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400 foot inv.vee fed with window line

Mar 20th 2015, 15:04

K4PDM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I've been using a 400 foot inverted vee fed with window line and a 9:1 balun on all bands for many years. The center is at about 50 feet and the ends are at about 5 feet. The antenna works so well and is so simple, I've never really considered any other wire antenna to go with my trap vertical.

However, lately I have read articles that seem to indicate that the antenna might actually do better if it were shorter due to the multiple lobes such an antenna will have, especially as the frequency is increased. I've also seen articles to the effect that I would do better with a 1:1 current balun such as the one in my tuner, as opposed to an external 9:1 balun.

Thoughts?

73 Paul K4PDM
Mar 20th 2015, 18:51

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

Are there directions in which the trap vertical is consistently better than the inverted vee that you find important?

The best solution might be a simple dipole to pick up an important direction. Changing your existing antenna to remove a null in one direction might very well create a problem in another highly desired direction--perhaps on another band.

Propagation does tend to change with the seasons--the best over the pole propagation tends to be around the Spring and Autumnal Equinoxes--right now would normally be pretty good--except to the recent solar flares that wipe out the HF bands. But, it is a lot of work for most hams to move around fixed wire antennas--so they tend to be in the same place for years.

Typically, you want moderate impedances at the antenna tuner output--too low and you get excessive losses in the tuner. Too high results in high voltage issues and possible balun overheating. In theory, swapping the balun for optimum performance makes a lot of sense, but, in practice, I don't know of anyone who does that. One could use a 4:1 balun backwards to step up low impedance loads and improve tuner efficiency.

If you have all band antenna that works well you should consider yourself fortunate--a lot of folks have antenna that falls a bit short of that--failing to work on one or more bands.

Zack Lau W1VT
ARRL Senior Lab Engijneer

Mar 20th 2015, 20:03

K4PDM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Thank you, Zack. Good info.

The terrain around me is very hilly. I don't know if any directionality is caused by hills or nulls in the antenna pattern. Some signals are stronger on the vertical, some on the wire, but it does not really correlate with distance. Guess I will stay with what I have.

73 Paul K4PDM

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