Just Sharing This Motor drive for C band LNB circular polarity

Good evening from a chilly Mullion Cove Cornwall.

Having just received my first stations on C band, the problem of switching from right to left circular polarity became obvious.

Not wishing to send poor Alanna out on cold winter evenings, I have made some progress in motorising the polarity on the C band LNB.

All parts so far are from a faulty VCR.

The effect of a metal shaft down the centre of the LNB is minimal, as is the metal nut locking the plastic bearing to the LNB cap.

The motor in the images was temporary and also useless as its rotation speed is much too fast.

The motor I have ordered on eBay will be mounted behind the scalar rings through one of the existing holes.

My original idea was to mount the motor at the rear of the LNB, but there is a bar across the centre where the shaft would have been.

I ground enough off the slab so that it clears the locating slots inside the LNB, again this did not reduce the quality much.

In all I may have lost one or two points, maybe none as signals go up and down all the time.

Will update when the motor arrives from China and is fitted.

God Bless Happy Easter to all. Spiff Allen & Alanna

DC 6V 12V Turbine Worm Gear Motor Variable Speed Shaft Slow Reduction Gear Box | eBay

Spiff said:

Good evening from a chilly Mullion Cove Cornwall.

Having just received my first stations on C band, the problem of switching from right to left circular polarity became obvious.

Not wishing to send poor Alanna out on cold winter evenings, I have made some progress in motorising the polarity on the C band LNB.

All parts so far are from a faulty VCR.

The effect of a metal shaft down the centre of the LNB is minimal, as is the metal nut locking the plastic bearing to the LNB cap.

The motor in the images was temporary and also useless as its rotation speed is much too fast.

The motor I have ordered on eBay will be mounted behind the scalar rings through one of the existing holes.

My original idea was to mount the motor at the rear of the LNB, but there is a bar across the centre where the shaft would have been.

I ground enough off the slab so that it clears the locating slots inside the LNB, again this did not reduce the quality much.

In all I may have lost one or two points, maybe none as signals go up and down all the time.

Will update when the motor arrives from China and is fitted.

God Bless Happy Easter to all. Spiff Allen & Alanna

DC 6V 12V Turbine Worm Gear Motor Variable Speed Shaft Slow Reduction Gear Box | eBay

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10 / 10 for innovation Allen, look forward to more results.

+1

Great innovation, well done.

Rgds

Great mod! Bits from a VCR live on....

@Spiff

This modification could be given the name of the "SVR Mod" (Spiff's Video Rotor Mod).


Rgds

Nice work Spiff, will done.

@ Spiff , dont that rather great chord wheel ,not obstruct the signal ?
My other interest , how do you control that new motor , ever thought about a servo as used in RC toys ?
For that servo motors are cheap but reliable servo-testers , the plate makes the same movement as the knob at that tester .

Trust1 said:

@ Spiff , dont that rather great chord wheel ,not obstruct the signal ?
My other interest , how do you control that new motor , ever thought about a servo as used in RC toys ?
For that servo motors are cheap but reliable servo-testers , the plate makes the same movement as the knob at that tester .

Click to expand...

Hallo Trust1,

We did signal quality tests before and after adding anything that could cause the signal to be degraded.

The large drive wheel made little or no difference, neither did the metal shaft.

The dish was set up before hand for absolute maximum quality level which was 81.

Today I tested it again with all the added parts for the polarity changing and it was 81.

It has surprised me that it made no difference, but there it is : )

As to controlling the settings, I shall use as low a voltage as I can on the motor which is already a low revolution device.

It will be fed with twin wire to the remote operating position from a polarity change switch and an on off toggle switch.

Maximum quality being obtained by watching the level on the quality bar.

I can then use a known signal to set it to right or left should I wish to do a blind scan.

The servo motors that you mentioned sound interesting, it may be that I will try that later.

The hope is that the motor when it arrives is slow enough, as when setting the device by hand a very small movement ether way made quite a difference to the quality level.

Also there were higher levels with the slab further in the LNB, so I will make sure that its position on the shaft is at optimum.

I may fit another pulley opposite the motor on the scalar rings so that there is no pull on the shaft towards the motor by the drive band.

This could cause the shaft bearing in the LNB cap which is thin to tilt and cause the slab to hit the inside of the LNB.

The motor is coming from China, we paid extra but it will still be a week or so.

God Bless Spiff

Nice to know there are no quality loss , well done !

Good going, if you don't mind me asking but what's the overall cost to motorise the plate?

Chris1979 said:

Good going, if you don't mind me asking but what's the overall cost to motorise the plate?

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Good evening Chris1979,

Most of the parts came from a scrap video recorder, the new motor with a reduction gearbox is on order as the one from the VCR had too fast a spindle speed.

The motor from China was £1.37 with free postage, I paid extra for faster delivery, £3.87 in total : )

It remains to be seen if it will be slow enough, if not there are many more listed at very low prices : )

It will also require about 20 meters of twin flex to my operating position, plus a low voltage power supply.

The long shaft required is often seen in VCR's running from a small motor at the rear to the cassette opening mechanism.

There are plastic and metal knitting needles that could well do the job.

If you do not have a suitable VCR donor, most of the parts will be found on eBay for very little.

God Bless Spiff