The G7FEK HF Multiband antenna.

The G7FEK HF Multiband antenna.

July 14, 2018 0 By Andrew

So I have been doing lots of research on various different types of HF Antenna for my home location. I wanted to set up a more permanent installation rather than keep taking the G5RV up and down which I use for Portable field days.

One of the challenges I face is the rather limited dimensions of my home location. But as all people have told me the best antenna you can use is the one that suits your location the best...

As you can see from the below my property is 20m x 8m. So the best option to keep away from the neighbour is to run down the side of the house which give me just about 20m from back to front, but to get the height at the apex, the distance is about 14m .  So not long enough for a 20m half wave dipole for the 40 meter band.  Also the orientation is not idea, but again we work with what we have!

 

I wanted to build my own rather than just buy an off the shelf antenna, not only because of the cost, but also the learning experience of building your own.  I had also been advised against a vertical as they tend to be even more noisy from human interference...

So after a few weeks of searching around the internet I came across an antenna called a G7FEK. It is a multiband HF antenna which works on 80,40,30,(20 see later),17,15,12,10 (with ATU) sounds too good to be true...

The G7FEK comes in at about 14m, again perfect! So lets start building.

 

 

Two lengths of wire and 7.4m of ladder line, plus some old cable for the counterpoise or earthing. In total it cost about £15 for the ladder line

I am not going to go into much details about the antenna itself as there is a wealth of information on the creators website which can be found here

 

The installation was straight forward here you can just about see the antenna with the feeder down the end of the garden away from the house.

 

I have also put down about 6 or 7 counterpoises just laying on the ground, with the last few meters raised up in the air as the instructions (and other users on youtube suggest)

 

The below images are from the analyser.. Not too bad without any tweaking..

(Click on photo for bigger image)

 

 

 

Here you can see the full HF sweep.

80M

Lowest VSWR at 3.661 Mhz at 1.14:1

Also pretty good across the whole band

 

40M

Lowest VSWR at 7.270 Mhz at 1.44:1

This is a little high and could do with some tweaking to lower it down a little. But again a nice wide curve.

20M

Lowest VSWR at 14.416 Mhz at 1.44:1

This is def too high, the 20m runs off another vertical wire, the Z is also creeping a little to high, so some work to do on this band.

(still been making contacts across Europe, but room for improvement)

15M

Lowest VSWR at 21.215 Mhz at 1.21:1

This is very good and well matched.

12M

Lowest VSWR at 25.783 Mhz at 2.97:1

Not so good here, VSWR too high and Z is too high too.

10M

Way off...

6M

Lowest VSWR at 50.697 Mhz at 1.69:1

 

Usable range across the band, 1.75:1 at 51mhz

So still some work to do, but ran out of time (which is a common theme!)

As of today 14th July, I worked about 30 stations across Europe and Across the Nordics using this as it stands.

Still some tweaking and trimming/lengthening to be done, but that's all part of the fun.

Please feel free to post any comments or suggestions, antenna building is an art form and  I am very much a novice...

 

73's