Multi lnb holder options for 80cm mix digital dish

[statalite]

Hi guys,

I just wanted to get you opinions on the holders pictured.
I have managed to acquire an 80cm Mix Digital dish which I am considering replacing my zone 2 (which has 28.2e) so I can add 13e and 19.2e.

If I centre the dish on 19.2e, will lose signal on 28.2e even with the best alignment I can get?

I have attached a photo of the end of the dish arm, the attached images (the ones that are curved and seem to follow the arc) are advertised as Triax so not sure if the oblong part would fit as they have plastic that sticks out on a part you squeeze to add to a Triax arm, would this be a problem?
Would the "curved" options be better for signal gain provided they fit or the "straight" holder.

thanks.

 

[ozumo]

If the rectangular bit doesn't fit the dish you can just use one of the extra LNB holders to hang the new arm off the main LNB, provided the neck of the LNB is long enough (like an inverto black ultra single). I do it on a zone 2 for 28.2e & offset 19.2e. If I can find the rectangle bit I will measure it.
Any offset LNB is going have reduced performance but these are strong satellites so shouldn't be a problem.

 

[jeallen01]

The problem with the first two of the multi-holders is that the additional LNBs are in the same vertical plane as the central one - whereas, with the latter aimed at 19E, the one for 13E must be a bit lower and the other for 28E must be a bit higher!

So, do you have the original LNB holder?

If so, use that with the multiLNB holder shown in s-11600c.jpg. with the centre holder clamped around the body of the LNB on the feedarm as the multiholder bar can be tilted to raise the LNB for 13E and lower for the LNB for 28E

I have several of those and they work quite quite well on various dishes as they can also be slightly bent to "follow" to allow the outer LNBs to be slightly closer to the dish - but, due to the combined weight of the multiLNB holder and the 2 extra LNBs, you might need to add:
- stabilising bars from the edges of the dish to the main feedarm
- then further stablizing strips (perforated car exhaust hanging straps work quite well!
- jubilee clips to hold the feedarm stabilisers to the feedarm, and then smaller ones to clamp the stabilizing strips to the stabilizing arms.

 

[ozumo]

The problem with the first two of the multi-holders is that the additional LNBs are in the same vertical plane as the central one - whereas, with the latter aimed at 19E, the one for 13E must be a bit lower and the other for 28E must be a bit higher!

The arm pivots on the central screw that's visible in the photos. Else it can be used in similar fashion to the c photo product, hanging off the central LNB.

 

[jeallen01]

The arm pivots on the central screw that's visible in the photos. Else it can be used in similar fashion to the c photo product, hanging off the central LNB.

Good point that I didn't know!, and thus the one in the first shot might be a better bet for 2 extra LNB's as it appears to already have the preferred "curve" in the bar

OTOH, if the first one won't fit the feedarm, then the third one can be used with a variety of dishes from various manufacturers.

 

[a33]

The first and second rail put the LNBs at about 2 cm height difference, IIRC.
So for a perfect fit, you'd have to compare the height and aiming angle with the original LNB holder.
The advantage of the third multifeedrail is that you use the original LNB-holder, so that the height of all three LNBs is automatically right (assuming the LNB holder is, in fact, at the right position ~ it not always is).

The main purpose of the curve is to let the sidecar LNB look slightly to the center of the dish again, and not left or right beside the dish.

As these multifeed rails are horizontally straight, and the clarkebelt is curved (as seen from most earth locations), I usually do the finetuning of the whole setup on the sidecar LNBs, so NOT on the central LNB.

Needed rail skew (or whole dish skew) would be about the satellite skew for 19.2E for your location, but WITHOUT the Astra preskew of 7.5 degrees. I believe the Satlexcalculator mentions that? (I have my own calculator, so I don't frequent the others...)

Greetz,
A33

 

[statalite]

If the rectangular bit doesn't fit the dish you can just use one of the extra LNB holders to hang the new arm off the main LNB, provided the neck of the LNB is long enough (like an inverto black ultra single). I do it on a zone 2 for 28.2e & offset 19.2e. If I can find the rectangle bit I will measure it.
Any offset LNB is going have reduced performance but these are strong satellites so shouldn't be a problem.

Good point that I didn't know!, and thus the one in the first shot might be a better bet for 2 extra LNB's as it appears to already have the preferred "curve" in the bar

OTOH, if the first one won't fit the feedarm, then the third one can be used with a variety of dishes from various manufacturers.

