Richard:

Let me try to answer your quiry here, which, I think actually contains two
questions.

Before I say anything, I should tell you that I use an MFJ 998 auto-tuner
with my TS590 and Ameritron ALS600 amplifier.

First, I really would urge you to use the amp enable in and out jacks on the
MFJ998 if at all possible.  I do this differently than you will, because I
have an ARB704 buffer box between my TS590 and ALS600, so I won't confuse
things further by giving you the details as to how that is done.

Keep in mind that the amp enable in and out jacks on the tuner invoke an
amplifier bypass circuit in the MFJ998 which is an additional layer of
protection, should you somehow inadvertently try to tune with a bad SWR and
too much power.  I am certain this has saved me from catastrophy on more
than one occasion.

Second, when I got my ALS600, I, too,  was concerned about whether or not to
worry about the ALC connection.

Based on the advice from some list members, and from MFJ Tech Support, I
have decided not to worry about the ALC.  In my case, I typically don't
drive my amplifier with more than 50 or 60 watts max, so I believe I'm ok
there.

I'll be interested in what others have to say.

Tom Behler: KB8TYJ


From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Richard B. McDonald
Sent: Friday, January 08, 2016 6:50 PM
To: [log in to unmask]
Subject: Necessity to Use MFJ-998's "Amp Enable In/Out" with Kenwood TS-2000
and Ameritron ALS-1306?

Hi!

 

This is not a short, simple or easy (for me, anyway) question.  I will not
be miffed if nobody grapples with it.  On the other hand, if you do
contemplate this I will be forever grateful.  

 

I have a Kenwood TS-2000, an MFJ-998
<http://www.mfjenterprises.com/Product.php?productid=MFJ-998>  antenna tuner
and an Ameritron ALS-1306
<http://www.ameritron.com/Product.php?productid=ALS-1306>  amplifier.  Both
the 998 and the 1306 are connected to the TS-2000 with their specific
interface cables.  My question is if it is additionally necessary to connect
the 998's amp enable in/out cables?  Below is a bit more information.

 

The 998 has two jacks: 1) "amp enable in" RCA phono connector and 2) "amp
enable out" RCA phono connector.  Presently, I am not using these amp enable
in/out jacks.  However, the 998 is connected to the TS-2000 with the
MFJ-5114K <http://www.mfjenterprises.com/Product.php?productid=MFJ-5114K>
interface cable.  The 998 manual does say though: "Note: MFJ *recommends*
[emphasis added] that a transceiver-specific interface cable be used between
the MFJ-998 and your transceiver, and that an amplifier enable/bypass
connection be used between the MFJ-998 and your amplifier, to *ensure*
[emphasis added]e that tuning only occurs at low power."

 

The 1306 is connected to the TS-2000 with the Ameritron DB-DB7DK
<http://www.ameritron.com/Product.php?productid=DB-DB7DK>  interface cable.
Basically, this cable is like a "Y."  On the end with the two connectors
(both of which connect to the TS-2000), one of the connectors is rectangular
and similar to a serial connector and the other connector is round similar
to a mic connector.  The other end of the cable has one connector which is
rectangular similar to a serial connector; which connects to the 1306.  The
1306 manual describes the relevant rear panel connectors as follows:

 

-          ALC: Optional connection. Connects to radio ALC input.

-          RELAY: Connect to radio amplifier keying [relay] line.

-          KEY LOOP SWITCH: Switch to turn on and off the KEY LOOP function.

-          RADIO INTERFACE: This connector is for use with Ameritron radio
interface cables. *It also provides amplifier actuation in transmit mode
with some radios.* [emphasis added]

 

Again stating that the ALC is optional, the 1306 manual says "In general,
transceiver internal ALC is all that is necessary. The ALC monitors the RF
output power and reflected power supplied by the ALS-1306 to the load."  The
1306 manual goes on to provide the following:

 

"When using an automatic antenna tuner that has the capability to inhibit
the amplifier from operating either during tuning or when conditions are
outside of the tuner's capability[as does the 998]; and when the radio
interface has the Amplifier Relay line included (not using the RELAY jack);
the KEY LINE can be used. The KEY LOOP Switch is used to route the key
signal from the interface to the amp directly or out the KEY LOOP jack.

a.    If the KEY LOOP is not used set the KEY LOOP Switch to OFF so the
Radio Interface Cable can key the amplifier.

b.    If the KEY LOOP is used with an automatic antenna tuner switch the KEY
LOOP Switch to ON, run a cable from the KEY LOOP connector on the amp to the
AMP ENABLE IN connector on the tuner, and run a cable from the AMP ENABLE
OUT connector to the RELAY connector on the amp."

 

I emailed Ameritron about all this.  They said "The radio gets the end with
two plugs on it. The DIN plug has your relay key line and your ALC while the
DB-9 connector has your band data.  The round plug is a DIN plug and the
other is a DB-9 plug. The DB-9 plug connects to the COM port on the radio
and the DIN plug connects to the REMOTE port on the radio.  See page 13 of
the TS-2000's manual."

 

Seriously?  I have no idea what all the above means : (

 

Many thanks &73,

Richard KK6MRH