The 31' Homebrew Vertical

Several people have asked me to post the results of our field test of the homebrew 31' vertical antenna.  Here it is:

Background –


At Chilicon 2011 some of the members of the Ottawa QRP Society arrived with a homebrew vertical antenna. It had a 28’ radiator, one 16’ ground radial, one 31’ ground radial, and a 4:1 Balun, all designed by Martin-VA3SIE. It intrigued VE3CLQ with its simplicity, and its possibility as a ground-wave antenna for emcomm work.

VE3CLQ built one at Chilicon 2011 using a MFJ-1910 collapsible mast, a 28’ radiator, four 16’ ground radials, and a 4:1 Balun. This antenna was not analyzed before use, but with 40w output from a FT-857D it worked VK3MO in Victoria, Australia and VK2KRR in New South Wales, Australia from his campsite.

Further Development –

Richard-VA3VDP played with the design using the EZNEC antenna design computer program for a few weeks and came up with the result that a 31’ radiator would work best with the 16’ ground radials. A rebuild of VE3CLQ’s antenna ensued and it was soon sporting a 31’ radiator, this antenna is now known as the Chilicon Vertical Mk.2.

VA3VDP bought the commercial version of this antenna, made by LDG, and called the S9v31 and is advertised to be good for 6m through 40m.

Over the past 12 months the antenna has been used, both the commercial and the homebrew versions, with good success from a variety of locations and grounds. A great deal of DX has been worked to date with it.

The only change to the Chilicon Vertical Mk.2 has been with the number of and the length to the ground radial system. 

Testing –

In order to find out which Balun, either a 4:1 or a 1:1 was more efficient, a test was designed. The antenna was set up at Lamoine Point, in a gravel parking lot.

The antenna was set up with the 31’ radiator, six 16’ground radials, and a 4:1 Balun. Frequencies where chosen close to the centre of each band for operating SSB. With exactly the same set-up we switched to a 1:1 Balun and the same test run again. The results were:

The 4:1 Balun
Frequency        Result
3.800                6.5:1
7.150                3.5:1
14.150              2.5:1   
21.200              1.8:1   
28.500              2.1:1   
53.0                  1.1:1       


The 1:1 Balun
Frequency         Result
3.800                12.1:1
7.150                2.6:1
14.150              6.3:1
21.200              1.6:1
28.500              4.5:1
53.0                  1.3:1

The antenna was set up for a second test with the 31’ radiator, six 16’ground radials, a 4:1 Balun and the addition of two 31' ground radials. Frequencies where chosen close to the centre of each band for operating SSB. With exactly the same set-up we switched to a 1:1 Balun and the same test run again. The results were:

The 4:1 Balun
Frequency           Result
3.800                  6.1:1        
7.150                  3.1:1        
14.150                2.4:1        
21.200                2.1:1        
28.500                2.1:1        
53.0                    1.1:1        

The 1:1 Balun

Frequency          Result

3.800                 12.1:1
7.150                 2.8:1
14.150               6.3:1
21.200               2.4:1
28.500               1.3:1
53.0                   1.4:1

The results show that the addition of the two 31’ ground radials did very little to change the feedpoint impedance of the antenna.

We then checked the resonance of the antenna using both a 4:1 Balun and then the 1:1 Balun. The results are:

The 4:1 Balun
Frequency          Result

9.500 MHz        1.0:1
19.700 MHz      1.0:1
42.600 MHz      1.0:1
61.900 MHz      1.0:1
132.000 MHz    1.0:1

The 1:1 Balun
Frequency           Result

7.500 MHz         1.0:1
35.000 MHz       1.3:1
64.500 MHz       1.1:1

On Air Test -

The antenna was quickly reconfigured to the 31’ radiator, six 16’ground radials, two 31’ ground radials and a 4:1 Balun. The antenna was then connected to an IC-703 10w QRP transceiver and a 12v 35Ah gel cell battery.

The results of the on air test are:

1901UTC    20m   G8A           57/55    Brian, Great Sutton, UK
1907 UTC   20m   VY2TT      58/56    Ken, Bloomfield Stn, PEI
1921 UTC   15m   CM8AKD  57/56    Jose, Las Tunas, Cuba

The SFI for that time was:

SFI = 129;  A index = 5;  K index = 3; and SN = 91.


Conclusion –

In its present configuration as the Chilicon Vertical Mk.2 it works very well and is especially good when hunting DX.

Further testing is scheduled to be done with more radials of different lengths.  If there is suffient interest I'll post the results.

