EA3GCY EGV-40, Инструкция по сборке

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EGV-40 CW QRP Transceiver Page 25
ADJUSTMENTS AND CHECKS
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Preliminary testing
- Adjust P2 (volume), P3 (fine tuning), and P4 (TX output power) to mid position.
- Turn P1 (RF attenuator) all the way clockwise.
- Connect headphones to the header “PHONE” on the board.
- Connect a PSU (12-14 V) to the “VDC” header on the board.
- Measure the voltage on the following points (related to the receiver path):
8 V from any leg of L6 and ground.
6 V from any leg of R4 or R5 and ground.
- Turn the volume (P3) to the maximum; you will hear a hiss on the headphones.
If all is OK, you may continue.
If not, please check your kit (see section "If your kit does not work after assembly")

Tuning adjustment of the inductor L5 and the Polyvaricon CV2/CV3
NOTE: it is recommended to make all VXO adjustments with the "fine tuning" pot in its mid position; this
way, once tuned the pot will allow you some extra coverage at both ends of the tuning range.
The following task is more fun that you may think at first; it is not a "plug&play” one, but it is fun; leave
one hour of relaxed time and enjoy it!
Solder the L5 pigtails on their place over the board. Leave it for now some slack, so you may compress
or spread the turns. Connect a frequency counter on the “VXO” header. If your counter has a low input
impedance, insert between the counter and the header a resistor (470 ohm or more) or a small
capacitance cap (try with 22 pF or less) to reduce the interaction between the counter and VXO.
If you don't have access to a counter, you may use an SSB or CW receiver with a digital dial covering
the VXO frequency around 11.950 MHz. Connect to the receiver antenna input a length of wire with a
small loop and place it over the EGV-40.
Note: A counter is highly recommended as the use of the receive is cumbersome.
On TX, the IF frequency of 4.915 MHz is subtracted from the VXO frequency to obtain the RF output
signal. For instance: 11.945 – 4.915 to get 7.030 MHz.
On RX, the antenna signal is subtracted from the VXO frequency to obtain the IF frequency. For
instance: 11.945 – 7.030 to get the IF of 4.915 MHz.
In both cases VXO = RF + FI
The polyvaricon capacitor contains two variable caps for tuning. J1 selects which section to use. Placing
a jumper on “B” the larger CV2 (around 150 pf) is selected. Placing a jumper on “A” the smaller CV3 (70
pf) is selected.
For normal use on the EGV-40 the jumper should be placed on J1 “A” (smaller capacity) you can
also try the place J1 “B”.
When the polyvaricon is placed out of the board, please notice that when
mounted upside down, with the terminals up, the jumper connections get inverted, and you will have to
place the jumper on J1 "B" instead of J1 "A".