Double Bazooka Advice needed:

[Vortex Joe - N3IBX]

Hello All,
             Does anyone have any knowledge of or experience working with double bazooka antennas? How do they compare to inverted vees, dipoles, etc. Is it best to install them as an inverted-vee, shooting for maximun vertical polarization and a lower angle of radiation?

I've been thinking of installing a double bazooka on 160M, and will probably have the feedpoint at about 60' or so. Any advice or tips will be greatly appreciated!

[W2VW]

Isn't that a scheme to make the king of all instruments read the all important value of 1:1?
What happened to your balanced tuna?

[Pete, WA2CWA]

I think we beat this one to death here last year.

Some people swear by them and others just swear at them.
Slightly greater bandwidth than a dipole but with higher losses. Made of coax, so much heavier stress on the antenna supports. Some claim gain over a dipole and "quieter" than a dipole. Lots of stories, pro and con, on the use of a double bazooka. I had one as an inverted vee for 75 years ago before it came down with a layer of ice on it. Found no difference when it was replaced by a dipole configured as an inverted vee. For 160, the weight will be even heavier.  A dipole configured as an inverted vee will work just as well and probably will stay up longer.

You should also read Walt Maxwell's article in Ham Radio, August 1976, "A Revealing Analysis of the Coaxial Dipole Antenna".

[Jack-KA3ZLR-]

Hello All,
             Does anyone have any knowledge of or experience working with double bazooka antennas? How do they compare to inverted vees, dipoles, etc. Is it best to install them as an inverted-vee, shooting for maximun vertical polarization and a lower angle of radiation?

I've been thinking of installing a double bazooka on 160M, and will probably have the feedpoint at about 60' or so. Any advice or tips will be greatly appreciated!

Morning Joe,

 I have Built and tested a few, NOT for 160 though..Atsa a lotta wire OM, 248 feet worth or better when tuned...UM, they do work, OK, but height is a MUST and 90 feet at the Apex OR Better is the Premium...if you wana see any, well, Quote"Projected Gain"Unquote...Da, BUT, what is Nice is the Noise Factor, with nothing exposed there is a reduction in static build up.....it has been said that Noise is reduced 6dB, again Projected...But i have noticed this...Nice an Quiet Antenna...Like a Loop...same same...you outta try a loop to Joe if you have the room...

 Build as an Inverted "V" center at 90 ends at 20 length 248 Ft.the ones I built i ended up lengthing them, but for 160 you'll have to try it, it'sa Lot of coax to sacrafice...it has Nice vertical properties...there are two versions one is all coax and the other adds twin lead, supposedly it lends itself to non radiation of harmonics and there is no feedline radiation, subsequently no TVI problemos...if that's a problem...

 length of coax is L=325/Freq for the coax, and the overall length is L=460/Freq. Now Total overall length minus Coax length=Twin Lead length then divide in half.

________ _______________ _____________ ________
Twin Lead*************Coax************Twin Lead

The Antenna Works, Works well, Projected Figures for Gain..well they're projected you'll have to decide that for yourself...I like the antenna but it's a hasstle getting up and keeping it there..

 Height is the Factor OM, The Higher the better...this my Take Joe hope it helps...

[W3SLK]

Joe,
 Ray, WD2AFJ did a variant on a double-bazooka. He used it as an inverted L on 160 with very good results. It was pretty much half of Pete's design where you used ladder line for the top section. I think if you prod Ray a little, he may be able to find the literature he had for the construction. He ran his T-368 & 810 rigs without any ill effects.

[Vortex Joe - N3IBX]

What happened to your balanced tuna?

Dave,
        I still have it and use it exclusively. I SWEAR by it! I just want to try something as a diversion to see if I could cut the Summertime QRN a bit, and put it up just to experiment with it. The antenna is already built and ready to go up as soon as I'm physically able to hang it (got some health problems with my left knee, but that's another story).

