How wide is the microwave signal coming from space?

[rcdallas]

I am curious as to how wide and tall the signals are coming from the satellites.

The reason I ask is because I recently picked up a suunto clinometer to check my azimuth and elevation with precision.

In my area a standard D500 (119/110) azimuth at 227, elevation 33.

Dish 300 pointed at 110 azimuth is 222 while Dish 300 at 119 is 233, elevation various between the two obviously.

Lets say I was working a Dish 300 focused on the 119 at 233, how wide is the microwave? 1 degree? If I had clear LOS at 233 but not at 234, would I get signal? Would certain transponders be cut off or lower signal pushing the limits like this?

Same thing applies to how tall is the microwave, if my elevation is 31, I had clear LOS at 31 and no LOS at 30, would I get signal?

I'm just trying to get a better understanding so I can take my job with extreme precision and accuracy.

Thank you in advance.

 

[micklewhite]

I don't think you are asking the right question for the answer you are seeking but since Ku band is 10.7-12.7 GHz (roughly) the wavelength will be about 2.8 cm (at 10.7) to 2.36 cm (at 12.7). Since the signal expands infinitely (with polarization considered) it is more of a question of how good of a signal is needed to receive programming and how best to align your dish on the the signal. Since the strength of the signal is very, very small (probably a billionth of a volt), alignment is crucial with a small dish. It really doesn't matter what the recommended AZ/EL is. Those are starting points. Whatever gives you the best reception is what you go with. I don't think more precision in your aiming will make much difference since the stated figures are for a area not a point. An engineer can probably calculate what the beamwidth at the minimum required level is but that is an academic exercise that won't help you. Just get a small TV and attach a piece of coax, since it is likely you will have to reaim after extremely strong winds or having someone or something bump the dish.

I am curious as to how wide and tall the signals are coming from the satellites.

The reason I ask is because I recently picked up a suunto clinometer to check my azimuth and elevation with precision.

In my area a standard D500 (119/110) azimuth at 227, elevation 33.

Dish 300 pointed at 110 azimuth is 222 while Dish 300 at 119 is 233, elevation various between the two obviously.

Lets say I was working a Dish 300 focused on the 119 at 233, how wide is the microwave? 1 degree? If I had clear LOS at 233 but not at 234, would I get signal? Would certain transponders be cut off or lower signal pushing the limits like this?

Same thing applies to how tall is the microwave, if my elevation is 31, I had clear LOS at 31 and no LOS at 30, would I get signal?

I'm just trying to get a better understanding so I can take my job with extreme precision and accuracy.

Thank you in advance.

 

[SmityWhity]

It's been at least 20 years since I last computed a wavelength, but using the above calculations, 2.54cm would mean an antenna the length of 1 full wavelength would be about 1" long. Not very long. Where as a full wave length of a CB signal would be about 11 meters +/- (or about 33-35 feet).

The length/size of a degree would vary depending on the size of the sphere.

I believe 1 degree equals a little more than 69 statue miles at the Earth's equator, and the distance from about 110West to about 119West would be about 622 statue miles. However, way out in space - about 22,250 miles, 1 degree around Clarke's belt would be somewhat more.

Back to Earth.

The circumference of a 1 5/8" (1.625") Dish 500 mast pipe would be about 5.1" making 1 degree equal about 0.014" (lilttle more than 1/100").
Hmmm... Then 9 degrees would be about 0.1276" or a (red) hair more than 1/8" movement on a Dish 500 mast.

Putting all the jokes to the side, "It's always good to see someone interested in learning to do their job correctly, and the best possible.

Lets say I was working a Dish 300 focused on the 119 at 233, how wide is the microwave? 1 degree? If I had clear LOS at 233 but not at 234, would I get signal? Would certain transponders be cut off or lower signal pushing the limits like this?

Also, you bring up a good point about being able to receive all transponders. The satellites aren't very big, but there are multiple antennas, which are slightly apart and with some broadcasting at angles.

