how to test lnb's

[satguy666]

first off i am requesting a sticky on this please?... what i am wondering is how to test an lnb? i use ku band, linear, and circular,..... the one in question is a linear lnb, but the true question is how to test all LNB'S thx in advance for the info

[Terryl]

The only real way to do it is to use a high frequency (12 GHz) RF generator and a standard "Ku" band transmit antenna, then a spectrum analyzer is used on the output of the LNB.

Without these types of RF test equipment the only way is to use a satellite dish antenna that is fixed in place and is easy to get to (ground mounted) and monitoring a particular circular (91W, 110W, 119W) or linear satellite (97W), you then use a known good LNB to setup the receiver, then substitute the unknown LNB in its place, this way you know the receiver, dish and coax are working before the unknown LNB is tested.

No other way around it.

[satguy666]

The only real way to do it is to use a high frequency (12 GHz) RF generator and a standard "Ku" band transmit antenna, then a spectrum analyzer is used on the output of the LNB.

Without these types of RF test equipment the only way is to use a satellite dish antenna that is fixed in place and is easy to get to (ground mounted) and monitoring a particular circular (91W, 110W, 119W) or linear satellite (97W), you then use a known good LNB to setup the receiver, then substitute the unknown LNB in its place, this way you know the receiver, dish and coax are working before the unknown LNB is tested.

No other way around it.

well i am trying to get 97 with a linear lnb seemed to be working before but couldnt get the dish plumb... i had Q but no signal now i have nothing and the sat finder wont squeel?

[Terryl]

Can you set this up on the ground? (It saves a lot of climbing up to the roof)

If so the best way is to setup a ground mount that wont move, I had a test setup using one dish pointing at 110W another pointing at 97W, all set up with working LNB's and receivers tied into a small TV setup in the work shop, (you can use a switch for one receiver) once you have everything setup on those dishes you lock it all down in place so it wont move.

You can then attach an unknown condition LNB to one of the test dishes LNB arm and see what comes up on the receiver, if you can’t get a signal like you had before it could be a bad LNB or the wrong type for that dish then try the other dish setup.

There is another way but it requires a good working LNB tuned to a satellite to setup the test, you have to make a current monitor coil for this setup, it would be a small metal box (1" x 4") with 2 “F” connectors and a test point, inside is a small coil wrapped around the center conductor (14 gauge magnet wire) connected to the 2 “F” connectors this will add to the signal drop from the LNB but it will allow you to connect to a volt meter to measure the current draw from the LNB.

Using a good LNB of the same type as the suspected LNB you can measure it current draw when locked on a known good satellite TP, the substituting the un-known LNB you should see a different (greater than ± 5%) current draw if it’s not receiving the same satellite TP, however to make a better judgment on this setup you need to establish a standard rating buy using 10 good LNB’s of the same type, this will give you a working average for the current on that type of LNB, a bad LNB will be outside the average.