Low Frequency Modification - Ramsey Electronics The `Logi' Log Periodic Antenna LPY915 Assembly And Instruction Manual

7. From the bottom side, slide the center conductor of the coax through the
open via at the front of the circuit board.
8. Gently bend the remaining cable to mount flush along the tinned center
ground strip.
9. Look closely at the ground
conductor and make sure there are
no stray braid wires hanging
around. They can short out the
coax near the via when you solder
it in place rendering your antenna
useless!
10. Solder the length of the ground
conductor to the circuit board along
the tinned center ground strip. Be
careful at this point not to overheat
the ground conductor and melt the
dielectric layer. Spot soldering the
ground braid at the element junctions works well to avoid overheating the
coax.
11. It's time for the last connection! Solder the center lead of the coax in
place on the top side of the circuit board where it passes through the via.
12. Visually examine the junction you just soldered and again make sure
the center feed of the coax is not shorted to ground.
Note that using an ohmeter to check you LPY915 antenna for shorts will not
work. By default, the top and bottom layers are connected together by small
traces near the end of the board. Normal operation requires these traces to be
left intact. An optional low frequency modification for improved performance
near 825 MHz will be discussed next.
Time to start playing! Interface the other end of the coax feed with your radio
and enjoy the benefits of a broadband
directional antenna!
LOGI LOW FREQUENCY MODIFICATION
If your radio system requires DC isolation
or you plan to use your Logi below 900
MHz, the small connecting traces near the
rear of the antenna should be cut. By
removing these traces you can extend the
effective frequency range down to 825
MHz. You will however wind up with some
'lumps' in the matching response on the
Soldered Coax Positioning
Final Installation View
LPY2 • 6