[K3PZN-List] bozooka antenna verse diapole antenna

[Curt Milton]

Ray
 
actually the dipole I made stayed in the bag.  Pete made a 40m dipole so we erected it on the club's mast.  on your rocket launcher we supported the 80m windom (commercial) that Pete brought.  
 
(our Field Day 'conops' actually worked pretty good to minimize the number of antennas we needed for our 4A station!  my little beam got us to KH6 on 20m - the mismatch on 10 and 15m did not kill us given scarce propagation.  we used 40m dipole for CW and SSB -- and the windom was used for 80 and 15m).  
 
what a 1:1 balun does for a dipole is to make its pattern more perfect.  it is intended to keep the signal from traveling onto the coax outer conductor (it's outside surface) -- where it would radiate from there.  I suspect for a dipole very high above the ground (like greater than one wavelength up) one would sense a difference.  But likely its less than an S-unit.  
 
a dipole will work fine without a balun.  a piece of PVC pipe makes a nice center insulator.  one can drill a hole through it to support the coax, then solder connections to the two wires.  or one can attach a connector to make the coax separate.  
 
if you use a balun, please insure it can handle 100 watts or whatever max power you seek.  for running an amplifier I would skip the balun entirely.  (ok I tend to be a CW op - some may buy a 1 kW balun to keep RF out of their microphone?)
 
if you are interested in an elegant portable antenna for higher bands -- check out the buddipole.  but before you take out your credit card note he has build it yourself instructions there also.  but these days i can imagine someone would be perfectly happy to only use 40 and 20 meters from a portable site with simple wires!  (also here in the east we often have trees available - the buddipole guy is oriented to high places in California where trees are scarce).  
 
I am also posting this 'wisdom' (or QRM) to the list.  I suggest a simple approach as then there is less to go wrong for your portable operating.  
 
By the way, your highly elevated antennas at home are working well.  I suggest enjoying what works and discovering limitations over time before deciding if you need anything else.  
 
73 Curt
 

From: Kerri Wright <razor42 at hughes.net>
To: wb8yyy at yahoo.com 
Sent: Thursday, July 5, 2012 11:37 PM
Subject: Re: Re: [K3PZN-List] bozooka antenna verse diapole antenna


 HI  Curt thanks for info

ok so if I have wire cut for 80 40 and 20 what would you suggest for the center conductor with a coax feedline.   i was thinking of an mfj 918 1:1 balun would really like to have something portable that i kind of made with my own hands.   Hey what was the 40m that we strung from the ab577 mast was that a diapole you made?  Daughter and son in law and grandson are in from MN so we have taken the rest of the week off.   

ray 



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>I presume you might be asking about 80m?  
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>For 40m, a dipole generally covers the whole band.  Note the percentage:  300/7000 = 4.3%
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>In contrast for 80m its 500/4000 = 12.5% -- as a result a dipole using has a 'match' over a smaller part of the band.  Hence the interest in the Bazooka antenna.  
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>I confess to not having a coax fed dipole for 80m, but in this modern age I suspect a dipole with decent coax and a decent tuner in shack should work fine - particularly in this age of auto tuners.  If the dipole has its resonance near the middle of the band, it might be ok.  
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>I can't remember if one of your wire antennas is ladder line fed?  If so the bazooka has no advantage over it - because ladder line is even lower loss than coax.
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>On the higher bands - greatly mismatched coax has a more dramatic effect -- the multiple bounces combined with higher coax loss equal greatly reduced power.  As a principle, coax is best used with matched antennas - but on 80 and 160m one can get away with some mismatch.  Usually the first problem down there is RF into the microphone.  
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>I sense bazooka antennas were much more popular before auto tuners - to minimize labor in operating a station on 80m.  They tend to be expensive and heavy as they are made of coax - so I suggest sticking with a dipole.  
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>I wonder what others think on this?
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>Curt
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>From: Kerri Wright <razor42 at hughes.net>
>To: k3pzn-list at mailman.qth.net 
>Sent: Thursday, July 5, 2012 4:18 PM
>Subject: [K3PZN-List] bozooka antenna verse diapole antenna
>
>
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