How to install H-H crypt/stab motor ?

[nobbly]

I'm trying to install a H-H crypt/stab motor but I'm having a few problems.
The instructions are not very clear,quite normal. The problem starts as I follow the instructions.
First I have to set the angle of the motor, which in my case is about 49 deg. After I set the dish angle according to the chart, about 24 deg. (Sounds easy) If I set these angles according to the instructions my dish is poiting nearly straight up and of course at that angle I will never find any satellites.
Has anybody ever fitted a crypt/stab motor like mine ?

It seams like if I set the motor at 49 deg. my dish will have to have a negative angle to be able to work.

Never had this problem with my last motor but I had to change it as it was frezzing up in the winter.

nobbly :+

 

[rolfw]

[updated:LAST EDITED ON 16-Mar-02 AT 10:23 AM (GMT)]Hi Nobbly, DaveM from Satdudez and Phill's has edited this from a much earlier post (sorry, don't know who wrote the original), but it seems to cover it in a straightforward way.


"The first thing to do is make sure your main pole is perfectly vertical. Having done that, proceed as follows:

1. Position your mount to as near as you can by eye and compass, so that it is pointing directly due south at it's highest point (Usually zero on the scale).

2. There will be two adjustments for the elevation - and it's crucial you adjust the right ones at the right time. One is on the mount itself, determining the arc angle at which it tracks the heavens, and the other is on the dish. Look up (I think there's a utility at satcodx.com, certainly at http://www.smw.se/smwlink/smwlink3.zip ) the correct elevation for your location, and estimate the position on the adjuster *on the mount* (usually crudely marked and not always accurate).

3. Tune your receiver in to 1 degree west, preferably a weaker signal, and position your dish so as to get the best signal *without* adjusting the mount, but using the adjustment on the dish clamp.

4. Drive your dish, by operating the motor, around to a satellite well to the west, e.g. Hispasat. Adjust the elevation on the dish clamp so as to get the best signal. This may take some time, but DO NOT adjust the mount settings at this point, only the dish.

5. Drive the dish back to due south (1 degree west), and move *the mount itself* up or down back to the strongest signal.

6. Repeat steps 4 and 5. The adjustments needed at each point should get smaller, and after 2 or 3 tries you should need no further adjustment.

7. Test you have the arc correct by going to a satellite well round to the East, e.g. Astra2. If the dish elevation is correct, you've finished: if it is not, your pole is not vertical, straighten the pole and start again."

 

[wolsty]

Are you measuring angles from the horizontal or the vertical? If your dish is about 90 degs out (ie nearly vertical) it suggests to me that you're measuring from the wrong reference plane.

wolsty

 

[Satman]

Polar mounts are set up initially with the antenna facing the highest point of the visible geo-arc (true south in the northern hemisphere). In this 'apex' position the antenna can be driven by an equal amount to the east or to the west. The following general alignment guidelines apply:

A Adjust the polar elevation angle to peak signals from satellites located at or near the geo-arc's apex.
B Rotate the whole mount assembly around its mast or pillar when peaking signals from satellites far from the geo-arc's apex. That is to say trimming the north/south orientation.

Step Action
1 Obtain the modified polar mount angles for your latitude
2 Find the elevation angle of a convenient receivable satellite about 30 degrees from the geo-arc apex. Call this SAT-1.
3 Ensure the mounting pole or mast is vertical and set the antenna to its apex position facing due south. This corresponds to a true azimuth of 180 degrees in the northern hemisphere. If using a compass, remember to include magnetic variation for your location.
4 Set the polar elevation angle (or the equivalent polar axis angle whichever is the most convenient to measure).
5 Set the apex elevation, (or the equivalent apex declination). The small, declination offset angle is transparently set. If an offset focus antenna is used, subtract the offset angle from the apex elevation (or add to the apex declination).
6 Connect up a wideband signal strength meter to the LNB (for DIY you can use a live signal monitoring hook-up).
7 Monitoring the resultant dish elevation angle rotate the dish around the polar axis until it matches that computed for SAT-1. Hold this position and slowly rotate the whole assembly around its mast until maximum signal strength is obtained from SAT-1 and temporarily clamp. This trims up the north/south orientation of the antenna by exploiting the station keeping accuracy of SAT-1. Optimise the feed focal length at this stage.
8 Move the antenna back around the polar axis until signals are detected from a satellite close to the geo-arc apex. Call this SAT-2. Fine trim the polar elevation (or polar axis) for maximum signal strength from SAT-2.
9 Move the antenna back to SAT-1 and further trim for maximum signal strength by slightly rotating the whole assembly round its mast, thus trimming the north/south orientation as in 7.
10 Repeat steps 7 to 9 as often as required for consistently peaked signals from both satellites. It may be necessary to temporarily tighten adjuster bolts at each stage.
11 Check the received picture quality and tracking over a number of satellites and when satisfied fully tighten and grease adjuster bolts. Recheck signal strengths in case final tightening has affected alignment. Loss of signals from certain satellites may be due to a line-of-sight obstruction. Remember microwaves behave like light waves, they can't travel through walls

 

[wolsty]

You may think this a very silly question, but....................

Are you trying to mount it upside down?

wolsty

 

[nobbly]

[updated:LAST EDITED ON 17-Mar-02 AT 11:22 AM (GMT)]It's not a silly question.I'm sure its fitted the correct way up. There is a picture with the instructions to help installation.
It's hard to explain but imagine first setting the motor to about 49 deg. The motor arm is infact a moving pole that you attach the dish to.(so it's like attaching your dish to a fixed pole set at 49 deg) This means when I set the angle of the dish to about 24 deg the total of the 2 angles is about 73 deg. surely this is too much. But that's what the instructions say.
At the moment it's sort of working but its not set correctly.To even get a picture I had to set the motor at 30 deg and the dish at 0 deg. This makes sense as the total of the 2 angles is about 30 deg.
The angle of the dish in the picture of the instructions looks like it's an angle less than 0.

I'm confused...

Look at this page :
http://www.geosat.fr/images/seva.h2.gif
See the angle of the motor and of the dish .
Is it me or is the angle of the dish less that 0 deg.




nobbly :+

 

[rolfw]

Hi Nobbly, I can't see what the readings on the scale are on the mount, but it would appear that the correct setting would be fairly close to where it is set on the web page. I would be inclined to set it at what you think it should be and then almost ignoring any scale on the dish itself, set the dish to 1W and then try moving across to say 13E and see if you can get a signal.

I haven't installed that particular mount, so I'm not sure about the settings.

Rolf

 

[wolsty]

Inclination is the angle between the horizontal and the axis of rotation. Declination is the angle between the axis of rotation and the dish mounting. According to my data. The angle of rotation is in the 40 deg plus range for the UK. The declination seems to depend on the configuration of the dish and the latitude, but on my setup is about 38 degrees.

You can see, from the attached picture of my own setup, the reason why I asked if your mount was upside down!

I've scanned into 4 JPEG files an article called 'Get Motor-vated 'from Better Satellite, Spring 2001. It deals with the issue of stting up an h to h mount. I tried to upload them with this note, but even one file seems to large to be accepted. If anyone wants copies, PM me your e-mail address and I'll send them to you.

wolsty