Just Sharing This Modified my CM LNB holder for KU and CBAND

[Manikm909]

I tried tackling the issue, of mounting both Ku and CBand LNBs today on my 1.8 - using the original holder.

Using some fibre glass putty, a bolt, and the holder that came with my cheapo CBAND LNB - i cobbled up something, that seems to be pretty ok, and sturdy.

Just need to test on some sats which have strong CBAND (if such a sat exists, on the central part of the ARC for now....what are some easy catch CBAND Sats...without me having to drive out to 40.5w.

thanks!!

 

[moonbase]

....what are some easy catch CBAND Sats...without me having to drive out to 40.5w.

thanks!!

3E, 5W, 8W

 

[Manikm909]

not had much luck with 8W - KU is fine on 8W - but cant get anything on 8W CBand - can those of you that can get it, please let me know of a strong TP on 8W Cband....thanks!!!

 

[nelson_b]

Not set up for C band currently on the 2.4 c.m. ...... when i was tinkering with a similar arrangement to what you have setup today ... i found the mount needed a considerable amount of elevation adjustment (more than i expected ) to bring the c band l.n.b into focus - i think it was around 5 degrees of shift ?

 

[suedschwede]

For this LNB arrangement, the elevation must be adjusted, otherwise it won't work!!!
With the structure, a different elevation curve is driven in the C-band on all C-band positions than in the KU-band, an elevation motor with the associated V-box is absolutely necessary in order to be able to control the elevation between KU- and C-band!!!

 

[John]

8 West C-band with me just now in North Nottinghamshire.
Strongest dB level LHC = 3889 L. 2981, 3/4. - 12dB. - 2.2 PF at focus.
Strongest dB level RHC = 3981R. 3408, 3/4. - 13.1dB. - 2.2 PF at focus.

 

[scopus]

Looks like one of those Fortec Star brackets..

 

[zorrin]

I'm not a fan of keeping the electronics down on C-band LNBs.
Personally I would turn it 180°

 

[John]

View attachment 143702

I'm not a fan of keeping the electronics down on C-band LNBs.
Personally I would turn it 180°

Agreed, electronics at the top, should any water find it's way into the waveguide it would settle in the bottom corner of the waveguide tube well away from the probe entry points and eventually evaporate with the help of the slight heat generated by the lnb. Ideally no water or moisture is welcome within that area

 

[Manikm909]

For this LNB arrangement, the elevation must be adjusted, otherwise it won't work!!!
With the structure, a different elevation curve is driven in the C-band on all C-band positions than in the KU-band, an elevation motor with the associated V-box is absolutely necessary in order to be able to control the elevation between KU- and C-band!!!

Thanks . I wasn't really expecting it to follow the arc. Just a way to save swapping over lnbs . I'm happy manually adjusting on a sat I want i.e 40.5w during footy season. However I can't get a signal when manually moving it about anyway so maybe it was all in vain. Same as when it was in a side car setup couldn't get a sniff. Still didn't take long to do and surprised at how solid it turned out

 

[scopus]

Thanks . I wasn't really expecting it to follow the arc. Just a way to save swapping over lnbs . I'm happy manually adjusting on a sat I want i.e 40.5w during footy season. However I can't get a signal when manually moving it about anyway so maybe it was all in vain. Same as when it was in a side car setup couldn't get a sniff. Still didn't take long to do and surprised at how solid it turned out

If you added a second Jack as like inclined orbit tracking, and lifted the dish a few degrees it would bring the C Band LNB into focus..For best results however, one of Trusts LNB changers is the way to go..

 

[Terryl]

Unfortunately the way your setup mounts the "C" band LNB wont work too good, as the dish your using does not have a wide enough receive beamwith for an LNB mounted that far outside the prime focus area.

According to satbeams, (take a look at the footprint map for 8W) your dish is about the right size for 8W, (1.7M) the EIRP for the footprint at your location is about 39 dBW, so you should not have a problem if the "C" band LNB was at the center of the dish and not outside the prime focus area.

This will work if you get a dual band LNB setup for "C" and "Ku" in one housing, then both LNB's with be in the correct position. (dead center)

Here is a link to satbeams, looking at 8W, (or what ever satellite you want) select the "Global" foot print, then zoom into your location and click on it, this will give you an idea on whats what.

https://satbeams.com/footprints?norad=40875

 

[dreambox1959]

captain jack tried this way of doing things and I adapted my program so that the Diseqc 1.0 command (A--D) activates a shift on the elevation jack.
I currently use the same thing on a prime focus, but the two LNBs (ku and C) must not be parallel but the offset LNB must aim for the same point as the KU, or slightly inclined ....
it will still be necessary to change the elevation but it is possible to work in 'offset' with a second LNB.

 

[Manikm909]

captain jack tried this way of doing things and I adapted my program so that the Diseqc 1.0 command (A--D) activates a shift on the elevation jack.
I currently use the same thing on a prime focus, but the two LNBs (ku and C) must not be parallel but the offset LNB must aim for the same point as the KU, or slightly inclined ....
it will still be necessary to change the elevation but it is possible to work in 'offset' with a second LNB.View attachment 143722

thanks for the diagram mate - even when i manually adjust the LNB to point like that, i'm getting zilcho.

 

[scopus]

thanks for the diagram mate - even when i manually adjust the LNB to point like that, i'm getting zilcho.

You still need to alter the elevation of the dish!

 

[Manikm909]

ah right!! ok, thanks.

 

[nelson_b]

You still need to alter the elevation of the dish!

Yes ... raise by 5- 6 degrees - and it will come into focus ..... i found so when tinkering with an "above" C band l.n.b ....

 

[Manikm909]

If you added a second Jack as like inclined orbit tracking, and lifted the dish a few degrees it would bring the C Band LNB into focus..For best results however, one of Trusts LNB changers is the way to go..

presume these aren't for sale? @Trust

 

[Manikm909]

Yes ... raise by 5- 6 degrees - and it will come into focus ..... i found so when tinkering with an "above" C band l.n.b ....

is the result as good as if the C-Band LNB was in the centre without any mods?
i have another idea, another 1.8 !!!! my mrs will love that! i could paint it pink.

 

[ViaHussun]

Yes ... raise by 5- 6 degrees - and it will come into focus ..... i found so when tinkering with an "above" C band l.n.b ....

wouldn't the ku band balance be disturbed then?