Gregorian dish and Diseqc 1.2 control

[nvingo]

Hi, I'm looking for advice in re-using a dish I have stored at my parents' home, with the modern generation of digital receivers.

I have a Philips Gregorian 90cm with Swedish Microwave LNB, voltage polariser and circular polarisation converter, originally used with a Philips D2MAC/PAL(&NTSC/SECAM) receiver and separate positioner.

My current setup is a (used) Phoenix Apollo FTA receiver which replaced a (also used) Grundig Sky receiver, and a Sky minidish.

If I can confirm compatability, I am considering purchase of a "VBOX" to interface the Apollo to the Gregorian.

My understanding is that the Diseqc 1.2 system allows the receiver to control a compatible motorised dish via digital commands and the existing 14/18v LNB power.
So to control a 36v actuator or H-H mount (the Gregorian has a compact direct-drive motor) a VBox is required to convert the Diseqc commands into 36v power and sensor control.
For a normal LNB, the 14/18v polarisor control and 22khz band switch are passed through the VBox to the co-ax input, and the motor/sensor connections are the four "speaker" terminals.

Question is, what do I do about Swedish Microwave voltage controlled polariser/skew, which is a separate pair of wires, the SM LNB uses 14/18v to switch bands (from before 22khz control) - do I replace the LNB, and what would be compatible ? Or is there a VBox equivalent that can convert this also ?

Many thanks for any help with this, it would be a shame not to utilise that dish.

PS I don't want anything too expensive - certainly not hundreds of pounds to gain "just a few more" un-encrypted channels...

Regards, Norman.

[robbo71]

Hi,

The V-box doesn't do any conversion of the LNB control signals as far as I know, it just lets what you send down it pass through to the LNB.

To be compatible with your receiver you need to get a universal LNB, which uses voltage for switcing the H&V and 22kHz for the band.

What you may be able to do is get a C120 LNB and use the feedhorn from your existing LNB.

Might be a good idea to post up a close-up pictue of what you have now, so that if one of the guys on here who has a Fibo could advise better.

Robbo

[wod]

just take off the polariser and old lnb and replace this with a c120 inverto or invacom lnb

[kerrywez]

Hi,
The V-Box sends signals and the 36V to the actuator/36Vmotor through a 4 core cable, it is not recommended to use telephone cable as it is way too light, the individual cable should be at least 1/2 Mil. You can get the cable at a specialist electrical shop, maybe Maplins. Two of the wires are used to send the 36V to the actuator/36Vmotor and the other two are connected to the reed sensor, for determining where the dish is and if it is moving.

The coax goes into the V-Box and then to the LNB (in a loop through fashion), but it is the receiver that controls the LNB.

Hope this is of some help to you. Good luck and I am quite sure you will get it sorted OK. I know where there is one, not far from me, it is at a house that used to be owned by a German family, but it has been sold and the dish is not in use, might try to get it some time.

Very best regards Wez

[crossbones]

As suggested just change the lnb to a C120 one. The Inverto works really well on the fibo dish`s. Forget the poloriser there old school now.

With the Vbox make sure it has +5v out, required for the the Fibo motor. So you will require a five core cable.

[nvingo]

Originally Posted by robbo71

What you may be able to do is get a C120 LNB and use the feedhorn from your existing LNB.

Might be a good idea to post up a close-up pictue of what you have now, so that if one of the guys on here who has a Fibo could advise better.

Robbo

IIRC the feedhorn is an integral part of the c120 mount.

Originally Posted by kerrywez

Hi,
The V-Box sends signals and the 36V to the actuator/36Vmotor through a 4 core cable, it is not recommended to use telephone cable as it is way too light, the individual cable should be at least 1/2 Mil. You can get the cable at a specialist electrical shop, maybe Maplins. Two of the wires are used to send the 36V to the actuator/36Vmotor and the other two are connected to the reed sensor, for determining where the dish is and if it is moving.
Very best regards Wez

I have the cable on the redundant setup, about 50' of co-ax/four-core/two-core (signal/motor/skew) bonded in a ribbon, but anticipate positioning the vbox to use only a couple of feet of that to the dish and running normal coax back to the receiver.

Originally Posted by wod

just take off the polariser and old lnb and replace this with a c120 inverto or invacom lnb

Originally Posted by crossbones

As suggested just change the lnb to a C120 one. The Inverto works really well on the fibo dish`s. Forget the poloriser there old school now.

With the Vbox make sure it has +5v out, required for the the Fibo motor. So you will require a five core cable.

OK so a modern c120 will handle straight H and V, whatever happened to skew ? Are the transponders in co-ordinated alignment now or does the LNB fine-tune polarisation - I remember my analogue receiver remembered skew for each satellite?
I'll check (I'm over there today) what connections the existing positioner has - I don't remember a +5v connection - and maybe photograph the dish.

[nvingo]

Philips90cmGregorian.JPG
I just realised I have this image (from Aug 2005) already on the PC.
There's a bit much green on the dish for my liking.
The "ribbon" cable can be (clearly?) seen, dividing below the dish to the motor, LNB and polariser.
The wall that the dish is mounted on faces more south-west than south, so a friend constructed a bracket from four U-section RSJ welded to form a rectangle onto which the Fibo mount bolts. This is to allow more easterly swing before the dish collides with the wall - where I'm planning to move it to is a better south-facing wall although it might need to be higher as a neighbouring house is about 12' away (luckily I have a gable end and they don't).
The black LNB is an extended band Swedish Microwave with both skew/polariser and a circular polarisation adapter between it and the feedhorn/mount. This LNB has never seen service, it's fitting coincided with the failure of the analogue receiver. It replaced a white equivalent without the extended low band (Astra 1d range).

[raindancerob]

iv seen quite a few dishes like this recently in my area.

[nvingo]

Originally Posted by nvingo

I'll check (I'm over there today) what connections the existing positioner has - I don't remember a +5v connection - and maybe photograph the dish.

OK I found the positioner (Philips SCC909) and user manual, the receiver itself was a STU909.
The black LNB in the image is branded Philips, but there's no doubt it's a SM, like there's (now) no doubt the dish/mount is a Fibo.

Anyway, as crossbones has said above, the Fibo motor has five connections to the positioner (by way of a five-pin inline socket), Motor +/-, sensor, ground, and sensor 5v supply. The Vbox does not accomodate that, so is not a suitable interface.

The SCC909 also has two D2B (data) sockets, the manual says to link the top one to the STU909 for positioner control. That of course is how I had it.

There's also a 7-pin Din socket (like the traditional tape deck+motor switch sockets) which the manual says is for control from a compatible non-Philips (non-D2B) receiver. There's no information at all about the socket, except the suggestion of East, West, Tracking and Overload.

If anybody knows the protocol for that socket and whether a manual control could be interfaced to it, I would be very grateful for that information.
If I can verify for free that the positioner and motor function, I can then consider changing the LNB and relocating the dish.

Thanks to everybody who has responded.

Regards, Norman.

[robbo71]

Hi,

I think I've come accross this before, the Technomate V-Box II appears to have a 5V terminal on it:-

_http://www.satellitesuperstore.com/vbox.htm

You could ring before purchasing to check. Southernsatellite may be able to help you out here.