[AMRadio] new antenna and matchbox a bust.


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Tue Jan 30 08:38:10 EST 2007


Well, that's a thought!

I would be kind of reluctant to change things as
the antenna seems to be working quite well on 80 and 40,
but I must keep this in mind, instead of using end insulators
and rope, just tie the rope onto the wire and pull it through
and partway down the trees.

I think the wireman sells insulated antenna wire that
should hold up well in the sun.
As it is, I have thick strong rope, and #14 solid copperweld
and both have a high breaking strength and that allows me
to pull the antenna quite tight.

There is a difference when running high power though,
many here seem to be running moderate power, which will
work with mfj antenna tuners and various baluns and feedlines,
traps, etc, but some of that stuff may not work with 
higher powers and high swr's. 
I would worry about setting fire to the trees
running the wire right on them, depending on the voltage/
current points, insulation rubbing through, wet or dry
wood, etc....

Even though I turn things down, I still seem to blow out
the ham gear designed for 2000 watts, the swan peak reading
watt meter bit the dust, as did the diodes used to
read SWR in the heathkit antenna tuner.

I replaced the diodes (with 1N34a) but the meter needs
calibration now. A giant pain in the butt to get at the
parts and adjustments.

I wonder if I could use a better diode type, higher
voltage and current to withstand the spikes.

Does anyone know why germanium diodes (1N34a) seem to
be used in all the SWR bridge circuits?

What advantage does germanium have?

Brett
N2DTS





I have lots of insulated wire 
> First, Nice QSO Sunday night. 
>  
> Second,  my antenna is a full 80m dipole supported at 75ft by 
> two  pinetrees 
> that are <50ft apart, that means that there is a LOT of 
> Dangle  there(around 
> 35 ft or so I think). I just pulled the support lines over 
> the  trees, and the 
> ends of the dipole actually drape over the top and down the 
> back  of each 
> tree. Its insulated #12AWG stranded wire, fed with cheap 
> brown  300 ohm twin lead, 
> that drops down to a choke balun inside the attic (15  turns 
> at 4.5 inch 
> diameter).  This is definitely NOT an optimal  setup.  BUT I 
> do get out, and I've 
> been heard as pretty far off on AM, and  work the North East 
> with No Problems. 
> (I run a Valiant at about 120watts  output).  I can load it 
> up on any band 
> except 160, using my el-cheapo  MFJunk tuner. (160 causes 
> quite a light show)... 
>  The biggest problem I  have with it is that the pines are 
> always dropping 
> branches after storms and  sometimes they pull down the 
> antenna or part of it 
> with them. 
>  
> SO if there is a significant vertical portion to your dipole, 
> don't sweat  
> it.  It will just add some vertical polarization, and change 
> the pattern,  but 
> using trees will skew that anyway. 
> ______________________________________________________________




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