New LNB on 10' amd mow weird reception

[thardie]

New LNB on 10' and now weird reception

I've had my Winegard 10' Buttonhook mesh dish for a long time (>10 years). I just placed the LNBF from a dual Cu/Ku with servo to a LNB that has C & Ku integrated together with polarity switching using Voltage instead of a servo.

When setting the f/D ratio on the dish, if I peak it so C-Band is strong, Ku is weak, and if I peak Ku, then C-Band is weak. I right now have it in the middle, so I get Ku and C mediocre, and I'm not happy with it. The dish has a linear motor to move it on it, and I haven't made any adjustments on it since replacing the LNBF.

What could cause this? My Old LNB seemed to do OK, but the new one is supposed to be more sensitive...

 

[Anole]

from what I've read:

The electrically controlled dual band LNBFs are more critical in being mounted dead on the money.
That's side to side, vertically, and aimed at the center of the dish.
Double check the in/out focus when you change feedhorns, too.

You may find that C and Ku peak at different places on the arc.
Getting the feedhorn back to within maybe 1/4" of center, should clear that up.

 

[Corrado]

I've been using such a LNBF for about 5 years now on the 10'. In my opinion it's as perfectly aligned as can be. It's capable of DVB-S2 at 8/9 FEC with Q approaching 85-90 on C band on a daily basis. 80-82Q on Ku.

I worked for days attempting to correct why the Ku was one click east for peak Ku over C band. Even though separately each works very well, I was under the impression it wasn't pointed correctly. My prior servo controlled feedhorn did not behave in this manner.

Finally, I came to the conclusion that it must be the locations of the internal probes inside the LNBF. I settled with the idea that it must be the way the beam is reflected rather than focused and learned to live with it.

 

[thardie]

Thanks for the tips. I'll put some rigging on my dish to center to feed proprely (It's a buttonhook, so is not exactly centered). Of course, I may have to re-aim my dish after that, since it was peaked with the feed where it is now

 

[truckracer]

those combo c and ku lnbf's don't work as well as a good corotor servo controlled feedhorn. It's not the servo that makes it work better but the overall design is better.

you will always have a great compromise using a combo c ku lnbf. You will probably always have sidelobe reception on ku where you have to bump the dish a little get ku peaked and then bump the dish back to peak c band on the same sat. My combo bsc 621 was alway like that where c and ku were at different place on the same satellite. My corotor is dead on. If ku is strong c band is strong and vice versa.

there is an article floating around on the internet where years ago chaparall persued a design for a combo lnbf and never released it because it could never perform to their specs.

if you google it you may find it somewhere.

 

[Anole]

BirdView Ku-band poster boy:

Read from here through the February post by Stogie in his Birdview Install Thread.
He discusses the accuracy he met to get his dish working as well on Ku as it already did on C-band.

For those who don't know the dish, it's an 8½ foot spun aluminum, on a battle tank mount, at the top of a six inch diameter mast (very stiff).
And the Paraclipse he refers to, is 12 feet of signal-suckin' sail!
Both dishes are on magnificent horizon-to-horizon mounts.
I believe both are equipped with Ck-1's.

 

[stogie5150]

Read from here through the February post by Stogie in his Birdview Install Thread.
He discusses the accuracy he met to get his dish working as well on Ku as it already did on C-band.

For those who don't know the dish, it's an 8½ foot spun aluminum, on a battle tank mount, at the top of a six inch diameter mast (very stiff).
And the Paraclipse he refers to, is 12 feet of signal-suckin' sail!
Both dishes are on magnificent horizon-to-horizon mounts.
I believe both are equipped with Ck-1's.

Lemme add to brother Anole's thoughts. I have used the ck-1's for about a year now, and I have only had one feed (ku) I couldn't lock on the Paraclipse, C or Ku. The Birdview locked it easily, with the same ck-1. The mesh on the Paraclipse is just not ideally suited for Ku, but it works 99% of the time.

It took a MASSIVE amount of tuning time to get it like it is. But, like I said, I have yet to see a feed I can't lock and display with my CK-1's.

Now I'd be an idjit (hey, some folks already think that...) if I said that they were BETTER, but dollar for dollar, a corotor or orthomode setup with good LNB's could easily cost 10 TIMES what my CK-1 costs. I'll put the money in more Azboxes, thanks.

Plus, with a corotor, you have to deal with the servo, with no way to automatically blindscan a satellite without being there to switch polarities, etc.

It just isn't worth it to me, and also a lot of other folks.

 

[thardie]

Does anyone make such a feed that has 2 cband band and 2 ku band feeds on it? I mean so you would put 2 Cband LNBs and 2 Ku Band LNBs on the 1 feed, meaning you have 4 LNBs on the feed?

 

[Anole]

ye$:

Yes, absolutely.
I'll get you some links....

Here are the two we generally find and talk about.
ADL
Chaparral
(no idea if that dealer is the best or cheapest; you should do your own search before purchase)

There may be another brand, but I'll leave that for someone else to post.

Typically, you would follow that feedhorn with a multiswitch which then feeds your receivers.
Here is a comprehensive discussion of that approach, with pitfalls and solutions.

Pendragon mods a 4x8 multiswitch for high voltage on both ports:
http://www.satelliteguys.us/fta-shack/174802-naughty-mods-ii-4x8-switch-all-18v-outputs.html

 

[emuman100]

I'd personally use a Chaparral Dual output C/Ku feedhorn, so you'd need 4 LNBs total, two Ku for H/V, and two C for H/V. But, this is for a stationary setup. For a movable setup, I think they have a C/Ku feedhorn that has one C and Ku outputs and adjustable polarity.