I have a Dish 500 with single LNBF on an I-bracket, set inside of a balcony pointed between overhangs and nearby roofs. I am able to pick up the transponders with fairly good signals, but am unable to pick-up one of the spotbeam transponders. Adjusting azimuth and elevation did no good. I'm sure if I moved the complete mount over to the east a little, I would pick up all transponders, but that would interfere with my SuperDish.

Keep up the good work.

SW
A mind is a terrible thing to waste.

PS - If my math is wrong, it was based on Louisiana math.

 

[Liquidforce88]

rcdallas

This is the way I teach our new guys to use the suunto clinometer.

First off your sats are going to be about 9* apart. So if you know where the sats should be, you know you need a window atleast that wide to get the dish in. I would not put a dish in a window that small though, would like to have atleast a couple degrees of area on each side to work with. If you have an area that is just to samll for the dish 500, or just barely wide enough, switch to a 2 dish solution if the customer is ok with it.

Also the suunto clinometer can be pulled off. So if you are working with a small window you want to make sure that there is nothing pulling that thing off. To do this go to the area where the obstuction is then look at the spot where you want to put the dish. You should see 2 numbers, the big one on the bottom is the direction you are looking, the small one on the top is 180*. This way you can make sure your reading is true.

Elivation is pretty simple you just need to know where the sat is in the sky. Just remeber that the sat does not really stay in one place unmoving. It does move a small bit in a figure 8 motion. So if your elivation is say 31* and you have a tree just below 31 you may have a situation where the dish will work when you put it in. Then in a week as the sat moves you may lose signal.

 

[hobojoe]

very very interesting! i would love to go to school and learn this! it really does help me to understand dish pointing and enginering design. thanks!:

 

[Pepper]

From reading your original question I think what you are asking is theoretically what size hole needs to be in any obstruction (i.e. trees) between the dish and satellite?

The answer is dependent on the surface area of the dish. Since at this distance all signal from a satellite is hitting the dish parallel to each other, you need an approximately dish-sized hole (offset for angle of course) assuming you have the geometry exactly correct and the LOS to the satellite is through that hole.

 

[SmityWhity]

Very interesting post from Dave nye. I knew the birds moved and/or warbled around up there, but either didn't know or don't remember about the figure 8. But describing that slight movement around 31*, I'll have to test my 500 I-bracket at 129 TP-2 and see if it comes and goes.

 

[rcdallas]

It's been at least 20 years since I last computed a wavelength, but using the above calculations, 2.54cm would mean an antenna the length of 1 full wavelength would be about 1" long. Not very long. Where as a full wave length of a CB signal would be about 11 meters +/- (or about 33-35 feet).

The length/size of a degree would vary depending on the size of the sphere.

I believe 1 degree equals a little more than 69 statue miles at the Earth's equator, and the distance from about 110West to about 119West would be about 622 statue miles. However, way out in space - about 22,250 miles, 1 degree around Clarke's belt would be somewhat more.

Back to Earth.

The circumference of a 1 5/8" (1.625") Dish 500 mast pipe would be about 5.1" making 1 degree equal about 0.014" (lilttle more than 1/100").
Hmmm... Then 9 degrees would be about 0.1276" or a (red) hair more than 1/8" movement on a Dish 500 mast.

Putting all the jokes to the side, "It's always good to see someone interested in learning to do their job correctly, and the best possible.

Also, you bring up a good point about being able to receive all transponders. The satellites aren't very big, but there are multiple antennas, which are slightly apart and with some broadcasting at angles.

I have a Dish 500 with single LNBF on an I-bracket, set inside of a balcony pointed between overhangs and nearby roofs. I am able to pick up the transponders with fairly good signals, but am unable to pick-up one of the spotbeam transponders. Adjusting azimuth and elevation did no good. I'm sure if I moved the complete mount over to the east a little, I would pick up all transponders, but that would interfere with my SuperDish.

Keep up the good work.

SW
A mind is a terrible thing to waste.

PS - If my math is wrong, it was based on Louisiana math.

