm dish, 1.8m dish, or 2.4m dish.

yep, makes sense with shorter wavelength.

Is there an easy way to tell if misalignment is with LNB or the dish itself? cheers

 

[Miika]

out of interest, why isn't the feedhorn provided with prime focus lnbs anymore?

Not 'anymore', but this has been this way from beginning of the satellite era. Old days every prime focus dish manufacturer made their own specific products - feedhorn matched with THE dish.

Prime focus dishes have various shapes and f/D (focus to diameter) number while almost all offset dishes have f/D 0,6. Thats why for prime focus has dish, feedhorn and LNB (in ancient history there were even more stuff between feedhorn and LNB, for example ferrotor) separate items, but offset dishes use combined feedhorn and LNB.

 

[Pride Of Cucamonga]

Not 'anymore', but this has been this way from beginning of the satellite era. Old days every prime focus dish manufacturer made their own specific products - feedhorn matched with THE dish.

Prime focus dishes have various shapes and f/D (focus to diameter) number while almost all offset dishes have f/D 0,6. Thats why for prime focus has dish, feedhorn and LNB (in ancient history there were even more stuff between feedhorn and LNB, for example ferrotor) separate items, but offset dishes use combined feedhorn and LNB.

that's really interesting, thank you. So unless the dish's original feedhorn is physically damaged, you could carry on reusing it indefinitely as its just a piece of plastic / metal?

 

[Satfaca]

You might want to try with something like this, doesn't cost much anyway...
1
2
3

 

[Channel Hopper]

Thanks. I asked because, I have a 5 meter comtech dish which I found without all 3 lnb arms. It hasn't given good signal and the information I have been trying to find is whether or not all 3 lnb arms measure same length? Anyone with the info may assist.

Comtech did make a 10' (3m) and 12' (3.8m) receive only dish, I'm not sure they made a 16' version. Can you send an image ?

 

[ymttt]

Comtech did make a 10' (3m) and 12' (3.8m) receive only dish, I'm not sure they made a 16' version. Can you send an image ?

Image of a comtech 5 meter prime focus dish.

 

[Channel Hopper]

Image of a comtech 5 meter prime focus dish.

That looks like the 12' version, where is yours ?

 

[Miika]

So unless the dish's original feedhorn is physically damaged, you could carry on reusing it indefinitely as its just a piece of plastic / metal?

Exactly. Or you can buy new one, which matches with your dish. Need to know dish f/D ratio.
Offset LNBs works, if signals are strong, but are not suitable for weak transponders and fine tuning. Offset LNB can "see" only middle part of prime focus dish, therefore collecting about or less than 50% available signals.

Feedhorn must be metal, other materials do not collect signals. If there is plastic addings, these are just for weather protections.

 

[ymttt]

That looks like the 12' version, where is yours ?

Here is mine. I lined it foil paper so the comtech inscription is covered.