Tandem Match
 

I'm putting together the bits to build the tandem match from the 2001 ARRL
Handbook. I do not have the original QST articles, but Googling has revealed
that some builders have had a few problems, particularly those using the FAR
Circuits PCB.

There's one thing I don't understand about the schematic and that just looks
plain wrong. If both W2 and W3 jumpers are present, the 5.6k resistor is
shorted out, thereby connecting the -2.5V and V- rails together. Surely this
can't be right, or am I missing something?

Regards,

Paul G3ZCU

Hi,

There's one thing I don't understand about the schematic and that just looks
plain wrong. If both W2 and W3 jumpers are present, the 5.6k resistor is
shorted out, thereby connecting the -2.5V and V- rails together. Surely this
can't be right, or am I missing something?

If operated from external supplies, all three links should be removed as
opposed to battery operation where they must all be in place. You are right in
that the 5.6k resistor is shorted-out but it is not needed in that
configuration. Two links (W2 & W3) are required then to 'remove' the resistor
and re-make the connection between the -ve power sensing detector and the
bottom of the battery.

I didn't know the piece of equipment but looked it up out of curiosity.


Cheers - Joe

You are right in that the 5.6k resistor is shorted-out but it is not
needed in that
configuration. Two links (W2 & W3) are required then to 'remove' the
resistor
and re-make the connection between the -ve power sensing detector and the
bottom of the battery.

Ah, I see now.

Many thanks,

Paul

QSK QSK QSK Paul, 6BW6, its 6v6 here, I repeat 6v6, Steve, do you read? over?

QSK QSK QSK Paul, 6BW6, its 6v6 here, I repeat 6v6, Steve, do you read? over?

6BW6, 6BW6, this is 6V6, 6V6 - do you copy over? (vitalinput.com)