I should take a little detour here, and say I picked up an antenna analyzer. No cutting and rebending, resoldering solid wire! So I trimmed down by the ratio of the intended center of resonance and the actual center of resonance. Now the great thing about copper foil tape: can score and peel it off. And sure enough the resonant frequency was a couple MHz below the simulation. 87-.95 (need to dig up the source again). This can vary for copper, but is in the neighborhood of. The physical dimensions of an antenna depend on a lot of things, but one of them is the velocity of propogation of the conductor. I've had issues with my antennas always resonating low, and so I suspected that I had a systematic bias of some sort. Plans made, and simulations indicating that the detuned antenna would still have some good gain, I began by simulating a simple dipole, and building said dipole. Such a tiny portion of the conductor conducting! Copper foils range typically range from about 50 um thick to maybe 150um.
I calculated the skin depth at 2m for copper to be about 5 um. I also needed something to support the conductors, which lead to the concept of using wodden dowels wrapped in copper foild tape. So I decided to try some bigger conductors to detune the antenna slightly. But simulations were showing, I wouldn't be able to get the full band at that length with 14 gauge wires. I chose to do a split boom design again, based on 6ft dowels that are available at Home Depot. I wanted to design a full band, high gain antenna.
And to satisfy my 2m needs that I can easily transport, I decided to try a Yagi for ease of construction. Never did get it to work on both bands at the same time, and it took up wayyy to much space. I started the write up a while ago, but can't find what I did with the file, so here goes starting the write up anew. So it's been a long time since I've updated here, and I really should talk about the latest antenna. Mushhead Radio KK6WLD Radio Related Reports