Dish Flop on C band dish

[wium78]

What causes dish flop .Has the attachment of the actuator to the dish any bearing
on dish flop.

 

[RimaNTSS]

Could you provide picture of your problem? Usually, flopping of the dish is caused by properer attachment of the actuator.

 

[wium78]

sorry i am not into pictures and how to get it on the forum.

 

[RimaNTSS]

You write your message in green square, and than push button "Uplode file" (I circled it red), chose picture from your PC and click "Open", picture will be automatically downloaded.

 

[skomedal]

Remember max file upload is 1Mb you might need to resize it, if over that limit size you get this message:-

The following error occurred
The uploaded file is too large.


Regards

 

[Costactc]

I unfortunately have flopped my 3m mesh several times. When pushing the dish too far away on the opposite side the dish eventually drops. I normally have my son go outside and help it as I manually send it in the opposite direction.

 

[wium78]

Am i correct in stating that a dish will only flop if the actuator is not properly secured to the dish.
In my case ,on two occasions i used two brackets which turned out not to be that strong (they bent)as
i should have used a stronger material.Or are there other reasons for a dish flop.

 

[RimaNTSS]

Or are there other reasons for a dish flop.

MAybe also other reasons, but without seeing your problem (on picture) it is hard to say ;)
It is easy to prevent flopping of dish by adding some kind of mechanical stop. After that will not be necessary to go outside and push antenna back to track.

 

[Terryl]

"Dish Flop" is due to mechanical advantage over taxing the linear motors braking system, or just plain stretching the hardware.

Increasing the length of the actuator rod's mounting point will decrease the dishes pull on the actuator, however the mechanical stress on the actuators mounting point will increase so you will/may have to beef up the mounting point.

You could also look for a bigger motor, if you have an 8 foot dish then look for one that can handle a 10 to 12 foot dish, or one that can handle a solid dish. (bigger wind load)

And as RimaNTSS mentioned adding stops to the end of travel will help, these can be hard stops welded to the dishes mounting base, or in some installs we used hard rubber bumpers to keep the motor from being damaged.

 

[RimaNTSS]

I've made several adjustable mechanical stops. With them I was able to even remove actuator from antenna at all and at the same time still be tuned to far-East or far-West satellite in my arc. On attached pictures my most Eastern satellite was 90*E.

 

[Costactc]

If your using a stand alone positioner, as I do on both my big dishes, setting your limits will prevent the dish from flopping.

 

[wium78]

Thanks for the valuable input from the members.It is greatly appreciated.

 

[RimaNTSS]

@wium78 So, what kind of plan you got to fix your issue? Ir it was just theoretical question?

 

[wium78]

No it was not a theoretical question.I have used my dish for years and a few days ago whilst using my actuator
my dish flopped over to the West.I noticed that my actuator rod mounting had a bent and i put it down to metal stress over the years.I then made two attempts to attach the actuator to the dish rib by way of a bracket.In both cases the dish flopped and bent the the bracket.I have decided to go back to the actuator rod by replacing it with stronger material and lenghtening it by about 4 inches,.
RimaNTSS as a matter of interest cant you use your limits instead of the mechanical stops.

 

[RimaNTSS]

Yes, it is possible to use actuator's limits alone, but it is much better to use them in combination with antenna's polar-mount mechanical stop.

 

[RimaNTSS]

And, still interested to see some pictures, not only stories

 

[wium78]

I have a 3M C band dish on a polar mount.I track from 78 East to 10 East (Southern Hemisphere) but going beyond that my dish flops.What causes flopping and will it help if i move my actuator mounting position away from the polar mount attachment by way of a bracket.

 

[Lazarus]

Mod Note: Is this the same issue as discussed in your earlier topic here https://www.satellites.co.uk/forums/threads/dish-flop-on-c-band-dish.163776/

 

[wium78]

Yes it is the same.I replaced my polar mount with stronger brackets to attach the actuator.My problem continues,however,i noted that the old Paraclipse dishes use a 3 point attachment bracket which moves the actuator
away from the polar mount.I wonder if any member have tried something like that to avoid flopping.

 

[Lazarus]

Ok, thanks.

We can either merge the two Threads or Members replying can simply use the link in Post #2 to check what has gone before.

For now, we'll keep the Threads separate and see how it goes