mechanical polarotor

[dreambox1959]

I wanted to build a mechanical system that turns an LNB or an orthomode.
the mechanical part was simple: a set of robotic parts found on ALI.
the motor is 12v but it exists in 6v and 24v.
there are 5V HALL sensors.
I am creating a printed card which will be quite close to the diagram of a V-BOX or Diseqc motor and I plan to send either the SKEW command or an 8-bit word via serial link.

 

[femi]

Ich denke das ist speziell beim Egis-Betrieb die bessere Lösung als der Corotor oder das Seavey.
Ganz außer Acht lassen sollte man dabei aber nicht die Länge des Hohlleiters.

Meine Gedanken gingen vor einiger Zeit auch noch weiter:
Diese Einheit als Steck-System in Schienen, wo man es leicht gegen eine C-, K-, X-Band Einheit oder was auch immer schnell tauschen kann.

I think this is a better solution than the Corotor or the Seavey, especially for Egis operations.
However, you should not completely ignore the length of the waveguide.

Some time ago my thoughts went even further:
This unit as a plug-in system in rails, where you can easily swap it for a C-, K-, X-band unit or whatever.

 

[dreambox1959]

this is an interface that detects the skew signal for polarotor and uses it to control a motor that drives the horn of the LNB.
it can be used with a single polarity head or a universal head, notably with an EGIS motor.
the card can be powered with 36V to 24V (egis) and the skew signal (+5V and pulse 0.6ms--2ms).
the motor is 12V and is easily found on ALI.... the printed circuit is of my design and I could provide it.

 

[pitussat]

That's interesting maybe i got!!

 

[Channel Hopper]

That's interesting maybe i got!!

It is important on any 'large' dish with a fixed (universal/OMT) LNB.

 

[femi]

No, it is important on all antennas, even those operated with polar mounts and especially at different frequencies.
Whether you screw a standard universal LNB onto it or a professional one is just a question of the adapter and the money.

Nein, es ist wichtig auf allen Antennen, selbst bei mit Polarmounts betriebenen und erst recht bei verschiedenen Frequenzen.
Ob man ein Standard Universal LNB dran schraubt oder ein professionelles ist nur eine Frage des Adapters und des Geldes.

 

[Channel Hopper]

No, it is important on all antennas, even those operated with polar mounts and especially at different frequencies.
Whether you screw a standard universal LNB onto it or a professional one is just a question of the adapter and the money.

Nein, es ist wichtig auf allen Antennen, selbst bei mit Polarmounts betriebenen und erst recht bei verschiedenen Frequenzen.
Ob man ein Standard Universal LNB dran schraubt oder ein professionelles ist nur eine Frage des Adapters und des Geldes.

Cross polarisation is not an issue on smaller dishes.

 

[dreambox1959]

the interface card detects the pulse signal (servo-motor type), 0.6ms to 2ms every 20ms.
it controls the motor with HAll encoder. I have planned a range of -90° to +90°.
-mode 1: with a single polarity LNB (replacement of a polarotor).
-mode 2: on an az-el mount (EGIS) with a universal LNB (2 polar).
-mode 3: on a polar mount and universal LNB to correct the declination.
in mode 2 and 3 (with universal LN only one adjustment is required and do not activate the polar on the 14/18V.
the card is powered by the voltage of the jacks (24v or 36V) then is transformed into 12V (motor) and 5v (µP).
the µP performs the same function as the electronic module of a servo motor, but a more powerful motor could be controlled.

 

[femi]

I would just like to mention that there are/were a number of LNBs in use with the Egis that operate the band switching with 14/18V.
It doesn't affect me personally, but pay attention to it when doing the Egis.

Ich möchte nur erwähnen, dass gerade beim Egis etliche LNBs im Einsatz sind/waren welche die Bandschaltung mit 14/18V bedienen.
Selbst betrifft es mich nicht, aber beim Egis darauf achten.

 

[s-band]

Very nice @dreambox1959 This has been my approach with the Prodelin offset dish. The examples here are a Gilat Ka band D and an SMW Ku. I've used the same technique for many others. I use a Pololu interface for control. The slots in the mounts allow the focus to be set.

Cross polarisation is not an issue on smaller dishes.

Hmm. I'm not so sure. Maybe if you're only using it for one provider like Sky. I've been used to having skew control on the Prodelin az-el. Now that's down for maintenance, I find it a real PITA having to get onto the roof to adjust the skew on a polar mounted 1.8. The 3.535 degree offset on some Eutelsat craft makes the difference between lock and no lock especially on feeds etc. Try getting BBC Persia (7E 10720H, Europe B beam) without nulling the BBC radio feed TP which is vertical pol on the Europe A beam. There's next to no room for error.

Regarding magnetic polarisers, apart from being lossy, they need per frequency skew since their skew varies with frequency.

 

[John]

Very nice @dreambox1959 This has been my approach with the Prodelin offset dish. The examples here are a Gilat Ka band D and an SMW Ku. I've used the same technique for many others. I use a Pololu interface for control. The slots in the mounts allow the focus to be set.

