4-Square Site

2E1FVS - Phased Pair of Verticals - 40m

Great news....Martin was successful in sitting the UK Advanced License exam on 1st March 2014 and now holds the call M0HOM.

Here is Martin's description of his phased pair of verticals on 40m .......whilst reading this remember, at the moment, Martin is a UK Intermediate licence holder and is limited to 50w output........

Luckily I was the recipient of a broken 12M Spiderbeam, which was part of my Dad’s (G4ATA) 80m 4-Square, until a big gust of wind broke it. I was able to repair the broken pole and put it to good use. It took shape of an 80M inverted L for a while, and playing on 80m, hanging about with the "Big Gun’s" and waiting for my turn in the list to attempt a QSO with the DX. Though I was quite successful at times, relying on good conditions, and the receiving station having good antennas rather than me having more power, and gain antennas like a 4 Square!

At the same time as my short period on 80, I had a Hy-Gain AV18 base loaded vertical, with a large coil, and a tap that I could change, to use it on various bands..... it wasn’t long before I discovered 40m!

I’m not sure what it was that made me do it, but the 80m Inverted L came down and a single ¼
ʎ vertical went up.  I had some fun with my single vertical on 40m and discovering this was a band that had more to offer and I wanted something better.  I think it was John, W2VP, who had suggested I try a phased pair.  This was definitely food for thought - Gain, and Front to Back from a pair of Omni-directional verticals?

After surveying the space I had for antennas in my suburban QTH (not a great amount of space – 60m long x 7.5m wide) I discovered that my garden runs pretty much bang on East/West.  Ideal, and yes, I can get this antenna to fit okay with the radials required.

Eventually another 12m Spiderbeam worked it’s way in to my possession. This was to be the start of my new antenna for 40m!

After looking through my Dad’s ON4UN Low Band DX-ing book at the info for 2 element arrays, I chose the Christman feed method for ease and simplicity, and with some help from my Dad calculated the required lengths of coax to feed each vertical and the length of the delay/phasing line.  I have since found a very useful tool on VA7ST’s website for calculating coax line lengths....... Tip...Don’t forget the velocity factor!
See the "Useful Links" page on this site...and the link at the bottom of this page.

 

I set to and constructed a simple relay switch for the centre to allow me to switch the direction of the verticals East and West.  I opted not to have a 2nd relay in my switch box.  After looking at the cardioid antenna patterns in the LBDX book, I came to the conclusion that I wouldn’t benefit that much from having the broadside direction included, and keeping cost in mind with control cables and components I stuck with a single relay for the end fire directions only.

 

In hindsight, the broadside direction might be nice to have.  Some of the stations I have heard directly due south of me are in the null of the antenna and this could be the difference in hearing/working the DX and not.

Sometime in 2009, the wire elements and radials were cut, the verticals went up and radials strung out.  2 radials on each antenna overlap toward their ends but space limitations gave me no options.  Each vertical, with it’s radials, is elevated off the ground so you can walk under the array.

No trimming has been necessary. I put that down to good luck, rather than just sheer good design! Nice SWR on the antenna, in either direction, and a good front to back was instantly observed on RX.  Encouraging.....

 

On air testing produced further encouraging results.  EU stations were reporting a good front to back, but it is on the long haul DX where the front to back really comes in to play.

On receive, I’ve seen as much as 4-5 S Units or 20-30db front to back.

On transmit, I’ve had reports of up to 4 S Units, which is nearly 25db, but these can depend on factors like the forever changing conditions, the arrival of signals at the receiving station, and what antennas receiving stations use.

For a short while in 2012, I had taken the array down and went back to a single vertical.  I didn’t like not having the front to back, and the gain, and it wasn’t long before I went back to the phased pair!

If you have the room for such an antenna, go for it, it’s not hard to build, not expensive to build and the instant direction changes are brilliant!  Build one and see for yourself!

So, here we go.......
Bragging rights!! :
A run down on a few of my accomplishments with using this antenna on 40m using only 50w......

 

Award Progress:

WAC – All SSB

WAZ – SSB & CW

DXCC (as of Feb 2014) - 153 SSB – 120 CW – combined 186

WAS (as of Feb 2014) - 35

Contests:

2011 CQ WW WPX SSB – SOSB 40 LP - #1 in G - #3 in EU – #4 World

2012 CQ WW WPX SSB – SOSB 40 LP – #1 in G - #3 in EU - #5 World

2013 CQ WW WPX SSB – SOSB 40 LP - #2 in G - #6 in EU - #6 World

 

2011 CQ WW SSB – SOSB 40 LP – #1 in G - #10 in EU - #11 World

2012 CQ WW SSB – SOSB 40 LP – #1 in G - #14 in EU - #14 World

 

Relay.....2E1FVS - Phased Verticals - 40m    Christman Phasing 2E1FVS

2E1FVS  2E1FVS

The above diagrams are all self explanatory and just go to show what can be achieved with a simple pair of phased vertical antennas.

 

How it is setup at the QTH of Martin, 2E1FVS

2E1FVS

 

Martin would like it to be known that there was no fancy test equipment used in the setup or measuring the feed lines or antennas themselves....just simple calculations and a tape measure!!  So, don't be fooled into thinking that you cannot do this without even buying an antenna analyser!  The purists amongst us would probably say that his radials between the two verticals should not overlap but this was initially an experiment that has turned into a more or less permanent setup.  Hey, this is amateur radio and there's a lot of truth in "if it ain't broke, don't fix it"!!  Let the results from the antennas speak for themselves....

 

Refs:

ON4UN Low Band DX Book
VA7ST - http://www.va7st.ca/home.html/2010/08/phased-40m-wire-verticals/

Martin is the 3rd generation of hams in the Hotchin family....first was Ray, my father (the first G4ATA, formerly G8DYT), second was me (my first call was G1UDF and currently holding G4ATA, G8DYT & M4D) and then came Martin, 2E1FVS.  Martin was first licensed at the age of 13 (nearly 17 years ago!) and since March 2014 has the UK Advanced license and the callsign M0HOM...... well done Martin!  He is an accomplished DXer, contest operator (phone!), avid classic Mini enthusiast and I think I am rightly proud of him. ........ John, G4ATA

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