Disaster!!

[Vipersan]

Thanks CH ..
Thats actually quite reassuring .. ;)
I will mount the new jack with the drain hole pointing down ..
I wont make that mistake again....
..or as you suggest ...upside down with the motor at the top..

..but all in all you think this way of adding declination is fairly durable ?
..particularly as the pivot bolt is a good fit and runs full length accross the width of the mount ...

rgds
VS

 

[Channel Hopper]

..but all in all you think this way of adding declination is fairly durable ?
..particularly as the pivot bolt is a good fit and runs full length accross the width of the mount ..

If the bolt and steel plates are of good quality then you have only the problem with the motor design, the ball race is the weak part in many designs.

Whilst its slightly more work for you, my suggestion would be to weld a bracket to the main mount, just under the lower polarmount bearing. Then make up a collar for the post, and mount the elevation motor forward of the pole so it always runs in compression.

 

[Vipersan]

A good idea CH ..
..and I will certainly consider doing just that ..
It will have to wait 'till I've re-charged my batteries so to speak ..
In the meantime ..any photos of mods you've already done to similar mounts or systems would make very interesting viewing
rgds
VS

 

[Huevos]

Elevation control ...is in my case in charge of declination not the polar offset

Just had a look at your other thread. That's not declination control, it's the wrong side of the polar mount for that. To work properly it needs to be between the polar mount and the dish, not between the polar mount and the groundstand. That way it will track the arc at any declination. So if you set it 5º below the arc it will say at 5º below right across the arc.

 

[Vipersan]

Huevos ..
I totally agree with you ...
..but this is a compromise ...
The polar mount was not designed with declination adjustment in mind ..
There isn't any way to implement motorized adjustment between the polar mount and the dish ..and since I can tweak the angle for any given point on the arc ..
..I'm happy with a compromise.
;)
It works ..and thats good enough for me.
Its why I don't refer to it as declination control ..
..and why I christened it elevation control ...and strictly speaking it isn't the right way to do it.....but I have to call it something..

rgds
VS

 

[Vipersan]

Hi friends ..
Its raining out ..but only light rain ..so been out fitting the new Jack/Arm
Settled for a more substantial Geotrack 12 inch ..
Ex display model ..that my local sat shop had in stock ..
It was the only one they had in ..so got it for a reduced price ..as technically ..it was a used item ..
;)
Took CH's advice and mounted it the other way up so that rain would not run backwards toward the motor ..
I now have better control and 'feel' the arm is under less tension at this angle ..
also the arm travel is more gradual ..and appears to give finer control over a larger spread of movement.

I've set the upper and lower (E/W) Limits ...and currently I can get approx about 20 degrees of movement ..so roughly 10 degree either side of optimum position.

Pics included showing the install ..and the limits ..
..
I'll have to touch up the paintwork on a nice warm day ...but currently my fingers are so cold I'm having a job typing this ...

Also included a picture of the completed and installed weatherproof Control box ..
Again this needs to be made more secure ...
..but not today ...I'm too cold now ..
That rain is almost sleet its so cold.
rgds all
VS

 

[sonnetpete]

Nice work and good to see it almost completed VS. Shame about the weather, I'll see if I can send some of ours LOL (clear blue sky and 15°C)

 

[Lazarus]

Thanks for the weather warning - we can expecgt it here in a couple of hours.


............................. Oh, and well done on the Sat stuff too

 

[Channel Hopper]

For somebody 'struggling', that was a really quick modification. well done.

 

[Vipersan]

Thanks m8's ..
Been in charge of the frying pan for the last 20 mins ...
Luvverly smell of bacon and mushrooms

..Stopped raining now I've finished the job ..
Typical..
..but its definately colder here today than of late.
You may get away with it Gordon ...as the rain was centered mostly over Manchester
rgds 2 all
VS

 

[Vipersan]

For somebody 'struggling', that was a really quick modification. well done.

Thanks CH ..
been sruggling for about a week now ..which is why I'm pushing myself to complete it asap ..
My hands are becoming less functional ..as they often do ..
I suspect I've pushed myself too hard recently.
rgds
VS

 

[Channel Hopper]

I suspect I've pushed myself too hard recently.

At least the hard work is almost done. A couple of quick snaps of the mods to fit the elevation motor on the H to H here.

 

[Huevos]

Huevos ..
I totally agree with you ...
..but this is a compromise ...
The polar mount was not designed with declination adjustment in mind ..
There isn't any way to implement motorized adjustment between the polar mount and the dish ..and since I can tweak the angle for any given point on the arc ..
..I'm happy with a compromise.

