Footprints

[Diamond Jim]

I have put this off for awhile at the risk of sounding ignorant, which I am, but would someone please explain to me how to read a footprint?

 

[Mr Tony]

good question Jim (I've wondered it myself too)

All I know is the lower the number, the bigger the dish needed

 

[jayelem]

I've always liked this chart.

 

[Mr Tony]

I LIKE!!

thanks for that...

 

[caddata]

The Effective Isotropic Radiated Power (EIRP) is the microwave radiation energy that is actually being absorbed by the earth. Think of it as the light from a flashlight in the dark. Brightest in the middle and dimmer toward the edges.

 

[Diamond Jim]

Thanks guys, that sheds some light on it. I just thought if the largest circle covered your area, you could get it.

 

[123tim]

AMC 3 has an typical EIRP of 49 in central Pennsylvania. If I'm reading Jaylem's chart properly, that would mean that you should be able to get by with a dish smaller than 24 inches here. I must not be understanding something correctly, because I know that this isn't possible. Would someone be able to tell me what I'm missing? Do these values come from the hottest transponder on the Satellite?

Thanks!

AMC 3 Footprint:http://www.ses-americom.com/americo...Teleports/coverageareas/kuband/amc3/index.php


Edit - corrected dish diameter.

 

[jayelem]

AMC 3 has an typical EIRP of 49 in central Pennsylvania. If I'm reading Jaylem's chart properly, that would mean that you should be able to get by with a dish smaller than 24 inches here. I must not be understanding something correctly, because I know that this isn't possible.

I'm a little skeptical about what some footprints claim is EIRP, but by looking at footprint on your link if correct, why would you think a 24 inch dish is not possible, it's the minimum size and you probably would have a lot of room for error receiving signal, rain fade , this is just not a practical size for most FTA stuff.

My 90 cm dish picks up NAHUEL 1 here in Chicago, eventhough it doesn't take much for me to get bad results on a cloudy day.

For Nahuel 1 , I would need a dish bigger than 1.2 meters, yet I get the test card and 2-3 channels from this sat on my 36 inch dish, hows that for a 39 EIRP.

Suprise suprise , you just never know until you try it out.

 

[123tim]

I'm a little skeptical about what some footprints claim is EIRP, but by looking at footprint on your link if correct, why would you think a 24 inch dish is not possible, QUOTE]

Jaylem,

Thanks for the response. The reason that I was thinking that a 24" wouldn't be possible was because my 36" Fortec dish has trouble with AMC 3. I don't seem to have trouble with any other satellites, but AMC 3 fades at certain times of the day. Iceberg suggested that it might be Sat wobble, and I'm inclined to agree, because it seems very predictable. Perhaps it's something in my setup. I always thought that the PBS stations on AMC 3 were weaker transponders. I was surprised to see such a low value on the EIRP considering what I thought I knew

Maybe I should readjust my thinking....I've gotten so used to seeing PBS loose signal that I assumed that I need a larger dish.

Thanks again.
Tim

 

[jayelem]

Well I have to admit I see less than favorable results on many sats, example SBS 6 and Satops channels (NBC feed stuff) . I have some frequencies that are stable and if I adjust my dish using Disecq 1.2 , I can peak the satops channels with a strong signal, then I go back to other frequencies and theyre barely watchable, and this has happened on many birds with my adjustments, peak one signal and lose strength on another.

Sometimes I switch back to USALS if I get lost.

I just live with it and since I hit every bird from 30.0 - 129.0 west I dare not play with my dish at this moment, using a sharpie to mark my original settings is smart if I decide to experiment, but I just think about my newbee experience when I first setup and how frustrated I was hitting my true south, things are different now that I have live tp's and channels in the STB.