[Elecraft] [OT] K3 IF Output Port

[Jack Smith]

Yes, it's 15 dB transfer loss. It's due to the choice of voltage 
dividing resistors in the J310 source follower stage.

Half or a bit more of the loss can be offset with a change in the parts 
values in the voltage divider feeding the gate.

Another option is an outboard amplifier such as the Z10000 I've designed.

Jack K8ZOA
www.cliftonlaboratories.com

Don Nelson wrote:
> Hi all,
>
> I am wanting to use the IF output on the K3 with the installed KVX3 board. My problem is knowing what I need to administer to activate the IF output port. 
>
> With the K3 as is, I put a 14.270 MHz RF signal into the ANT1 port on the K3. The 14 MHz signal is from an HP 8640 at -120 dBm. The K3 is set to use ANT1. I connect the IF output from the K3 into an HP spectrum analyzer and see no signal at 8.215 MHz. The K3 is tuned to 14.270 MHz USB. So I put Mini Circuits amplifiers with 50 dB total gain between the K3 IF output and the spectrum analyzer. With the amplifiers in the path, I see a signal at – 85 dBm which suggests a signal out of the K3 on the IF output of -135 dBm. If I increase the 14.270 MHz signal by 10 dB I see a 10 dB increase in signal out of the IF output port.
>
> Is this right? I would expect a signal out of the IF output with much greater signal strength. In essence, there is a 15 dB loss in the signal path from the antenna jack to the IF output port in my K3 as configured. Is this correct? Is there something I need to administer? Where is this documented?
>
> Thank you for your help.
>
> Don, N0YE
>
>