VK Logger Ham Radio Forum Archive

I am trying to repair a Fukner rotator. It runs of a stepdown transformer which is US and needs to be replaced but I have no idea what it's output voltage is supposed to be. Anybody got one of these rotators? What are commonly-used voltages for rotators?

73

Wayne VK4WDM

Wayne,

Not sure what model you have but a quick google brought up this page, indicating 24V http://www.rigpix.com/rotators/fukner_fu400.htm

73s

Murray

Hi Wayne

Yes, nominal 24VAC although have measured upwards of 30 VAC no load on some transformers (probably 220VAC primary!).

Have two still going (Dick Smith sold these as well), both with newer digital readouts

Cheers

David VK5KK

Hit send too quick ...

BTW: Similar (24VAC) voltage as most rotators and same control circuitry as some others (KR400, etc) viz one winding for left one for right. I use a 100VA 12 + 12 VAC transformer from Jaycar with one of mine. You could probably get away with a smaller transformer but extra few dollars worth it

Cheers

David VK5KK

Wayne,

Those rotators were marketed under a series of names such as: Iwasaki, Fukner, SkyKing. Commander

Essentially they were a 550Kg-cm rotation torque and a 1500 Kg-cm breaking torque and ran off a 6 core cable.

Our club station VK3ER/p uses 7 of these rotators on our various VHF/UHF microwave antennas and generally they are simple, reliable and relatively accurate once setup properly.

By far the greatest complaint is that the voltage regulation is not that great, which means that under heavy load, the dial light dims and the direction inductor can be up to 10 degrees out whilst rotating - of course it settles back correctly once rotation stops.

The power transformer secondary is nominally 26 volts AC and I have seen various modifications done over the years to try and regulate the voltage to the direction meter - the original design used a second winding (11 volts) on the transformer to supply the direction indicator circuit, however many have used a single winding and tapped off that winding with a 330 ohm resistor to the indicator supply.

For some time, the units were sold in Australia with a separate transformer external to the case - (to do with AC type approval issues).

Most units I have seen have had the transformer mounted in the case (in some cases retrofitted).

There is available on www.mods.dk a pdf file of the Commander FU-400 operation manual which has a copy of the circuit diagram.

Cheers

Peter VK3QI

FYI

Ditch the old meter and update the Fukner control box with a digital readout ... a 2 line display fits (almost) pefectly.
The position pot is reasonably linear in the rotator so readout is within a couple of degrees. The Big knob is a direction preset (smaller number in display) the red switch is the park button.
This design uses a PICAXE20 but plenty of other rotator projects using arduino, etc platforms on the web. Two of these turn VK5AKM's microwave antennas 1296, 2400, 3400, 5760, 10368 & 24048

Cheers

David VK5KK

The old clunker is up and running again and ready to go on the VHF/UHF mast. Removing, cleaning and replacing all the ball bearings was tedious. The gears and the rest of the workings are surprisingly good considering the age. Directional readout is spot on.

Thanks for your help guys.

73

Wayne VK4WDM

Wayne we had to do the same to mine... still, mine had not turned for nearly 20 years & now works a treat.

Cheers,


Richard
VK2AAH

Hi All

Have been cleaning out the junk box (again!) ... free to a new home two (2) of Fukner rotator controller meters with PCB's and lamp, one has its "zero" pot still connected.
Nice meter movements, both working ok before removed from controllers ... upgraded these to LCD read outs for microwave home station pointing as per post above. Shame to throw them out, could be used with any rotator with a typical position pot.

Cheers

David VK5KK

Does anyone have a copy of the schematic for the FU-400 controller? The one suggested in mods.dk doesn't exist any more.
Thank you
Alex

Alex,

I have sent a pdf file with the information to your yahoo address.

Make sure you read my post from 2013 earlier in this stream.

Cheers

Peter VK3QI