Ariza T-55 Toroidal Dish

[robg1965]

Got an Ariza T-55 dish given to me and I thought I would give it a try on but I noticed that the LNB's say reverse polarity on them. I didn't think it would make a difference(signal is signal just bounced once) maybe I'm wrong on this but can I use standard circular LNB's with this dish?

Thanks in advance
robg1965

[Terryl]

No you have to use the reverse polarity LNB's with the T-55, why?

Because of the way the toroidal dish works, it has a second reflector, this causes the signal to be 180 degrees out of phase, (this is a problem with RF signals) a normal LNB wouldn’t be able to pick up the signal as they are designed for a singe bounce not 2 like the T-55.

[Terryl]

The 180 degrees wouldn’t matter if the signal was just an FM signal like radio, but a satellite signal is different, it uses QPSK (Quadrature Phase Shift Keying) and 8PSK (8 Phase Shift Keying) as modulation, this is how the signal is sent down from the satellite, it is phase shifted and any difference in phase would cause a signal loss or “Q”.

[robg1965]

Just finished looking for a couple of RP LNB's, thanks for the info.

[Bowhunters]

I have a T-90, Sadoun is probably one of the cheaper places for reversed LNB's for Dish and Bev.

This is an excellent site for setting up the dish and where on the bar to put the LNB's for the different sat's. - .satlex.de/en/wavefrontier_calc.html

[dale1010dog]

Did you guys use the settings from the calculator on here because my T-90 I cant get any signal. sombody posted somewhere that settings on here are different thanks..

[Bowhunters]

If you can get WaveFrontier to reply and email you your dish setup info fairly quickly then theirs is much better than the calculator site I posted above as WaveFrontier will not only give you precise spots on the LNB bar for where to place the individual LNB's but they will also tell you how many degrees to 'angle' the LNB's on the bar mounts. (but that LNB angle isn't that big of a deal except on the outer ends of the LNB bar).

I don't know if they have layed people off at WaveFrontier due to the economy but getting a response from them does seem to take a lot of time or repeated tries.

The calculator is not as precise but i've used it and its fairly close, I would suggest you do your 110 and 119 LNB's in the center of the dish first, set them and lock them down on the bar exactly as the calculator says and then move the dish by their compass setting and once the two dish LNB's are getting tv then lock the dish down and then work your way outside adding LNB's in the bar positions as you need them and use a meter to peak them into perfect position.

As I said, the calculator on the site I included in an earlier post isn't perfect but it does get you close, I posted some more info in another thread on the T-90 also.

I don't know if you bought your LNB's at WaveFrontier with your dish but I would point out that you need to make sure you use reversed LNB's, a cheaper place to get them is Sadoun as they sell standard and reversed LNB's.