GM1BSG
28th April 2009, 08:40 AM
It seems this post went missing somewhere so I am reposting the images.
The before shots seem to have gone astray but here are some shots after the rotator was refurbed with a few mods.
The KR400 was modified in the following ways.
* Capacitor moved to the rotator body itself so I could drive it from any AC source via relays (as a second project of mine was to be a digital controller with touch control and memories as well as CAT driven).
Having the cap in the controller limited its flexibility to using only that type of controller.
* Only mehcanical limits exist on these rotators and many suffer from getting their limits rammed on a regular basis which causes wear and often I have seen the threads on the top bell casing being stripped as the bottom race is forced off due to play/motor force distorting the top bell housing.
So microswitches were added in similar style to the KR-600, you will sacrafice 5 degrees or so of travel but given we realistically will never mount any antennas on it with a beam width that narrow I doubt the loss will ever be noticed.
* Cable entry block. Again, these do not weather well at all, the gasket rots or the plastic cracks, or is cracked due to over tightening of the 4 screws. Overall a bad design.
Removes and replaced with a blank plate and IP65 gland, the short cable tail is then terminated in an outside junction box.
* Pot usually wears or rots
Pot was changed from a 500R 360 deg pot with a centre dangly wire which rots/breaks to a 1K sealed pot, movement is now much nicer.
Enjoy the images.
BR, John
The before shots seem to have gone astray but here are some shots after the rotator was refurbed with a few mods.
The KR400 was modified in the following ways.
* Capacitor moved to the rotator body itself so I could drive it from any AC source via relays (as a second project of mine was to be a digital controller with touch control and memories as well as CAT driven).
Having the cap in the controller limited its flexibility to using only that type of controller.
* Only mehcanical limits exist on these rotators and many suffer from getting their limits rammed on a regular basis which causes wear and often I have seen the threads on the top bell casing being stripped as the bottom race is forced off due to play/motor force distorting the top bell housing.
So microswitches were added in similar style to the KR-600, you will sacrafice 5 degrees or so of travel but given we realistically will never mount any antennas on it with a beam width that narrow I doubt the loss will ever be noticed.
* Cable entry block. Again, these do not weather well at all, the gasket rots or the plastic cracks, or is cracked due to over tightening of the 4 screws. Overall a bad design.
Removes and replaced with a blank plate and IP65 gland, the short cable tail is then terminated in an outside junction box.
* Pot usually wears or rots
Pot was changed from a 500R 360 deg pot with a centre dangly wire which rots/breaks to a 1K sealed pot, movement is now much nicer.
Enjoy the images.
BR, John