http://www.anagmate.php5.cz/share/redstoneSignal.png

Signal is sent, but it disappears after 15 blocks from source. Red alloy wire should transmit signal for any amount of blocks.

My question is, is it intended behavior or is it a bug? If it is intended, is there any way of connecting it with full signal strength without any delay (so without repeater)?

Just apply the power directly into the redstone wire instead of going through redstone dust. Dust only powers the wire enough to go for 15 blocks or so.

OK, I will try. I was using redstone, because in that particular case, redstone was working better that redwire.