[tweaked]

I'm finding the almost countless Ka/Ku dish alignment discussions posted at this forum so interesting to read. I don't know if it's because I'm not 100% satisfied with my Slimline's numbers or it's something deeper. The science and methods behind the aiming process is easy to understand.

I've got zero problems with my reception. I won’t go into particulars but none of the TP’s are showing numbers >70 (the lowest numbers are off sat’s 99(c) and 103(c)). 101 is in the mid 80’s to 90’s.

Here’s my dilemma (aka, obsession).

The best I’m able to peak 99 or 103 is 85 with most TP’s in the 75-80 range. If I didn’t know me real well, I’d say (to me), “Get a grip man, leave it alone!” Well, I can’t (that's the obsession part ). Here’s a twist…

The dish that was installed wasn’t included on the work order. My upgrade only included an HD DVR, not the dish. That was quickly resolved when a new work order was issued. The guy just happened to have an already assembled Slimline in the back of his pickup, loosely piled amongst other (very unorganized), loose hardware. It looked as if everything was just tossed onto the bed of his unlined pckup. The dish he pulled out had several scratches on the reflector but it didn’t appear to have any noticeable dings or obvious damage… I could have lived with that. I have a feeling however that the dish might have been used; if that was the case, no problem (it‘s not like I purchased it). The issue is, it might be damaged (“might” being the operative word).

You alignment specialists, see if this makes any sense:

I realigned from scratch… coarse settings on 101, tilt on 119, peaking 101, peaking 99(c)… the whole drill (plumb, plumb, plumb). I arrived at the ‘satisfactory’ numbers I’m now seeing. What I don’t understand and it may just be insignificant is this: The tilt for my area is supposed to be 113 degrees. On my dish, peak numbers off 119 (when adjusting for tilt) require a setting of 110 degrees, not 113. I would think a deviation of three degrees from what’s specified could be an indicator that something’s off with respect to my Slimline’s geometry i.e., a troubled dish. Possible?

 

[Mertzen]

You're focusing too too much on the tilt#. On slimlines it barely matters.

 

[davring]

I don't know how easily the dish could be bent, twisted or otherwise distorted, but the numbers that are on those stamped steel brackets are really only for reference, to get you in the ballpark. They certainly are not accurate like the scales on an expensive telescope or a surveyors tripod.

 

[eakes]

I think you may be over-adjusting. Starting with the mast being plumb (I am sure it is, but had to say that), set elevation and tilt to spec based on your zip code. Now adjust az and el for max on 101. Check 119, if the numbers there are similar to those on 101 do not adjust tilt. Now do the fine az and el adjustments on 99/103.

It is possible for a dish to be damaged and not be detected by the naked eye. Usual damage would 'flatten' or warp (twist) the surface of the dish. To effect tilt the feedhorn arm would need to be physically twisted, that is not likely although possible. If the dish surface is distorted that could effect alignment and would be expected to provide less gain (lower signal numbers) than 'normal'. A slight distortion could change gain characteristics greatly but would be vitually undetectable to the untrained eye.

 

[K4SMX]

Exactly what model receiver do you have?

 

[flipptyfloppity]

I would say some combination of Mertzen and eakes' answers.

119 is a very "wide" signal. It can tolerate a misaim far more than the 99 and 103s can. So I wouldn't adjust the tilt from recommended for 119. Adjust azimuth and elevation to peak the 119. Lock the tilt at the recommended figure and then tweak to get 99 and 103s. Make sure you're happy with that, then recheck 101.

After all that, check your numbers. If you think you can do better on 119 and if you are feeling really crazy, try fiddling the tilt. Peak 119, then recheck and see if 99 and 103 are about the same. If 99 and 103 have gone to pot, return the tilt to the recommended value and live with the results. If you decide you like the new tilt better, go around on the azimuth and tilt on 99 and 103 again and see if you can get them back to what they were before you readjusted the tilt or higher. If you can't, then return the tilt back to recommended and readjust 99 and 103 again. Otherwise, stick with the new tilt and you're done.

In the end, it's okay to be a little lower on 119 than 99 and 103 because 119 is more tolerant of misaim and rain fade, so weather and such is less likely to reduce even a low 119 signal to an intolerable level than it is to take an 80s 99 or 103 down to an intolerable level.

