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     ::Home::    Magdelta loop antenna 80 Meter PA3ECT@AMSAT.ORG

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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The idea of the Magdelta loop was created by the need to have an antenna with a reasonable performance and easy to carry.
The experiences of the Magneticloop were very good but to take to the antenna fieldday was a bit cumbersome.
 
The idea for this Magdelta loop, I give it that name, and that means a magneticloop in triangular shape, formed by the conductor, and handy to carry for fielddays. 
For a good conductor, I use coaxial cable about as thick as RG59 with a foil outer cover.
 
The circumference will be now as large as possible and should come into resonance with about 50pF.
The circumference is then about 24 meters.
The triangle has three planes of 8 meters.
 
This is for an 80 meters antenna relatively small.
Also this delta model is suitable for 1 mast mounting.
A mast height of 7 or 8 meters is enough.
 
EZNEC pictures below show the model, radiation pattern and gain
Do not mind the text "Dipole in freespace" I forgot to change that. In the model, the base is lightly widened in favor of the height.

 

 

If you can see the radiation pattern then you can see that this really is NVIS.
There is little directivity and it all looks good.

 

The gain looks good but depends on the chosen soil parameters

 

The best test is the practice test and following up on a beautiful countrysite in  Waterland between Zunderdorp and Broek in Waterland.

I have marked the Magdelta loop with some little red markers to indicate the wiring.

The Faraday loop above and below the red framed vacuum C tunable from 5 to 80pF

Detail Vacuum C mast clamp



The mast is12 meters high and too high for the Magdelta loop, top height is 9 meters and the base is slightly shorter than in the model.

Without scientific data, I can say that the reports were very good.

The faraday loop, the RG58 is a part of the feeding coax and about 1/5 th of the loop circumference.

The base does not need to hang high 1.5 to 2 meters above ground is fine.

A simple antenna for 80 meters, a small footprint for small gardens and holidays field work.

Advantages:

good performer

low space

1 mast construction

easy to build

good preselection

low pF capacitor

no tuner

easy to put in a handbag

Disadvantages:

narrow band

single band
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You are guaranteed to send and hear a good signal.

PA3ECT © 2007 • Zunderdorp Amsterdam