Ku versus Ka

[sathunt]

I am trying to set up a Hughes dish for 97w. From the research I have done, the model I have, AN8 074P, was intended for Ka. My question is, if I use the original lnb mounting mast, would the offset be the same for a Ku lnb? Using Avenger PLL321S-2 Ku lnb. I have set declination and skew according to my long&lat, and made necessary modifications to raise lnb so it would be centered with dish accordingly w/ the mast. No luck. But then again, this is my first attempt w/ a Ku setup. Thanks.

(Attachment does not show lnb attached)

 

[FaT Air]

would the offset be the same for a Ku lnb?

Yes. The focal point is at the same location no mater the frequency. If you had the original LNBF measuring the distance, to the front center of the LNBF, from the upper and lower lip will be the same for the Ku LNBF. Might have to be able to adjust closer/further away from the dish face to account for differing manufacture of the feed horn throat (How much plastic is in front ot them)
Don't know if this helps or not, found on google search:
http://www.montanasatellite.com/man...elin Ka-Band Antenna - Installation Guide.pdf

Another question: Ku LNBF type? If it's intended for a normal offset dish, it will under illuminate a elliptical. Better performance will be had by using the original feed horn. Mate a FTA LNBF to it. Some here have done it.
- - That might be a problem Scotty! It's optimized for Ka.- -
My 2 cents worth anyway

found thread http://www.satelliteguys.us/threads...-dish-74-Good-for-FTA?highlight=hughsnet+dish

 

[sathunt]

Thanks FatAir. Unfortunately I don't have the original lnbf. Hate to say it but original owner threw it away! I am using Ku lnbf Avenger PLL321S-2. I found center of dish, then held a 2foot level on that and got it parallel w/mast. Measured up from mast to bottom of level to find center from mast to dish. Thats the only way i could think of figuring what center of lnbf would be. Tried moving lnbf in&out and several blind scans. Actually didn't spend a whole lot of time messing w/it. Was running through my checklist of what I may be doing wrong. That's when I thought about it being originally made for ka. Thanks again.

And thanks for web link. That's actually where I found most of my info about the dish.

 

[FaT Air]

Well the only thing I see is you may be way too low. Look at fig 29 @ page 34 of the pdf. Since you know the height of the LNB support, think you can measure on the pic and transfer to your mount.
BTW: are you skewing the dish with the LNBF at '0'.?

 

[Anole]

I described this idea several years ago:
Pick a strong satellite near your TS.
Set the post plumb.
Dial in elevation on the mount.
Adjust for azimuth.
Leave skew of dish at zero.
Now move the LNBF around manually 'till you peak the signal.

 

[sathunt]

@ Anole: it was my understanding that dish skew had to be set according to your location. Does it work better leaving it at zero?

@FatAir: tried scaling picture(I am using a smart phone) the best I could come up w/ the lnbf needed to be raised about 7/8 of an inch. I am standing in front of dish and centering lnbf w/ center of dish if this is what you mean by '0'.

Also, do I need to be setting to true azimuth, or magnetic azimuth?

 

[Anole]

I took your original query as, "how do I get my LNBF located at the focal point?"
My answer was for that.

If you in fact have the original feed, that's where your LNBF needs to be.

The feedhorn on your replacement LNBF may not match the dish shape, and performance may be reduced.
Let's see the shape of the original to offer a better opinion.

Yes, once you have your LNBF at the one proper focal point, then you DO want to skew the dish as required!

If you have surveying equipment, feel free to use true azimuth.
For everyone else using a compass, use magnetic azimuth.

 

[sathunt]

I made a bracket out of unistrut so I would be able to adjust lnb up and down to find center instead of guessing. I am about to the point where I am starting to believe the lnb isn't working. I have adjusted up&down, in&out, different declinations, skews. Nothing. Even I weren't aimed perfectly for 97w, I would think after the hours & hours of trying, I should have hit something by now. Of course I did order this lnb from the same company that sent me a c band lnb that wasn't working correctly, and a digital meter that doesn't work at all! Kind of adds to the belief this ku lnb isn't working! Idk. Thoughts anyone?

