pulling my hair out aligning dish

[Techfizzle]

low signal that cuts in and out

 

[Techfizzle]

well since you "randomly" picked two satellites on the western arc for you how about eastern?

try EWTN on G11
This TV or TVU on 87W

you mention NASA is "horrible"...define horrible
-low signal so it cuts in and out?
-no signal?
-lower signal?

Heck on my 4 footer I locked NASA at 31 which is just above threshold and it worked fine with no breakups for almost an hour that day I watched it
last pic in thread
http://www.satelliteguys.us/1800641-post4.html

the only channel i can get to come in on the h-side of 87 is a channel mvs-better level 69-70 quailty 59-60

il try to get this tv ina minute

EDIT i locked it it level 71 quaility 89-90

i also got the unemployment channel at level 70 quaility 44-48

 

[Kb Cool]

the only channel i can get to come in on the h-side of 87 is a channel mvs-better level 69-70 quailty 59-60

il try to get this tv ina minute

EDIT i locked it it level 71 quaility 89-90

i also got the unemployment channel at level 70 quaility 44-48

At the beginning of this thread. Somebody posted some great info. Inside there is a diagram called "philosophy of tuning dish to satellite arc". Did you even look at it?

 

[Techfizzle]

im thinking its tracking good, just that some of those transponders are weak

 

[tvropro]

im thinking its tracking good, just that some of those transponders are weak

A 10 foot dish properly aligned should do quite well with the whole arc. You cannot cut corners when aligning and expect good results.

 

[Cadsulfide]

A 10 foot dish properly aligned should do quite well with the whole arc. You cannot cut corners when aligning and expect good results.

Amen!

 

[Phottoman]

Hasn't that been said several times in several ways?

Did you ever REPLUMB the pole? If not, there in lays MOST of your problems, no matter HOW you talk yourself into believing (or trying to convince others) that anything LESS than plumb is OK.

I've noticed techfizzie, that you ask questions, get answers that you don't like and avoid answering other's questions designed to help you. Is this standard? Avoid what you don't want to hear and go on with what you think is right, disregarding other's attempts to help you?

I'm not flaming, I'm asking so I can learn from you how to go about life, without taking serious account of what others tell me, and wondering why it "works sometimes, other times not," and why your WHOLE arc isn't coming in booming.

Photto

 

[turbosat]

photto, thats why they call it the "turbulent teens"
DO it MY way.

Anyway, he'll learn..growth takes time.
btw NASA comes in like a high wind on AMC7 on my little 10'Sami. Wish I would adjust the motor so it could go over east far enough to check AMC6 NASA with it.

 

[Lak7]

thats why they call it the "turbulent teens"
DO it MY way.

Yep, my kids are like that too, 6 and 3 years old

 

[Techfizzle]

This i have said twice-----> I dont care how plumb the pole is, there is a gap in the mount making a quarter inch gap on the pole. Even if I level the pole, the mount would still be unlevel, the pole is level east and west. So I leveled the mount on the pole. The analog channels come in booming, only one or two stations have sparkles on them.


The lnb is over twenty years old, and is a 25 degree. So im thinking the lnb is not that great with digital reception


if i point it on a sat say Amc 4 on 101, and move the dish up, down and left and right, and the picture doesnt get any better, then its the lnb. If i move it to another satellite 30 degrees away, and the picture is the same, the arc is being tracked, because after moving the dish up, down, left, and right, and it doesnt improve, then its the lnb, I peaked the dish by hand on over 4 satellites, and like i said the picture is good.. ON ANALOG, but not digital, so im blaming the lnb

its the same principle as if i moved an ota antenna and pointed it right at the station, and the picture is bad, its the receiving elements of the antenna

people call that a dish antenna, witch is improper, the dish part is a satellite reflector, the dish itself does not act as an antenna, it just reflects the signal to the lnb, the metal wire inside the lnb, is the antenna

I could have the best satellite dish in the world, like a birdview, but if the lnb is outdated, it wont work to well with digital reception.

