Saturday, October 22, 2022

Time to add a balun.


When I moved to the East coast from Ontario at the new QTH I purchased and installed an EndFed antenna and it worked great for me. It was a huge step up from the condo balcony mag loop antenna. The EndFed is a compromise-type antenna and does come with some issues. The main issue is (if you don't use a counterpoise) the coax shield is used as the counterpoise. This can cause some issues and an isolation balun is needed in the shack. I purchased a quality isolation balun from balun designs to take care of the feed line issues. In time I did install a counterpoise but it's not that effective when your Endfed goes from 10m-80m. 

I still had some RFI issues in the shack that ferrites did an excellent job in looking after. I still had some off-and-on issues with our electronic washing machine, the motion sensor light on the shed and some Google home devices. I then moved from the EndFed to a vertical antenna the Hustler 4BTV antenna. In the manual for the 4BTV, it is advised if you have any RFI issues due to the coax radiating RF place an isolation balun at the antenna. It seemed as time passed I was issue free. 

Drainage holes 1/16th

Now and then I started to notice while operating my Icom 7610 in CW mode I would have my N1MM contest program lock up. There was no rhyme or reason as to when this happened, what power level and what band I was on. I could make it through a CWops mini-test of an hour with no issues. The next CWops mini contest I had nothing but issues. I also noticed when using my VPN on the PC I would have the VPN disconnect and then reconnect messages coming up as I transmitted. I was reading online when coax radiates RF it can be very hit-and-miss as to when it happens and what is affected each time. This sounded like the issue I was having and I decided to place the isolation balun at the base of the 4BTV vertical. 

Once the isolation balun was installed I am RF free and have been for over a month now. My electronic washing machine, N1MM logger and VPN connection have no problems. 

Waterproof connections

I had to take into consideration some precautions when putting the isolation balun outdoors. It was recommended to drill 2 1/16 holes in the bottom so any condensation would not build up inside. Also around all PL-259 connections, I waterproofed them with self-amalgamating tape.


MadDogMcQ said...

Hi Mike, I was getting a little bit of RF in the shack a while ago. It was hardly noticeable and I only noticed it when I tried to use my computer mouse while transmitting.

Anyway, I bought an MFJ-915 RF ISOLATOR and inserted it right at the back of my radio. It works a treat!

Take care,

Tom, M7MCQ

VE9KK said...

Hello Tom, yes RFI can be an issue that shows itself at the most inopportune times. As for the self-amalgamating tape I have had in on my End-Fed connection for over 3 years now with no issue so I am going to forgo the regular tape for now.