Best alternative lnb for invacom c120 quad or quattro

[RimaNTSS]

Recently I've cut several feedhorns away from LNBs. In some cases I knew exactly what to do, but in some cases that was just for fun. The last one (pointed by yellow arrow was about 1/2 an hour ago) just to measure the diameter of the second ring. So, it is exactly 35mm. I think if I continue to fo forward and cut away more flesh then it is possible to go down to 25mm and next step is 21.5mm

 

[Trust]

Years ago I bought for the fun a PF feedhorn adaptor to attach to a standard LNBF for offset dishes .
Since the new Inverto lnb has a wider outer feedhorn , this adaptor does not fit over a LNBF but it is possible to tape it to this Inverto lnb

 

[Sleepingwiththefish]

@RimaNTSS what (tools) do you use to cut away the feedhorns so cleanly?

@Trust1 that adaptor fits outside first (conical) ring?.. Do that actually work, did you tested it?

I will eventually modify an LNBF for my PFA, but first I need to get a flat scalar feedhorn, hunting for one locally, there's some old PF dishes not too far... found a 2m dish some time ago, owner gave it to me for free, still need to collect it, but it's missing the entire LNB arms and LNB, someone cut it off and stole it because the dish is easily accessible.

 

[RimaNTSS]

what (tools) do you use to cut away the feedhorns so cleanly?

Lathe

 

[Trust]

@Trust1 that adaptor fits outside first (conical) ring?.. Do that actually work, did you tested it?

Yes it fits over the outer ring of the most lnbf's , but not over that new Inverto with that square waveguide .
As I wrote , I bought it for the fun and to have the chance in the future to test it on a PF dish .
Maybe next year I will test on a 1.8 m Precision PF .

 

[Sleepingwiththefish]

Yes it fits over the outer ring of the most lnbf's , but not over that new Inverto with that square waveguide .
As I wrote , I bought it for the fun and to have the chance in the future to test it on a PF dish .
Maybe next year I will test on a 1.8 m Precision PF .

No, I meant the 'inner' ring, the one on center, I was curious if that forms a uniform (same diameter) throat because at first sight it seems it fits outside the center ring

 

[dreambox1959]

@dreambox1959 Can you measure diameter of the first ring (red line)?

*
i have made a aluminium thick washer : diameter 42mm with a hole diameter 22mm .
stuck up in the 42mm ring and in the hole an aluminium pipe diameter 22mm (in 20mm)
this pipe is 20cm long (to tune the focal) and a prime focus feed on the other end of this pipe

 

[RimaNTSS]

@dreambox1959 I think, physically it is possible to cut the feedhorn of your PLL LNB leaving just a 34mm ring. Than take any PFA feedhorn, as an example I have here feedhorn salvaged from SMW LNB then cut away it's first 2 rings till the diameter of inner hole becomes 34mm. Then just frankenshtein PLL LNB into the feedhorn. Mechanically it is possible, but how this modified LNB will work I have no idea. That is what I've measured

 

[Trust]

Made some pics from different offset horns .
With non of them the waveguide of that PF scalar makes a smooth connection with the throat of a offset LNBF

 

[antrabe]

Could I adapt the orange lnb to the other ?

and somebody knows how it works the televes lnb with 4 wires output?

thanks

 

[Waveguide]

I have been running a converted Inverto Black Ultra for three years now without any problems.
The interface consists of two parts made in a lathe and held together with a tight shrink-fit.
(a tube for the circular waveguide and a plate for the flange, a thin line shows where they meet)
Normally you would have to remove a lot of metal in the lathe if the part is both long and with
a large diameter somewhere but this is made with a shrink fit between a tube going into the
old feedhorn and a plate to make up the C120 flange. You can also optimise each part before assembly.
There is metal to metal contact in the bottom of the new circular waveguide. It can be improved further
by conducting paint (with lots of silver in it) but this one works without it. The tiny locking screws
press the interface down onto the other side. The polarisation angle is adjustable so it can be made to be
the same as other LNB's, easier to swap LNB's for tests if they are close to the sweet spot at the start.

