Thread: Strange Results Between Two Diffewrent DIshes

Recently purchased a WS9036 99cm dish and had strange results with it. No matter what i did with it it would not track the arc. I take the WS Spitfire Linear LNBF off the new dish and replace the Universal LNBF on my old Fortec Star 33" dish wwith it and remount my older 33" dish, line up the settings like i had them before and my signal readings are pegging the meter. I'm dumbfounded. Why would a 33" dish perform better than a 36" dish? Has anyone else had dimilar results between the two dishes?

I am not familiar with the dish, but I do know that dish design can make a difference. Specifically for quality, but I have not seen so much with arc tracking. Unless it is really warped.

I know if you compare most older Channel Master dishes with less name dishes or newer dishes, the Channel Master will give much higher quality.

So it could be a flawed dish mold or warped etc. Just throwing out some thoughts.

It could also be the way it is mounted and installed.

I totally agree dish design is very important. The Fortec dishes are pretty flawed - I had to devise and carry out a few mods to make the 90cm and 120cm perform great.

I bet the dish in the original posting might have some design issue that a mod could make it perform better (especially if attaching a LNB pulls the LNB support structure/LNB out of the focal point of the dish).

Here is one possibility... Your focal position of the LNBF is way off.

I would investigate the focal distance of the LNBF to the dish. Consult with someone here who has the same dish or with the manufacuter to determine what it SHOULD be, then measure yours. If it isn't really close, then this could be your problem.

It could simply be that you have attached the support arms at the wrong points, the mountin holes were set in the wrong positions from the factory, or possibly the supporting rods are not the proper length.

Here is another possibility... Your dish elevation is incorrect. Either the scale is not marked properly (maybe it wasn't stamped right at the factory) or you are using the wrong angle for this dish model.

Other items could be at fault, too, but I think I would check these for sure.

RADAR

Originally Posted by milepost72

Recently purchased a WS9036 99cm dish and had strange results with it. No matter what i did with it it would not track the arc. I take the WS Spitfire Linear LNBF off the new dish and replace the Universal LNBF on my old Fortec Star 33" dish wwith it and remount my older 33" dish, line up the settings like i had them before and my signal readings are pegging the meter. I'm dumbfounded. Why would a 33" dish perform better than a 36" dish? Has anyone else had dimilar results between the two dishes?

Hi, when I installed my WS9036 I noticed there was no mention in the instructions on how to align the dish mount to the motor axis. On my Fortec dish there is a bolt in the top of the mount that goes into the upper hole in the motor axis and locks it in place. The WS9036 does not have this bolt and I think it would be easy to mount it out of alignment and if this was done the dish would not track the arc. I ended up using a long rod to sight the alignment and to make sure the dish mount was 90 degrees to the rod. I even double checked using a index card (my speed square would not fit) to make sure it was spot on at 90 degrees.

My WS9036 is tracking the arc fine. Hope the pictures below help, DC

Edit --- Radar made a good point on the focal point. Let me know if you need some pictures of the LNB mount and arms. DC

If I may add, the offset angle of both dishes are different as follows;

Fortec Star FC80CM 32" = 22.75° offset angle

WSI WS9036 = 24.62° offset angle

The difference of these offset angles may be the issue, if I'm correct, the motor elevation should be compensated in relation to the dish offset angles, therefore the motor elevation might have to be adjusted to accomodate the WS9036 dish. I may stand corrected but check it out.

Originally Posted by McGuyver

Snip>>>> if I'm correct, the motor elevation should be compensated in relation to the dish offset angles, therefore the motor elevation might have to be adjusted to accomodate the WS9036 dish. I may stand corrected but check it out.

This is not correct. Leave the motor elevation angle set to the same position. The motor remains set to match your location latitude.

Are you finding that the dish needs to be motored east or west to peak the signal when mounting the WS9036? If so, I agree with the posts suggestion that the LNBF mount may not be positioned correctly. The misplacement could be horizontally or vertically. If the LNBF arms are not correctly placing the LNBF in the exact position, the dish will be unable to accurately track the arc. I might add that the reflector could be bent or warped causing the signals to not relect to the sweet spot to be gathered by the LNBF.

If is this is just a situation where the larger dish is not performing as well in a fixed position, dishes and LNBFs are not always matched and dishes do not always provide gains with increased size if the reflector is damaged, or reduced performance due to design and production issues related to an aging press or mould.

Give the Dish a quick String Test, see if it's a little warped.

A couple additional comments.
First of all, I notice that the 1st post says that the problem is tracking the arc, and not that you can't get better reception on a single sat, like the south sat?
A bigger dish will have a narrower beam width, and you need to be more accurate in your alignment. The smaller dish may not have really been tracking the arc, it may have just been that the wider beamwidth made you THINK it was tracking the arc.
Also, the 1st post seems to suggest that you didn't go through the alignment process with the new dish, but just expected the old settings to be the same. SatAV is correct that you shouldn't need to change the motor elevation, provided that it was set correctly in the first place, but many don't set the motor elevation properly, and with a smaller dish the error may not be noticed.
Also, as someone mentioned above, Fortec dishes seem to be of rather poor quality with respect to the lnbf being at the actual focal point. On my Fortec dish, I found that the focal point was about 2" away from where the LNBF holder put the LNBF. This could end up having you mis-align the old dish with respect to both declination AND with respect to the apparent azimuth, ie mount on pole aiming south. Again, if you ended upchosing the best compromise between south and extreme sats, the smaller dish may not have noticed the difference.
Ie you really should have started over and align the new dish from scratch. If you were VERY careful with the motor elevation, and used the modified tables, then you can leave that the same, but I'd recommend not trusting any other setting, particularly the azimuth adjustment of rotating the whole mount on the pole.
If it still can't get good results, then I'd suggest that you try an experiment that I did a couple times, by putting a bunch of little mirrors on the dish surface, and aim the dish at the sun, to see if the spots focus on the mouth of your lnbf. Like I said, when I did this, the true focal point was off by 2" on my Fortec, and I know of a fellow over on the Sadoun site whose Fortec's lnbf holder was off by about 8". Since these WS dishes have 3 arms, they are not likely to be off, but if your alignment was affected by the original Fortec dish being off, then you can't expect to just put the new dish on, and expect it to work.