80m Inverted L antenna

 

After the big full-size vertical and some searching I dismantled the full-size and made it a inverted L configuration.

The vertical part was around 10m high (like the 40m 4sq verticals) and the rest of the antenna was horizontal.

 

 

The first thing I noticed was the smaller bandwidth.

So decided to make it resonant on the SSB DX part of the band  around 3.785 Mhz

I could not really compare with the full-size but it seemed that the differences between a full-size and an inverted L were not much except the smaller bandwidth.

Be aware that an inverted L has a very low impedance at the feedpoint.

Some matching will be needed.

 

After I had some experience of the 40m christman feeding system, I started building a second inverted L for 80m shortly afterwards.

 

Searched a lot on Google but found very little about such a system. I know there are operators who use this but unfortunately there are not many who writes about it.
There is some information that can be found in the books of John ON4UN.

 

2 x inverted L on 80m with 1/8 wavelength from each other.

 

So, with little information that i could find I still began the new project.

Christman feeding of two inverted L’s on 80m with only 1/8 wavelength between them.

Information of a system with ¼ wavelength can be found online but again not a lot but there will be some.

 

Luckily I had my old 40m 4sq mounting feet's still at my property so I used them to erect  the inverted L’s .

The wire that was hang horizontal was stretched and attached to the top of the 40m 4sq antennas.

Ohno that was a good attempt but it was not working at all.

 The difficulty of phasing them is because its a inverted L "low feed point impedance."

To tackle that problem I tried a lot to get the feedpoint up and after some weeks its starting to work.

After the impedance was going up the system was coming alive.

The next problem was directivity on the page of VA7ST you find that the phasing would be for 1/8 wavelength apart from each other should be 157° and 39° degrees.

Well that wasn’t working for me.

After some testing and  really a lot of testing I finally got the best F/B that I could get with my inverted L’s .

 

I know many operators would be happy and so did I but only two directions East and West.

 

So what about a third inverted L ?

 

My email is my call (at) telenet.be

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