Ku-band C120 feed/LNB on 5' spun aluminum prime focus dish

[phlatwound]

I just set a new 3 1/2" pole today, and going to install a 5' spun aluminum prime focus dish on it (may be a Paraclipse Hydro?).

The dish has 3 equally-spaced feed support arms so I am going to use one of those LNBF adapter collars for 3-armed prime focus dishes, like this:

C Ku Prime Focus Dishes LNBF Holder

Here is the feedhorn and LNB that I am going to put in the collar:

Global Invacom - Product

LNB 11.7-12.75 DRO MTI AP8-STW for Parabola Antenna | eBay

Here is the specs on the LNB:

RF INPUT:
L: 10.7 ~ 11.70 GHz
H: 11.7 ~ 12.75 GHz
IF OUTPUT:
L: 950 ~ 1950 MHz
H: 1100 ~ 2150 MHz
LO:
L: 9.75 GHz
H: 10.6 GHz

I was wondering if anyone could tell me:

1.) Will this LNB switch polarities with voltage...or is it single polarity?

2.) What should my receiver settings be? I will be scanning the high-band only, and initially will just be taking a tv and receiver out to the dish, so no switches will be involved.

Thanks!

I have attached some pics of the dish from 3 years ago when I was playing with a CoRotor on it, also pics of the adapter plate, feed and LNB.

 

[SatelliteAV]

It is a Universal type LNBF with voltage polarity switching.

Set your receiver to LO 10600 with 22khz ON.

 

[phlatwound]

It is a Universal type LNBF with voltage polarity switching.

Set your receiver to LO 10600 with 22khz ON.

Thank you sir! Never had any experience with Universal LNBFs before...won't be able to say that anymore soon.

I will report my results once I get this rig lashed together.

 

[brex2001]

Very glad Brian knew the answer about the polarity switching. It had been so long since I'd tested that C120 LNB that it was very un-IIRC! lol!

 

[Anole]

What! No ortho mode?
Dont know that LNB, but otherwise it sounds like a winner.
5' on Ku can't be a bad thing.

 

[phlatwound]

Here are some pics to update this project, pole, feed and actuator installed.

 

[Bongu]

I'm thinking of doing a similar thing with a 1.8m prodelin offset. I am not happy with my results using standard LNBFs and know I can do better. The 1.8 should be reflecting a TON of signal, but with unmatched feeds, I am having trouble gathering enough signal even with the center mounted LNBF to reliably receive the S2 signals on 103 Ku. I have the feedhorn for the dish and it is set up for a single polarity wr-75 lnb. I am hoping to be able to mate an invacom QTF-031 or a QPF-031 to the existing horn. I know I will have to open up the rectangular part of the horn and drill new holes to mate with the C120 flange.

I hope I am not hijacking the thread from the OP.

Has anyone had success with this type of change?

Sent from my Timex Sinclair using SatelliteGuys

 

[turbosat]

I see a tree with a 6' crack in it, seems to be right in the way, phlat!

 

[phlatwound]

I was able to do some testing of this setup yesterday.

After setting the elevation and declination with my digital meter, I locked the Azteca signal at my true south (93W) by rotating the whole dish/mount assembly about 2 degrees east.

From there I started working my way east a sat at a time, and had no problem locking the usual suspects at 91, 89, 87, 85, 83, 72 (tweaked the azimuth slightly here) and 61. I didn't try going any further east, I know the Spoon dish would shade this location from seeing 30W anyway.

Then I went back to 93W and began working my way west, had no issues all the way to 116.8W, then I got blocked by a walnut tree.

I am seeing pretty good quality numbers on most sats but nothing outstanding, and some have been rather weaker than I typically see with my 90cm offsets. This is with minimal feed centering/focal length adjustment/tweaking of f/d. Probably more quality there to get, with some effort.

So far it has been a very enjoyable and fairly successful project, and thanks to brex2001 for the great deal on the feed/LNB/adapter, they really fit this dish well.

Here's some more pics.

 

[phlatwound]

I see a tree with a 6' crack in it, seems to be right in the way, phlat!

That tree is gonna get a MAJOR haircut this winter, I hope.

 

[brex2001]

Did you find any gain or other info on that spun dish for Ku band?