14 Mhz 2 el inverted Vee

Since this article is not  100% original , I will post the source links on the bottom of this page

Goal was to achieve a single pole directive wire antenna using cheap and ordinary materials

What came to my attention was a document published by LZ1AQ where he fulfilled  my all my expectation

Basically, it a all about a 11 meters long wood pole, 4 wires just about 5.5 meters long ,  2 plastic box enclosures and some ropes.

Near the top of the pole there is a balun box (1:1) using RG58 coax over 2  stacked T240-43 toroids in order to push about 1 Kw power if needed.

From this box , the cable goes to  another one on the very top of the pole, a box who has 4 relays 12V capable to support 10A  to switch those 4 wires and a 235 pF capacitor as needed in order to achieve 4 electrically switching directions (in my case NW , NE, SE and SW).

The wires are oriented toward N,E,S,W and sloped about exactly 56 degrees from the pole to achieve 2 oposite inverted Vee’s .

So ,for NW radiation direction, relay box should  switch S and E wires as radiator,  but N and W as director by putting  a 235 pf capacitor between to shorten them out. Rotating is possible by combining different relay statuses (on , off).

LZ1AQ was using 5.54  m wire length about 1.5 mm  thickness , but in my case  coz relay wire inserted about 3 cm extra and also from the box to the wire there are 10 cm metallic rods  , I had to cut off about 33 cm from original length  to achieve perfect resonance (lucky me the pole is not heavy and got some extra help handy while I had to put the pole down 3 times).

From the relay box down to shack i used quality shielded 6 wires and 3 RF chokes along to avoid common mode RF , and another  arduino  box and some transistors to switch the relays accordingly for all desired directions.

To make it more complicated , I connected Arduino box to my laptop, wrote C code for manual / auto azimuth for Arduino and another python code for laptop.I found this very useful in cw contests when N1MM sends {TURNROTOR} macro to localhost UDP   (this macro has to be put behore  ! macro in His Call ) where my python code listen and parses the message to send via USB serial just azimuth integer.In this way  when typing callsign and hit Enter, the antenna is autorotated toward corespondent short path, of course adding a 50 ms delay on N1mm for cw send to allow relay to settle down.

Results are quite good for 4 simple wires  such as :

Here in Europe does not matter what direction I use.The main gain is for long DX where for example Sporadic  PY station was about S5  but switching to NW the signal completely disapeared. Front /Back ratio was a constant 2- 3 S points , but as PY  example   could be better.

It is not a Yagi antenna but considering the cost / time / and results , I’d say is not a bad antenna at all.

 

Links :

https://www.lz1aq.signacor.com/docs/2-element-single-mast-wire-beam.php

 

 

 

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