General Forums > Antennas
Double Bazooka antenna plans
KE7TRP:
I just got this info from a friend of mine. They built this antenna and he said it does cover the entire 80 meter band under 2 to 1. His signal is stronger then his old wire and he no longer needs the tuner. I thought I would post this info up in case there are any other antenna experimenters out there.
C
W5LZ:
I don't doubt your friend's findings, but you have to keep in mind that they are subjective, not objective in nature. A bazooka antenna does have a wider 'apparent' usable band width, but only at the lessening of efficiency the further you get away from it's 'design'(resonant) frequency. As the frequency range increases from it's design frequency the efficiency of the antenna lowers because of reactance present in the antenna because of it's method of being 'fed'. Reactance doesn't radiate anything, it contributes to a 'dead' loss in radiation. The means of measuring SWR, a typical SWR meter can't distinguish between 'R' and 'X' (which combined equals impedance). The SWR meter 'sees' a combination of 'R' and 'X' that it 'thinks' equals 50 ohms impedance, but doesn't mean 'R=50' and 'X=0' at all.
Why does it seem like an improvement over his wire dipole? Because of how he's measuring things, using an SWR meter. Those things are just not very 'accurate' in measuring radiation efficiency, just impedance matching.
- 'Doc
KE7TRP:
I agree. There is no free lunch Doc.
What do you think about the loss of say a standard 80 meter dipole stretched to cover the entire band using a typical T match tuner, VS, having the Bazooka antenna with no tuner?
A typical dipole will have 150 KC of usable bandwidth before you must go to the tuner.
I enjoy experimenting and testing out different antennas so its all fun to me!
W5LZ:
In general, meaning that there are a lot of variable in that sort of comparison, I think it'd probably work out about even. Both are 1/2 wave antennas so the difference in 'performance' isn't going to be that different.
I don't mind using a tuner and have for a long time. I'm not too 'fixed' on having a 'perfect' antenna system, I've found that one that isn't exactly 'perfect' will do just as well in some cases. That tuner can also make an antenna 'usable' on other bands, sort of, you know? Tuners aren't a 'cure-all' but they can make things easier...
- Paul
KE7TRP:
I agree Paul. I enjoy working with antennas and plan to try a few different styles. I just wish it was not july in Arizona.. Its to hot to even go outside, yet alone, work on an antenna.
C
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