Home |
Search |
Today's Posts |
|
#1
![]() |
|||
|
|||
![]()
On Nov 2, 2:54 pm, Tim Shoppa wrote:
I am very very proud that I hung a 80-Meter dipole about 100 feet above my QTH last week. But I also had a hankering to cover 40 Meters with it too (although I already had a 40 Meter dipole). So the section in the antenna book about fan dipoles came to mind. I looked in the ARRL antenna book, it told me that the seperation of wires was not all that important. So I sort-of duplicated one of the sketches in the book, and hung the 40 meter wire from an tiny little egg insulator on the 80 meter wire. I've been running those for years. Placing the wires closely together is a problem as far as coupling, and it almost always effects the higher of the used bands. The best way to orient is at right angles, if looking from overhead. At right angles, there is basically no interaction at all, and the dipoles act pretty much the same as if separate. In fact, I've had legs fall down and have no effect on the other bands. The closer the wires, the more coupling, and the more tweaking you will have to do to get the higher band tuned. I've even seen cases where the higher band would tune a higher frequency by adding more wire. Exactly the opposite from normal. I don't really like having the wires in the same plane at all, but if no choice, I would use as large a spreader as possible. I often have multiple bands.. Here at the house, I presently have an 80m turnstile, and a 40 dipole on the same feedline. At my place in OK, I have 160,80,40 and 20m on the same coax feed. All wires spread as far apart as possible. Looks like a big spider from overhead. MK |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
80+40 MTR Dipole | Antenna | |||
Fan dipole.. | Antenna | |||
off set dipole | Antenna | |||
best low dipole? | Antenna | |||
80/40/30M dipole? | Antenna |