Sunday, October 6, 2019

Some positive steps forward with shack RFI

Old HDMI monitor cable
I have had some positive moves forward with regards to my RFI in the shack. I am the kind of person who has to sit back and just think things over, go on the internet and step back and have a good look around. Over the past few days that is what I have been doing. I have had great feedback from my blog readers and it has cause me to think and search out ideas. This was the first time I had ever had these types of issues in the shack but then again I have never used an Endfed antenna before. With regards to my internet adventures I came to the understanding that the Endfed antennas that uses the coax as a counterpoise there can be expected issues of RFI in the shack. My Endfed antenna from W1SFR does not have a separate counterpoise connection. On their website the purchaser is informed the coax is the counterpoise. With regards to my W1SFR Endfed antenna I have contacted the owner Steve many times via email with my questions. His support has been great and Steve has been very willing to afford me as much of his time as needed.
I am the kind of person that things just don't click right away and I need time to mull things over. One  thing that came to mind was my monitor issue I was having. I was using an HDMI feed from my PC to the monitor as I always have in the past BUT in the past I was not faced with the RFI issue. Chameleon Loop antenna  and I remembered the coax that came with the antenna had a set of RF
Chameleon coax choke
chokes on the coax. The reading that I have been doing the the comments on my blog all backed up the fact that with Endfed antennas there is a very strong possibility of RF on the coax if it is being used as a counterpoise. I was able to add the coax from Chameleon to my setup with the RF choke section of coax connected to my radio. I did some testings and found my capacitive touch keyer no longer locked up, my SWR was no longer speratic and I have not as of yet checked my electronic washing machine to see if it stops but that will be when the next load of laundry goes in.
I replaced the HDMI cable with a DVI cable that had RF chokes at either end. This solved my monitor issues of it waking up from sleep mode on it's own and characters showing up on the screen.
I did on Friday end up ordering the Balun Designs 1115 Balun and it should be arriving within the next week or so. My positive tests using the RF choked coax tells me that the purchase of the Balun was a good choice. My next step will be to try out a counterpoise that is 25 feet long secured at the PL-259 that feeds the W1SFR Endfed antenna and see what this step produces. I am hoping with the new Balun, the counterpoise and changing the monitor cable will solve the issues I have been experiencing.
It now the next day and my experiment with the separated 25 foot counterpoise have been completed. I stripped one end of the 25 foot piece of wire and attached it to the outside of the PL-259 using a screw clamp similar to the clamps you see on automative rad hoses.....but much smaller. I checked the SWR on 40m, 30m, 20m and 18m and it really did not change much but what did change was the amount of RFI what was showing up on my waterfall on the 7610. I then removed the counterpoise and the offending RFI was gone. So that was good enough for me I am going to keep the Chameleon coax with the chokes in place until the Balun from Balun designs comes in.

No comments:

Post a Comment