QCX assembly Rev 1.08
11
The PCB track and circuit (schematic) diagrams are shown on the previous pages. Tracks shown
in BLUE are on the bottom layer. Tracks shown in RED are on the top layer. There are only two
layers (nothing is hidden in the middle). Not shown in this diagram are the extensive ground-
planes, on both sides of the board. Practically everything on both layers
that isn’t a RED or BLUE
track, is ground-plane! The two ground-planes are connected at frequent intervals (not more than
0.1-inches) by vias. This is the kind of layout I have done previously for a quad-band GSM device
operating at up to 1900MHz… it is probably overkill in an HF transceiver… but if you can, why not!
I used to say often that you can never have too much supply line filtering and decoupling, and
never have too much shielding. Both these statements don’t apply so conveniently to kits as they
do to homebrew projects. In a kit every decoupling capacitor has a cost in both money and PCB
area (which also means more money). Shielding is even more difficult and expensive. So shielding
and decoupling should be applied where needed only! But ground-plane
– well that’s another
story. It’s free, and without drawbacks – so why not, let’s just put it everywhere.
The PCB silkscreen component numbers are necessarily quite small and may be overlapping
pads or vias, or near to other components. It may be nice to have doubled the size of the PCB and
have more space to print nice silkscreen labels of the component numbers. But the result would
n’t
be such a cute and neat little radio and the price wouldn’t be so friendly either! So check carefully,
before soldering each component! Check the location and check again
– with reference to the
diagrams in each step.
All components are installed on the top (component side) of the PCB and soldered on the bottom
(solder side) of the PCB.
Take care when installing integrated circuits. All through-hole integrated circuits are supplied by
the manufacturers with their pins bent a little wide. You need to carefully bend the rows of pins
together a little, in order to fit them in the PCB holes, or in the 28-pin IC socket in the case of the
ATmega328P microcontroller.
The band-specific Low Pass Filter (LPF) parts are supplied in a separate LPF kit bag.
In the construction for some bands, not all of the capacitors supplied in the kit are used. Do not be
alarmed if you have a few components left over at the end!
Wind the L1-3 inductors with the enamelled copper wire supplied in the LPF kit bag. Wind the
other inductors (L4 and transformer T1) using the wire supplied in the main kit bag.
The component colour coding of the layout diagram at every step of the assembly instructions is
as follows (kind of: components past, present and future):
•
Components shaded grey have already been installed
•
Components shaded red are the ones being installed in the current assembly step
•
Components shaded white are the ones which have not yet been installed
The following photographs show the final assembly, with and without the LCD module plugged in.
You can keep these photographs in mind when assembling the kit, they will give you some idea of
how the kit fits together and help avoid assembly errors.
Summary of Contents for QCX 5W CW
Page 9: ...QCX assembly Rev 1 08 9...
Page 10: ...QCX assembly Rev 1 08 10...
Page 12: ...QCX assembly Rev 1 08 12...
Page 50: ...QCX assembly Rev 1 08 50...
Page 105: ...QCX assembly Rev 1 08 105...
