Strange Results Between Two Diffewrent DIshes

[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?

 

[phpinfo]

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.

 

[skysurfer]

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).

 

[AcWxRadar]

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

 

[delta_charlie]

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

 

[McGuyver]

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.

 

[SatelliteAV]

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.

 

[Lak7]

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

 

[B.J.]

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.

 

[Othea]

WS9036

I had the same symptom with my new WS9036. The dish is sturdy and the packaging for shipping is excellent (best on the market in my opinion). I concluded that mine was not warped.

My problem was focal length: the specs at the website did not match those of my newly assembled dish. I had to remove the two lateral support arms and bend them slightly so that the lnbf would be about 1 inch closer to the reflector dish. That solved my problem and its reception now seems to be slightly better than the Fortec 36-inch.

My suspicion is that the support arms on the most recent batch of WS9036 dishes are about 1/2-inch too long; or the holes were drilled just a tad off. Regardless -- I'm not complaining at all. I am very pleased with the quality of the product. It just needed a little unconventional adjusting.

Two tips: (a) check to see if your lnbf is already flush against the lnfb holder; (b) measure your focal depth from dish to plastic cover of your lnbf.

 

[delta_charlie]

Hi all, if anybody wants to compare the LNB support arms and focal point here are some pictures of my WS9036. I think mine is spot on as I checked the LNB when I first installed the dish by moving it in and out in a loose bracket while listening to the audio meter on my receiver and could not tell any difference when peaked on a satellite. The signal quality has been as high as 85 on my Mercury II (breakup is below 30 on this receiver) The picture of the LNB arm is showing the center to center of the mounting bolts measurements. On the picture of the LNB the tape goes to the face of the top left bolt.

Please post a follow up if anybody finds a difference on there dish.

Thanks, DC

 

[Othea]

Yes, the website states 24 inches; that's 25 inches as you measured it from the upper bolt. That's what I have now.

 

[B.J.]

Yes, the website states 24 inches; that's 25 inches as you measured it from the upper bolt. That's what I have now.

The website states that the focal length is 24". Is that what you're referring to? The measurement pictured in the 2nd and 3rd picture above does not represent the focal length. That would be measured to some point near the bottom of the dish, near where the lower LNBF arm attaches. Actually, there is no universal way to know where to measure this, as there is a good chance that it may not be a point on the dish, but instead a point just off the dish, however measuring to the bottom of the dish is pretty close. Ideally, it WOULD be a point off the dish, since the goal is not to have the LNBF block any of the signal, and if the center of the parabola is actually on the dish, then you'll be blocking signal.
The measurement to the center of the dish is really meaningless, other than for comparing one dish to another, and it SHOULD be greater than the focal length.

 

[Othea]

24-inch focal depth

Thanks for your comments, BJ. My measurements are the same as what delta_charlie has photographed, and that's the optimal setting for me too. The distance from the upper bolt (as in delta_charlie's picture) is 25 inches. The distance from a central point in the middle of all four bolts is 24 inches.

 

[pjcl]

Hey, when I was first installing my WS9036, I was using a Spitfire LNB, and I couldn't get any signal. I switched back to the LNB that came with the dish, and picked signal right up. The design of the Spitfire does not allow for adjustment in terms of the distance from the reflector pan, because the indent on it is the exact size of the bracket holding it. On the original LNB, however, there is room for adjustment, and I was successful when I pushed the LNB all the way towards the dish. I still have to experiment, now that I know signal is there, to switch back to the Spitfire and see what happens. I'm also curious to see what the focal point measurements on my mount will tell...