I looked at the data sheet on this and my intuition told me the top hat didn't make sense either electrically or mechanically. I did some quick and dirty modeling with EZNEC over perfect ground and got a drive impedance around 6-j34 at 1.83 MHz. I then deleted the horizontal skirt wires and pulled out the 39 foot top loading wires to a 45 degree angle. I then got a drive impedance of around 8-j9. A rope tied to the guy anchors in the manual works perfectly to do this. These hybrid wire/ropes then become top guys. Its almost as if this was the original design, and then they wanted to make a fancy top hat. The data sheet brags about the uniform current in the vertical, but this simplified version kept the current within +/-7%. Good enough for me. I don't have a mechanical modeling program, but I don't like the DXE design in that respect either. It doesn't lend itself to a falling derrick erection method, so you have to use their patented winching fixture and bolt it to a concrete base. It seems like this is the hard to way to build a vertical.
I needed an emergency 160 meter vertical a few years ago and I made a 60 footer out of 2 30' long 3" diameter irrigation pipes with 2 top loading wires pulled out. A third pipe was used as a falling derrick. Pretty simple and it worked great. Rick N6RK On 1/1/2016 8:16 AM, K4OWR wrote:
:::: Does anyone recall that I originally asked about this? http://www.dxengineering.com/parts/dxe-160va-1?seid=dxese1&gclid=Cj0KEQiAno60BRDt89rAh7qt-4wBEiQASes2tUOULTlQpNyMARBk4ZWRxw70jODW_FJCuBJ1Td47YMgaAhgQ8P8HAQ I appreciate all the advice, but a lot of people recommended antennas that I have had for years. BILL K4OWR _________________ Topband Reflector Archives - http://www.contesting.com/_topband
_________________ Topband Reflector Archives - http://www.contesting.com/_topband
