A Satellite Signal meter:

This article describes a tool you can build yourself that can aid you in aligning your TV satellite dish optimally without carrying your receiver or PC outside.

Other sources call this device a Satellite Finder, but I disagree - it cannot find a sat for you, it will only aid in optimising alignment once you have found the right satellite.

How does it work:

The LNBs we use (digital or analogue) do not receive a single channel, but the complete range of all transponders that are operating on that particular satellite. Together with the high gain that modern LNBs have (over 50 dB) this yields in a lot of RF energy that is fed to your receiver if the dish is correctly aligned. This design measures the amount of RF energy over a wide frequency range by summing the power from all transponders, then rectifying and amplifying for display.

Don’t try to align your Meteosat dish using this device, because with only two “low power” channels on Meteosat you won’t be able to distinguish the signal from the noise.

How to use this device:

Disconnect the coax running from your receiver to the LNB at the LNB end; and connect this device using a 1 to 3 m length of coax to your LNB, and reconnect the receiver to this device. As the device is symmetrical, you can connect it either way round.

Power from the receiver is needed, so leave your receiver powered on. But it is not necessary to set your receiver to a specific channel.

Set-up the dish roughly in the right direction using either a compass, or the shadow of the sun at a predetermined time. Use your favourite tracking program to determine the compass heading or the time that the sun reaches the same direction as the desired satellite.

Turn up the gain on the satellite signal meter and gently vary the azimuth and elevation to maximise meter readout. Be aware that only 5 degrees off direction can mean that won’t receive anything, or even worse, you have optimised on a neighbouring satellite! Decrease gain if needed. Once you have found the best dish alignment you can optimise the position of the LNB in the feed clamp. Try rotating the LNB slightly from the normal position and shifting it towards or away from the dish to get maximum readout.

Always check reception on your receiver to verify that you have optimised on the right satellite before fixing up your dish!

If you are using a motorised polar mount, you can use this meter at the receiver side too. Although this design does draw only a very small amount of RF from the LNB, it could degrade the performance of your system, so remove it after dish alignment.

Acquiring parts, building and aligning:

The key parts are the two detector diodes, the type used is a low barrier Schottky diode capable up to 3 GHz. Type HP2800 can be used too.

Some sources mention that other types like the AA119 can be used, but I have not tested this. Don’t use ordinary silicon diodes (like the 1N4148) because these won’t detect signals of up to 2200 MHz.

Keep the wires shown thick in the schematic diagram as short as possible (less than 5 mm) as we are dealing with high frequencies here. Solder these parts directly to the back of the F-connector. Use a short length of coax to connect both F-connectors to each other inside the box.

The 5K trimpot is used to limit the meter readout to full-scale once you found the maximum signal with the 10K gain potentiometer set to maximum sensitivity.

Use only a metal box to prevent RF leaking out. A printed circuit board design is not available.

Arne van Belle Co-ordinator Radio Observers WERKGROEP KUNSTMANEN (www.kunstmanen.nl)

Thanks to David Taylor for correcting my grammar.

Schema e excelenta...problema sunt diodele foarte greu de gasit si ampermetrul care e vreo 200 de mii

Mai jos va prezint unul facut industrial shi comercializat in ro de firma xxxx (pupamar in cur cas excrosci la pretul pieselor electronice)

Dupa cum observatzi schema acestuia este asemanatoare cu a celui de sus