2 (or more) lnbs on a CM 1.2?

[Dggrr]

I'm wondering if anyone has a good solution for this.

I currently only have Triax 88 on a diseqc motor and it misses a lot of feeds on both 7 & 10 East.

I'm thinking of putting my CM 1.2 backup as fixed but would like to get both 7E and 10E.

My thoughts are that this would require some surgery, maybe replace the feed arms with perspex rods, or fashion a single arm like a Triax. Even so it is going to be quite difficult to get a 2nd LNB mounted with the CM LNB holder for 3 degrees spacing.

Anyone have a good solution to share?

 

[Lazarus]

I believe there are skinny LNBs available (Alps) that would permit the 3 deg spacing, subject to you being able to find a suitable bracket etc.

 

[RimaNTSS]

+1 to make new feedarms. However, if you only need multifeed for 2-3 LNBs, than it is possible to make new LNB holder and use original feedarms. I was never interested in making multifeed for CM 1,2m, but I am pretty sure it is possible and without major surgery.

 

[Archive-8]

I believe there are skinny LNBs available (Alps) that would permit the 3 deg spacing, subject to you being able to find a suitable bracket etc.

You can get an Inverto multi connect lnb's and rail. They are for a 3° split.

Inverto Multi-Connect Starter Kit 5453001045986

 

[Captain Jack]

1.2m CMs are tricky for multifeed arrangements without modifications. Make new arms for it rather than mess around with existing ones.

If you want it less painful then get a Gibertini 1.25m.

 

[Archive-8]

1.2m CMs are tricky for multifeed arrangements without modifications. Make new arms for it rather than mess around with existing ones.

If you want it less painful then get a Gibertini 1.25m.

I have 3 lnb's on my Gibertini 1.25. Very easy to do. Well worth thinking about.

 

[archive10]

+1 to make new feedarms. However, if you only need multifeed for 2-3 LNBs, than it is possible to make new LNB holder and use original feedarms. I was never interested in making multifeed for CM 1,2m, but I am pretty sure it is possible and without major surgery.

You can do the "Stuka-trick" and rotate the feed-support arms downwards by adding an piece of metal bracket (say, 15 cm) to the new end positions, and the original points of the LNB mount.
Other members on the forum have documented how to do this.
The primary benfit of this is that you can attach additional LNBs using generic multi-LNB holder that attach to the main LNB (make sure you get long neck-versions of LNBs so there is something to clasp onto!)

In fact, CM did originally produce a multi-feed holder for the CM120, from the picture I believe it worked exactly like that.
However, I have never seen one anywhere, so it may remain an option that was never avaialble to the general public.
(See page 2 of the attached product sheet).

But I agree with @RimaNTSS - most versatile approach is to make new feed-arms.
This, however, requires some basic metal-working skills, and if you feel more like a tinkerer, you can try first with the "Stuka"-modification.

 

[Journey]

I would love a multi setup on my CM 1.2m, a former member here had promised me the ones he had fabricated himself but he is no longer here

Would be ideal for 0.8w and 4.8e, 4.8e in my location is dire, even the SD channels

 

[timo_w2s]

I would love a multi setup on my CM 1.2m, a former member here had promised me the ones he had fabricated himself but he is no longer here

Would be ideal for 0.8w and 4.8e, 4.8e in my location is dire, even the SD channels

Yes, I was planning to do that for 1W/5E but never got around to doing it. These days I don't watch anything on 5E so I've left it, but now I'm thinking it might be nice to have 1W/8W. If you could still buy the proper conversion kit I would have done it long ago.

 

[RimaNTSS]

Agree with those who saying CM is not good for multifeed. I do not like multifeeds at all, I think they stealing useful part of signal, but, if I was making multifeed for CM 1,2m my first option would be to make completely new feedarms and LNB-holders. Another option would be to use original feedarms (at least side-arms) and adjust system for multifeed. I did some modeling today: made new bottom-feedarm, extended side-arms little bit till all 3 arms come together. If all feedarms connected in this point than construction will have enough strength. Then multifeed-holder can be attached between side-arms. Of course, that can be made more nice-looking. Couple of picks:

 

[timo_w2s]

Agree with those who saying CM is not good for multifeed. I do not like multifeeds at all, I think they stealing useful part of signal, but, if I was making multifeed for CM 1,2m my first option would be to make completely new feedarms and LNB-holders. Another option would be to use original feedarms (at least side-arms) and adjust system for multifeed. I did some modeling today: made new bottom-feedarm, extended side-arms little bit till all 3 arms come together. If all feedarms connected in this point than construction will have enough strength. Then multifeed-holder can be attached between side-arms. Of course, that can be made more nice-looking. Couple of picks:

For me, one of the best features of the CM120 is the solid design and knowing it's not going to budge. However, changing the LNB holder and arms to make way for extra LNBs seems to compromise that.

 

[Captain Jack]

I think Rimant should become our resident feedarm/LNB holder fabricator, together with Wim.

 

[RimaNTSS]

However, changing the LNB holder and arms to make way for extra LNBs seems to compromise that.

Not necessarily. As we all know, the weak point in CM dish is plastic LNB-holder. Not always, but from time to time users have them broken. And this piece of plastic holds together 3 feedarms. Continued mine today's project: Made small cone for 3 feedarms connection . Needless to say that it holds all extended feedarms together very firmly. Multifeed-bar will give additional strength to all construction.

 

[Pipedream]

Just seen this idea on the internet

 

[timo_w2s]

Not necessarily. As we all know, the weak point in CM dish is plastic LNB-holder. Not always, but from time to time users have them broken. And this piece of plastic holds together 3 feedarms. Continued mine today's project: Made small cone for 3 feedarms connection View attachment 96641 . Needless to say that it holds all extended feedarms together very firmly. Multifeed-bar will give additional strength to all construction.

I must admit your solution does look good. Have you considered making more of these and selling them on here??

 

[archive10]

Just seen this idea on the internetView attachment 96649

Nice solution, and proably works to some degree, but it would require skewing the dish+mount.
If using standard CM hardware, that would mean tilting the mount pole (as you can't skew the CM mount).

Why? Well, due to the mirroring of the reflector, an ideal line through the center LNBs and the side-mounted ones would be an upside-down arc exactly the opposite of the clarke-belt. In other words, a big smily. \_/
Which is why the CM arms are so darned in-the-way, as they are smack in the middle of the side-mounted LNBs view of the dish.

In the picture, the LNB is mounted to the side and down, meaning either reduced signal reception on the side-mount, or a tilting of the dish to provide centricity for the side-mount.

 

[RimaNTSS]

Have you considered making more of these and selling them on here??

Should first finish the prototype and test it. Afterwards, I think I will be able to make couple of replicas.

 

[RimaNTSS]

Overall, the construction becomes complicated. I will also be not so easy to tune such a system. But I am sure, when it is properly adjusted it will be rigid enough and rust-free. Will try to do installation for 3 satellites.

 

[Journey]

Overall, the construction becomes complicated. I will also be not so easy to tune such a system. But I am sure, when it is properly adjusted it will be rigid enough and rust-free. Will try to do installation for 3 satellites.

this is such a sweet setup, I want that so bad

 

[RimaNTSS]

Made multifeed 4,8*E-13*E-19,2*E . I can not say that it was fast&easy, but... doable. I would not recommend such a multifeed for people who has no experience adjusting multifeeds and for those who has not enough patience. Again.... I do not like multifeeds, they still signals.
I spent so much time, material and efforts making this construction, that I am not sure I can further optimize the process to become profitable. Of course it depends how much users are ready to reward. Ideas I can share absolutely free