CP on a LP lnb? (Probably an Iceberg question!)

[CharredPC]

There seems to be no ryhme or reason, but sometimes I can pick up CP with my LP Universal LNBF. I just did a scan of G11 and pulled up some Nimiq stuff; confused the heck out of me for a minute Then I did a true Nimiq1 scan; only 12676/H/20000 will pull up! It gets me CJPX (99.5FM, Montreal classical music) and 13 scrambled channels. Is that the proper freq. for that? Could I alter my LO and recieve more, or do very strong TP's just bleed over enough for a LP lnb to work?

Any insight?

 

[Cascade]

strong TP's just bleed over enough for a LP lnb to work

Nail on the head.

 

[rkrenicki]

A Linear LNB will pick up Circular transponders at about 1/2 power.. a Circular LNB would do the same with Linear, if it could pick up the same range.. since circular tps are higher frequency than linear tps, the circular lnb wont go low enough for linears. but the linear lnb does go high enough for circulars..

 

[rkrenicki]

if you told your reciever that on nimiq, that your lo is 10750 instead of 11250, it would probably pick up most of the TPs

 

[CharredPC]

if you told your reciever that on nimiq, that your lo is 10750 instead of 11250, it would probably pick up most of the TPs

I guess that was my question. With a modified frequency list, and a modified LO, can I set up my linear lnb to recieve CP birds, albiet at half strength? LNB settings can be set up on a satellite - by - satellite basis in MyTheatre, so it would work out, if somone can verify...

 

[rkrenicki]

I can vouch for it.. When I was looking for G10, I kept finding Echo 9 at 121 and Echo 6/8 at 119. The best quality I could get on 119 was 49

 

[CharredPC]

But setting the LO to something other than default (my universal's is 10600) would skew the frequencies, correct? Therefore, I'd have to alter all the frequencies accordingly to match up... ?
Edit: keep in mind: no blnd scan

 

[rkrenicki]

When you select Nimiq in your receiver, its probably defaulting to 11250 instead of 10600 make sure the LO is set to 10600, and it should pick everything up. Basically, the reciever is looking in the wrong part of the L-band IF for everything. (too high up, and runs out of space)

Should have seen me trying to figure out why I was picking up the 121 test card, and NasaTV at the same time.. it was one of the odder moments in life

 

[CharredPC]

Actually, I have to set the lnb settings manually for each different satellite; the "real" settings (LO1:9750/LO2:10600) is what I'm already using.

 

[rkrenicki]

hmm.. I would double check this, but my FTA setup isnt really setuping at the moment.. the motor wont move at all for me.

When my new motor shows up on tuesday, I will give it a whirl.

 

[Stefan]

A circular polarized wave is actually composed of a horizontally polarized and a vertically polarized wave shifted 180 degrees out of phase with each other. So, yes you can sometimes recieve circular polarized signals on a linear LNB, but since a linear LNB cannot differentiate between right handed and left handed polarized signals and instead only sees the linear components of the wave if you have both a left handed and right handed polarized signal on the same frquency the linear LNB won't be able to differentiate between the 2 and they will likely interfere with each other. So to get all around realible reception of circular signals you need either a cricular LNB or to convert your linear LNB to a circular one. To do that you simply insert a dielectric slab into the throath of your feedhorn and orient it such that it's at a 45 degree angle to the 2 probes inside the LNB. The dielectric slab can be a piece of somekind plastic or teflon. Anyway, it's usually somekind of material with a high dielectric constant.

"Is that the proper freq. for that? Could I alter my LO and recieve more, or do very strong TP's just bleed over enough for a LP lnb to work?"

No. you shouldn't alter your LO setting as it is what it is and is detemined by the LO inside your LNB. The reason universal LNBs generally are able to recieve some circular signals is that most of the circular signals are in a frequency range that is outside that of which a regular linear LNB is designed to recieve. If you want to recieve more circular signals you can make a dielectric plate out of a piece of teflon and insert it in the throat of your LNB at a 45 degree angle to the probes inside the LNB but doing this will have a negative impact on the regular linear FTA signals you normally recieve as the dielectric plate will impede the signals traveling down the feedhorn into the LNB.

 

[Mr Tony]

easiest way to think about this...when I change the LO frequency to 10600, it scans IF frequencies 990-2150

Add the IF to the LO and thats the frequency...so it picks up DBS signals too...mostly its bleed over. When using a standard LNB and LO frequency is 10750, my unit stops at 1600, so it doesnt get all the DBS ones.

When I scan 83 it sucks because it picks up a lot of frequencies form 82