2 (or more) lnbs on a CM 1.2?

[Lazarus]

I'm full of admiration for your skill and enterprise

 

[samoloko]

some Ideas for alternative multifeed

Channel Master dish

I followed an ad on Craigs list for a 36" dish for $40... When I got there it ended up being this heavy duty fiberglass dish with the brand Channel Master on it. It measures up to be 1 meter in its longest dimension. It has this big heavy duty dual LNB bracket and 2 lnb's... The whole LNB...

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look at picture 6, 7, 10 at this advert

 

[RimaNTSS]

some Ideas for alternative multifeed

CM antennas are well known as being not friendly to multifeeds, especially if original feedarms going to be used. Couple of times I was facing this issue and finally came up with such sophisticated construction.

 

[RimaNTSS]

I have just found in the papers this one. CM has made original multifeed setup, however I did not see it in live.

 

[samoloko]

Rima,
what Is max width that you can achieve with your multifeed clamps when used on Ch M 1.2
from your pic It Is somewhere 10 - 12 deg
I am trying to get 23.5 E to 46 E with min 2.5 deg step without buying gibbi OP125

 

[RimaNTSS]

what Is max width that you can achieve

I am not sure, all depends on the length of the horizontal bar. TBH, I am not big fan of the multifeeds unless they are installed on multifocus antennas.

 

[Captain Jack]

I have just found in the papers this one. CM has made original multifeed setup, however I did not see it in live.

I have those brackets in my garage - they are OK but annoying to set up.

Channel Master multi-feed

Finally, the sun stayed out long enough to do stuff outside. One of the things I wanted to try was setting up the multi-feed for my 1.2m CM dish in hope of recreating it. The goal is to create a multi-feed arrangement for 1w and 5e. These are generally borderline here on anything less than 1m...

satellites.co.uk

 

[RimaNTSS]

Did some more trials & mistakes on CM multifeed issue. Came to this solution. New length-adjustable made of 10mm SS tubes feedarms. Feedarms connect to the original holes, no need to drill additional holes.
LNB-holder/ pate 3mm SS. Central LNB adjustable up/down. Additional (easy to install) LNB rail, 8mm SS bar. Up to 4 separate LNBs can be attached to the rail. If instead of 40mm clamp 63mm is used then C-band LNB also can be attached to the rail. Maximum distance between LNBs on the edges is 24cm as on the picture, but if there is a need, distance can be increased to 27-30cm. Each individual LNB can be adjusted in all possible directions.
Same setup can be used on 1,8m CM but another feedarms need to be used.

 

[RimaNTSS]

Well, I was asked whether it is possible to install multifeed on Channel Master antenna but on original feedarms. Of course, there is original Channel Master multifeed system optionally available. But, TBH, I do not think it is a good solution, it does not allow installing a central LNB in the focal point of the dish, it will stay too much outside the proper location.
So I starter by first issue: How to fix anything to the end of the bottom feedarm, as it is just an end of the round tube. The easiest way would be just to stick a piece of wood in the pipe and then use a simple wood screw to attach anything to it. But that would be to easy.... So, I made a conical nut and an insert made of Teflon. When the nut is tightened, the insert expands and sticks very firmly in the tube. Then I played with the horizontal 8 mm INOX bar and it's fixing elements to the side-arms. That is what I have by now. There is still a need to lift the central LNB a little bit up to have LNB installed when its phase center is colocated with the antenna's focal point (approximately in the red circle) But that should be easily solved by using the longer piece of the threaded rod. After the central LNB is in place, then several additional LNB-holders can be installed in multifeed on the same horizontal 8 mm bar.

 

[RimaNTSS]

Came to this solution, it should be very close to the final one. Will wait for the spring to have some real tests.

 

[tompouce]

I have just found in the papers this one. CM has made original multifeed setup, however I did not see it in live.

Bravo for this treasure, RimaNTSS, never seen before, this original CM multifeed !!

 

[Captain Jack]

Bravo for this treasure, RimaNTSS, never seen before, this original CM multifeed !!

I have one in the garage. It's OK...

Channel Master multi-feed

Finally, the sun stayed out long enough to do stuff outside. One of the things I wanted to try was setting up the multi-feed for my 1.2m CM dish in hope of recreating it. The goal is to create a multi-feed arrangement for 1w and 5e. These are generally borderline here on anything less than 1m...

satellites.co.uk

 

[daro2096]

I know there used to be a bracket made by Channel Master for multi LNB set ups but that was way back in the 1990s.

 

[pitussat]

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.

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).

Somebody has original channel master depliant data sheet of 1,8m model?