What use is an F-call? During the week I was spending a little time with an experienced amateur and I lamented that getting ferrite cores locally was a trial in futility. I'd spent hours attempting to find a reliable supplier and as of yet have not actually succeeded. I want to experiment with ferrite cores to build some antennas and to test different balun designs, seeing that the Internet is full of them, each with different opinions on what is good and bad, what works best and how to magically make something work with a balun. Of course I can read all I want, but actually getting your hands dirty is generally a better way to get a feel for what happens and what's needed. It was suggested that I could make an equivalent solution, creating a choke using coax cable, 6 inches, 6 windings was the suggestion. Since then I've also found 4 and 4 and 8 and 8 and other variations. I should note that I've not yet built one with all the other distractions in my life, but I'm feeling much less worried about locating a ferrite and much more confident that such a choke might get me what I need, the ability to build a dipole and string it up without RF coming back into my shack - which currently is my car. What this taught me is that the Internet is full of wonderful suggestions, but just chewing the fat with someone who's been around the block a couple of times will give you some hands on experience, which might get you to the next step of your understanding of Amateur Radio. So, talk to your fellow amateurs, buy them a coffee and see what they have to say. I'm Onno VK6FLAB