Subject:  [QRP-L] ZM-2 Emtech Antenna Tuner Question 
From:  Barry Keating 
Date:  Sat, 27 Dec 2008 09:52:28 -0500 

Some of you use the ZM-2 ATU (Antenna Tuning Unit) from Emtech. Could you 
answer a question about the unit for me? I cannot find the answer in the 
documentation.

In the upper right-hand corner of the control panel is a "GND/Link" toggle 
switch. What exactly does this toggle switch do? What should be its setting 
when tuning? What should be its setting when operating?

Thank you for the clarification.

WD4MSM


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Subject:  Re: [QRP-L] ZM-2 Emtech Antenna Tuner Question 
From:  Jonathan Poland  
Date:  Mon, 05 Jan 2009 17:07:09 -0600 

The switch position depends on the type of antenna feed line you are 
using.  It determines how the black binding post is used.

If you are using an unbalanced lead (i.e. coax) then the switch should 
be set to GND.  And you then connect your counterpoise (i.e. ground) to 
the black terminal.  The antenna gets connected to the BNC terminal.

If you are using balanced leads (such as TV twin lead or the "NORCAL 
doublet") then the switch is moved away from ground and and the antenna 
gets connect to both the red and black terminals.  With an antenna that 
uses a balanced lead, you don't need a counterpoise.

Does that help?

jon N0WL


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Subject:  Re: [QRP-L] ZM-2 Emtech Antenna Tuner Question 
From:  Rick McKee 
Date:  Mon, 5 Jan 2009 18:11:49 -0500 

You must be talking about the switch that converts the ZM-2 from a
balanced tuner to an unbalanced tuner.  What it does is it grounds one
side of the output link so you can use the tuner on unbalanced antennas
like coax fed antennas or end fed wire antennas, so when using that type
of antenna you want it in the ground position.  Ohterwise when feeding a
balanced feedline you want it in the ungrounded position.

Rick McKee, KC8AON, Ohio 
www.angelfire.com/electronic2/qrp
With God all things are possible ~ ><(('> ~


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Subject:  Re: [QRP-L] ZM-2 Emtech Antenna Tuner Question 
From:  Rick McKee
Date:  Mon, 5 Jan 2009 18:51:58 -0500 

If you are using an unbalanced lead (i.e. coax) then the switch should 
be set to GND.  And you then connect your counterpoise (i.e. ground) to 
the black terminal.  The antenna gets connected to the BNC terminal.
[snip]

You can also connect a random wire to the red terminal and a counterpoise
to the black terminal when that switch is in the ground positon because a
random wire is unbalanced !  The ZM-2 is a fairly versatile little tuner
and I have 2 homebrew clones here that I built !

Rick McKee, KC8AON, Ohio 
www.angelfire.com/electronic2/qrp
With God all things are possible ~ ><(('> ~