Page 1 of 1

Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Mon Feb 25, 2019 12:44 am
by CUBA-DVB-S2
Saludos, alguien sabe como hacer una parabólica offset de 1m. Agradeceria que alguien me suguiera un plano.
Muchas gracias.

Greetings, someone knows how to make a parabolic offset of 1m. I would appreciate someone to follow me a map.
Thank you.

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Mon Feb 25, 2019 2:40 am
by kolithawick
constructing a prime focus dish is not very complicated and can be calculated.
But off set actually is a part of the prime focus dish, and can not be constructed unless you make a complete prime focus dish and cut a part of it
or use a already made dish as a mould.

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Thu Mar 14, 2019 8:52 pm
by amelito
Hola hermano. Si se puede. tengo una de foco central de 1.20m y le prepare aditamento para convertirla en offset. En internet hay bastante de eso. Sobretodo como localizar el nuevo foco, que es lo principal.saludos

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Fri Mar 15, 2019 2:14 am
by kolithawick
you get so many false information on internet.
yes you can move the Lnb to side of the dish and you can make it look like off set dish.
But with that you can not get any advantages of offset dish.
read the wikipedia or any other souse to find the theory about offset antenna.

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Sun Mar 17, 2019 2:20 am
by amelito
Discrepo del comentario anterior. En eso se basa que las dish, direct etc sean peques. La offset da un porciento mejor de ganancia, no es mucho pero lo da. Simplemente con no tener los sostenedores cruzando la parabola ya ayuda. solo debes saber la diferencia entre una parabola y una semiesfera. Las parabolas tienen un unico foco, las semiesferas(antenas circulares que miden lo mismo desde el centro a cualquier extremo y esa medida coincide con la profundidad) permiten calcular el foco, que varia de posicion para adaptarle un offset..solo es cuestion de saber los calculos..te reitero, la mia de 1.20m la converti en offset.saludos.

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Mon Mar 18, 2019 3:13 am
by kolithawick
I think this is a problem with google translation. what I am trying to say is same as you say. parabola has only one focus. So if you move the LNB to side,
it is not in focus point.To avoid it what they have done is they left the lnb in the focus point and took only the part of the parabola.check this diagram which I took from the
wikipedia.
320px-Parabolic_antenna_types2.svg.png
320px-Parabolic_antenna_types2.svg.png (15.64 KiB) Viewed 1571 times
This you cannot calculate unless you make a complete parabola and cut a part of it or use a already made dish as a mould.

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Mon Mar 18, 2019 2:06 pm
by amelito
De acuerdo. Solo notar que el LNB queda en otra posicion,por lo que la antena debe reorientarse..es una de las ventajas (como en mi caso) para recibir el mismo satelite. Otra ventaja es que realmente disminuye la forma de la antena para obtener la misma ganancia..yo he logrado alrededor de un 5% de ganancia con la offset.saludos

Re: Como hacer un plato de 1m offset. How to make a parabolic offset of 1m

Posted: Tue Mar 19, 2019 2:29 am
by kolithawick
you must learn antenna theory from the basics. you did not even understand the diagram.
see the diagram, the position of the lnb and dish are same for both dishes.
in your case you have to reorient dish to new position because you are using complete parabola for off set.
the gain you lose due to moving lnb off is much more than the advantage you get with other.
if possible make your dish in prime focus. and measure the signal with a signal strength meter.
and measure the signal strength of your setup with the same signal strength meter.
you will see the prime focus is much more than 5%.
this is the last post in this matter. it is wasting of time.
regards.