Any experience in usage of large C band dish for Ku band?

[DiscoveryWanted]

Hello everyone from other end of the planet!

I looked a lot in internet, and found that, very very few people use large dishes recently, since everyone switched to cable or high power ku satellites, where's 60cm is enough in all cases. I found your site still dealing with large dishes. I have a couple of questions, hope someone here had such experience.

I want to receive a certain satellite (Astra 1KR at 19.2E) which's footprint, in theory, is quite far from my location. But guys about 400 km far from me (closer to coverage zone, but still out from it) can receive it, using plain 1.2m offset dish. And guys, far from me nearly 900km, to opposite direction of coverage zone, receive it successfully using 7 meter prime focus dishes. So this means, I have some chance, which I want to use.

Local market lacks of Offset dishes larger than 1.2m, there's only one offer of 1.4m offset dish, but it's for VSAT, and costs $700.

Which we have here in plenty, it's prime focus dishes, starting from 120cm ($30) ending with 240cm ($350). The main problem is, that these dishes seem to be for C band reception only (by my guess, since it comes with C band LNB holder only), so I don't know, how well they will perform in Ku band.

As I know, to receive Ku band with prime focus dish, you need C120 Flange LNB, and apropriate feedhorn, which are also impossible to find on local address.

So I came up with two questions:

1. Does anyone used large (more than 160cm) C band dish for Ku band purposes? what was the result?

2. Has anyone tried to use milling or lathe machine to manufacture ku band feedhorn, and convert plain Ku band LNB into Flange one?

Thanks in advance!

 

[Radioguy41]

I have a 7.5 foot (228cm) dish that I receive C and Ku with. I'm using a Chapparal Corotor mount with separate standard Cband and Ku band LNB's. I live in eastern Pennsylvania and am able to pull in Ku signals from all but one satellite from 139W to 72W. The only Ku signal I can not lock is OETA on AMC 5 at 79W. Sometimes it pops in and other times it's not there at all.

Something to keep in mind is the dish material itself is as important, or maybe even more so, than the size of the dish. First, the holes in the dish must be smaller than a pencil. If you can push a pencil through the holes it probably will not do well with Ku. Another consideration is the amount of material between the holes. More is better. A really fine mesh isn't as good at Ku as a thicker mesh. A solid dish is probably best of all.

 

[DiscoveryWanted]

Thanks for reply! do you had a chance to compare this setup in Ku band to some other dish? I mean, for example, how it performs against plain 120cm offset dish?

Well regarding of local C band dishes, most of dishes are solid ones. Just cheaper ones are segment, while expensive ones - made from one piece of steel. We do not have any mesh dishes here currently (can only buy some used ones, which are in very poor condition)

 

[jayelem]

Welcome to Satellite Guys !!!

I want to receive a certain satellite (Astra 1KR at 19.2E) which's footprint, in theory, is quite far from my location.

Where exactly is your location ?

Which we have here in plenty, it's prime focus dishes, starting from 120cm ($30)

That sounds real cheap

1. Does anyone used large (more than 160cm) C band dish for Ku band purposes? what was the result?

Hopefully someone with a Birdview answer's this question.
Better yet would be someone who has experienced getting Ku band signal outside of a coverage area , a while back I was getting marginal signal from Nahuel 1a but I was using a 90cm dish , I wonder how much of an improvement I would see with a Birdview.

 

[DiscoveryWanted]

Guy with 7 meter prime focus:

35°43'59.72"N
49°55'42.54"E

My location:

41°42'4.28"N
44°38'17.45"E

Guy with 1.2m offset.

45°20'3.84"N
38°50'50.41"E

 

[jayelem]

My location:

41°42'4.28"N
44°38'17.45"E

You live in a conflict zone , I hope your area is safe.

I was looking at the satellite footprint and your geographic location and I'm glad you pointed out that someone is receiving Astra 1KR with a 7meter prime focus that far away so at least that is very hopeful.

Your solution sounds like hit or miss since you don't have exact data to determine the proper dish size for your area , the prime focus should work fine if you can get the 240cm that will probably give you the best results.

I'm not sure if the C120 Flange LNB is your only option , Invacom makes them and they're relatively cheap , i would like to know why that is the type of LNB you have to use , many of the C-band users here use the BSC-421 on either C or Ku band , maybe someone can chime in with their Ku band experience using the BSC-421 and how it performed on a big dish.

 

[sergei]

This site may be of help to you with your dish...check it out

SatLex Digital :: Technology :: Calculators :: AZ/EL Calculator

 

[ACRadio]

You live in a conflict zone , I hope your area is safe.

I was looking at the satellite footprint and your geographic location and I'm glad you pointed out that someone is receiving Astra 1KR with a 7meter prime focus that far away so at least that is very hopeful.

Your solution sounds like hit or miss since you don't have exact data to determine the proper dish size for your area , the prime focus should work fine if you can get the 240cm that will probably give you the best results.

I'm not sure if the C120 Flange LNB is your only option , Invacom makes them and they're relatively cheap , i would like to know why that is the type of LNB you have to use , many of the C-band users here use the BSC-421 on either C or Ku band , maybe someone can chime in with their Ku band experience using the BSC-421 and how it performed on a big dish.

I believe the signal he is looking for is on KU band. I use the Invacom TWF-031 which is a C120 flange LNB along with a Invacom C120 prime focus feed that works well.

I have 2 prime focus dishes being used for KU band, both are 2.4 meter Channel Master fiberglass. One has a dual orthomode feed with a pair of C and a pair of KU LNB's, the other has the LNB that is described above. In a lot of instances the dish with the invacom will outperform the dish with the orthomode. I mounted the KU prime focus feed inside a C band scaler...

 

[DiscoveryWanted]

I know where's exactly astra 1KR located - I hooked a spectrum analyser to LNB on 1.2m offset dish, and I can see characteristic "waves" of DVB-S signal on it's screen, when pointing to Astra 19KR, but signal is too weak, regardless of LNB (Invacom, inverto, supermax, tokyosat, premiumx, pauxis, next & nextstar, samson, delsat, etc - I tried more than 25 types), receiver can't even lock the transponder.

Now I'm checking ways of purchasing C120 horn and lnb overseas, but as mentioned, I live in conflict zone, and overseas delivery is quite hard this time. Local shops only have invacom LNBFs for offset dishes.

 

[DiscoveryWanted]

So this is why I asked, if anyone knows exact dimensions of Ku band feedhorn for prime focus dish, since I have acces to lathe machine, can manufacture one by my self