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Re: [TenTec] Open Wire Line - A CASE FOR OCFD

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Open Wire Line - A CASE FOR OCFD
From: Ronf404 via TenTec <tentec@contesting.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 20 Oct 2015 12:13:06 -0400
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
MFJ makes a series of passthroughs that fit under s standard window do you 
don't need to drill holes in windows or plexiglass. I use one for my long wire 
antenna (119' sloped over a 70' tree) which I feed directly. 

Ron, KX1W

Sent from my iPhone

> On Oct 20, 2015, at 11:02, Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de> wrote:
> 
> Feeding through house walls is simple Simon.
> Drill two holes through the wall.
> Insert a short piece of PVC pipe through each, and seal all on both sides.
> Insert a bronze screw through each pipe and fasten the openwire to each
> side.
> 
> Or with the sliding windows typically used in the states, just insert a
> piece of Plexiglas across the bottom, close the window until the Plexiglas,
> and drill holes in the Plexiglass.  You can secure the window with short
> pieces of wood.  That way they can't be slid open from the outside.
> 
> And if you are lucky to have wooden doors or window frames, just run the
> open wire through it, like I did in the pictures of my OKC QTH.
> 
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
> 
> 
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Barry N1EU
> Sent: Tuesday, October 20, 2015 4:29 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Open Wire Line - A CASE FOR OCFD
> 
> Great post Rob, great discussion!
> 
> I'd love to hear more about the practicalities of routing open wire line
> from feedpoint through heavily wooded lots, through house walls, etc etc, to
> the shack.
> 
> 73, Barry N1EU
> 
> On Tue, Oct 20, 2015 at 10:17 AM, Rob Atkinson <ranchorobbo@gmail.com>
> wrote:
> 
>>> Perfect example. Another would be a full wave dipole. :)
>> 
>> A full wave center fed dipole will be voltage fed and have a Z of 
>> around 5K ohms and put a vswr on the line of around 10:1.  The line 
>> loss is negligible because it is a balanced line with an air 
>> dielectric.  I will go up against a horizontal 1/2 wave balun and coax 
>> fed dipole on 40 m. with my balanced line fed horizontal 1 wave center 
>> fed dipole on 40 any day of the week and I will come out ahead across
>> 40 m.   Both same height.
>> 
>>> 
>>> But more generally, I'm talking about putting up a single dipole, 
>>> whether
>> center-fed or off-center fed, feeding it with open wire or window 
>> line, and loading it on all bands.
>>> 
>> 
>> Brown, you are off in your own world of open wire line hating and you 
>> are free to be irrational about it to your heart's content but you 
>> occasionally pop up in some on-line forum somewhere and I see your 
>> dis-information.  Perhaps you attempted the folly of feeding an 
>> unbalanced (i.e. off center fed) dipole with balanced line as you
>> included it in your description above.   Surely you understand the
>> concept of unbalanced load fed with unbalanced line and balanced loads 
>> fed with balanced line.  You don't feed an unbalanced load directly 
>> with balanced line.
>> 
>> A high dipole 1/2 wave on the lowest frequency of interest and fed in 
>> the center with decent open wire line with a characteristic impedance 
>> of at least 600 ohms and matched with a correctly designed and 
>> constructed truly balanced link coupled matching network, will run 
>> rings around any coax fed dipole, especially on 80 meters where the 
>> band is 500 kc wide.  You won't need a ridiculous ferrite core balun 
>> at the feedpoint, sitting there adding to your losses with heat 
>> reactance; you won't need a dozen dipoles to cover HF, and such a 
>> system will deliver more power to the load on average on any HF
>> frequency than some hammy coax fed dipole will.   If any ham wants to
>> be obsessed with feeding a balanced load with an unbalanced line he is 
>> free to do so and live in denial (I work everyone I hear blah blah) 
>> but professionally designed and constructed shortwave broadcasting 
>> plants always use balanced antennas and feed them with balanced line.
>> If they didn't work they wouldn't do it.
>> 
>> To be objective, there is one problem with a low band dipole used on 
>> the high bands, and that is the pattern you wind up with.  An 80 m.
>> half wave dipole on 10 meters has many lobes going off in all 
>> directions and even though the system in terms of power transfer is 
>> efficient, the pattern is not reliable if the operator wants a good 
>> idea of where is signal is going.  For that reason, I employ a second 
>> dipole, 1/2 w. on 20 meters to cover the high bands.
>> 
>> 73
>> 
>> Rob
>> K5UJ
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