View attachment 157338 View attachment 157337

Hmm. I'm not so sure. Maybe if you're only using it for one provider like Sky. I've been used to having skew control on the Prodelin az-el. Now that's down for maintenance, I find it a real PITA having to get onto the roof to adjust the skew on a polar mounted 1.8. The 3.535 degree offset on some Eutelsat craft makes the difference between lock and no lock especially on feeds etc. Try getting BBC Persia (7E 10720H, Europe B beam) without nulling the BBC radio feed TP which is vertical pol on the Europe A beam. There's next to no room for error.

Regarding magnetic polarisers, apart from being lossy, they need per frequency skew since their skew varies with frequency.

>> "Try getting BBC Persia (7E 10720H, Europe B beam) without nulling the BBC radio feed TP which is vertical pol on the Europe A beam. There's next to no room for error". - - - that is so very true

 

[dreambox1959]

I would just like to mention that there are/were a number of LNBs in use with the Egis that operate the band switching with 14/18V.
It doesn't affect me personally, but pay attention to it when doing the Egis.

Ich möchte nur erwähnen, dass gerade beim Egis etliche LNBs im Einsatz sind/waren welche die Bandschaltung mit 14/18V bedienen.
Selbst betrifft es mich nicht, aber beim Egis darauf achten.

for me , i had tested a small board to use a single polar lnb (single or dual band) (on EGIS)
i set on octagon "universal LNB " and on my small card i use 14:18V and 22khz or not to choose polar H/V and band :
14V 0khz = V low OL
18v 0khz = H low OL
14V 22khz =V high OL
18v 22khz = high OL

14/18 is used to select polar H/V
22khz is used to send 18V (14V if 0khz)

nobody ask me for get it.
my new card (polarotor) can be used with universal LNB or single polar single band LNB,
in case of dual band lnB single polar there is model either with voltage or 22khz , an special interface is required .
,

 

[Channel Hopper]

Very nice @dreambox1959 This has been my approach with the Prodelin offset dish. The examples here are a Gilat Ka band D and an SMW Ku. I've used the same technique for many others. I use a Pololu interface for control. The slots in the mounts allow the focus to be set.

View attachment 157338 View attachment 157337

Hmm. I'm not so sure. Maybe if you're only using it for one provider like Sky. I've been used to having skew control on the Prodelin az-el. Now that's down for maintenance, I find it a real PITA having to get onto the roof to adjust the skew on a polar mounted 1.8. The 3.535 degree offset on some Eutelsat craft makes the difference between lock and no lock especially on feeds etc. Try getting BBC Persia (7E 10720H, Europe B beam) without nulling the BBC radio feed TP which is vertical pol on the Europe A beam. There's next to no room for error.

Regarding magnetic polarisers, apart from being lossy, they need per frequency skew since their skew varies with frequency.

Interesting, what size reflector below the 180cm mentioned in the post ?

 

[pitussat]

the interface card detects the pulse signal (servo-motor type), 0.6ms to 2ms every 20ms.
it controls the motor with HAll encoder. I have planned a range of -90° to +90°.
-mode 1: with a single polarity LNB (replacement of a polarotor).
-mode 2: on an az-el mount (EGIS) with a universal LNB (2 polar).
-mode 3: on a polar mount and universal LNB to correct the declination.
in mode 2 and 3 (with universal LN only one adjustment is required and do not activate the polar on the 14/18V.
the card is powered by the voltage of the jacks (24v or 36V) then is transformed into 12V (motor) and 5v (µP).
the µP performs the same function as the electronic module of a servo motor, but a more powerful motor could be controlled.

For best performances --< mode 4 :rotate OMT +2XLnb wr75 ol's 9,75 and 10.6 GHz, for example njrc 2842s or invacom spv10 lnb

 

[RimaNTSS]

Some time ago, on a local online flea-market, I spotted this LNB with mechanical polarizator (as written on it). Of course, I bought it..... just for fun. It is in working condition. Warranty seal is not broken, so it still has German warranty , just kidding.

 

[dreambox1959]

hi aldo !
the two lnb s you talked are bi-band with 22khz selection .
so on a static mount you need two model of them with an orthomode .
but if you put my motorised polarotor you ll need only one and not orthomode and you set your receiver as "universal lnb) (mode1).

 

[dreambox1959]

very curious !!
what is for the two flange ? WR75 and C120 ?

 

[Channel Hopper]

very curious !!
what is for the two flange ? WR75 and C120 ?
View attachment 157352

A pass through for the BUC (opposite polarity)

 

[s-band]

Interesting, what size reflector below the 180cm mentioned in the post ?

I think of 1-1.2m as small. Reflector size doesn't matter, it's the relative level of the wanted to the unwanted signal that does. If you're on a satellite where the TPs you want are all similar levels then you'll get by with just adequate X polar rejection. There will still be a bit of extra margin to be had though. I used an extreme (unfair?) example but extreme is the goal for many people here.

A pass through for the BUC (opposite polarity)

Looks like it as it specifies TX power

 

[dreambox1959]

I've resumed my research on a mechanical polarizer to rotate an LNB.
My first model took up too much space, so I found a more compact 24V motor.
The principle is to receive the standard skew signal and convert it into a number that positions the motor.
This is the principle of Diseqc motors, but controlled by the skew signal.
I created this system for the EGIS motor, but it can be used on a polar mount.
In this case, with a universal or KA dual-polar LNB, I can apply a slight offset, and the 14/18V control will choose between the two polarizations.
Almost all the components come from ALIx and are inexpensive.