Ok the wavelength is about 1", that sounds right, I knew that would be small considering 440 Mhz is 70cm, 1.2 Ghz is 23cm.

You must be a ham, eh?

Thanks for the reply.

 

[rcdallas]

rcdallas

This is the way I teach our new guys to use the suunto clinometer.

First off your sats are going to be about 9* apart. So if you know where the sats should be, you know you need a window atleast that wide to get the dish in. I would not put a dish in a window that small though, would like to have atleast a couple degrees of area on each side to work with. If you have an area that is just to samll for the dish 500, or just barely wide enough, switch to a 2 dish solution if the customer is ok with it.

Also the suunto clinometer can be pulled off. So if you are working with a small window you want to make sure that there is nothing pulling that thing off. To do this go to the area where the obstuction is then look at the spot where you want to put the dish. You should see 2 numbers, the big one on the bottom is the direction you are looking, the small one on the top is 180*. This way you can make sure your reading is true.

Elivation is pretty simple you just need to know where the sat is in the sky. Just remeber that the sat does not really stay in one place unmoving. It does move a small bit in a figure 8 motion. So if your elivation is say 31* and you have a tree just below 31 you may have a situation where the dish will work when you put it in. Then in a week as the sat moves you may lose signal.

Okay, I'm getting an even better understanding now, but I still have some further questions:

Like in my area (assuming your is very similar since your really not that far away as the crow flies)

110 only example. According to the reciever in Dish 300 mode for my area 110 is 222 azimuth, 34 elevation, skew obviously 90.

I could really have a hole say 5' x 5', to the left I could be at 219, to the right 224, elevation within that hole could be 32 degrees to the bottom, 36 degrees to the top.

Bottomline, as long as I give it say at least a 2-3 degree window for movement of the bird, it should threoreticly be ok, you think all transponder would be coming in ok as from the post prior referencing all transponders are slightly apart from each other?

Now for the 110/119 on a Dish 500, this is where I'm not totally clear on as to why I originally ask how wide the beam is.

I know the wavelength is about 1", that to me as being only a technician class ham tells me from front to back the wavelength is 1", but how wide is it or frankly how fat is it?

if doing a single dish for 110 is as said az 222, elev 34, single dish for 119 az 232 elev 31 -- to pickup both on a 500 in this area is az 227 elev 33 skew 119, I ask how "fat" is the microwave coming in is I'm pointed in the middle of the 110/119 or is it with the reflector the signal is actually reflecting off the outer edges of the dish that is making this possible?

With that in mind if I wanted to shoot through a limited area for LOS on a single dish 500, I would need to make sure I'm clear at least..

220 to the left - 234 to the right
30 bottom 36 to the top

...and if I had to, I could use two dishes

110 - 220 left - 224 to the right
32 bottom 36 to the top

Sorry if my post has become kind of cumbersome to understand my mind is brainstorming about a 1000 different things at once - but I believe I'm getting an even better understanding for this.

The figure 8 you mention does make complete sense, as I notice on some days with the 129 doing a dish 1000 I've tuned in at just about 90 points, 110 about the same -- other days I'm fighting if I turn it to the left I get 110, just a fraction of a hair to the right I only get 129 and the signal is about 73 points.

Anyone know if there is a referenced link that can explain into detail about all the focul points, bore sites, etc... with picking up multiple birds?

Thanks!

 

[Liquidforce88]

Well if you were to stand behind a Dish500 with the polar arm straight out in front of you. Take your arms and make a v infront of the dish at a 9* angle from center on each side. Then you could visualize where the signals are comming from.

Next time you peak a dish leave your meter on and stick your hand just in front of the reflector. You will be able to see where the signal drops when you move your hand in the way for each sat.

 

[Smith P.]

Since his POP is not in a center of Earth, the 9° must be turn into 10° or 11° or 12°, use that screen setup for obtain the real angles.

 

[rcdallas]

Well if you were to stand behind a Dish500 with the polar arm straight out in front of you. Take your arms and make a v infront of the dish at a 9* angle from center on each side. Then you could visualize where the signals are comming from.