Could you have a warped dish? Yeah, I suppose so. But if you're gonna blame that, make sure you check the arm and the connection of the LNBs to the arm too to make sure those aren't messed.

 

[bobnielsen]

Three degrees tilt offset is not the same as three degrees (Az or El) pointing error. Tilt is used to line up the dish to the orbital plane. It has no effect on 101, a very slight effect on 99 and 103, more on 110 and even more on 119. Just peak the tilt for 119 and forget it.

 

[tkrandall]

Even though 99 and 103 are close to 101 and tilt would not seem to matter much, tilt being off (or maybe mast not plumb) would seem like the only geometric cause to get non equivalent results for 103c and 99c. Before I realigned my dish (turns out my mast was not quite plumb - just a bit off left to right) I tried drawing out scenarios on paper to determine geometric alignment possiblities, and the only explanation for unequal 99 and 103 I could come up with was if the tilt plane was off, with the dish pretty close to peak on the 103 signal, close engouh for the wider 101 and 119 Ku beams, but off just enough on 99 for it to be 10 points weaker in my case. I was able to improve 103 by 10 points, and 99 by 20 points and they are not basically equal in the low to mid 90s for the most part.

 

[tweaked]

Thanks everone. I get it; tilt's not that critical an issue in the overall aiming process. My only observation and question with respect to tilt had to do with whether or not the 3 degree variation from specification "might" be an indicator of an underlying dish component or structural issue.

Put simply, my current alignment's providing the best numbers possible from this particular dish. If that's assumed, that begs the question, is the necessary offset in tilt of any significance? That's a rhetorical question as I've decided to just be happy with 'not bad' and enjoy the weekend.

 

[K4SMX]

The reason I asked you the question at post #5 is that we have found that HR21-100's frequently read 5-10 points lower than other HR's on 99(c) and 103(c). Do you have that receiver or another?

 

[iluvtv]

i couldn't get over 75 on 99 or 103 even though 101 had good readings, i then pushed with my thumb on one of the outside edges of my dish and the 99 and 103 signals went up to 85, in other words my dish was warped, i then put one hand in the middle of the dish and with the other grabbed the outside of the dish and gently rocked the dish until it stayed in the position i wanted now all my readings vary from 82-96.

 

[tweaked]

The reason I asked you the question at post #5 is that we have found that HR21-100's frequently read 5-10 points lower than other HR's on 99(c) and 103(c). Do you have that receiver or another?

Sorry I missed your post (and thanks).

I do have the HR21-100. It was a replacement for an HR21-200 which had a defective HDMI port. I'll have to go back and compare readings I was getting off that receiver with the *100 I'm currently using.

FWIW... I was contacted today by a DTV "case management" person and explained to them that I was having reception issues with my Slimline, those noted in my earlier posts. I tried my best to have them send me out a replacement, one that I'd install myself and I'd send back the dish I've been using (if necessary). I honestly didn't think that would fly and sure as heck, it didn't.

A specialized, 'advanced' tech from Montana Satellite Co. (I guess they're filling in for Ironwood) is scheduled to come out to my house this Sunday and see what he (or she) can do. I've got the feeling that unless I deliberately throw the dish off just enough to make 99 and 103 look really terrible, nothing will be resolved as far as a dish replacement's concerned. If I were to do that, they'd simply hook up their Birdog or other meter, attempt to peak 101 and at best, end up with numbers that are no higher than the ones I was able to achieve and leave it at that. If that's how it turns out, that's okay… I'll live with it.

 

[K4SMX]

It would probably be worth your peace of mind just to buy yourself a new Slimline. You could then use your old dish for a spare LNB, a nice thing to have on hand. Too bad it wouldn't be there by tomorrow's appointment.....

 

[tweaked]

It would probably be worth your peace of mind just to buy yourself a new Slimline. You could then use your old dish for a spare LNB, a nice thing to have on hand. Too bad it wouldn't be there by tomorrow's appointment.....

I hate to think of myself as a squeaky wheel but...

D* agreed to allow me to receive and install an AU9 Slimline dish which is scheduled to be delivered this upcoming Monday, August 25. D*'s Case Management support folk wrote up a work order which instructs Ironwood to allow for customer install. Those instructions will most likely need to be confirmed by the tech when they arrive as it's not an everday transaction.

The way I see it: I get a new dish, it gets installed correctly, it frees up the tech, Ironwood gets paid... it's a win-win.