Good point, Don. I probably wasn't clear.
I was only referring to how to calculate the position of the feedpoint.
In fact one wavelength is actually 1005/f but for the feedpoint using 250
(for one quarter wavelength) is accurate enough.
For the total length of wire use 1005/f, just as you would for a quad.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Don KO7i
Sent: Sunday, November 23, 2014 4:22 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 17 Meter Antenna
One point 500/MHz =1/2 wavelength
I would hate for someone to think that is all the wire they need to use for
a delta loop.
Using the 1/4 wave 75 ohm transmission line is vital.
73 Don KO7I
Sent from my iPad
> On Nov 22, 2014, at 11:09 PM, Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de> wrote:
>
> Reed, a 17m vertical delta loop (no a lazy loop) is what I'm talking
> about, and you need only about 20 ft. of width for it. It takes up
> less space than a dipole. The point is at the top of the single pole
> and the horizontal wire is at the bottom. The feedpoint is 1/4
> wavelength down either leg from the point. Use a quarter wavelength
> matching stub of RG-59 or RG-11. The
> 50 Ohms the rest of the way.
>
> Here is a picture of my 40m vertical delta loop:
> http://www.dj0ip.de/my-favorite-antennas/my-favorite-40m/
> Just scale it down to size for 17m.
> The exact length of the sides and horizontal wire are not critical,
> but the sides must be at least 1/4 wavelength long.
>
> You'll maybe notice that the quarter wavelength of wire above the
> feedpoint on my 40m loop looks just a little long.
> It is longer than a calculated quarter wavelength if when using a
> dipole formula (468/f). That's because there is no "End Effect" present
in a loop.
> Use 500 instead of 468 (or "250" for a quarter wavelength) when
> calculating where to place the feedpoint.
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Reed
> Sent: Sunday, November 23, 2014 12:05 AM
> To: tentec@contesting.com
> Subject: [TenTec] 17 Meter Antenna
>
> Yeah Rick I have heard good things about the delta loop. I don't know
> if I have the real estate for one, but will look into it. I have 2
> portable magnetic loop antennas that work really well for their size,
> but they are not designed for wet WX. Low noise is one great
> advantage of any loop antenna.
>
> Thanks!
> Reed W4JZ
>
>> Reed, try a full wave delta loop,
>> Horizontal segment on the bottom
>> Fed in one corner with 1/4 wavelength of 75 Ohm coax, then fed to the
>> shack with 50 Ohm coax.
>> You'll knock em dead with that!
>
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt am Main)
>
>
>> Thinking about building a Moxon. Easy to build &
>> inexpensive. Anyone here used one before?
>
>> 73,
>> Reed W4JZ
>
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>
>
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