On 9/28/2011 10:46 AM, Jeffrey Angus wrote:
It comes with an adapter cable for Icom radios, but it's a
4-pin Molex connector and the manual doesn't show what the
connections/signals are for the radio.

Multiple Homer Simpson "Do-oh!" moments.

LDG was kind enough to supply me with the application note for
the interface cable.

I have two Icom radios. An IC-761 with an internal tuner and an
IC-726 designed to use with an external tuner. The IC-726 has the
mating 4-pin Molex connector.

The two signals are essentially a "request to tune" and an "tune
complete". The IC-726 has a TUNE button on the front panel for
telling the external tuner to do it's thing. (By the way, I do
have the matching AT-150 auto-tuner for the IC-726.)

All three of the tuners, the IC-761 internal, IC-726 external and
LDG have an SO-239 connector for the output and would require an
external balun to connect to an open wire balanced feed line.

The reason I was using the MFJ Versa Tuner with the IC-761 was
fairly simple. It has an internal 4:1 balun and connections for
open wire balanced feed lines.

Since I had to purchase a balun to use the LDG tuner I realized
that "Oh, I can use the Icom tuners with the balun as well."
That was my first "Do-oh!" moment.

Subsequently on researching the interface signals to/from the
LDG I realized that the IC-761 doesn't have a TUNE button or the
signals externally because the tuner is already inside the radio.
That was my second "Do-oh!" moment.

Once the MFJ 4:1 current balun I ordered arrives, the only question
that remains is whether or not the specified matching range of the
Icom tuners is sufficient to deal with my antenna system.

The Icom tuners are specified at 16.7 to 150 ohms.
The LDG Z11 Pro II is specified as 2-1000 ohms.
Oddly enough, the MFJ Versa Tuner has no specified range.

Jeff-1.0
wa6fwi

--
"Everything from Crackers to Coffins"

Jeffrey Angus wrote in news:j64hp4$i7g$1@dont-
email.me:

The two signals are essentially a "request to tune" and an "tune
complete".

That is not quite correct.

Though the protocol is not published by Icom, and the implementation varies
a little from radio to radio, the four wires are usually labelled and none
are "tune complete".

Owen

Jeffrey Angus wrote in news:j64hp4$i7g$1@dont-
email.me:

The Icom tuners are specified at 16.7 to 150 ohms.
The LDG Z11 Pro II is specified as 2-1000 ohms.
Oddly enough, the MFJ Versa Tuner has no specified range.

Impedance is not a simple scalar quantity as expressed above. The
'specification' is incomplete, you would need to ask the sellers what
they meant.

If for example, they mean the R component only, do they imply that X
must be zero, or that X can be any value?

If they mean the magnitude, do they imply that any angle of impedance is
acceptable?

Also missing is any bounds on efficiency.

I have heard from time to time on air, OMs boast that their tuner is so
good, they have matched it up with no antenna plugged in. Obviously,
efficiency is zero in that case. A tuner with lower internal losses
might not achieve the same feat.

Owen

On 9/30/2011 2:04 PM, Owen Duffy wrote:
Jeffrey wrote in news:j64hp4$i7g$1@dont-
email.me:

The two signals are essentially a "request to tune" and an "tune
complete".

That is not quite correct.

Did you miss the word essentially?

Since it bothers you. From LDG "Start Line." Ground this from an
external switch or open collector to initiate a tuning sequence by
the external tuner.

And "Key Line" This is similar to a PTT line to the transmitter,
but in this case tells the transmitter (which is capable of doing
it) to, regardless of mode, transmit a low lever CW carrier.

When the key line changes state because of a request to tune, it
turns on the transmitter. When tuning is complete, the key line
toggles back to it's normal state.

Though the protocol is not published by Icom, and the implementation varies
a little from radio to radio, the four wires are usually labelled and none
are "tune complete".

If you put an indicator such as an LED on the key line watching it
change state is a pretty good indication of "I'm tuning" and "Tune
complete" regardless of what it's called.

Jeff

--
"Everything from Crackers to Coffins"

On 9/30/2011 3:03 PM, Owen Duffy wrote:
Jeffrey wrote in news:j64hp4$i7g$1@dont-
email.me:

The Icom tuners are specified at 16.7 to 150 ohms.
The LDG Z11 Pro II is specified as 2-1000 ohms.
Oddly enough, the MFJ Versa Tuner has no specified range.

Impedance is not a simple scalar quantity as expressed above. The
'specification' is incomplete, you would need to ask the sellers what
they meant.

If for example, they mean the R component only, do they imply that X
must be zero, or that X can be any value?

If they mean the magnitude, do they imply that any angle of impedance is
acceptable?

Do you just like to argue? These are published specifications from
the manufacturer. If you have an issues with the validity of their
claims, take it up with them.

I suspect both Icom and LDG took the time to play with resistive
loads to verify the tuning range. If that is the case, then yes,
it's a simple scalar quantity. I doubt they took the time to fiddle
around adding a reactive components to the test loads otherwise they
would haved published a Smith Chart with a "We can match anything
within these bounds" as the specification for tuning range.

Also missing is any bounds on efficiency.

I have heard from time to time on air, OMs boast that their tuner is so
good, they have matched it up with no antenna plugged in. Obviously,
efficiency is zero in that case. A tuner with lower internal losses
might not achieve the same feat.

I am aware that a frightening majority of licensed amateurs wouldn't
be able to pour **** out of a boot with the instructions printed on
the heel. Perhaps you're unaware tha I'm not one of them.

Jeff-1.0
wa6fwi

--
"Everything from Crackers to Coffins"

Jeffrey Angus wrote in
:

On 9/30/2011 2:04 PM, Owen Duffy wrote:
Jeffrey wrote in news:j64hp4$i7g$1@dont-
email.me:

The two signals are essentially a "request to tune" and an "tune
complete".

That is not quite correct.

Did you miss the word essentially?

Since it bothers you. From LDG "Start Line." Ground this from an
external switch or open collector to initiate a tuning sequence by
the external tuner.

And "Key Line" This is similar to a PTT line to the transmitter,
but in this case tells the transmitter (which is capable of doing
it) to, regardless of mode, transmit a low lever CW carrier.

When the key line changes state because of a request to tune, it
turns on the transmitter. When tuning is complete, the key line
toggles back to it's normal state.

Though the protocol is not published by Icom, and the implementation
varies a little from radio to radio, the four wires are usually
labelled and none are "tune complete".

If you put an indicator such as an LED on the key line watching it
change state is a pretty good indication of "I'm tuning" and "Tune
complete" regardless of what it's called.

The /KEY line can be used to initiate a tune carrier, it is used to
sustain the tune carrier until the tx aborts or the tuner ends the
process, and it is used by the tuner to signal whether the tune was or
was not successful.

Owen