Advice Needed C band LNB for 1.4 m aluminium Triax prime focus dish

[Spiff]

Good evening gentlemen, some more of your most excellent advice it you would be so kind : )

I have a 1.4 m aluminium Triax prime focus dish, which at present has a KU band feed horn.

The LNB when fitted bolts through the bracket ( that is supported by the three arms from the dish ) to the feed horn.

Are C band LNB's made that will mount in a similar way ?

The C band LNB in this eBay add looks to mount with a clamp ?

C1W-PLL lite C-band LNBF Integrated Feedhorn Phase Lock Loop Wideband LNB | eBay

I could be wrong as there are holes that look as if it may mount through the bracket mentioned above.

Is this feed horn going to be for a prime focus dish.

Are C band dishes only made for prime focus dishes.

Thank you for your time : )

God Bless Spiff

 

[RimaNTSS]

Hi Spiff! Could you post some pictures of your dish?

 

[RimaNTSS]

LNB you linked to connects to the feedarms by bolts directly to feedhorn. In case you go that way you will need to have feedarms adjustable. I prefer connect C-band LNB to feedarms by same LNB holder as for Ku-band LNB, but only clamp is bigger.

 

[Spiff]

Thank you for your reply.

I have taken two images of the dish.

The colour is deeper green that apears in the image not that it matters : )

The fixing in your image has a clamp where as mine does not, well not yet : )

Spiff

 

[Spiff]

Thank you for your reply.

I have taken two images of the dish.

The colour is deeper green that apears in the image not that it matters : )

The fixing in your image has a clamp where as mine does not, well not yet : )

Spiff

So I require a clamp so that the position can be adjusted rather than bolting the feed horn to the clamp and having to figure out how to adjust the length of the support arms : )

 

[RimaNTSS]

how to adjust the length of the support arms

I do not think this is a big deal, just use pieces of threaded bars.

 

[RimaNTSS]

As a bracket you probably need something like THIS, but not for such a money of course.

 

[Spiff]

I do not think this is a big deal, just use pieces of threaded bars.

Hallo RimaNTSS,

Yes have to find the correct spot first.

I will try the clamp out first as I can fabricate one from parts I have, and it will be adjustable.

The LNB on the eBay link looked a fair price, I am sure I saw others of the same model listed for more.

 

[Spiff]

As a bracket you probably need something like THIS, but not for such a money of course.

No they like a holiday out of each sale : )

Thank you for the link, it helps to see what can be done, I shall make one, its more fun.

Kind Regards Spiff

 

[Spiff]

No they like a holiday out of each sale : )

Thank you for the link, it helps to see what can be done, I shall make one, its more fun.

Kind Regards Spiff

Just had a thought, I have a box of old electrolytic clamps, could be just the job : )

 

[RimaNTSS]

Just remembered.... You can buy GI-209P LNB (10EUR plus shipping), it has star bracket in the set, only missing clamp itself. Agree with you- making something is fun.

 

[archive10]

Good evening gentlemen, some more of your most excellent advice it you would be so kind : )

I have a 1.4 m aluminium Triax prime focus dish, which at present has a KU band feed horn.

The LNB when fitted bolts through the bracket ( that is supported by the three arms from the dish ) to the feed horn.

Are C band LNB's made that will mount in a similar way ?

The C band LNB in this eBay add looks to mount with a clamp ?

C1W-PLL lite C-band LNBF Integrated Feedhorn Phase Lock Loop Wideband LNB | eBay

I could be wrong as there are holes that look as if it may mount through the bracket mentioned above.

Is this feed horn going to be for a prime focus dish.

Are C band dishes only made for prime focus dishes.

Thank you for your time : )

God Bless Spiff

I have the same dish. And I am attempting to do exactly the same thing; mounting a C band LNB on the dish.
And probably a Titanium PLL one.
(My dish is grey, though, but it's definitely the same Triax model 2140! One of the green ones is currently up for sale in DK...)

The triangular plate at the end of the feed support arms were designed to hold the Ku-band feed horn.
I believe it is close to a 23mm ins size.
It will not accomodate C-band LNBs (60mm), and it will not accomodate a "normal" universal Ku-band LNB (40mm).
Mine has been butchered to accept a 40mm. It is not pretty...
Also, the scalars of a C-band LNB may be too far away if mounted onto the triangular bracket.

As RimaNTSS points out above, you're probably better off with three threaded rods and some bent L-brackets to hold the feed.
This is what I will be attempting shortly, once the current winter spell has gone away

 

[archive10]

As a bracket you probably need something like THIS, but not for such a money of course.

As you point out yourself, that bracket practically comes with the GI-209P...
But the OP would need to do a bit of bending to make the bracket fit the threaded rods, or even the original ali rods...

 

[Spiff]

I have the same dish. And I am attempting to do exactly the same thing; mounting a C band LNB on the dish.
And probably a Titanium PLL one.
(My dish is grey, though, but it's definitely the same Triax model 2140! One of the green ones is currently up for sale in DK...)

The triangular plate at the end of the feed support arms were designed to hold the Ku-band feed horn.
I believe it is close to a 23mm ins size.
It will not accomodate C-band LNBs (60mm), and it will not accomodate a "normal" universal Ku-band LNB (40mm).
Mine has been butchered to accept a 40mm. It is not pretty...
Also, the scalars of a C-band LNB may be too far away if mounted onto the triangular bracket.