I'm very concerned about the interaction with the 260' dipole and the current fed 123' Marconi. The Marconi isn't worth a fiddlers f$%!,(6-12db down from a reference diople) so I'll most likely take it down. Again, it was an experiment. If I could get something that would cut my rx noise down a bit, it might be worth a try. There's only one way to find out.

Many thanks for your inpoot!

[Vortex Joe - N3IBX]

Joe,
 Ray, WD2AFJ did a variant on a double-bazooka. He used it as an inverted L on 160 with very good results. It was pretty much half of Pete's design where you used ladder line for the top section. I think if you prod Ray a little, he may be able to find the literature he had for the construction. He ran his T-368 & 810 rigs without any ill effects.

Mike(y),
           Was that the one he had up about two years ago when the original trap inverted-vee gave him problems?

[Vortex Joe - N3IBX]

Jack,Dave,Pete,Everyone,
I GREATLY appreciate your inpoot. I've spoken to a few people on the air about double bazooka and the consensus is as varied as taking a survey on the attributes (or lack thereof) of using a G5RV. A lot must depend on soil conductivity, interaction with other antennas, configuration (it seems unanimous that it's best configured as a "vee" due to a lower takeoff angle and the physical bulkiness of the antenna). I guess the only way to find out is to hang it and give it a "roadtest".

I've also read that it's very broadbanded. From a performance aspect, this doesn't sound like a good thing to me. If it has a lower "Q" I would suspect it also has lower performance to a reference dipole. Also, I can't understand why it's supposed to have "quieting" attributes if the polarization is mainly in the vertical plane when hung as a "vee". I would think that would be a disadvantage, particularly on 160M.

Best Regards,
                   Joe N3IBX

[K1JJ]

Hi Joe,

A dipole is a dipole is a dipole.

As the guys have said above, the only advantage of a Bazooka is using a bigger cross sectional conductor producing a broader swr curve/match for the 50 ohm coax.  To cover the 160M band completely this can be important since 200kc on 1.9mc is a big percentage vs:  200 kc on say, 14mc.  [10.5%  vs: 1.4% !! ]

Discharge noise will be the same as using a bare wire dipole -  as will atmospheric noise. The dipole doesn't know the difference between a real signal and atmospheric/lightning noise....    In additon, I've used PVC covered wire vs: bare wire and see no difference from static build up [popping] nor see any difference when Yagi elements are grounded to the boom or are insulated.... same schtick according to the ant gurus I've talked with about it too.

Putting a dipole into an inverted V is a compromise compared to using flat legs. I don't buy the "better lower angle" story with sloped legs as being an advatage for a few reasons.... Lower angle is a function of height above ground and sloping the legs down will lower the AVERAGE height above ground - plus sloping will create more radiation cancellation as well as ground loss/coupling at these lower freqs where height is so precious.  For an extreme example, picture the antenna legs VERY close together and you will create a transmission line that will not accept ANY power.

In addition, the more vertical polarization you have (as a percentage) the better radial system you better have in the ground to return RF currents to the feedpoint.  A flat, horizontal and high dipole is pretty much immune to ground system requirements, though a low one can be more dependant if the Earth soil is marginal.

If you were to comapre a properly matched coax fed dipole, openwire fed dipole, "double bazooka"  or any other version of a dipole, [at the same average heights] you will find they are close to the same.... assuming they are in the clear and not INTERACTING with each other. Adding another dipole within 300 feet of another on the same 75 or 160M band is inviting pattern interactions.

I would stick with your open wire 160M dipole that is as flat and as high as possibe in the clear, and be assured that it will put out the best signal you can for local 160M work, bar none.  A flat dipole in the clear about 1/4 wave above ground is the best antenna for LOCAL work you can find. I've tried them all and always come back.

73,

T

[Steve - WB3HUZ]

There are no non-directional antennas I've ever heard of that can reduce the effects of QRN. Claims for "quiet" antennas are usually for those that respond less to local noise or are just bogus.