VS, I didn't do a very good job of explaining what I was getting at. What you are doing is at 180º (due South) you are changing the dish elevation, but at the extremes of the arc (just below the horizon) you are changing the LNB skew only rather than the elevation. At all points in between you are changing a varying combination of the two. That might mean, for example, that at 58ºW when you move the mount 10º in elevation that the dish is really only changing elevation by about 3º, but changing skew by 8 or 9º. Being a comprimise you have to balance somewhere between the correct elevation and the skew error, whereas if the second ram was controlling declination only the skew would always be correct (for satellites with 0º skew in relation to the equator) and only the elevation would change.

 

[Vipersan]

Hi friends ..just to prove how the system has improved ..
there is now enough signal to lock Fox sports HD ..on all three stbs @ 55W

Here is a quick cap of the ManU V Bolton game ..
taken with the AZ box ..which previously could not lock this channel..
rgds
VS

 

[Vipersan]

VS, I didn't do a very good job of explaining what I was getting at. What you are doing is at 180º (due South) you are changing the dish elevation, but at the extremes of the arc (just below the horizon) you are changing the LNB skew only rather than the elevation. At all points in between you are changing a varying combination of the two. That might mean, for example, that at 58ºW when you move the mount 10º in elevation that the dish is really only changing elevation by about 3º, but changing skew by 8 or 9º. Being a comprimise you have to balance somewhere between the correct elevation and the skew error, whereas if the second ram was controlling declination only the skew would always be correct (for satellites with 0º skew in relation to the equator) and only the elevation would change.

That makes perfect sense Huevos ..
Indeed its a bit of a fudge granted ...but since a compromise is all I can achieve ..
..I settle for that ..
Its only really about tweaking for fringe reception ...as there are few birds broadcasting anything useful from inclined birds anyway..
cheers m8
VS

 

[Lazarus]

Truly, a Phoenix has arisen from the Ashes.

You must be pretty chuffed, VS: 12 out of 10, methinks

 

[Vipersan]

Many thanks for the photos CH ..
certainly inspirational and gives me something to think about for future mods..
;)
rgds
VS

 

[Vipersan]

I shall be going quiet about 1:30 ...as I've aranged to have a massage at 2 ...
Gawd knows I need it ..


Seriously guys ...
Many thanks for all help received from everyone over the last month..
Its been quite a journey ..
..not neccessarily over yet ...but for now at least ....as Gordon says ..
The Phoenix has indeed risen..
rgds 2 all
VS

 

[Huevos]

since a compromise is all I can achieve ..
..I settle for that ..

Well the skew thing is only a problem on the handful of satellites that are linear polarised. For the rest of the bunch the skew is irrelevant.

 

[Vipersan]

Good morning peeps ..
Been busy logging optimum postions of maximum signal for various birds to assess how well I'm tracking the arc ..
Huevos ..perhaps you could give your opinion ..
Please discount skew changes etc ..and take into account that Express Am1 @40 East is inclined but is the only comparable bird I can pick up to balance NSS806 at 40.5 West ..

I've paired comparable birds at a few locations ...and of course taken a set of values for 1 west

The readings have been take at mid elevation (maximum signal) on the Echostar I'm using to drive the 'elevation' jack then I went outside to read as accurately as possible the actual reading off the dish scale on the side of the polar mount ..

This is the list ..
Sadly I can't get anything East of 40 degrees ..so cannot make a comparison for 55W and 58 W


------------------------
Intelsat 10-02 -0.8 West
Pentagon Channel

Mid scale echostar reading 1172
dish scale reads approx 53.5
------------------------
Intelsat 907 - 27.5 West
RTPI Africa
Mid scale echostar reading 1167
dish scale reads approx 53.0

&

Arabsat 5A 30.5 East
Ethiopia TV
Mid scale echostar reading 1159
dish scale reads approx 52.5

---------------------------------

NSS 806 - 40.5°W
MGM Venezuela
Mid scale echostar reading 1181
dish scale reads approx 53.6

&

Express AM1 40.0°E (incl. 0.8°)
Kultura 1
Mid scale echostar reading 1157
dish scale reads approx 52.4

---------------------

Looks to me to be tracking reasonably well ..but the arc may be slightly compromised ..possibly requiring a slight tweak on th polar offset ..
Not easy to get right this adjustment as its 1 single big hex bolt with no 'fine' adjustment..
It moves a little as its tightened up ..

Comments welcomed ..as usual.
rgds all
VS