As RimaNTSS points out above, you're probably better off with three threaded rods and some bent L-brackets to hold the feed.
This is what I will be attempting shortly, once the current winter spell has gone away

Good evening from a wet Mullion Cove Cornwall.

I have the KU band feed horn for my Triax dish and have had it running fine with a Inverto Black Pro C120.

It has not been got at, at least not yet : )

Picked it up for £50 including a mount and floor stand plus two jacks which after a service and paint job are running fine.

The difference in the price of second hand dishes to new is quite something, I suspect carriage is the problem, I have three I cannot shift : )

The Triax is surplus to requirements as I now have a Precision Antenna 1.3 setup on KU band with two actuators.

Just watched Nilesat drop to 50Q then up to 63 in good weather it is 72 : )

It is raining according to our weather station with heaver rain on the way.

Interesting to watch the weaker satellites : )

I shall watch to see how you get on and will post when mine is up and running.

Good Luck Spiff

 

[moonbase]

Spiff,

Get one of these C Band LNB holders, they are used to attach a C Band LNB centrally to a prime focus dish. The seller is from Latvia but he sends stuff quickly and is reliable, a few of us on the forum have bought items from him. The LNB holder I have linked to will secure an LNB up to 65mm diameter, he also sells a 62mm version.


LNB holder 65 mm inner diameter for Prime Focus Dish | eBay


Rgds

 

[Spiff]

Spiff,

Get one of these C Band LNB holders, they are used to attach a C Band LNB centrally to a prime focus dish. The seller is from Latvia but he sends stuff quickly and is reliable, a few of us on the forum have bought items from him. The LNB holder I have linked to will secure an LNB up to 65mm diameter, he also sells a 62mm version.


LNB holder 65 mm inner diameter for Prime Focus Dish | eBay


Rgds

Goodmorning Moombase,

Thank you for the link, it looks just the job : )

God bless Spiff

 

[moonbase]

Spiff,

Did you order the C Band LNB holder from the link? I have recently setup a temporary dish for C band using one of those holders and it seems to be working OK on the few tests I have carried out so far.

I dont think it would be suitable for a long feed type of arrangement such as an AV-COMM polariser barrel, the weight at the back end would pivot the LNB aperture away from a central focus. There would need to be some type of secondary clamping further back for an elongated type of feed. However, it seems to work OK for a Titanium LNBF and a Zinwell LNBF on their own.

Rgds

 

[Spiff]

Hallo Moonbase,

Thank you for your message : )

I thought it was a touch expensive and I found an old KU band one that I can maybe modify.

I am getting bits together for the installation : -

A Pair-of-Primesat-satellite-dish-mounting-brackets-300mm-stand-off used £35

Pair of Primesat satellite dish mounting brackets 300mm stand off | eBay

A C1W-PLL C-band LNB new other £11.00 : -

C1W-PLL C-band LNB | eBay

The size of it surprised me as I have never had one in my hands before.

Looking at some clamps

U BOLT HEAVY DUTY STEEL EXHAUST CLAMP AUTO U BOLT REPAIR TV AERIAL 28mm - 92mm | eBay

and a pole : -

76mm / 3" Galvanised Pole - Various Lengths - Optional End Cap

I would be interested to hear what you have received on C band, it will give me a good starting point when I get it all installed : )

I wonder did you have trouble with the support rod lengths?

My 1.3 Precision dish and mount are all up and running very nicely.

It looks fantastic, at least I think so, it would not be out of place on a Moon Base or Goonhilly : )

God Bless Spiff

 

[moonbase]

....The size of it surprised me as I have never had one in my hands before....

The mind boggles.

I would be interested to hear what you have received on C band, it will give me a good starting point when I get it all installed : )
I wonder did you have trouble with the support rod lengths?

Spiff,

I have only tested out 34.5W on the temporary setup I installed recently. The setup consists of a 1.5m Precision prime focus dish with the three feed support arms used for Ku Band but with a C Band LNB holder attached to the arms. The C Band feed holder was bought from the seller in the link I provided earlier in this topic.

I have tested the setup with a Titanium LNBF and the next test is with a Zinwell LNBF, then I hope to start using the AV-COMM polariser barrel on it if I can get it aligned and supported correctly. As a quick test, I scanned in a few transponders from 34.5W, the strongest was RTI-1 at 7.5db (3643 R)

It is easy to attach the C Band LNB holder to the three feed support arms and there is plenty of backward/forward movement available to get the aperture of the LNBF at the dish focal point. I have attached a picture below.


Rgds

 

[Spiff]

Yes when I wrote that about the size, I thought mm perhaps I should find another way to say that : )

Thank you for the information.

I have several KU band polariseres that were given to me, some still new in the boxes.

There is also a y shaped tube that looks to be for splitting the signal from a KU band feedhorn to two LNB,s.

There are also two LNBs in the box, one I think looking at the dipoles inside is for vertical, the other for horizontal.

No use any more as far as I know.

You mention an AV-COMM polariser barrel, do C band LNBs not voltage switch as KU band types do ?

Or has it to do with circular polarisation perhaps ?

Kind Regards Spiff