Your best bets for beating summertime thunderstorm QRN are directional antenna systems:

* small rotatable loop (even better if combined with a phased monopole for unidirectional pattern

* beverage(s)

* use of a phasing box (MFJ or similar) with two antennas


The idea with all these antennas is to place a null in the antenna system pattern in the direction of the offending thunderstorm.

I understand Eimac also makes some static elimination devices.

I just want to try something as a diversion to see if I could cut the Summertime QRN a bit, and put it up just to experiment with it.

[W3SLK]

Steve said,

Claims for "quiet" antennas are usually for those that respond less to local noise or are just bogus.

I would dispute that Steve. The loop that I use is technically a DC short, since I feed it with coax. I don't suffer the noise associated with dipoles in dry climates. IE Low humidity snow storms whereas it causes 'snow static' since the the static potential is shunted to ground. Other than that, you stand correct.

[K1JJ]

Steve said,

Claims for "quiet" antennas are usually for those that respond less to local noise or are just bogus.

I would dispute that Steve. The loop that I use is technically a DC short, since I feed it with coax. I don't suffer the noise associated with dipoles in dry climates. IE Low humidity snow storms whereas it causes 'snow static' since the the static potential is shunted to ground. Other than that, you stand correct.

Mike,

There's many opinions on this, of course.   Here's mine...

I feel generally it doesn't matter whether or not an element is a DC short or in the case of a Yagi, grounded to the boom or not. The static discharge popping  you hear is caused by something other than that, like a piece of gear in the shack like an ant tuner or whatever holding a charge and discharging..  An element that could short out static will also short out a signal too.

One way to put both systems at par is to add an RF choke across the feedline at the antenna and in the shack. I do that here and find I have no more "pops", but snow static is still there. Some antennas have more "snow static" than others, but I feel it is not related to the configuration of the driven element or parasitic elements being at DC ground on the boom for that  matter.  I have both grounded els and insulated els on Yagis and see no diff. In addtion, I have up several high quad loops on 75M that are DC shorts... and they are just as noisy as my dipoles/Yagis with single driven eles.

But, then, that's just my own experinences...

73,
T

[W3SLK]

Tom said,

The static discharge popping you hear is caused by something other than that, like a piece of gear in the shack like an ant tuner or whatever holding a charge and discharging

I won't dispute that point. I was making the point that "I" don't get the static build-up so typical of dipoles. I remember the last one I had up (which was the reason I went back to the loop), would snap and pop into the antenna tuner/transmatch. I don't have that anymore. What would be interesting would be to attempt to measure the static of both of them side by side. Unfortunately, that won't happen, (at least at the new QTH) since the supports won't be there for a dipole. However there are some interesting possibilities.

[Jack-KA3ZLR-]

Build the Antenna Joe,

 Build it and use it as a Single band Antenna as it is designed for, it will Not Radiate Harmonics of the design operating frequency, and what's nice is there's Little or No Feedline radiation, that's a Big Plus.

 Build it as an Inverted "V" and feed it direct with 50 Coax, the outside of the Coax and the Ladder line acts a 1/2 wave dipole, the inside of the coax which does not radiate are quarter wave shorted Stubs, thus we have Termination...which will present a High resistive impedance to the feed point at resonance, off resonance, the stub reactances cancel the Antenna Reactance, thus increasing the Bandwidth of the Antenna.

 We're Not Talking about Gain, we're talking of a More Efficient Dipole IMHO.
 And i did note some quieting....

[Pete, WA2CWA]

A dipole is a dipole is a dipole.

Discharge noise will be the same as using a bare wire dipole - as will atmospheric noise. The dipole doesn't know the difference between a real signal and atmospheric/lightning noise.... In additon, I've used PVC covered wire vs: bare wire and see no difference from static build up [popping] nor see any difference when Yagi elements are grounded to the boom or are insulated.... same schtick according to the ant gurus I've talked with about it too.

Tom, said it best.

Having used both double bazooka and inverted vee type antennas over the years,  an inverted vee is nothing more than a dipole with drooping legs. Make it from coax, bare wire, covered wire, 3 inch metal irrigation tubing, etc., it's still a dipole with drooping legs.