KU LNB on a C-Band feed horn ?

[Greg Mueller]

I've got my eye on an approx 7' Bud (tight mesh). I'm wondering if I can take off the C-Band LNB and put a KU LNB in it's place and use that dish for KU only.

Just wondering.

PS
I have a 12' dish for C-Band

 

[Anole]

They are not mechanically interchangeable.

edit: here are some pictures of an orthomode feedhorn.
It takes two C-band and two Ku-band LNBs.
The big holes are for C-band LNBs, and the little ones for Ku.

edit again: looks like Gabshere has a much better idea.
Sorry for being dense.

 

[gabshere]

yes it should work if you remove feedhorn & lnb ( if not see anole post above)
might want to consider a prime focus ku lnbf Sat AV has some on sale in the regular FTA Forum

I found that my primestar dish gets as good or better signal for Ku than my 7 1/2 ft dish did but i can't remember how it handled during a rainstorm.

another problem is movement ( it would take a v-box / g-box type of mover to move the big dish) unless you used an old analog mover.

EDIT added info

 

[gabshere]

another thing you can do is mount the above lnbf listed offset on the 12 ft dish

you could offset it so when you have the dish parked at 101 for c-band you could get 97 ku
just a thought

 

[Greg Mueller]

I was wondering if the gain would be better than on the 1.2 meter Primestar dishes.
I do have a standalone satellite dish mover. It's a Uniden model UST 300 I bought it new but never used it.
I also have some of the Primestar LNBs that I could make adapters for. I could mount them at prime focus on the little big dish.

The idea of being able to adapt a little BUD for use as a KU dish and have it trackable is what intrigued me

 

[gabshere]

well i suspect for Ku you won't see a great gain ( and probably see a loss)

maybe if the dish was a solid but not mesh ....

i tried the same thing a couple of years ago thinking i would get dbs signals with my big dish
the quality levels just barely made it to 70% its then i realized that for some things bigger isn't always better. ( the little 18 inch dish had better signal )

i don't have a 1.2 meter dish but i will suspect it will out-perform most all mesh dishes for Ku (now the rain fade area is where i don't know , and suspect heres where the larger mesh dish will gain some ground)

also have some of the Primestar LNBs that I could make adapters for. I could mount them at prime focus on the little big dish.

its still something you can try and tinker around with. i always enjoy tinkering

 

[Anole]

going out on a limb

The 1.2m Primestar is built for Ku, and is a very accurate dish.
And, the supplied feedhorn matches it quite well.

Some of the members have reported equal or superior performance on their 1 or 1.2m Primestars, compared to their BUDs of various sizes.
That may even extend to the stamped steel dishes by Fortec and GeoSat....
There could be a lot of contributing factors:
- the BUD may be inaccurate at Ku
- the BUD may be equipped with an inferior Ku LNB
- the BUD may have a hard-to-tune C/Ku LNBF
- the BUD positioner might be fine for C-band, but not precise enough for Ku

What is generally reported though, is that while the signal may be lower on a BUD, rain fade reduces the Ku signal on the little dish, and hardly affects the BUD.

 

[14karat]

Dad's 7.5 Winegard mesh blows my 10' mesh away on Ku.
Although, his is using a Corotor II while my 10' has the stinking 621... I'll get there, eventually.
I figure I'll use the 8' as a Ku only dish once I get it going.

 

[voomvoom]

You can get something like this:
C Ku Prime Focus Dishes LNBF Holder
http://www.skyvision.com/store/mi5000074.html

Or you could modify yours to something similar....

 

[Greg Mueller]

Sounds like I would get as much gain if I just mounted one of the 1.2m on a c-band mount.

Are there any FTA (KU) receivers that will run a C-Band mount?

 

[voomvoom]

Sounds like I would get as much gain if I just mounted one of the 1.2m on a c-band mount.

Are there any FTA (KU) receivers that will run a C-Band mount?

They aren't ku receivers, they are DVB receivers, and they do both C-Band & Ku-Band. But, you have to set them up as different sats for both C & Ku. Such as AMC6 C @ 72.0w for NASA and AMC6 Ku @ 72.0w for the MSNBC mux, they would be set-up for 2 different satellites in the DVB receiver.

Edit: ooops..... I missed "mount" somehow, so I misunderstood the question. Thanks gabshire, reading your post, made me realize my goofyness....? Greg disregard my response....!! Sorry..!!!

