Retune and back to basics

[gabshere]

ok i got a digital level and thought i would take some readings

first is there a site that has just elevation for a prime focus dish ?
my readings are from the correct locations but my dishes are not pointed at TS so i will have to wait for a dry day to move them.

so far nothing between the two dishes has lined up ( they are pointed at different satellites. I've never adjusted the elevation or the declination on either of the dishes and i know the smaller 7 1/2 ft dish tracks the arc and receives c & ku

the bigger dish has never been tuned for ku but at one time in the past picked up c-band fairly good. but i'm to the point like linuxman trying to squeeze every bit of signal out of both of these dishes

here are some numbers-------10 ft dish---------------7 1/2 ft dish
angle at axis-------------------- 31.1-------------------------37.8
angle at base plate on dish-------67---------------------------52.7
angle at ring mount--------------66.8--------------------------50
angle at scaler------------------71.3--------------------------44.1
angle at lnbf---------------------72----------------------------44.4

my long is 34.009 N
my lat is 92.141 W
and i think the declination is 5.51

 

[linuxman]

I use this site George.

According to it,

Your polar axis main elevation bar should be 34.68 degrees

and your declination should be 4.84 degrees.

For a total on the back of the ring or face plate on the dish of 39.52 degrees.

That's using 93W as your TS satellite since you are just a little past 92W on your longitude.

Check it out for yourself. It is a pretty easy calculator to use.

 

[voomvoom]

Since they are both pointing at different sats, it would be hard to figure the differences in them. When it dries up, give it your best shot....!!

 

[gabshere]

well i'm going to try turning them in a few minutes thanks guys

one thing i thought was the scaler would be at the same angle as the dish (or should be)
to bad i didn't get this digital level earlier to take some readings on the 7 1/2 fter befor i adjusted the feedhorn support arms but i will have to go from where i'm at now and improve on that

 

[gabshere]

ok i got it (the 10 fter) moved to 93w and i have c-band only signals from 107 - 93 (thats as far east as i've checked.

the readings are
axis is 31.1
ring is 36.2
which means the declination is set to 5.1 ( and i know this was the declination back when the dish was setup in 1991

reading at the center of the dish 36.7
i can't reach the feedhorn or scaler ( today to wet)

i will try to reset the axis to 34.67 and declination to 4.84

 

[gabshere]

ok I reset the axis to 34.6 and declination to 4.8 for a total of the reading at the ring is 39.5
i lost signal on all the satellites i was getting but i really suspect that i had the feedhorn tuned & adjusted for the signal and not for the proper settings . i will have to reset the feedhorn & scaler tomorrow.

 

[linuxman]

Hey George,

Go ahead and set the F/D and Focal length, and then move the dish from East to West or West to East until you acquire signal again.

Then twist the whole assembly to peak for best signal before you adjust the elevation again.

I think you will get much better signal than you had before.

 

[gabshere]

well thats one of my problems lol

ok first i can't even work on the feedhorn when its pointed at 93w due to the extream wet weather...... i'm hoping to turn the dish to 123 and finding both c & ku signals and setting it from that satellite and then testing the rest of the arc ..... ground is just to wet for working on the dish.

another problem i have is the F/D and focal length
both of my dishes i was unable to get the proper f/d and focal length
the 10 ft calculates out to 42.9 inches and a .36 F/d
i can only get it out to 42.375

so i will have to test it from there tomorrow

 

[gabshere]

i don't know after sitting here thinking about everything
i know 3 degrees isn't much but
my starting point at the ring was 36.2 and the new reading says it should be 39.5
thats 3.2 degrees

ok the axis was at 31.1 and it said it was supposded to be 34.67
the declination was 5.1 and new measurment said it was to be 4.84
when i adjusted the axis it was up 3.57 degrees
when i adjusted the ring (declination) it seemed like i was moving the dish up. so i will have to recheck it at the dish again tomorrow.

it could be the actual axis should be closer to 31.1 because the 5.1 isn't far off of 4.84

 

[linuxman]

well thats one of my problems lol

ok first i can't even work on the feedhorn when its pointed at 93w due to the extream wet weather...... i'm hoping to turn the dish to 123 and finding both c & ku signals and setting it from that satellite and then testing the rest of the arc ..... ground is just to wet for working on the dish.

another problem i have is the F/D and focal length
both of my dishes i was unable to get the proper f/d and focal length
the 10 ft calculates out to 42.9 inches and a .36 F/d
i can only get it out to 42.375

so i will have to test it from there tomorrow

I would set the F/D and Focal Length with the factory specs if you have them. If not, tell us exactly the brand and model, and some of us will have them somewhere.

