C-Band satellite transponders alternate between horizontal and vertical polarity. What is this and why is it expressed in numbers on a receiver?
On different satellite subjects, how to you get rid of those red sparklies? Why is the position of the antenna given in a four digit number instead of degrees?
Simply speaking C band satelites are really only 12 channels. 3.7 to 4.2 ghz. They get another 12 channels by polarizing the antenna. Sort of like this + the even channels are on the horizontal and the odd channels are vertical. The polorator is built into the fedhorn. all it is is a short piece of gold plated wire that turns 90 degrees each time you change channels. Assuming you have a modern reciever.
The nunbers that you refer to are the oldway --sorry about that --of finding satellites. the more modern antenna positioners are programmed. They have a memory for where the satellite is.
The sparklies are interference due to the antenna not being correctly positioned.
That is as simple as I can answer your question.
I sold several of those old systems.
I have several still in the basement.
I thought I’d sell them but the technology moved too fast.Sort of typical of electronics.
Before I get a bunch of flack I’d better say that not all satellites are polaiized the same. some have odd channels as vertical and even as horizontal and some are opposite.
As cheap as satellite recievers have gotten I’m surprised that anyone has one that is not programmed so that you have to use numbers.
Sorry Carnivorousplant,I didn’t read your profile until after both of my posts.
The steering Gear,aka satellite jack,usually used a simple magnetic reed switch as a sensor. The signal,which is usually a simple closed circuit,Short, is sent to a counter built into the antenna positioner.It simply counts revolutions or magnets passing the sensor. It is set usually with the lowest number to the west stop.The numbers that you read are the counter counting the pulses as the
jack moves east.The newer positioners have a built computer which identifies satellites by their letter and number designation. F3–G1–T4–etc. The ones that I’m familiar with were programmed west to east just like with numbers.
As far as the polarity numbers go I really dont know except that it is easier to set up programing of the reciever with numbers. It is easy to see that the polorotor is going to be adjusted differently for a satellite on the east end than on the west end. You just adjust for optimum.
Thanks, Justwanna.
Got any Ku stuff in the basement you want to get rid of?
Sorry Carnivorousplant,I don’t, Thank God.
I got out of the buisness just as The 12 ghz stuff was getting popular. I couldn’t afford to stay in it any longer. Around here everybody was selling the things.
And I was afraid the Programming would sell and they would give away the electronics. Good move Huh.
Really all I have is a 4/12 adapter plate and an extra 12 ghz down converter.
I am looking for a product they used to sell called a 4/12 shotgun. I have a bet with a gun dealer that there is such a thing. It would have to have all the paperwork with it.