Altinex VGA Line Receiver DA103-217 - Manual (Page 5)

AP-016 Rev 1 Page 5 of 6
the sync threshold from 0 to 100% of the sync amplitude. This adjustment level guarantees
accurate sync recovery for the longest cable length.
For extra long cable lengths, it is possible to use two DA103-217s to extend the distance to over
400ft. When two units are interconnected, EQ and GAIN controls should be set to 0 and the
SYNC ADJ control should be set to 50%. Initially, only the receiver should be adjusted until
there is no more adjustment range. After that, the transmitter’s EQ and GAIN can be adjusted to
provide additional improvement in the image quality. Transmitter SYNC ADJ should be always
set to 50%, while the receiver’s SYNC ADJ should be set for the best stable image.
Figure 8. Extending VGA cable length using two DA103-217s
In real life applications, the DA103-217 will significantly improve the displayed image
sharpness and contrast. Figure 9 shows 250ft of a standard VGA cable without equalization and
gain control. All of the text is smeared to the right as evidence of very severe signal degradation.
Figure 9. 250ft of coaxial cable without DA103-217
After properly adjusting the DA103-217 located next to a monitor, the image quality has been
improved dramatically by removing ghosting and making text edges sharp and crisp. The gain
was also adjusted to bring image contrast back to its original level. The sync control was set to
50% for this test.