Chan Master 1.2 dish surface repair?

slayer7

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i have channel master 1.2 dish but the paint has scraped off in a lot of places and is getting very poor gain. i have just sanded down by hand the surface and the gain has improved say 20% only. i have a 1.1 metre that is getting 15.3 db and my channel master is getting 11.8 db just about.i am thinking of painting it, anyone ever tried this? and if so what did you use? the old surface when new was rough but even

suggestions?
 

RimaNTSS

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@slayer7 Could you post couple of pictures of your installation? I personally think that poor performance of your CM 1.2m could be it's tuning question or bad LNB. Channel Master has reflective surface (mesh) melted inside the body and paint on the surface makes not much difference to reception.
 

RimaNTSS

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Interesting picture! I have never seen CM in such a bad shape! Did you paint this dish before? As for me , simple washing with soap and kitchen sponge would be enough. Why do you additional painting?
BTW, 100% new LNB does not mean it is good enough.
 

slayer7

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nope i have never painted it, i neglected it and left it lying around for years, silly really. the surface natural texture/paint from new has scraped off and created an uneven surface so just cleaning it would not suffice in my opinion. i have read a few people painting or spraying them but was unsure as have never done it:)
 

slayer7

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1 of the 4 dish surface bolts has loosened and broke i will hacksaw it off tomorow. i have a replacement i think,maybe tightening it up will get me the missing 3-4 db but cant see it. your lnb holder is working good so cant be that either all tightly screwed up. i have also skewed lnb to maximum strength....actually thinking about it maybe it is causing the concave shape to distort
 
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RimaNTSS

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What is the reason to paint plastic? Just cosmetic! If you already sandpapered the surface than leave it as it is. Paint will never improve the performance of the system. CM is nice and very durable dish, it should work as it is. Could you show more pictures of sanded dish?
Are you sure that cabling is OK and F-connectors are perfectly working?
If the dish was not in use for years how can you tell now that it's performance has dropped so much?
 

RimaNTSS

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maybe tightening it up will get me the missing 3-4 db
Wait a minute.... of course everything should be tightened firmly and you still need possibility to adjust antenna's azimuth and elevation very precisely. What do you have other side of the dish? Polar-mount or fixed mount?
 

slayer7

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its gone very dark so will do pics tommorow of sanded. cabling is fine. i have tried two leads to my sat metre, i will try another tomorow. i cant really remember what its peformance was but i know its bad judging by my 1.1 metre solid dish and thats rusted a bit. the more i think about it that back plate bolt must be the culprit. its a polar mount on it but the actuator is not active at moment needs a vbox or similar
 

barney115

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Dish looks in Great shape no signs of any dent or warping
if there was that close up picture would show it even more clear than normal .
Paint is always a great idea to preserve the dish for future weather etc.. you will loose 0% by painting as long as you use NON-Lead Based paint .
i painted my 1.2m channel master dish a few times since i got it 10+ years ago exactly same as yours @ slayer7 .
Did not loss no signal whatsoever plus lead based paint was banned in EU since 1978 so you pretty much have nothing to worry about i went to my local CO-OP and got them to mix paint to get a nice bright grey color similar to original paint that was on it already ,
i put two coats on it but only because i wanted to use up the paint as i had no other use for it .
 

RimaNTSS

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its a polar mount on it but the actuator is not active at moment needs a vbox or similar
I think I see what is the issue here! You have polar-mount which is not tuned properly! Put your polar-mount in dead-center position and catch you due-south satellite (which is 4*W). Then you will see that CM 1.2 antenna-system (dish, LNB, F-connectors, cables) is performing much better than another antenna, namely 1.1m whatever name it has. After that you go to second step- tuning of the polar-mounted system. Everything should be done step-by-step.... crawling-walking-running-flying :)
And, again, painting will not in any case improve performance of your antenna-system.
 
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slayer7

Donating Member
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154
i have aligned the polar mount up flush dead centre and still same results. i have changed the broke face screw bolt with a new one and tightened up and still low gain. tried a third older lnb and same results but less db. i am now getting 12.8db on thor 1 west so a little improvement.

close up dish face pics
https://postimg.org/image/fv1reot7n/
https://postimg.org/image/p43xopucz/

polar mount pic
https://postimg.org/image/xjti62s1f/

the only thing remaining to try is put some string on to see if its contorted and also to paint it
 
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slayer7

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hammerite

looks good, yes i was gonna ask about something to galvanize,
as rusting a bit.:D
 

RimaNTSS

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i have aligned the polar mount up flush dead centre and still same results. .....
the only thing remaining to try is put some string on to see if its contorted and also to paint it
No, Mike, this is not the dead-center, you are way away from that Thor is not your due-south satellite, but Amos @4*W.
Did you also try to change LNB's skew?
You can make a string-test, but I am sure your antenna will pass it. Channel Master 1.2m never bends, at least I did not see any bended. You can paint the face, but, again, it will not improve the reception performance.
 

slayer7

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154
hi thanks rimaNTSS that picture was taken just before the adjustment. i cant understand it either because channel masters are a very rigid material. maybe it was never in shape even from new :confused:
 

RimaNTSS

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If polar-mount is not properly adjusted than, it is for sure, you will not get good performance of the satellite system. I wold advice to adjust polar-mount properly and then make signal comparison. If you are only looking for 1*W than adjust not only azimuth and elevation, but also skew of the LNB.
 
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