Gang,
When I built my QRP LDG autotuner, I noticed the wiring diagram
for the front panel connections is not quite correct. I thought I would
pass along my findings and save you some errors and de-soldering.
Figure 7 in the assembly manual shows the connections for the
IND UP and CAP UP connection to be on the top of the momentary
SPDT toggle switches. Actually, this connection should be reversed
with the IND DWN and CAP DWN connections, respectively.
This is because a toggle switch typically activates the opposite
terminal from the direction it is switched. In other words, UP on the
toggle means DWN on the terminal. It is due to the mechanics internal
to the switch. If you've ever taken one apart, you'll know why.
So, to agree with the front panel legend for the switches, wire the
back of them OPPOSITE to what Figure 7 indicates. You'll know if you
have it wrong, if when you first turn on the tuner, a press down on the
CAP or IND toggle starts the relays clicking. At that point, all the
relays
are off, and should remain off when you select DOWN on either the
IND or CAP switch. The LEDS should just flash, indicating that minimum
CAP and IND settings are already achieved.
This agrees with the intended operation of the unit, and also with the
operation of the QRO unit which I have, but it uses pushbuttons instead
of momentary toggle switches.
Do I hear lots of groans from you that have already built the QRP unit?
Or did you catch this? :-)
It certainly will work if you build it according to the instructions. It
just
won't be right, according to the front panel legend.
Mine works really well, and although it couldn't tune my 40m dipole
on 80m, it DID when I loosened the coax fitting on the antenna connector,
making the feedline and antenna together look like a Marconi antenna!
Now I'm looking everywhere to find something to "tune" into an antenna!
72,
Gary Surrency AB7MY
S&S TAC-1(40&80m) and ARK30, AT-11 (QRO and QRP)
QRP-L #571 Chandler, AZ (near Phoenix)Grid Square DM43BH
Az ScQRPions
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