 

[Anole]

What are the LNB settings on your receiver?
Do you have a Universal LNBF or Standard?

 

[gpflepsen]

Hard to tell the geometry from these images, but your lnb may be pointing high on the dish. Only guessing here. It may be easier to freehand the lnb in space with the dish at the proper elevation and azimuth for your south satellite. I was able to simply hold my ku lnb in front of my BUD and find the spot there for an offset mount. This is where a decent signal meter is invaluable.

 

[gpflepsen]

Looks like you're close. This is my understanding of where you should be located.

 

[sathunt]

@Anole: universal, 10.600, that's the setting the lnb called for.

@gpflepsen: I set azimuth & elevation for 97w, I hadn't tried true south tho. That's the same pdf I was trying to scale off of for lnb setting. Didn't have any luck, that's when I came up with the unistrut bracket so I could adjust up & down to take the guess work out. But yes, I would have to agree about a good meter. Granted it was a cheapo meter, but I even hooked it up to my BUD which I know for a fact was working, never budged it.

Thanks guys

 

[SatelliteAV]

Is the LNB setting Universal 9750/10600 with 22khz - AUTO or is the LO setting for a single 10600 with 22khz - ON? Either of these two settings will work with an Universal type LNBF.

The LNBF should not need to be tilted up or down. It should be mounted level and parallel on the support arm. This should aim the feedhorn into the correct area of the reflector.

What transponder frequency are you using? 12177 is quite strong, but it is also duplicated on several other satellites.

Is the skew set correctly for 97w?

Do you know anyone with an FTA setup that you could swap LNBFs on their presumed dish to test yours to confirm operation? I would find another vendor with as many DOAs as you have dealt with!

You have a triple whammy working against you. 1. Don't know if the dish is even aimed at the satellite. 2. Don't know where to place the LNBF in the sweet focal point. 3. Don't know if the LNBF is working.

I would first test the LNBF. Second, set the LNBF in the approximate position of the previous feedhorn, set the skew, then only adjust the dish elevation and azimuth until signal quality readings are observed.

Once you have roughed in the dish aiming, then optimize the LNBF placement and keep adjusting the dish aiming and LNBF positioning. Each setting works against the other. Both have to be exact for the combination of reflector elevation/azimuth setting to be focused in the "sweet spot" for feedhorn placement.

 

[catamount]

For a universal lnb, you can use: Lnb standard
Lo 10600
22 khz on

Edit: Brian beat me to it,

 

[sathunt]

Let me clarify. Im not tilting lnbf, I made the bracket to adjust up and down to find center. The only reference I have to where the old feedhorn was located is the pdf I downloaded that shows how to install original hughes equipment. Every time I adjust I make sure lnbf is parallel w/ support arm, and stand in front to check it is centered.

I have set skew, azimuth, and elevation for 97w according to my zip code. Post is plumb.

Don't know any1 else w/ an FTA setup. And yes, im never buying anything else from them again, even if I do get this working. Bought all of this in the same shipment.

Lnbf is 9750&10600. Honeslty didn't know about the 22k part. But I have been setting LO at 10600. Tried turning on 22k when I got home but still didn't have any luck.

Thanks again guys

 

[SatelliteAV]

I would take the LNB support arm as reference and level the LNBF to it.

The LNBF must be skewed counterclockwise approximately 20 degrees. Once the LNBF is sitting at about the same height and the feedhorn opening is sitting at about the same distance away from the reflector as the previous feedhorn, do not touch the LNBF again until you have located the Signal Quality reading.

If the LNB LO setting has been at 10600 without the 22khz turned ON and be set to an active transponder, the receiver would be unable to lock on a signal or display a satellite Signal Quality reading.

Your searching to this point has been for practice only... But the good news is, with all that practice, you should find the satellite quickly!

Your dish aiming will likely be close to the correct elevation and azimuth, but it is only in the ballpark. Now it is time to aim the dish, not the LNBF...

 

[Anole]

You must turn on the 22khz and set LO on your receiver to 10600 (or one of the variations mentioned above).
This is not an option.
Then set the receiver for a strong transponder, and start over.