Thread: C-band Linear/Circular Orthomode Feed Modification

Pendragon;

Everything fits well, and looks great!

Thanks to everyone over the past few months for their encouraging comments. As I complete other projects I'll be sure to publish my results. The 'siamese feeds' are still where I left them with the sunset alignment and I am one happy camper about the performance to date. I don't consider the 3m a problem child anymore

I'm about to try modding some lnbs similiar to this. NSS7 at 22W has very strong transponders. Currently my 6 ft dish is parked there, and it is becoming a hassle removing the dielectric plate. I had to put up two poles this weekend, requiring 40 50lb bags of cement. Waiting for them to dry/cure.

Originally Posted by 1ADAM12

Thanks for sats. NSS looks interesting to me and has strong HEMI footprint.

Pendragon-

We have a new member who claims his dielectric plate outperforms the normal hunk of fiberglas.

Doctorofsat and others on another site have found substantially better performance on C Band Circular.

This foil pattern is laid out on a 1mm sheet of plastic, Perspex?
They use thin foil.

Still trying to comprehend how these strips come together as a dielectric plate. Anybody? I'm looking at trying to add some sats further to the east that are circular with the least loss, but Pens solution is too awesome for me to handle at this time.

I did a little math and checking on the Internet sometime back regarding this 'foil pattern' technique. In the very best possible light, it is not a general solution as it will only work for certain frequencies and not others. In a more pragmatic light, it is a poor technical solution. You would be much better off getting a cheap dielectric plate (under $10) and inserting it into your feed.

man this was one interesting readin there in the beggining guy. . .looks patent and all.

i have one question, i have been readin over the starters post but im tryin to understand with this setup what where you tryin accomplish?

Originally Posted by greenguy

man this was one interesting readin there in the beggining guy. . .looks patent and all.

i have one question, i have been readin over the starters post but im tryin to understand with this setup what where you tryin accomplish?

there are 2 orthomode feed horns. one is set up for linear cband and one is set up for circular cband. i have copied the great pendragons concept except using a lnbf for the circular portion. ive had it sitting on my bench for months. was gonna install it today but i couldnt find any conduit to make new supports. ah well.

crackt out,.

Originally Posted by crackt

there are 2 orthomode feed horns. one is set up for linear cband and one is set up for circular cband. i have copied the great pendragons concept except using a lnbf for the circular portion. ive had it sitting on my bench for months. was gonna install it today but i couldnt find any conduit to make new supports. ah well.

crackt out,.

this is what i understood from it all, still a good idea with the maths and all. . .DIY im all for.

im usin the corotor II wideband with the same norsat LNBs (8115 c band and 4106A ku band) thats my linear and circular c band and linear ku band there.

i was thinkin of a way to get some circular ku in there without removin what i have.

Will do! I will try and find my plate that came with my geosat.