Horizontal Vertical .... and ?

Anchises

struggling to learn .............


On Lyngsat some transponder data shows R or L where normally i would have expected H or V .

What does R and L mean ?

Right and Left ?

A.

tomslick

It stands for Right and Left as you said. If I remember correctly it is only for Circular polarity. You can get LNB's for this but I don't think you can pickup any of the signals in this part of the world.

byte

Yeah, pretty much!

They're for circular polarised signals (left or right handed), as opposed to the usual linear H/V signals you're used to.

Unless you have an LNB capable of receiving circular signals, you won't pick up anything.

Anchises

Thanks Guys

A,

The Cush

Anchises wrote: »

What does R and L mean ?

Left and Right Hand Circular Polarisation (LHCP & RHCP). (http://www.abadss.com/forum/102-faq-how/5880-understand-lnbs-standard-linear-circular-universal-lnb-lnbf-stacked.html)

From the average European satellite TV viewer point of view this was the polarisation type chosen for the high power Direct Broadcast Satellites (DBS) i.e. satellite television broadcasts intended for home reception (Europe Region 1 11.7-12.5 GHz). In 1977 at WARC-77 countries were allocated a number of DBS channel frequencies using LHCP or RHCP. In Europe only a few countries launched DBS services Germany (TV-Sat), France (TDF), UK the failed BSB with the Marco Polo satellites and Sweden's Tele-X. Ireland planned a 5 transponder satellite called Eiresat / Atlantic Sat.

Due to the limited number of transponders available on DBS satellites, medium power satellites e.g. Astra 1A, with up to 16 transponders and horizontal and vertical polarisation became the de facto standard for DTH broadcasting in Europe.

LHCP & RHCP continues to be used by some C-Band satellites (3/4 GHz) and DBS satellite services (12.2-12.7 GHz) in N America.

watty

H or V mode on an LNB will recieve L and R, simultaniously, but at 1/2 power.

So a regular LNB (Ku Band) will only work if:
L and R frequencies don't overlap (otherwise interference/ no reception).
The LNB can tune the frequency. Many L& R are C-band.
You are in footprint (Likely not for Ku Band)
Your dish is big enough.

If it can work, then H or V will work equally no matter if signal is L or R circular polarization.

Usually C-band, apart from needing a C-Band LNB needs a 2m to 4m dish as it's often for cable head-ends, not DTH (Direct to Home).

Some C-Band LNBs are H & V rather than L & R.

Another reason for circular polarisation is that if the satellite is slowly spinning it is more stable. H or V will only work with a stationary satellite WRT to ground. A Slow spin on dish axis will not affect signal from circular polarisation, it would cause H and V both to vanish completely twice per revolution.

Final reason is that at lower frequencies (S, L and C band) the atmosphere/ weather / ice crystals can cause a shift in polarisation. Again, this can reduce H or V to almost nothing but has no effect on circular polarisation.