Magic Antenna - 160m Inverted L - MMANA on different frequencies.

Using the antenna tuner in my Yaesu FT450d I am able to successfully load it on 40, 30, 20, 17, 15, 12, 10 and 6m.   The antenna works quite well in some cases better then the 1/4 verts  and I totall credit it sitting on a 120' tower ...its really a very steep gravel hill! 

40 Meters

Actual VSWR no tuner 3.6:1

Ran MMANA for resonance ....

8.3 MHz

7.1 MHz

SWR is 49:1 ,   in reality its 3.6:1 but the modelling software has it resoant not too much higher in freq.

On 30 M

Actual VSWR no tuner 3.1:1

The software models it at 18.7:1 at 10.1 MHz
















Ran MMANA for resonance but it found it around 19 MHz with a 50:1 VSWR..



On 20 M

Actual VSWR no tuner 2.1:1

The software models it at 17.2:1 at 10.1 MHz
















Ran MMANA for resonance but it found it around 15.1  MHz with a 3:1 VSWR..

On 17 M

Actual VSWR no tuner 2.1:1

The software models it at 4.1:1  at 18.1 MHz

On 15 M

Actual VSWR no tuner 1.5:1

The software models it at 6:1  at 21.1 MHz

On 10 M

Actual VSWR 28 no tuner 1.4:1

The software models it at  4.8 :1 at 28.0 MHz

On 6 M

Actual VSWR 50 no tuner 1.5:1

The software models it at  6.3 :1  at 50 MHz

MMANA Antenna Modeling - My 160m inverted L

Had some quiet time over the holidays so I have successfully used MMANA Software to model my 160m Inverted L.   I can see that there is a huge advantage to building ,  optimizing and using an Antenna before building the model.  MMANA is fantastic but finicky for the casual user,  More then anything its just takes a bit of familiarity to be successful at it. 

So  here is my antenna.  The radials all slope away with the exception of the one that runs along the X axis ....more or less straight North.   The radiating element more or less runs along this axis too!














In reality the radials have not been tuned each one is 45.7 m long.  The program was told to optimize for VSWR and below is the recommendations for the radials. 


















The vertical component or if you prefer radiator started at 45.7 m.  Took at least a meter off tuning the antenna so its really very close to 44.7 m.   

The optimized length is 44.48 m. 

Performance...optimized to the above dimensions...

The data was all done using free space.   The radials are at a around are around -30 degrees off  level all but one sloping away from the antenna.   The antenna is sitting at the apex of a gravel hill and is connected via 500' of LDF4. 

Here is the same antenna not optimized .....the real deal.  Each radial is 45.7 m and the radiator is close to 44.7 m. 

The VSWR is quite a bit different.  In reality its around 1.5 to 2.0 at 1.85 MHz but the program does not have 500' of LDF4 connected to the antenna!   So the numbers are close enough to the reality to believe the model,  That being said I will have to try tuning certain radials to optimize performance.

BELOW is the model built with the actual dimensions.....

At 1.85 MHz ...

At resonance ...

At 1.85 MHz

Here is where the antenna is actually resonant....

At 1.85 MHz

At resonance ...

I really did find this antenna to be resonant 100 KHz lower in frequency around 1.7 MHz.   I brought it much closer to 1.8 MHz taking a meter or so off the radiator but did not touch the radials.   It truly is quite dramatic what a difference the modem show in  SOME of the radials to get it to resonate at 1.8 MHz. 

Regardless of the resonance one thing that remains constant is the deep null at 90 and 270 degrees  10 to 15 db is HUGE!!!!!   Planning on playing around with the model moving the AZ of the radiator ....this is something I can do in the real world too but before I do anything I would like to try tuning 4 of the radials particularly the ones that run east west.