[Moon] Regarding the OM6AA Dubus article about the Septum Feed for a Dish

[Jerry Kleker]

I have been making cursory observations of the email about the subject.

For those that do not get DUBUS (and even those that do), I have attached
the prelude to the 1-2007 Dubus article which is in color and of higher
definition.

At this point in time, there does not appear to be any hard evidence that
the 5 step Septum has any advantage over the 4 step Septum (either in a
round or square waveguide). There is one chart that indicates a port to port
maximum isolation of 28 DB (figure 30), but it is admitted that this high
isolation goes away when the feed is put on a dish (2.4 GHz).

The only dimensions (of any importance) that are missing from the published
data, are those for the Septum (divider) itself. These should be easily
obtained from someone that has one. We all can then build one of the feeds
and argue about how good or bad it is.

You may notice that I have put dates which indicate when the documents below
were put in PDF form. OM6AA has not "actualized" his website since September
11, 2006. He has stated that he would put all the information on his
webpage.

Good reading to all.


SEPTUM FEED REVISITED  (NOVEMBER 6, 2006)
http://www.attplus.cz/hamradio/projekty/article/Septum_feed_revisited.pdf

OPTIMIZATION (NOVEMBER 10, 2006)
http://www.attplus.cz/hamradio/projekty/article/Septum_feed_EUCAP2006.pdf

DUBUS ARTICLE (JANUARY 15, 2007)
http://www.attplus.cz/hamradio/projekty/article/Prime_focus_circular_waveguide_feed.pdf



Additional related information:

SEPTUM TRANSFORMER IN A ROUND WAVEGUIDE
http://www.on7un.net/round_septum_feed.htm


By the way.......... I believe that I have enough information so that
we can all DUPLICATE Tay Howard's (W6HD-Chaparal) 3 ring scalar for 1296 
MHz.

I have to put it together from information that he had given me of the 2
ring scalar and then the 3 ring modification (with hardware cloth) that he
made shortly before he died. He said that the 3 ring modification "made a
definite improvement".

More later.

73,

Jerry   W7QX