Dish Diameter/Satellite Footprint

[spongella]

If one is out of a satellite's footprint, could using a larger diameter dish compensate and thus allow you to receive that satellite? For example, if a Ku band satellite's footprint covers the Southeastern USA, and you are in New England, could you use a larger diameter dish and get coverage? Assuming you have a clear path to the satellite of course.

 

[Titanium]

Footprint charts are only for generalized reference and may not accurately indicate the true signal coverage. These computer generated estimations and simulations are based on full bandwidth and full power transponder operation to provide an acceptable level of reliability.

Typically there are footprint maps generated for each of the transmitted polarities. The footprints are usually different for each polarity. There are also many signal variables that are not modeled such as regional geomagnetic fields and actual transponder power, bandwidth, FEC ratio, etc. Often there are radiation irregularities that may produce signal hotspots outside of the estimated footprint.

A dish can only collect a signal that is present. If the footprint does not cover your region, there may not be enough signal to be received to amplify above the noise threshold and produce enough reliable data to decode. It won't matter the dish size or signal amplification, zero times 100 or even 1000 still equals zero.

With that said, if there is some signal present, it may be possible to increase it to be received via increasing the reflector size / efficiency and with optimized feedhorn / LNB low noise amplification and tuner sensitivity.

Several articles have been published about satellite DXing. It used to be much easier to receive an extremely weak or out of footprint analog signal as the snowy or unstable sync images still show up on the monitor even if the signal is at the noise threshold. With digital signals, the decoding will not happen unless a signal is a certain level above threshold and enough data is received over time to apply the FEC (error correction) to produce a viewable image.

There is an older Tele Satellite article that is a great read about a hobbyist using a gigantic dish and chilled LNB to receive the Austra/HotBird European footprint transponders in South America.

Out of footprint reception is not predictable and one would have to simply just give it a try using the largest / most efficient reflector, optimized feed and electronics available.

 

[spongella]

Excellent reply Titanium, thank you very much. Yes I read about that fellow in TeleAudioVision. Was hoping to perhaps try the Eastern Atlantic Satellites beyond Telstar 12 Ku 15W. Don't think there's much Ku FTA though, probably more C Band.

 

[Vallenato]

signal is a certain level above threshold .

Sorry for "Hack" the thread
What means thresold?
Normally used On receivers enigma 2 advanced configuration menu.
For example for C band LNB (5150) what could be "Thresold"?

Lo F/L 00000
Lo F /H 00000
Thresold 00000

 

[Titanium]

thresh·old
?THreSH?(h)?ld/
noun

The magnitude or intensity that must be exceeded for a certain reaction, phenomenon, result, or condition to occur or be manifested.
"nothing happens until the signal passes the threshold"

In my description, the signal strength of the transponder must be greater than the base noise level.

The Threshold in the Enigma 2 GUI is the frequency at which the STB switches on the 22KHz tone signal to trigger the switch from the LNB low band LO frequency to the high band LO frequency. This is typical for a Universal LNB with two LO frequencies (I.E. 9750/10600). The switch point and secondary LO frequency is not used with a standard type LNB with a single LO.