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A FEW WORDS ABOUT JC-5s
JC-5 was designed to cover the needs of high power professional use and increased
reliability. So, materials of the best in market were used, despite the high cost of some of
them, due to their limited production! At the pictures you can take a look at the inside of
the coupler
.
In the photos we can see mounted in a row the vacuum relays, by which the high
voltage doorknob ceramic capacitors are selected. We can also see the high voltage copper
wiring above the p.c. board. The reason we did not construct the high voltage paths on the
board is that we don’t consider the p.c. board reliable enough for withstanding voltages of
the order of 8 KV that may appear at the output of the coupler when λ/2 or short vertical
antennas are used!
TUNING PROCEDURE WITH THE CONTROL BOX
We set the switch of the control box to the M position if we intend to use memories or to the O
position, if not. We set the transceiver to AM, FM, CW or RTTY mode with the output power
adjusted in the range 10 – 20 W. We push the PTT and keep it pushed. We push the button until the
LED is lit. We wait until the LED goes off and then we stop transmitting. If the LED quickly turns on
and off at the end of the tuning procedure, the tuning procedure has failed and the coupler goes
THROUGH. Starting up the coupler, if the switch is at the M position, it recalls the last used
memorized frequency, otherwise it goes to the THROUGH state!
If the tune button is pushed for less then 0,25 seconde , in any case, the coupler
goes
THROUGH
and the LED does not glow at all!
In case we use more that 50 W during the tuning procedure, the control box LED remains constantly
lit and the coupler waits until input power falls below 50 W to complete the tuning process!
IF WHILE TUNING, THE RF POWER MOMENTARILY EXCEEDS 40 – 50 WATTS, THE LED ON THE
CONTROL BOX GIVES THE DANGER CODE AND THE COUPLER FREEZES, PUTTING THE CONTROLLER
TO THE “POWERDOWN” STATE. THIS MEANS THAT THE USER MUST REMOVE THE 12 V SUPPLY
FROM THE COUPLER FOR ABOUT 5 SECONDS ! THE REASON FOR THIS IS TO GIVE THE USER TIME
TO REALIZE WHAT WENT WRONG AND REMEMBER TO KEEP RF POWER AT THE RIGHT LEVEL
WHILE TUNING . THE DUMMYLOAD (USED INSIDE THE COUPLER WHILE TUNING) AND
THE RELAYS WILL BE DESTROYED IF THE COUPLER IS FREE TO PERFORM TUNING WITH HIGH
POWER!
THE RELAYS USED IN ALL OF OUR COUPLERS, ESPECIALLY THE VACUUM ONES,CANNOT
TOLERATE HOT SWITCHING !
To erase the memories :
WHEN YOU START JC5 WITH 12V ON CONTROL CONNECTOR PIN 4, THE
PREVIOUS MEMORIES ARE SAVED AND NEW MEMORIES CAN BE WRITTEN!
IF YOU START IT WITH 0 VOLTS ON CONTROL CONNECTOR PIN 4 ALL MEMORIES ARE ERASED !
(The memory erasing process is carried out without transmitting!)
REMARKS:
1.
The closer we use an antenna to its resonant frequency (λ/4), the more power we can apply to it
via a coupler, because in this condition the coupler is using the least of its components to
match the antenna and there is no possibility of overheating inductors and capacitors!
2.
The performance of the system depends on the used antenna and counterpoise. The role of the
coupler ends when the SWR is reduced to the lowest in any case possible level.
3.
In case we face problems, we act as follows:
a.
We check /fix the counterpoise system.
b.
We ensure that any wires, cables or metal posts are located far enough from the antenna and
their directions are perpendicular to the antenna
.
c.
We use another transceiver which is in good condition to check the system.