Yes I see what you mean about still using it without the rectangular bit, I didn't think of this.
In addition to the comments by jeallen01, these do point to product A and B being the better solution because of the "curve". Although as jeallen01 says the straight one can universal and work with a variety of situations.

@ozumo any measurements welcome, to reiterare are you measuring lnb rectangle as depicted in picture A and B of a holder you have?

For the record I do have the original LNB holder.

 

[ozumo]

I have the item in photo A, but use it without the central black rectangle part. I will look for said part tomorrow.

 

[jeallen01]

FWIW, w.r.t. the 1st/2nd images, I would have reservations about the use of a single "self-tapping"-type screw to allow the LNB bar to be swivelled because it can't provide a high level of clamping force (and that will loosen over time due (literally!) to "plastic flow") - if I had to use that design, I would drill out the hole all the way through and use a bolt and nut (and a spring washer to try to compensate for "plastic flow"!) instead of the existing screw.

 

[ozumo]

TBH I can't remember if it's a self tapper or a machine screw, I think it must be the latter for the reasons mentioned. The LNB holders are secured with self tappers but they are pretty tight on the bar so I don't bother with the screws.

 

[jeallen01]

TBH I can't remember if it's a self tapper or a machine screw, I think it must be the latter for the reasons mentioned. The LNB holders are secured with self tappers but they are pretty tight on the bar so I don't bother with the screws.

FWIW, All the fixings on the multi-LNB holder in the 3rd image are machine screws - although no spring/crinkle washers are provided (but don't appear to be needed as I haven't seen evidence of any lack of gripping force).

The only evidence of issues with that type of holder is fracturing of the plastic in the actual LNB clamps themselves - notably in colder weather when the plastic is less pliable when you open them to fit/change an LNB.

 

[a33]

FWIW, w.r.t. the 1st/2nd images, I would have reservations about the use of a single "self-tapping"-type screw to allow the LNB bar to be swivelled because it can't provide a high level of clamping force

IIRC, there is a screw as 'the axis', and a securing screw for the set angle.

The LNB holders of both ar far thicker than the LNB holders of picture 3. So when you have the central LNB in both the original LNB holder, AND the extra multifeed rail holder, you have to take these thicknesses into account.

Greetz,
A33

 

[sonnetpete]

From what I remember of the first multi bar pictured, it has two positions in the centre where it can be raised slightly, however I did have to 'modify' the plastic holder to get the LNB height difference to work properly.

 

[RimaNTSS]

@statalite If you wish you can have this multifeed set for a shipping price.

 

[ozumo]

I have the item in photo A, but use it without the central black rectangle part. I will look for said part tomorrow.

Sorry I couldn't find it

 

[jeallen01]

.....The LNB holders of both ar far thicker than the LNB holders of picture 3. So when you have the central LNB in both the original LNB holder, AND the extra multifeed rail holder, you have to take these thicknesses into account.

Greetz,
A33

In such situations, it pays to use LNBs with long necks that allow them to be slid backwards or forwards in the holders to get the highest signal strength.

 

[jeallen01]

FWIW, w.r.t. the 1st/2nd images, I would have reservations about the use of a single "self-tapping"-type screw to allow the LNB bar to be swivelled because it can't provide a high level of clamping force (and that will loosen over time due (literally!) to "plastic flow") - if I had to use that design, I would drill out the hole all the way through and use a bolt and nut (and a spring washer to try to compensate for "plastic flow"!) instead of the existing screw.

Should have mentioned that, even if you only want 2 extra LNB's, it might pay to get the multiholder in the 2nd image as that will give you a spare LNB holder if one of the others breaks as it might do as I mentioned in post #11 - that way , you would not have to a complete new holder kit in order to get just one replacement LNB clamp!
(I did that with the multi-holders in the 3rd image when I only needed to mount 3x LNBs - a good job as a couple of the LNB clamps did later fracture just above the rail mounting section (but those were "sort of fixable" with nylon cable ties ).

 

[statalite]

@statalite If you wish you can have this multifeed set for a shipping price. View attachment 132416

@RimaNTSS this is a kind offer but will the size fit into the Mix Digital LNB arm and or be too heavy?

 

[RimaNTSS]

I do not know will it fit or not. If needed it is possible to take the file and make it fit. Even it is made out of aluminum it weighs ~600 grams.

 

[statalite]

Sorry I couldn't find it

No problem thanks for looking.