K3 IF Output Port

[Don Nelson]

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

[Jack Smith-6]

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
>
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[KK7P]

> ...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?

See <
URL:http://www.cliftonlaboratories.com/elecraft_k3_and_panadapters.htm >

73,

Lyle KK7P

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html