ku Orthomode Feed Assembly question

[jduffin]

I have a spare 1m Channel Master commercial-grade ku dish that I would like to set up as a orthomode (2 LNB, one for H and one for V) feed configuration. I have done a fair amount of research on the internet, but can't seem to find a reasonably priced RX-only "T" adapter that will allow me to do this. So, my question is will a OMT (ortho-mode transducer) assembly that is designed for TX/RX applications work?

Here is one in particular on *bay that I was considering: http://www.ebay.com/itm/271104509832?_trksid=p5197.c0.m619

It seems like I would just need to remove the transmit filter (between the side port and the elbow), re-attach the elbow to the "T" and then bolt on my LNBs. Any reason why this wouldn't work?

One concern that I have is that the TX and RX frequencies for these OMTs are different. I would think that this could affect the inner waveguide dimensions and that they might be different. However, if both ports are WR-75 waveguides, then the dimensions *should* be the same and it should just work.

Has anyone done this? Comments?

 

[FaT Air]

It seems like I would just need to remove the transmit filter (between the side port and the elbow), re-attach the elbow to the "T" and then bolt on my LNBs. Any reason why this wouldn't work?
One concern that I have is that the TX and RX frequencies for these OMTs are different. I would think that this could affect the inner waveguide dimensions and that they might be different. However, if both ports are WR-75 waveguides, then the dimensions *should* be the same and it should just work.

I tend to agree, but have to admit, I've not done it. Although, for that price, I might attempt it. I've seen them listed before, maybe not the same unit or seller, but similar at a price many times this listing. (Only 19 minutes left on listing)
Hopefully some who's done it chimes in.

 

[Anole]

it ain't rocket science

Stogie5150 has something similar.

Sometimes leaving off the elbow gets a bit better signal, at the expense of being ugly.

I would get it, expecting it would work, but I can't guarantee it will.
If not, that beautiful feedhorn is the consolation prize.

 

[Bongu]

If I had seen that one, I would have been bidding. Sold for 19.99. It should do exactly what you want. The filter is what restricts the different frequencies. Take it off and you have a good orthomode feed.

 

[primestar31]

You got his attention with your post:

http://www.ebay.com/itm/USED-ANDREW...Signal_Amplifiers_Filters&hash=item416eee2bf1

It's relisted for $300 + $50 shipping...

I hope you got the one for the $19.95...

 

[KE4EST]

That is for a lot of 20

 

[primestar31]

That is for a lot of 20

Yup, I see now down in the body of the auction listing it says it's for 20 feedhorns. That's crazy though, he should list these with no more than two maximum. Who would ever need or buy 20 at a time?

 

[KE4EST]

I have to agree.

 

[Panavision]

I can't believe I missed this! $20 for an ortho is a steal!

 

[KE4EST]

I know I am watching this guy so if he re-lists singles..

 

[primestar31]

I can't believe I missed this! $20 for an ortho is a steal!

a KU ONLY ortho, and built for a specific off-set dish. That's not a C band ortho for a prime focus dish...

Just do a search using the terms; "ku feed"

You'll find a bunch more...

 

[Panavision]

It's my hope that it would fit my Andrew/CM/ASC Signal/Raven 1.2m. I've got two, very stable Norsats that are begging to be put into use.

 

[primestar31]

You'd be best off to go for a Channel-Master feed then. That's what Andrews and Ravens originally were. If you can't find one, then try for a brand one that says it's specifically for a 1.2 meter dish, no larger. Otherwise it'll illuminate too much dish, and might cause issues.

 

[Panavision]

I just figured that for $20 (plus shipping), I'd take my chances. I would need to get a plug that adapts my larger feed holder to a smaller size that the OMT uses.

 

[Anole]

Unless someone can show evidence to the contrary, I would think the included feed would match to *some* high quality commercial dish.
Without looking, I'd bet the 4' & 6' Andrew and the same size Prodelin molded dishes all have the exact same F/D.
Why? Because anything else would be foolish.

So, if I were to have such a dish, I'd happily spend the $20 on one of these.
Could be wrong of course.
Anyone want to prove it?

 

[Panavision]

Anyone want to prove it?

I'd love to!

 

[ACRadio]

I have a bunch of them...they work great! And the feed is a C120 so adapting other feeds to the ortho plumbing is easy.

 

[Tron]

Are there 17 people here willing to buy one? Or fewer willing to buy more than one?

I'd keep 3 of them and sell the rest ...

 

[Anole]

That quantity price is no discount.
HALF for all , makes more sense, and no futzing with shipping, either.


edit: I don't need one, but you get the price down around $20 delivered, and I would add one to my collection.

 

[kingofku]

The tx/rx OMT will work fine since it's designed to work with one pole vertical and the other horizontal. I repurposed a few VSAT antenna as RO antennas and used the existing OMT and they work great.