New Coax Choke And A Mobile DX Contact

I decided to redo the run of coax in my truck and see if I could solve a few issues.

I read somewhere on the Chameleon Antenna website that 25ft of coax was ideal. Why that was I don’t remember. Originally, I had 25ft snaked through the cab so it would use all 25ft and end up clean and have no extra at the antenna feed point. This worked fairly well.

I have had some frustrations with performance. I could make contacts up and down the west coast with relative consistency and occasionally longer range contacts.

After reading through the forums, I discovered that it was also advised to create a choke right under the antenna at the feed point. I never really bothered with this since it seems to mostly be used when excessive noise is heard in a mobile environment and this had never been a problem. As I learned, (yes I keep learning) it reduces common mode currents. I’m not sure I fully understand this yet, but I thought I’d give it a try since I heard it makes the antenna more efficient…at least as I understand it.

So, I re-ran the coax straight through the firewall and across to the left side which left me with about 10 extra feet of coax. I created a 7 turn choke that sits about 12 inches from the feed point. There did seem to be a little less noise but nothing substantial.

Now the big question, will I be able to make any contacts?

Today, I had to pick a friend up from the airport. On the way, I tuned around 17M and heard a pile-up with a guy in Portugal. I usually don’t even bother with those because I’ve never had any luck and it’s always been a waste of time. This time was different. I kept trying for about 15 minutes or so. I wasn’t having any luck and just when I was about to give up, I gave my call one more time. He came back with a 5/5 report. Well now, that’s pretty damn good for a mobile install. Maybe luck played a big part in it, but a contact with someone 5200mi away was a first for this antenna and it happened the day after I re-ran the coax and made the choke.

After dropping off my friend, I headed home and started tuning around 17M and heard someone calling CQ. I was only a few minutes from home, but wanted to answer. He came back on the first try. He was running 900W and I received him 5/7. He told me I was coming in at a nice 5/7-5/8 with my 100W mobile station.

Is this just a fluke or did that choke really improve things? 17M was only forecast to be “fair” today and usually I need “good” to have much luck. I suppose time will tell. I’ll keep you updated.