I only use the calculator when I don't have the factory specs.

Those setting can be set anywhere on the arc or even pointed at your neighbors house.

 

[gabshere]

with the factory specs if you have them

i thought i had them but what i have is the warranty information .. its a Odom Antennas Inc. dish made in Arkansas i suspect that its a SAMI predecessor.

 

[gabshere]

ok still adjusting on the dish
set everything back to where it was at start except the declination
so i set the axis back to 31.1 and now declination is at 4.9 ( it was 5.1)
had TP on 93 at 67% and some of the arc over to 121 a strong TP was at 67% and could push on the dish and gain signal .... i wasn't on declination . adjusted about 1/8 of inch maybe 1/4 ( its marked)
and gained the TP on 121 to 94 % but lost on the TP on 93 its now at 63% and i can puch up and gain signal (maybe elevation is off ... i will have to think about it no eastern arc yet ( haven't tried that much) and these are all c-band.

real wet today and lots of rain showers so i will have to find another day to continue

 

[linuxman]

Hey George,

I made the mistake once or more of moving the declination from where it was supposed to be.

Once you set the declination and you know you have it right, don't touch it again.

The rest has to be elevation only adjustment and complete assembly twist from East to West, and of course motor movement E/W to gain the highest signal across the arc.

 

[gabshere]

yeah 4.9 is closer to the # on the site that you gave me it was 4.84

just will have to play with it more to see if & what way i need to go next

this is the 10 ft dish and its harder to work on that the 7 1/2 fter

 

[linuxman]

yeah 4.9 is closer to the # on the site that you gave me it was 4.84

just will have to play with it more to see if & what way i need to go next

this is the 10 ft dish and its harder to work on that the 7 1/2 fter

You are absolutely correct!

No one seems to believe me when I tell them that the bigger the dish, the harder it is to tune in.

 

[stogie5150]

You are absolutely correct!

No one seems to believe me when I tell them that the bigger the dish, the harder it is to tune in.

Listen to the man. He made a believer out of me....LOL

 

[gabshere]

lol well i believe him i know i will get it
just pacing myself

i hope to get it back in shape for kickoff

 

[truckracer]

10' dish is much harder to tune than smaller ones, especially on ku - Believe me!!!

 

[gabshere]

well i finally got some time to continue tuning on the 10 fter
and got everything set up and running and started and after 5 hours i still don't know if i got it any closer lol

now i'm tuning c-band only right now
everytime i make an adjustment i lose one end ( my west i was using 121w) or my Middle (TS) weakens.

i adjusted for being to far east and it improves my signal a bit on the west (121) but weakens the middle (91) after my last adjustment i gained 89 & 87
i can twist upwards & to the left (west) and gian signal on 121 , i can pull down and to the east and gain on 87

i think if i read the chart correctly my axis is to far east and my elevation is too high

so hopefully i will get some more time tomorrow to work on it....

also i haven't even tried ku , i was wondering if i tried it , that it might pinpoint my east-west better as there is a bit of play with c-band. also i noticed i have slight movement / play in one of my washers on the lower axis pivot , so i might have to tighten it up or replace the nut with a lock nut.

more later

 

[linuxman]

Hey George,

I would use Ku for tuning, and it looks like all you need is a twist of the assembly to be there, and then maybe another slight adjustment on elevation.

i can twist upwards & to the left (west) and gian signal on 121 , i can pull down and to the east and gain on 87

Twist the whole assembly towards the West about 1/16" at the pole and see what that gets you.

EDIT: Pulling down on the East indicates that you have to look down on the arc. pulling up on the West indicates that you have to look up on the arc, so the adjustment I suggested should take care of that.