Meaning of frequency ?

[beer4me]

Nice and short. I get [ example ] 11775 V 30000 , but what does 3/4 or 5/6 etc. mean ? Just trying to become edumacated . Thanks.

 

[Magic Static]

that's the FEC rate (Forward Error Correction)

 

[beer4me]

I appreciate that , thanks. I thought it might have been something I had to program etc.

 

[Tron]

Forward Error Correction (FEC) is usually automatically detected by the receiver.

FEC is embedded error-correction data in the stream. The more error correction data used, the easier it is to receive and lock the signal. FEC is expressed as a ratio. 3/4 means three "bits" of every four are program, with one of every four being error correction data. 5/6 means that five out of every six are program, with one error correction "bit" in every six. 3/4 has more error correction data than 5/6, so its easier to lock. Easiest to lock would be 1/2, but that's very rare. 3/4 seems to be the most common. Some hard to lock signals are 7/8, only one error correction "bit" for every seven program "bits". For those you need a really big dish...

 

[Mr Tony]

and when you get into S2 you can have 9/10 FEC which is a bugger to lock unless you have a big BIG dish

 

[beer4me]

Thanks to all for the info. Much appreciated. I actually do understand. I do still enjoy going to school here . I have just started searching for channels on C band , using my 39" dish , invacomm lnb , and 2100 motor . Almost tried as a wild idea , but was surprised to find quite a few. I do realize I need a big dish for most , but , for now it still is fun .

 

[SatelliteAV]

Thanks to all for the info. Much appreciated. I actually do understand. I do still enjoy going to school here . I have just started searching for channels on C band , using my 39" dish , invacomm lnb , and 2100 motor . Almost tried as a wild idea , but was surprised to find quite a few. I do realize I need a big dish for most , but , for now it still is fun .

I don't believe that you are receiving C-band channels with an Invacom LNBF. To my knowledge, Invacom does not manufacture a consumer C-band LNBF.

While the 39" dish may be able to marginally receive a few C-band channels, you must have a LNBF that is capable of receiving the C-band frequencies of 3.7 - 4.2MHz. The only Invacom models that I am aware of receive only the KU-band frequencies (10.7 - 12.75GHz or 11.7 - 12.2GHz).

 

[beer4me]

Now I am confused . I enter the C-band transponder frequencies , and am getting channels , some duplicated on KU , some not. I suppose I better read some more. Also , where would I get the LNBF aforementioned.

 

[SatelliteAV]

A receiver doesn't care if you are connecting a C-band or KU band LNBF because all LNBFs output a similar IF (Intermediate Frequency) range between 950 - 2150MHz. You are fooling your receiver into "thinking" that a C-band LNBF is connected, but in reality you are only changing the LO frequency and the transponder frequency that the receiver is using to calculate the displayed frequency.

Satellite AV sells a great C-band LNBF with the best quality design and performance of any other C-band LNBF available, the GEOSATpro C2. We also offer a C-Band Mount that is designed for a GEOSATpro 1.2M dish, but it may not fit your brand of dish.

All C-band LNBFs are designed for mounting on a low FD (Focal Distance) prime focus dish design (LNB center in the middle of the dish), so the scalar (the rings around the feedhorn) will not appropriately illuminate your reflector with the higher FD and at an angle. You will need a special scalar designed for an offset dish and may need to design your own custom mount for the C-Band LNBF / Scalar.

Honestly..... it is totally experimental and a lot of work for the few channels that you MIGHT receive if the dish and LNBF are perfectly optimized. I wouldn't waste my time unlss you want bragging rights that you managed to receive a few channels........

 

[beer4me]

Naw , I like to play not brag , and , as per your info and advice , I believe I'll stick with KU , for now. I am going to keep your product info. Maybe some day , who knows ? Thanks much for the reply , and , your time and expert advice.

 

[SatelliteAV]

The absolute minimum for semi-reliable C-band reception is a 6 foot dish. Most hobbyists will have a 8' or larger so the adjacent satellite interference can be minimized and difficult signals like high FEC DVBS2 can be received.

Enjoy the hobby and be on the look-out for a free C-band dish before the local scrappers take them all away!