[Top] [All Lists]

Re: [TowerTalk] Moxon questions

Subject: Re: [TowerTalk] Moxon questions
Date: Thu, 16 Dec 2010 21:06:20 EST
List-post: <">>
Just curious here; were the broken wires at a soldered connection?
Gerald K5GW
In a message dated 12/16/2010 11:28:26 A.M. Central Standard Time, writes:

I  have a problem with a 30m Moxon. It is a two element yagi with 
aluminium  elements & wire to make the rectangle. The wire  is #16 silver  
coated stranded with teflon jacket. The wire broke yesterday at the  
element joints on one side of the rectangle. I assume one joint broke  & 
the wire was hanging  vertical. The wind made the wire fatigue  & the 
second wire to element connection failed & the wire  fell  to the ground.
I used a Y or yoke arangement to tie the wire to  the aluminium 
elements.I  didn't think the joint would fatigue in  just 4 weeks but it 
did. I  might put in little eye bolts & hang  the wire thru them with 
the wire tip bonded to the element end. That  might  allow flexing & ease 
the stress on the wire.
I have  been reading my ARRL antenna book this AM. I built it using 
Cebiks Moxgen  formula. The boom is 12'10'' which was the software 
spacing for the Moxon.  I am thinking of going to a basic 2 ele yagi. I 
can't change the   boom length. I would just add aluminium to the 
existing  elements. It  would be apx. 6' 6'' to each side of the 
reflector & 5' 5'' to the  driven element. The tips would probably be 
3/8'' taper to 1/4''.  A  bit floppy in the wind but I think it would 
survive OK.
My question is  the spacing. I'm guessing the  element spacing  @ 12' 
10'' is  .23-.27 wave. It would be  the minimum I could get away with &  
still have gain & F/B. The impedance should be in the 40-60 ohm  region. 
That is also close enough.
Mosley markets a TW32XL  2 ele  WARC beam [trapped] with a 12' boom. It 
covers 30/17 & 12m. Commercial  antenna makers of multi band trapped 
antennas play with the element  spacing & boom length to get a close to 
50 ohm feedpoint  impedance.
Anyone have any thoughts on my plan  or at minimum   how to  releave the 
stress on the wire /element  connection?

TowerTalk  mailing  list


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>