Hi John,

Pin 7 of the Acc connector is the transmit inhibit input that is enabled
in the config menu.  That is the only way to ensure that the K3 remains
in Rx until the sequencer has completed its cycle. I use this with all
my transverters and LNAs to ensure their correct sequencing.

It is described in both the manual and the F Caddy book.

As you are using the PQL amplifier I assume that you are also using the
PQL control board V6 that has an output that may be used for this
purpose, just check the polarity of the output as it may need inverting.

Good luck with your project

73

Peter

G3SMT



On 23/09/2018 19:54, John Stengrevics wrote:
Hi Peter,

Thanks for the reply.  But, what would I be using an ACC cable for?

73,

John
WA1EAZ

On Sep 23, 2018, at 3:41 PM, Peter Torry <peter.to...@talktalk.net> wrote:

Hi John,

I agree with Don's comments as I use a K3 with an amplifier and an LNA in a 
similar configuration to yourself.  I would never use ALC under any 
circumstances to avoid radiating a poor signal. To protect the LNA I use a 
signal from the sequencer in the amplifier to inhibit the K3 from transmitting 
until the sequencer has done its stuff.  Setting the delay on the K3 still 
leaves you at risk as 20ms is too short a time for all the relays to operate 
satisfactorily.  Use pin7 on the acc connector as detailed in the manual on 
transverter control - TX INH.

73

Peter

G3SMT


On 23/09/2018 15:29, John Stengrevics wrote:
Hi Don,

That was timely as I just got off Skype with Jim, W6PQL.  He mentioned that the 
ALC should be held high for some milliseconds to allow for the amp’s relays to 
switch over thereby protecting the LNA.

Since the K3S works differently than most, he suggested that I look for an RF 
Hold-Off setting on the K3S and set it for around 50 milliseconds.  That being 
said, I don’t see that in the manual or in Fred’s book.  Any suggestions?

73,

John
WA1EAZ

On Sep 23, 2018, at 11:12 AM, Don Wilhelm <donw...@embarqmail.com> wrote:

John,

I do not understand how the amplifier or the ALC could protect the LNA.
I assume the LNA is only used on receive, so if you have good sequencing 
between receive and transmit, no damage could occur.
ALC is only applicable to transmit, and Elecraft does not recommend using ALC 
to limit the drive to the amplifier.  Set the power to the amp properly and all 
will be well.
Using ALC to control the exciter power is a bad way to do things, it will only 
lead to distortion and spurious emissions from the amplifier.

73,
Don W3FPR

On 9/23/2018 10:58 AM, John Stengrevics wrote:
My apologies - I should have added that I am using a Downeast Microwave DTR 
relay to take the LNA out of the line when voltage applied to the relay drops 
as a result of transmission.
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