Kth - sdr - kit

6/13/2010 KTH - SDR - KIT Page 31
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Soldering the Pin-diodes.
Note on the Pin-diodes:
On the left side, near J1 on the HF board, you will see in white paint the connection of the BA892 pin-diode.
The little line indicated with ‘K’ is the cathode and is the same line in the schematic indicated with ‘K’.
Everywhere on the board where a pin-diode must be soldered, you find that little white line.
The BA892 has a SCD80 size and is very tiny and vulnerable. For that reason 2 spare diodes are added to
the kit. Be sure that you solder the diode in the right direction; use a magnifying glass with lighting. Don’t
heat to long and don’t put to much force on the diode when soldering.
If you doubt about the right ‘A’ and ‘K’ direction, compare a 1N914 and the BA893 with an ohmmeter.
Place both diodes on a whit piece of paper, to prevent losing the parts….
As desired you can install the MAV-11 gain block. This increased the sensitivity and decreased the noise
figure of the receiver. A disadvantage is a worse strong signal behaviour (IP3).
If you don’t install the MAV-11 you have to make a wire bridge from the input condenser C106 to the output
condenser C114. See schematic figure 2.6-1.
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Instruction manual KH-SDR wideband receiver Kit No-1021. All rights reserved KTH-SDR-KIT. Software design by PA0RWE.