 

[satesco]

What surprises me about the alternative solutions at Invacom,but it can be combined with other lnbs,is that no one gives us a graphic report or text in which the advantage of the proposed solutions counts. I mean to show us what he got with Invacom and what he got with the proposed alternative,i.e., with signal tables with Invacom or with another lnb.Thus,aesthetically all solutions look good

 

[jeallen01]

Ref those stepped feedborns and the transitions to the waveguides, could one not use one of the metal-loaded epoxy filler compounds and quickly blend and smooth the joint between the two sections together before it sets hard?
(that should also bond the two sections together pretty well on its own)

 

[Waveguide]

Unfortunately metal filled epoxy is also the recipie for a microwave absorbant. On the other hand, what
you have beneath surface doesn't matter if the surface is a really good conductor. I use Eccoshield ES
from Emerson & Cuming (Belgium) but there are other useful coatings like the conductive paint used to
fix broken heating filaments (in rear windows on cars). If the conductivity is really good only a very thin
layer is necessary. The spillage on the outside of my Eccosorb bottle has 0,3 Ohms resistance for around
2-3 mm distance and this layer is really thin.

[search for "Rear Window Defroster Repair"]

 

[Channel Hopper]

Unfortunately metal filled epoxy is also the recipie for a microwave absorbant. On the other hand, what
you have beneath surface doesn't matter if the surface is a really good conductor. I use Eccoshield ES
from Emerson & Cuming (Belgium) but there are other useful coatings like the conductive paint used to
fix broken heating filaments (in rear windows on cars). If the conductivity is really good only a very thin
layer is necessary. The spillage on the outside of my Eccosorb bottle has 0,3 Ohms resistance for around
2-3 mm distance and this layer is really thin.

[search for "Rear Window Defroster Repair"]

With anything that is 'glued' together in a waveguide situation (at any frequency) I always hammer a thin piece of metal plate along the seams to match the original shape.

I did mention cutting up aluminium drink cans sometime before, the K Cider metal is about the best you can get (though beware of the sharp edges, and the reviews - Beer Review: ‘K’ Gaymer Cider )

 

[RimaNTSS]

I've got feedback from friend of mine (to whom I sent several modified IBUs). He tested single IBU on single IBU flange (flange feedhorn is from INVACOM) on 1.8m solid PFA. Flanged LNB gave slightly better reception results. Of course it is not very right to do such a comparison, but anyway. There are results he sent me:

10970 Pol: V Symbol rate: 32720 - single IBU 11.1snr, IBU modified - 12.4snr
10970 Pol: H Symbol rate: 32720 - single IBU 7.4snr, IBU modified - 8.6snr

 

[Channel Hopper]

15% improvement, even on paper isn't bad.

 

[ac1139]

Could I adapt the orange lnb to the other ?

and somebody knows how it works the televes lnb with 4 wires output?

thanks

This orange thing looks like mechanical polariser Hirschmann CSP 1210 C. Its for one polarity LNB. You need some positioner to control it. Old analogue receivers with positioner can control it, or some modern - like Titanium Satellite ASC1 Positioner. It is for skew adjustment for one polarity LNB. Some info about it: Mechanical polarizer Hirschmann CSP 1210 C & Magnetic polarizer IRTE and their advantages and disadvantages in practice . | CZECH AND SLOVAK DX SATELLITE CLUB
I think its not good idea to adapt it...

 

[ac1139]

This orange thing looks like mechanical polariser Hirschmann CSP 1210 C. Its for one polarity LNB. You need some positioner to control it. Old analogue receivers with positioner can control it, or some modern - like Titanium Satellite ASC1 Positioner. It is for skew adjustment for one polarity LNB.

Anyway, I would be happy buyer of this orange polariser... (I am outside UK).

 

[Trust]

Anyway, I would be happy buyer of this orange polariser... (I am outside UK).

Will this Chapparral polaraiser do ?
Can be controlled by such servo testers .

.