 

[gabshere]

Are there any FTA (KU) receivers that will run a C-Band mount?

a dvb receiver & a v-box / g-box type of mover to move the big dish

 

[Greg Mueller]

Hmmm
Sounds like we're back to multiple dishes on a switch then

 

[Anole]

At least two guys come to mind who've put 1.2m dishes on the BUD mounts driven by the linear actuators and V/Gboxes.
TurboSat did that last year, and 1captain posted just recently about a home-made H-H (but it still requires the Gbox).

Other members have 1.2m dishes on HH120 motors and similar.
They operate with USALS commands (or can).
Ones who come to mind with Channel Master 1.2's include: Bloomdog, PopcornNmore, LongHalKilo,...
I think QWERT1515 has a 1.2m Fortec, and JsatTV has a 1m Fortec...
Then with Prodelin 1.2's: DreamFox, Gremlin, LoneWolf, ACradio...

Well, the point was, if you search for posts by any of the above, you'll see pictures and comments from actual owners.

 

[ACRadio]

Ones who come to mind with Channel Master 1.2's include: Bloomdog, PopcornNmore, LongHalKilo,...
Then with Prodelin 1.2's: DreamFox, Gremlin, LoneWolf, ACradio...

Well, the point was, if you search for posts by any of the above, you'll see pictures and comments from actual owners.

I have both 1.2 meter Prodelins and Channel Masters, along with 2 KU capable 8 ft Channel Master SMC prime focus. My experience is that unless you have a really good prime focus (CM, Birdview, DH, Patriot, certain Prodelins) that a 1.2 meter on an old C band polar mount is the way to go. A good linear actuator should last a really long time, whereas a DiSEqC motor will fail much sooner because of the weight and stress.

PS
I have a 12' dish for C-Band

Properly feeding a KU only prime focus is much harder...you'd just as soon put a Corotor on your 12.

 

[phlatwound]

..........that a 1.2 meter on an old C band polar mount is the way to go. A good linear actuator should last a really long time, whereas a DiSEqC motor will fail much sooner because of the weight and stress.....

AC, do you have this setup (C band polar mount/linear actuator/"small" offset dish) anywhere in your farm?

How is the pointing accuracy with a setup like that? I would like to try that sometime, but was wondering if the slop in a linear actuator would be too great for good Ku aiming.

 

[ACRadio]

AC, do you have this setup (C band polar mount/linear actuator/"small" offset dish) anywhere in your farm?

How is the pointing accuracy with a setup like that? I would like to try that sometime, but was wondering if the slop in a linear actuator would be too great for good Ku aiming.

No I don't...mainly because I don't really need it since I have two 8 ft dishes with KU capability, but the thought did cross my mind. I was thinking about doing it with a 1.8 meter Prodelin that I still have yet to go get. The actuator slop would be no different than with a prime focus, and might not be quite as bad because of the difference in beamwidth between a 7.5-8 foot prime and a 1.2 offset. The prime would probably have a bit tighter beamwidth so actuator slop would affect it more...

 

[phlatwound]

No I don't...mainly because I don't really need it since I have two 8 ft dishes with KU capability, but the thought did cross my mind. I was thinking about doing it with a 1.8 meter Prodelin that I still have yet to go get. The actuator slop would be no different than with a prime focus, and might not be quite as bad because of the difference in beamwidth between a 7.5-8 foot prime and a 1.2 offset. The prime would probably have a bit tighter beamwidth so actuator slop would affect it more...

Understood, thank you.

Actuator and mount slop, positioner/counter resolution, beamwidth.....variables and compromises...I'm learning!

Apologies to Greg for the minor (I hope!) derailling, back to your regularly scheduled thread...........

 

[Greg Mueller]

Apologies to Greg for the minor (I hope!) derailling, back to your regularly scheduled thread...........

Sometimes these little forays can be pretty educational.

 

[ACRadio]

Actuator and mount slop, positioner/counter resolution, beamwidth.....variables and compromises...I'm learning!

Beamwidth is the amount of sky area a dish "sees"...the bigger the dish the narrower the beamwidth. An 18" DBS dish sees a big chunk of the sky at once so DBS satellites could never be put at 2 degree spacing because they would interfere with each other.

An 8 ft prime focus dish will have a narrower beamwidth than say a 1.2 meter offset. Since it's sight to the satellite is more of a "pinpoint" it will have a greater effect than it will on a 1.2 meter when the wind blows and the actuator slop lets the dish move a few tenths of a degree.