Next time you peak a dish leave your meter on and stick your hand just in front of the reflector. You will be able to see where the signal drops when you move your hand in the way for each sat.

Good point, why didn't I think of that? :

I went outside of my own house a little while ago and found a hole through the trees, I believe if I put a dish pointed at the 119 I would get it, but definately not the 110 so it's all coming to me. Best bet I'll just get a test dish built up and get my hands on a non pen and spend a few hours on my own time seeing what I can do.

Thanks for the help.

 

[yooper.mi]

Remember to post your results. We all learn from each other.

 

[SmityWhity]

Now for the 110/119 on a Dish 500, this is where I'm not totally clear on as to why I originally ask how wide the beam is.

I know the wavelength is about 1", that to me as being only a technician class ham tells me from front to back the wavelength is 1", but how wide is it or frankly how fat is it?

You being a ham, you know that the very basics to receiving the strongest signal at the receiver is somewhat dependent on: full wavelength is better than partial; shortest lead-in possible, but also a certain length of lead-in depending on the frequency (slightly longer may be better); SWR; and a few other factors.

If the signal touches your antenna, you'll get reception, even if it needs to bounce/reflect off the side of a building in the middle of downtown.

Using satellite dishes, the signals are reflected from the dish pan back to the LNBF (except on a toroidal the signal is reflected twice). It is not hard to have the satellite signals hit the dish, but you must have that weak signal reflected back to the LNBF for it to work, while at the same time the dish pan is rejecting other signals or reflecting them away from the LNBF. So even that infinity signal is no good if it's not directed into the LNBF.

I suspect you were trying to figure out how much compensation in your settings you could get away with (if you had to) because of small openings in a tree line or other nearby obstructions.

On your more recent post, you mentioned getting a dish and go outside and test. Here are some things to remember.
The Dish 500 is designed to pick up 2 satellites (110 & 119) spaced 9 degrees apart from the surface of the earth in the U.S. I have picked up 119 and 129 (10 degrees).
And if you replace the Y-Bracket with a I-Bracket, your physical settings would be different, such as using another dish, maybe a dish for FTA.
If you change the skew, you could then change elevation and azimuth and still pick up the signal, maybe better - maybe worse. But not with the Dish 500 for 2 birds, because you will then change the arc you are looking at (attempting to receive).

 

[mbarnes]

This thread has been entertaining. I had to check my calendar to be sure it wasn't April 1st. Was anyone really serious about spending over $100 for a Suunto clinometer for aiming dishes? Kind of reminds me of a civil engineer acquaintance who spent over $200 on a highly accurate compass and rented very expensive surveying equipment to align a satelite dish. He knew for sure he had all the measurements right, yet couldn't get a decent signal. He was putting his money in the wrong area.

Unless you are a research facility working with deep space or something with a huge dish and precise aiming requirements, the basic cheapest alignment equipment will do fine. After all, you only need to get close with those tools. I have been aligning professional broadcast dishes as well as DBS stuff for ten years and use nothing but a $5 compass from Wal-Mart and a $15 clinometer from Sears. And the only reason I got that expensive of clinometer was because I got tired of breaking my plastic protractor with a string and weight on it.

They key to good signals from the dish is the signal strength and quality. After all, Dish uses the zip code to calculate the look angles. That can cover many dozens of square miles. Once you get the dish pointed in the right vicinity, then you use the electronic equipment to peak the signal. You can use the screen information, but it is terrible slow. I typically use a signal strength meter and a spectrum analyzer. Granted, the average home user is not going to spend $3,000 on equipment he only will use once or twice, but you can do an adequate job with a $29 signal strength meter from Camping World or similar places.

So, leave all the calculus trials, wavelength computations, and expensive surveying equipment for other hobbies. You want a good signal, so measure the signal and peak it. You don't really care what the final hundredths of a second turns out to be.

 

[Smith P.]

:up

 

[Liquidforce88]

mbarnes,

Come up to my neck of the "woods" and try to put in dishes with your compass & clinometer. You will be out buying a tandem soon.

