Entire transponder swap on Hobird?

[SAT-WORLD]

Can entire transponders swap their channels with other transponders?
Reason being,I was channel hopping,when I discovered channels on Transponder 84 of Hotbird12380V-27.5-3/4,were showing no signal quality.
I then noticed that the channels of Transponder 76 of Hotbird12225V-27500-3/4,were also displaying no signal.
So went in to the installation menu,to check all the settings.
All the settings were in order,however,when I changed the lnb universal setting: 9750/10600 to a higher setting: 9750/10750,both the transponders started to show signal quality.
However,the channels were still black(all fta).
I then deleted the transponders and added them again,and rescanned.
The channels on Transponder 76 are now appearing on Transponder 84.
On the lnb universal setting,there's still no signal quality on both transponders.
The lnb is a monoblock,there's absolutely no problems with any other transponders/channels
I'm pretty certain,its not a problem of alignment,or is it?
Any ideas about the cause and correct solution.
Thanks

[diapason]

That's strange - I am getting channels galore on both 12380V, 27,500 and 12225V, 27,500 - the LNB setting is simply set to Universal and all's well - that's on a Fortec Lifetime Classic box.

[BGonaSTICK]

You shouldn't mess with the LNB Local Oscillator settings, or you will get very confused.

It's an offset from which all other Intermediate Frequencies are calculated by the receiver - a kind of 'base heart rate'.

If you up the LO frequencies by 150MHz, all transponder frequencies will be out by 150MHz in that band, even though the figure entered in the transponder list will still read the same.

The receiver stupidly subtracts the figure it finds in the LNB setup for LO (for the band it's using, i.e. normally either 9750 or 10600 for a universal LNB) from the transponder frequency (say 12380MHz in your example) to give the IF which it then tunes.

So with a correct LNB setting, the tuner will hunt down 12380MHz - 10600MHz = 1780MHz.

If you change the LNB LO frequency, the actual LNB frequency won't change, but the receiver thinks it's different because you told it so!

Therefore, the receiver tunes 12380MHz - 10750MHz = 1630MHz - a whole 150MHz out.

That's what I believe to be the case anyway. If someone wants to prove me wrong, I won't be at all upset

12380MHz - 12225MHz = 155MHz. Close enough to explain the phenomenon you're seeing.

HTH

STICK

[SAT-WORLD]

Originally Posted by BGonaSTICK

You shouldn't mess with the LNB Local Oscillator settings, or you will get very confused.

It's an offset from which all other Intermediate Frequencies are calculated by the receiver - a kind of 'base heart rate'.

If you up the LO frequencies by 150MHz, all transponder frequencies will be out by 150MHz in that band, even though the figure entered in the transponder list will still read the same.

The receiver stupidly subtracts the figure it finds in the LNB setup for LO (for the band it's using, i.e. normally either 9750 or 10600 for a universal LNB) from the transponder frequency (say 12380MHz in your example) to give the IF which it then tunes.

So with a correct LNB setting, the tuner will hunt down 12380MHz - 10600MHz = 1780MHz.

If you change the LNB LO frequency, the actual LNB frequency won't change, but the receiver thinks it's different because you told it so!

Therefore, the receiver tunes 12380MHz - 10750MHz = 1630MHz - a whole 150MHz out.

That's what I believe to be the case anyway. If someone wants to prove me wrong, I won't be at all upset

12380MHz - 12225MHz = 155MHz. Close enough to explain the phenomenon you're seeing.

HTH

STICK

Ah,that explains that,Thanks BG
I had previously read Analoguesat's advice,that you should leave the LNB universal setting well alone.
I'm one to get in to the nooks and crannies,even if regret it.
Whatever gremlins had got in to the works,last night,have thankfully gone.
Transponder 76 corrected it self,a few hours later,set back to lnb universal setting.
Transponder 84,is back to normal,today,(again on lnb universal setting)however the signal quality is well done to around 35%,with slight breakup.
Hopefully,it sort itself out further still.
Damned,if I'm getting on a ladder,in this weather.
Thanks guys.

[BGonaSTICK]

Fiddling with stuff is the only way to find out how it works

[jontydog]

Fiddling with stuff is the only way to find out how it works

Hear Hear Stick I don't agree with the phrase "if it aint broke don't fix it" My philosophy is If it ain't broke mess with it til it is broke and then fix it