I like my dish, while depeer dishes such as the winegard pinacle, have better control over adjacent satellites, but dont have good gain, the deeper you go, the less gain you have

this dish is somewhat shallow, so it shoud have good gain, so im pointing my finger at the lnb, because i get about the same ammount of signal on ananlog on all satellites, so my arc is tracking

 

[Mr Tony]

The lnb is over twenty years old, and is a 25 degree. So im thinking the lnb is not that great with digital reception

incorrect answer....some of the older units work great. I have a old 25K LNB and it got me better reception than my old ASC421 LNB on some of the weaker TP's

 

[Pismire]

I agree with Ice..I have a bucketfull of old lnb's ALL of them can bring in the digital no problem. I hope no one throws you away when you are 25. Give it a break and play with it. It will all come in time. Have fun with your hobby, that's what it's about. At least for me.

Damn I though we were gonna have a fizzle free evening.

 

[B.J.]

.....
its the same principle as if i moved an ota antenna and pointed it right at the station, and the picture is bad, its the receiving elements of the antenna

people call that a dish antenna, witch is improper, the dish part is a satellite reflector, the dish itself does not act as an antenna, it just reflects the signal to the lnb, the metal wire inside the lnb, is the antenna

Yeah, it's a reflector, but the reflector is still part of the antenna. The OTA antenna you refer to is made up of dozens of elements, including director, and reflector elements, and "driven" elements. With a C-band system, the probe inside the feedhorn would be referred to as the driven element, and the dish itself as the reflector element. It IS proper to refer to a dish as an antenna. I have a book on antenna theory, and there is a whole chapter on parabolic dish antennas.

I could have the best satellite dish in the world, like a birdview, but if the lnb is outdated, it wont work to well with digital reception.

I agree with the other responses, that the lnb is probably not the problem. If you get analog.

I like my dish, while depeer dishes such as the winegard pinacle, have better control over adjacent satellites, but dont have good gain, the deeper you go, the less gain you have

, ...

This issue has always confused me.
All the equations I've ever seen relate gain to only 2 parameters, the freq and the diameter of the dish. I've never seen an equation in which F/D was related to gain. Also, re the resolution or beamwidth, your control over adjacent satellites thing, the equations I've seen relate that only to gain, ie basically the more gain, the more narrow the pattern of the antenna.
I have owned both a high F/D and a low F/D BUD, and never noticed much difference with respect to gain, at least on C-band. Relative to adjacent sat resolution, the shallow dish seemed to be better, however when I had that dish, all the sats were separated by 3 degrees, so it wasn't as much of an issue back then.
The one big difference I've noticed relative to deep vs shallow dishes, is that with a deep dish, the feedhorn has a harder time illuminating the entire dish, particularly on Ku. My CoRotor only sees about 1/3 of my deep dish BUD on Ku. Basically, it's hard for reflections from the edges of a deep dish to get into the feedhorn. The scalar rings help in this respect for C-band, but I don't think they have much effect on Ku. My old shallow dish BUD was pretty good on Ku.
I think the main advantage of deep dishes is elimination of ground noise, but I think I'd prefer to have my whole dish illuminated and give up a bit of S/N to ground noise.
Anyway, it's always seemed strange to me that the equations don't seem to relate resolution to F/D. It seems intuitive that a shallow (long FL) dish would be better for resolution, since this would be analogous to a long FL camera lens or telescope, where your field of view is very narrow, compared to a short FL lens, which virtually would see the whole sky. Comparing again to a camera or telescope, a low F/D lens generally lets in more light than a high F/D lens.
I think that part of the problem comparing a sat dish to a camera or telescope, however is that generally with a camera or telescope, you are looking for light from the entire field of view, whereas with a sat dish, we're only concerned with a point source, ie the one satellite we're looking for. I think the light gathering advantage of a low F/D lens is lost if we're just looking at a point source within the field of view. I'm thinking that this might be the reason that the gain from a point source is only related to the overall diameter or area of a dish. And the apparent advantages or disadvantages of shallow vs deep dishes with respect to gain are probably all related to the feedhorn illumination issues. Having said that though, it still seems intuitive that a long FL dish should be better for resolution, but I am at a loss for an explanation.
Interesting topic, ie comparison of sat dishes to cameras and telescopes and the point source vs whole field of view issues.

