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Author Topic: Double Bazooka antenna plans  (Read 23047 times)

KE7TRP

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Re: Double Bazooka antenna plans
« Reply #15 on: July 29, 2013, 11:33:34 AM »

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K3DAV

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Re: Double Bazooka antenna plans
« Reply #16 on: August 02, 2013, 08:43:04 PM »

Clark, one of the reasons the 75 meter DBZ is not as broadbanded is because you used RG-11  75 ohm coax to make it.  75 and 160 meters are very picky with that kind of thing.  And if you used the RG-11 for the 40M DBZ, I am a little surprised that your SWR is that good, but then again 40 meters is not as picky.

Bazookas work best with regular basic RG-8 or RG-8X.  Bazookas love leaky coax.  Coax with tight shields do not perform as well,  And never use a coax with a foil lining around the foam insulator to make a Bazooka.  They still work but they are nowhere near as broadbanded.

It sounds like the 40M DBZ is going to work out very well.  Mainly you will notice weaker signals seem a bit cleaner because of the lower noise floor as your video shows clearly.  I watched your meter closely as you switched between antennas, and I think I saw a slightly higher signal on the Bazooka.  Not a big difference mind you, but that lower noise floor alone makes it worth it.  The choice of LMR-400 for feedline is a good idea.  That is the only coax I use these days.

Good goin' Clark.
« Last Edit: August 02, 2013, 08:52:50 PM by K3DAV »
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KE7TRP

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Re: Double Bazooka antenna plans
« Reply #17 on: August 03, 2013, 12:04:26 PM »

Yes. Performance is very close. This was a surprise as the open wire line antenna is a double on 40 and has some slight gain. 

I am really enjoying the lower noise floor and lack of noise.  The signals are slightly higher on RX and weak signal is far better.

The RG11 is much lighter coax and it Is 75 ohms and that really helps when you run full size coax like this from a weight standpoint.  When the weather cools off, I will try some RG8U and see if the bandwidth increases.  For me, I don't mine walking out to the yard and unfolding the ends of the antenna to work 80 meters.  It takes about 5 minutes and I take the golden retriever out back all the time anyways.
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KE7TRP

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Re: Double Bazooka antenna plans
« Reply #18 on: August 04, 2013, 01:05:36 PM »

I have a problem with SWR on the 80 meter DBZ.  I had it tuned very flat.  I then installed it on a Fiberglass Arm of the top of the tower,  Now the minimum SWR is 1.8 to 1.  I swapped feedlines with no change.  I moved the legs around with little change. 

I had this same antenna and feedline pulled up the tower with rope and pulley to the same hight and the match was low. Now its high.  I have exhausted Ideas for now. 

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