Put a KU lnbf on my 8' SOLID Cband Dish

[iBoston]

I have a 8' SOLID dish that i would like to dedicate to KU. I will need to 3D print a KU holder to fit/slide into a Cband scaler ring.

I believe the hole diameter should be 40mm for KU, but what should the outer diameter be to fit inside the scaler ring.

I am thinking of making it my new 103w / 99w and use my 1.2m for another location.

Any insights anyone would like to share?

 

[waylew]

I have a 8' SOLID dish that i would like to dedicate to KU. I will need to 3D print a KU holder to fit/slide into a Cband scaler ring.

I believe the hole diameter should be 40mm for KU, but what should the outer diameter be to fit inside the scaler ring.

I am thinking of making it my new 103w / 99w and use my 1.2m for another location.

Any insights anyone would like to share?

Best thing would be to measure the scaler and the lnbf that you are going to use.

 

[a33]

Any insights anyone would like to share?

You are aware of the fact that a Ku-LNBf usually has a narrower 'viewing angle' than a C-band feedhorn? So that it might see just a smaller part of the surface of the dish?

Greetz,
A33

 

[primestar31]

I have a 8' SOLID dish that i would like to dedicate to KU. I will need to 3D print a KU holder to fit/slide into a Cband scaler ring.

I believe the hole diameter should be 40mm for KU, but what should the outer diameter be to fit inside the scaler ring.

I am thinking of making it my new 103w / 99w and use my 1.2m for another location.

Any insights anyone would like to share?

You need to find a PRIME FOCUS Ku lnbf. Don't use a standard Off-set Ku lnbf.

Prime Focus Ku Band Lnb With High Gain 70db Low Noise 0.1db | eBay

Find many great new & used options and get the best deals for Prime Focus Ku Band Lnb With High Gain 70db Low Noise 0.1db at the best online prices at eBay! Free shipping for many products!

www.ebay.com

High Gain Ku Band Prime Focus Single Output Universal LNB With LNB Holder | eBay

Find many great new & used options and get the best deals for High Gain Ku Band Prime Focus Single Output Universal LNB With LNB Holder at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[iBoston]

I bought one a couple years back. I wish they made a dual output one... I was going to try both the one i bought specifically for Prime Focus, and the standard KU lnbf to see the difference.....

 

[iBoston]

You are aware of the fact that a Ku-LNBf usually has a narrower 'viewing angle' than a C-band feedhorn? So that it might see just a smaller part of the surface of the dish?

Greetz,
A33

Which means what???

 

[Titanium]

Viewing Angle =
KU LNBFs are typically designed to be mounted on an offset type dish with a .6/.7 FD ratio. Approximately 90+ % of the offset reflector will be illuminated. Prime focus type dishes FD ratios are usually between .3/.4. A feed designed to illuminate .6 FD ratio reflector will under-illuminate a .3 FD ratio reflector. Example: an 8 foot prime focus dish will partially illuminated by an offset type feed, and provide gain similar to a 5 foot reflector (minus the additional loss caused by the feed shadow).

A prime focus type feed (or LNBF) is often designed for mounting on a reflector with a .3/.4 FD ratio and illuminate over 90% of the surface.

 

[iBoston]

Viewing Angle =
KU LNBFs are typically designed to be mounted on an offset type dish with a .6/.7 FD ratio. Approximately 90+ % of the offset reflector will be illuminated. Prime focus type dishes FD ratios are usually between .3/.4. A feed designed to illuminate .6 FD ratio reflector will under-illuminate a .3 FD ratio reflector. Example: an 8 foot prime focus dish will partially illuminated by an offset type feed, and provide gain similar to a 5 foot reflector (minus the additional loss caused by the feed shadow).

A prime focus type feed (or LNBF) is often designed for mounting on a reflector with a .3/.4 FD ratio and illuminate over 90% of the surface.

So, in laymen terms, if i use the prime focus LNBF, ill get much better performance???..

I just did another search and found a dual LNBF prime focus.. Ill wait for your confirmation Titanium, and ill get that dual one ordered.

 

[Brct203]

I 3-d printed such adapter a few years ago. the file is only half of it so print it twice. It just fills the gap so that a 40mm Ku LNBF can be secured in a C-Band scalar.

As mentionned by others, the LNBF was not optimized for such low F/D and the result was very mediocre. With a 6ft mesh dish aimed at 103W and Ku LNBF I could get about 12 dB on NHK, could not get DW-TV at all. So quite a bit worse than a 90cm offset.

Which brings the question... Has anyone attempted to modify the built-in scalar of a Ku LNBF to increase the "viewing angle"? could it be done by shortening the aluminum rings? Or maybe inserting a thin metal sleeve in the throat of the feed to make it stick out a bit more (a bit like when we slide the C-band LNBF in and out of its scalar)

 

[Titanium]

Yes. A "prime focus" .3 - .4 FD ratio LNBF will provide significantly better performance on a "prime focus" reflector with similar FD ratio. In my opinion, the best prime option is an Inverto Black Pro Flange KU LNB mounted on an Invacom adjustable KU prime focus scalar: ADF120. Good luck finding the Invacom scalar as it has been out of production for several years.
Here are sources of NOS:
Invacom Adjustable feed horn Waves Guide for C120 and Prime Focus ADF-120
Invacom Adjustable feed horn ADF-120 – Satboy.com
INVACOM ADF-120 'C120' Adjustable Feedhorn

An option that is available is the Primesat prime focus feed. I have never seen or tested. Primesat prime focus feedhorn, c120 flange. For prime focus dishes. F/D 0.41 Feedhorn with c120 flange LNB. Feedhorn support clamp. Ku band

I had several scalar designs fabricated many years ago to optimize mounting the GSP KU Bullet LNBF on either a .6 FD offset or .3 FD prime reflector. There are some photos somewhere on Satelliteguys about this project (2007-2010?). Another thread shows a project where I modified a Ti KS1 LNBF to mount on a channel master scalar for a Muzak dish. While not a prime focus project, it demonstrates how feeds can be adapted.

