Home |
Search |
Today's Posts |
#22
![]() |
|||
|
|||
![]() Ed Cregger wrote: Yes, BUT, the 5/8th wave radiator will put more of the signal toward the horizon, instead of launching it at a 40 degree plus angle away from the horizon. So while one configuration can have higher dbi ratings, it doesn't count unless the signal goes where it will be most effective. That is born out he http://www.cebik.com/gp/58.html I have a friend (engineer) that designs and builds his boats (some rather large sailboats) with everything quantized mathematically. I showed up one day with a model sailboat sitting on a carry stand that I had made. He asked me how I calculated the angles needed to accommodate the hull accurately. He said that this problem had been bugging him for a while. I was surprised because this guy is really smart. I grabbed two rulers and put each one along the side of the boat and then clamped them at that angle. I then transferred the angle of the two rulers to a sheet of paper by simply drawing lines along the inside of the v that was created. His jaw dropped in surprise. He was amazed at how easy the process was and he realized that the same process would work with his full size boats. No math required. While EZNEC is a fantastic program, it is no better than the programmer that wrote it. No one person can take absolutely every variable into consideration because many of them are very, very complex and nearly impossible to quantize. I suggested a simple 1/2 wave J-pole antenna earlier that was easy to make, super easy to tune and one that worked very effectively. Yet everyone is beating their brains out trying to come up with the best 5/8th wave J-pole, even though this design will require lossy matching devices to get the impedance down to a manageable/acceptable level. What's up wid dat? I do realize that figuring out such a design is fun in and of itself and may be the real purpose of the exercise. Still, I'll betcha no one on the receiving end of the OP's signal could tell if he was using the 5/8th wavelength J-pole or the 1/2 wavelength J-pole. W4RNL may have provided the definitive work on the subject. http://www.cebik.com/vhf/jp4.html Ed, NM2K 73, ac6xg |
Thread Tools | Search this Thread |
Display Modes | |
|
|