Help Required Identify C Band OMT & Feed

S

s-band

Member
My Satellite Setup
1.5m IRTE PF, Invacom SNF-031, TBS6983,
Various L, S, C, X & Ka bits. 1.2m S/X/Ku/Ka Prodelin on Az-El (being refurbished), 1.8m Precision PF with Bullseye Ku LNB or various C & X bits
My Location
Essex
What have I just bought? It looks like an ADL OMT with a scalar ring but I'm only working from pictures from the web. This one looks similar but with a longer barrel to accommodate the circular polariser: http://adlfeed.com/cat_sec_1_4.htm It's from Australia so I presume it is for linear polarisation. It looks quite rough but I think it will clean up ok. Oh, and if anyone wants it, the seller has a 3m dish for sale/disposal.

Oz_OMT.webp Oz_OMT2.webp
 
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It does look like some ADL stuff i have G. Can you flip it over and take a pic of the rings please.
 
s-band,

The ADL orthomode that I have is a two piece arrangement without the pressed indent in the feed. With the ADL feed, it is a fully cylindrical barrel and it can accept either a single WR229 adapter or an orthomode dual WR229 port adapter at the non dish end of the barrel.

The pressed indent on the side of the feed and the lack of option to fit a single or dual WR229 port possibly indicates it is not an ADL feed. In the photo you linked to of the actual ADL feed, you can see the split/join at the OMT end of the barrel and no pressed indent.

However, it could be an earlier version of the ADL feed that I have?

I have attached a photo of a C Band OMT that I have but without the scalar ring, it looks similar in shape to the one that you purchased?


Rgds
 

Attachments

  • Chinese_OMT_01.webp
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John said:
It does look like some ADL stuff i have G. Can you flip it over and take a pic of the rings please.
Click to expand...
Thanks, it's on its way from Aus. at the moment. It will be clearer if I could see the side where some ADL's have embossing.

moonbase said:
s-band,

The ADL orthomode that I have is a two piece arrangement without the pressed indent in the feed. With the ADL feed, it is a fully cylindrical barrel and it can accept either a single WR229 adapter or an orthomode dual WR229 port adapter at the non dish end of the barrel.

The pressed indent on the side of the feed and the lack of option to fit a single or dual WR229 port possibly indicates it is not an ADL feed. In the photo you linked to of the actual ADL feed, you can see the split/join at the OMT end of the barrel and no pressed indent.

However, it could be an earlier version of the ADL feed that I have?

I have attached a photo of a C Band OMT that I have but without the scalar ring, it looks similar in shape to the one that you purchased?
Click to expand...
Thanks. To me it looks like the ADL circular polariser ones without the polariser extension but I can't find a picture of the linear version.

I'm not sure about the scalar ring, at first that looked like an AV-Comm.

The photo is of a Chinese one that looks like a Chaparral copy Did you post the correct pic?
 
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s-band,

The good pics of the ADL feeds/OMT are in the PM topic, if you check that PM topic the ADL pics are in there.

Rgds
 
Browsing what's left of the ADL catalogue, the scalar looks very similar to this http://adlfeed.com/cat_sec_1_2.htm

I reckon it may be the OMT from here cp_or100.webp

on top of the scalar from here rp1_or_100.webp

I guess I'll have to wait until it arrives.
 
It arrived and it is as in the previous post. It needs a bit of a clean after apparently enjoying sea air for a while. Naturally, the AV-Comm polariser will not fit in the middle without some modifications or adaptor bits.

adl_20_std.webp adl_21_std.webp adl_22_std.webp adl_23_std.webp
 
s-band said:
It arrived and it is as in the previous post. It needs a bit of a clean after apparently enjoying sea air for a while. Naturally, the AV-Comm polariser will not fit in the middle without some modifications or adaptor bits.

View attachment 104657 View attachment 104658 View attachment 104659 View attachment 104660
Click to expand...


Thanks Graham, that scalar looks very very similar to one i have thats classed as a high effeciency scalar. After a good sand blasting & a coat of paint they would look great.
 
John said:
I wonder what the official actual theory & explanation is for the two different lnb flange shapes ?.
Click to expand...

Just a guess but I think it is part of the rectangular to circular transition on the straight through port. The side port feeds into the WG and doesn't need the transition. There can be bandwidth differences between the 2 ports with the straight through having wider BW than the side.

blademedia said:
That looks easy to duplicate :)
Click to expand...
Go for it.
 
s-band said:
It arrived and it is as in the previous post. It needs a bit of a clean after apparently enjoying sea air for a while. Naturally, the AV-Comm polariser will not fit in the middle without some modifications or adaptor bits.

View attachment 104657 View attachment 104658 View attachment 104659 View attachment 104660
Click to expand...


s-band,

Have you got one of those cheap and cheerful orthomodes from Ali Express? It would be very interesting to see how the genuine ADL orthomode and the Chinese option fare against each other? If you have not got one, I have one that I can bring over or post to you on loan for testing?


Rgds
 
I had a cheap Chinese one but don't any more. I did not use it. I haven't forgotten about the measurement session, it's been a bit chaotic recently.
 
I did a "quick 'n' dirty" test on the response of the ADL and a cheap straight through feed. The straight through was good at 2.9-5.8GHz. The ADL straight through did about 3.2-5.4GHz and the ADL side port 3.4-4.3GHz. So if you want full band, don't use the side port.
Note: The theoretical response of the coax transition is 3.3-4.9GHz but it doesn't drop rapidly until WG cut off at the low end (~2.9GHz) and drops slowly >5.5GHz.
 
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