 

[iBoston]

In my opinion, the best prime option is an Inverto Black Pro Flange KU LNB

Is this what you mean ??

Twin Universal PLL Flange LNB

Twin Universal PLL Flange LNB

www.inverto.tv

And then you attach those adjustable feed horn directly to that?

 

[Titanium]

Is this what you mean ??

Twin Universal PLL Flange LNB

Twin Universal PLL Flange LNB

www.inverto.tv

And then you attach those adjustable feed horn di

I only have experience with the Inverto Black Pro Flange model, so can't comment on this model. Here is a link to the dual output Black Pro Flange model:

Twin Flange LNB

Twin Flange LNB

www.inverto.tv

Any C-120 Flange LNB will mount to a C-120 feedhorn. Match the hole pattern and bolt together.

BTW... C-120 to WR-75 waveguide adapters are available to attach mismatched devices.

 

[arlo]

Two cents. I happen to be using a sidecar Geosat Pro ku lnbf on my dish along with the C Band.
It's for an offset dish of course (Geosat). But it works. And true. It's probably illuminating just a little over a meter of the 12' prime focus dish. And "shoots" around 6 degrees more east than the C band lnbf. But it works. Pretty darned well.
Where bumping the dish just a little E-W causes signal loss on C Band. Ku has a much wider beamwidth. I mean. You could lean on the dish and smoke a butt and drink a beer and signal would still be there.

Considering the limited content of FTA ku band there out there worth watching. I mean (for Brian) I can get all of the shortwave Jesus ever needed from the gravely-voiced 'vangelist from spinnin' the dial in the evening.
I get 6-10 dB of signal. And a good, steady picture. Strange, since at around 9.2 dB on C Band, pixelation starts happening.
Rain loss is as expected. Ku dies, C Band is still there.
My question for anyone with a full-fledged, dedicated, and of course proper flange mount ku/scalar lnbf like the Inverto. What is your average signal strength and with what sized dish?
Not to say it won't, can't work and just plain isn't correct to slap an offset ku lnbf on any old reflector.
It's working. At 17 bucks and a bit of fabrication for a bracket. Not bad.

 

[iBoston]

Well, i heard back from inverto..... regarding the Black Pro Flange

Due to low market demand this LNB is currently not available. We have currently no flange LNBs.

Any backup suggestions on what to buy, or should i buy a china knock off?!?!

 

[Titanium]

I see the Inverto Flange C120s listed as in-stock on many store sites. Here is one on Ebay:

Inverto PRO Twin Flange LNB C120 UltraHD DVB-S2 5391509252201 | eBay

Find many great new & used options and get the best deals for Inverto PRO Twin Flange LNB C120 UltraHD DVB-S2 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[arlo]

Well, i heard back from inverto..... regarding the Black Pro Flange



Any backup suggestions on what to buy, or should i buy a china knock off?!?!

Easy and cheap and you won't be too bummed out when you find not much worth watching on ku.

 

[Titanium]

Love the support and encouragement that we give people involved in this hobby....

 

[cyberham]

Easy and cheap and you won't be too bummed out when you find not much worth watching on ku.

There's more of value on Ku than I can often find on regular TV on a given night. But allowing varied opinions is freedom we enjoy. We just don't have to believe them all.

 

[arlo]

There's more of value on Ku than I can often find on regular TV on a given night. But allowing varied opinions is freedom we enjoy. We just don't have to believe them all.

Oh. To the OP and all the rest of you guys. Don't take it wrong. Much as I cannot get PBS. Because I haven't subbed to cable or sat in years. PBS and a very few others on ku are okay. But honestly me personally am steered on c band 99% of the time. If I found content on ku as satisfying I would have a flange mount also. Or grab one of the Chaparral feeds out of the box-o-stuff and wire it up. Price wise and ease of mounting the Geosat Pro. After finding out how easy it was to do it. Was 'enlightening' as the very least. Sorry if you took it wrong. Feed hunting is kind of fun though.

 

[iBoston]

Okay, i put in my orders... I had to order from two different places, because i couldn't find the feed horn on Ebay.. We shall see how this goes... Now, the next question what do i get to attach or hold it to the dish??

Titanium, can you pull another rabbit out of the hat? The below image i posted is the only thing i see for holding the thing.. But, the Inverto isn't circular? Or, will it attach to the feedhorn itself? and is this what i should get, or is there a better option that i couldn't find....

And in response about KU - 103/99 , in my opinion has become a VALUABLE duo. I believe i am going to point this 8' to 99w and then put a second on it to get 103w. 90% of all my KU watching comes from those two birds now thanks to the PBS move. I am excited about over-killing a KU and i want to get the MOST signal i can get so that weather or weak signals, i want 99/103 booming with globs of signal. I have 4 Cband dishes, and the 8' is the smallest, and to be honest, i don't need it for Cband, its just too small to be used to collect signals that i may want, that i don't already get.

Thank you Titanium.. I ended up purchasing both items from the links you supplied. I really appreciated that... Luckily, one of the feedhorn links took paypal, and i have one item coming from Dublin, and another from the UK.