 

[BarryO]

I am curious as to how wide and tall the signals are coming from the satellites.

Well, if it's a CONUS satellite, which most transponders are (other than the spot beams), then the signal is as wide and tall as the USA!

The reflector on the dish intercepts a miniscule portion of this at any given location, and reflects it to the LNBF. That's why you can improve your signal strength just by making the dish bigger.

Making the reflector bigger does something else, too, and I think that's what you are getting to in your question. Making the dish bigger also makes it more directional. A key parameter for any antenna is what engineers call its "gain"; i.e., how much stronger a signal the antenna will receive, if it's pointed right at the source, compared to the signal that would be received at the same distance by an omnidirectional (called "isotropic") antenna. Higher gain antennas work by being more directional; i.e., it concentrates on receiving the energy from one specific direction. The extreme cases are radio telescopes: the huge refelectors have such high gain they can receive emissions billions of light years away, and they can point at tiny portions of the sky, and distinguish them from nearby portions.

Antenna gain is a function of wavelength, and size and configuration of the antenna. Bigger antenna for a specific wavelength == higher gain, and more directional, antenna. Shorter wavelength for a fixed antenna size == higher gain, and more directional, antenna.

Dish antennas are used for most satellite applications because for the frequencies used, they have very high gains, often over 30 dB. The directivity of typical DBS dishes is a few dgrees each way (<5); it has to be less than the satellite spacing (for satellites operating at the same frequencies), or the antenna would end up mixing the signals together (not good).

 

[rcdallas]

This thread has been entertaining. I had to check my calendar to be sure it wasn't April 1st. Was anyone really serious about spending over $100 for a Suunto clinometer for aiming dishes? Kind of reminds me of a civil engineer acquaintance who spent over $200 on a highly accurate compass and rented very expensive surveying equipment to align a satelite dish. He knew for sure he had all the measurements right, yet couldn't get a decent signal. He was putting his money in the wrong area.

Unless you are a research facility working with deep space or something with a huge dish and precise aiming requirements, the basic cheapest alignment equipment will do fine. After all, you only need to get close with those tools. I have been aligning professional broadcast dishes as well as DBS stuff for ten years and use nothing but a $5 compass from Wal-Mart and a $15 clinometer from Sears. And the only reason I got that expensive of clinometer was because I got tired of breaking my plastic protractor with a string and weight on it.

They key to good signals from the dish is the signal strength and quality. After all, Dish uses the zip code to calculate the look angles. That can cover many dozens of square miles. Once you get the dish pointed in the right vicinity, then you use the electronic equipment to peak the signal. You can use the screen information, but it is terrible slow. I typically use a signal strength meter and a spectrum analyzer. Granted, the average home user is not going to spend $3,000 on equipment he only will use once or twice, but you can do an adequate job with a $29 signal strength meter from Camping World or similar places.

So, leave all the calculus trials, wavelength computations, and expensive surveying equipment for other hobbies. You want a good signal, so measure the signal and peak it. You don't really care what the final hundredths of a second turns out to be.

Spoken like a true conservative...

No it doesn't take fancy equipment to install a Dish Network system. However regardless of your opinion a Suunto Tandem does, I repeat does make your job alot easier when dealing with the trees of Michigan when the customer wants a dish in a particular spot.

If I was still in Plano, no I doubt I would bother owning one as the trees around DFW frankly are not that tall.

If I had the $3,000 to spend on a spectrum analyzer I would due to the fact that is the kind of person I am.

 

[SmityWhity]

I sure hope this is entertaining!

I don't really like watching TV, but like any other hobby, I'm just like rcdallas; I like to know what makes it tick, how to make it tick louder, and sometimes why it is no longer ticking. So when I get tired of fishing or helping out at school, I come to this forum.

Me, I don't even own a compass. Why should I? Even in Louisiana there are only 360 degrees in a pie, and we are only using less than 1/2 of those!

Yep, we're all correct, and keep up the entertainment.