 

[Lak7]

Google "deep vs shallow dish" you will find the answers.

 

[turbosat]

You can have a $400 lnb and STILL not get every channel perfectly, analog or digital. It's just a fact of life. It's possible to improve some signals with a newer lnb or one with lower noise ratings, but the stability figure is prob just as important as the noise figure number. The tracking of the dish, lnb focal distance, feedhorn centering, surface inaccuracies of the 'reflector', terrestrial interference and other factors come into play.

 

[B.J.]

Google "deep vs shallow dish" you will find the answers.

Oh I have, and have never found anything explaining any relationship between gain or resolution and F/D ratio or FL. Every equation I've ever seen for gain and resolution says that there is no relationship.
One example is :

G= 10 log ( k * ( Pi * D / WL)**2 ) { WL=wavelength, D=dish diameter, k= efficiency}
And
Beamwidth= 70 * WL/ D { I've also seen this expressed as a function of gain}

Ie the only parameters besides dish size and frequency is this so called efficiency factor, which I have to assume must be related to the feed illumination, but the text I got the above from suggests that it is usually about .55 , so it's apparently not FL related.

I do, intuitively believe that there IS a relationship, however I have never found reference to one.

 

[pendragon]

I like my dish, while depeer dishes such as the winegard pinacle, have better control over adjacent satellites, but dont have good gain, the deeper you go, the less gain you have

This is part of a common misconception. What is critical for receive-only dishes is SNR, not gain. Gain is part of SNR, but so is noise rejection. Radio astronomers employ deep dishes because their noise rejection is higher than with shallow dishes. All things being equal, we should do the same.

However shallow dishes are easier and cheaper to make. A feed designed to match a shallow dish will only illuminate the center portion of a deep dish. Hence the illusion that deep dishes have lower gain. Unfortunately there are very few FTA feeds that perfectly match deep dishes. The scalar ring design is wrong and normally cannot be pulled far enough back. If you look at the theory of feed design, one can achieve almost the same gain out of deep dish as a shallow. Coupled with the better noise rejection, the result can be exceptional.

 

[B.J.]

This is part of a common misconception. What is critical for receive-only dishes is SNR, not gain. Gain is part of SNR, but so is noise rejection. Radio astronomers employ deep dishes because their noise rejection is higher than with shallow dishes. All things being equal, we should do the same.

However shallow dishes are easier and cheaper to make. A feed designed to match a shallow dish will only illuminate the center portion of a deep dish. Hence the illusion that deep dishes have lower gain. Unfortunately there are very few FTA feeds that perfectly match deep dishes. The scalar ring design is wrong and normally cannot be pulled far enough back. If you look at the theory of feed design, one can achieve almost the same gain out of deep dish as a shallow. Coupled with the better noise rejection, the result can be exceptional.

Would I be correct in assuming that the scalar rings on the C/Ku feedhorns are only effective on C-band?

 

[pendragon]

Would I be correct in assuming that the scalar rings on the C/Ku feedhorns are only effective on C-band?

Pretty much, a Ku scalar ring needs channels much closer together and is less deep (everything scales by wavelength). There will be some effect from the C-band rings on Ku, not all good and not all bad. I haven't looked at it, but its possible the C-band mouth surrounding the Ku-band mouth acts a bit like a scalar ring.

I confess I had hoped to achieve better performance with my dual ortho feed on my deep dish. I was able to modify the feed to improve performance on C-band so that it is close to optimal. I might be able to improve this a bit more, but the Ku performance is so disappointing that I doubt I can match both C and Ku at the same time. When I put up the 3 m, I went dual ortho because I thought this would be the only FTA dish we would need. I was dead wrong. Now I am considering moving the dual ortho to another dish and putting together a "take no prisoners" C-band only ortho for the deep dish.

 

[Techfizzle]

this lnb im am using, doesnt have a scalar. it has some dipole looking thing inisde of it

EDIT

I have a standard c band lnbf, the antenna probe is bent on the top of the s, will this hurt?