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SDR on K3 IF to look for RFI

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Jim AB3CV

SDR on K3 IF to look for RFI

Now that 160 season is almost over and my antenna farm is doing good I'm
going to start chasing RFI at my new QTH.

I plan to use my RSP2Pro with HDSDR to do some time lapse recording to see
when things come and go as a first step.

To do this I plan to use my existing antennas and I'd like to avoid
connecting and disconnecting my rig as much as possible.

So I'd like to use the IF port of the K3s. That's currently passed to the
P3 and I thought I could use its IF output to drive the SDR.

That would allow me to leave it connected all the time even while using the
K3 for normal use.

How wide is the bandwidth of that port? Is it limited to the 200Khz the P3
presents?

Thanks

Jim ab3cv
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NK7Z

Re: SDR on K3 IF to look for RFI

Hi Jim,

You want to look at a wider range of frequencies than the K3 IF
presents. See:

https://www.nk7z.net/sdr-rfi-survey-p1/

for a how to do this, using an SDRPlay radio.

That link goes to part 1 of a multi-part set of articles covering how I
use SDRPlay radios to see just what is happening in my RF world. Part 2
covers interpreting what you see using a very wide band long term
recording of your RF environment. It helps very much in taming RFI to
look as you are proposing to do.

73s and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL OOC for Oregon

On 4/1/19 7:22 AM, Jim Miller wrote:

> Now that 160 season is almost over and my antenna farm is doing good I'm
> going to start chasing RFI at my new QTH.
>
> I plan to use my RSP2Pro with HDSDR to do some time lapse recording to see
> when things come and go as a first step.
>
> To do this I plan to use my existing antennas and I'd like to avoid
> connecting and disconnecting my rig as much as possible.
>
> So I'd like to use the IF port of the K3s. That's currently passed to the
> P3 and I thought I could use its IF output to drive the SDR.
>
> That would allow me to leave it connected all the time even while using the
> K3 for normal use.
>
> How wide is the bandwidth of that port? Is it limited to the 200Khz the P3
> presents?
>
> Thanks
>
> Jim ab3cv
> ______________________________________________________________
> 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
>

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Bob McGraw - K4TAX

Re: SDR on K3 IF to look for RFI

In reply to this post by Jim AB3CV

The approach I've used is to use a couple of BNC to BNC jumpers and a
BNC "T" connector. Connect the RX OUT to one side of the "T". Connect
the RX IN to the other side of the "T" connector. Connect the RSP2 to
the other port on the "T" connector. Then press the RX ANT on the
radio. This allows the radio to be active and the RSP2 at the same
time. All is protected when/if you transmit.

This gives a very wide bandwidth based on the front end of the K3 and is
much wider than the K3 IF.

73

Bob, K4TAX

On 4/1/2019 9:22 AM, Jim Miller wrote: