[RFI] New equipment shake down...

[Dave (NK7Z)]

Forgot, no attachments, see:

https://www.nk7z.net/wp-content/uploads/2022/11/Proof-of-Coneept.jpg

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 11/24/22 11:22, Dave (NK7Z) wrote:
> Howdy,
> 
> I am testing a totally new setup for DFing...  An untuned, small, 
> shielded loop, and a Icom IC-705.
> 
> I want a fast setup and tear down process, and I want to be able to 
> distinguish between multiple RFI sources.  The 705 has a waterfall 
> display, so I can see different RFI signals.  This allows me to null 
> just the one I am interested in.  It is odd to see one pattern null 
> while the other pattern does not null...  But it works like a champ!
> 
> I have two strong sources close to me, one is a current pain in the 
> rear, (I am getting ready to report it), the other was a pain in the 
> rear, and has been dealt with, (thank you Steve at the ARRL), and is no 
> longer a problem.  This pair sources makes a perfect test bed for this 
> sort of thing...  So using the above setup I headed out in the field...
> 
> I was able to easily distinguish each source of RFI from the other, 
> using the spectrum analyzer style display of the 705.  This enabled me 
> to null the RFI source I wanted.  Then using the nulls I found via the 
> loop, I was able to take a few bearings, and add them into SigTrax.  See 
> attached image.
> 
> I have three more images, each closer to the source than the ones 
> attached.  Each image show greater and greater detail, as to the 
> location of the RFI source.
> 
> I am completely satisfied with the loop, and the directionality of the 
> nulls, even though it was just hand held and loose...  Next step is to 
> get the loop mounted in a way I can just yank out of the back of the 
> car, take a bearing, and move on...
> 
> I will build a small cross like you see in church,  then pivot the 
> horizontal section so it is parallel to the vertical section for 
> storage, and perpendicular to the vertical section for usage.
> 
> I'll add some sort of loop hangers, so the loop can be hung in a hurry, 
> (in a repeatable fashion), then permanently mount the feedline and 
> ferrites, (must keep the pattern symmetrical for best nulls), on the 
> vertical part of the mounting frame for the loop.
> 
> That will give me a loop, I can coil up and put in a small bag, and a 
> stick...
> 
> I can take the stick out, open up the cross piece, hang the loop on it, 
> connect it to the feedline, plug it into the 705, and start DFing...
> 
> This should allow for a very fast stop, take a heading, and move on, 
> sort of approach to DFing...
> 
> Happy Thanksgiving to all of you!!!
>