Brewers Mill Island

As we went to breakfast this morning Noah was putting the finishing touches on the Ark as the torrential rain fell.  It soon looked more like Bangladesh during the monsoon season than Princess Street in Kingston.....of course some people were just upset because they have not had to mow their lovely and crisp golden brown lawns in six weeks.

The rain continued during breakfast and then during the long ride up Highway 15 to Brewers Mill.  Noah must have finished the Ark on time because as we parked our vehicles the rain stopped and the sun came out from behind the black clouds.......and the rain continued on to Ottawa.

George VE3SIQ quickly set up his 20m dipole and a 15m and 10m dipole, and after sorting out a power problem he was on the air and spotted on the DX Cluster................remember George, the black wire is ground and the red is hot!!

Many thanks must go to the guys who run the US Islands Award website for very promptly posting the announcement of our island activation.  It was posted on their website within one hour of my sending the announcement to them.......and did I mention that after sending three emails, over a two week period, to the Canadian Islands Award webmaster, that we're still waiting for the announcement to make it onto their website? 

I put up my 31' vertical and numerous 16' radials on the ground, connected the FT-857D, and got stuck into 15m.  First station in the log was Tim VA3TIC, next up was John VE3OMA.    I then switched over to 6m to give John VE3ISE in Grimsby a call...with no success at all.  Unfortunately 6m did not want to play today.  Several other station went into the log in quick succession after that, but the QSB was pretty bad at times.

In the afternoon I switched to my IC-703 and made good solid contacts with Frank EA5HJV in Spain, and Rumen LZ1MS in Bulgaria.  Not too shabby for 10w SSB.

The island is a nice spot to operate from and the Lock Master was very accomodating to us. We will have to do this again!

Chilicon 2012

VE3CHILI

Plans are now well underway for this years annual Chilicon gathering of QRP enthusiasts in Eastern Ontario.

Chilicon is held at Rideau River Provincial Park, just across the river from Kemptville over the weekend of September 14th & 15th........Rain or Shine.  Group organization is minimal, so this weekend is a pretty casual QRP camping experience.....but we have fun!

Chilicon is an annual event of the Ottawa Valley QRP Society and has quickly become a fixed event on my calendar.  Lots of good discussions on radios and antennas to be had there, and if you come away from the weekend without learning a thing or two you didn't try hard enough.

Held the same weekend as the QRP Afield event which is sponsored by the New England QRP Club, we have lots of on air activity, and normally a couple of different modes on the air as well.

Come for the weekend or just come for the Saturday.........occasionally you get to meet celebrities there like Bob-VA3QV!!!

Saturday on the Bands

It was off to Hay Bay after our club's regular Sunday breakfast today to use the high dipoles we have set up out there at Don-VE3MNE's cottage.

Today was the Colorado 14er's big day, and it was for that event that I primarily wanted to use the high antennas.  However, the Gods didn't smile and I didn't make a single contact with any of the Colorado stations.  Better luck next year....as the saying goes.

I did manage to work five stations before I closed down the station:

KD0ETC and KD0EFW who were both activating US lighthouses;
W8COD who was activating the submarine USS Cod;
XL31812, a special event station celebrating our glorious victory in the war of 1812; and
9A208DX, a special event station celebrating 20 years of the 9A callsign.

So not a wasted day on the bands.

Next two weekends.......

There's a couple of busy weekends coming up in August.  Next Sunday, the 12th August, our club will be activating Brewers Mill Island, just south of Seeley's Bay on Hwy 15.  This Island has never been activated before, and is not listed on the Canadian Islands Award Site, so it doesn't have an official number yet.  We plan on having at least three stations up and running, all on battery power.  I'm going to assume two HF and one 2m/6m stations.

We have sent emails to the Canadian Islands Award website asking for this activation to be listed but as they have already ignored three requests so far for islands this summer.....we're not holding our breath.  You will be able to read about this activation on the US Islands Award Scheme website....along with other Canadian hams who have long since realized that sending activation notices to the Canadian website is a waste of time.

The weekend after that, the 18th & 19th August sees our club taking part in the International Lighthouse Lightship Weekend.  Once again we will be activating two lights, the first at Nine Mile Point on Simcoe Island, which is CA0031, and will be using the VE3FRG callsign. 

The second site is the light at Point Petre in South West Prince Edward County.  This is CA0026, and will be using VE3FCT as its call.  The Nine Mile Point light will be active on Sunday only, but we are hoping that the Point Petre light will be active on both days.

The event evolved from the Scottish Northern Lighthouses Award Weekend a biennial event which was first held in 1993 and became the ILLW in 1998. Over the years it has continued to grow and to date more than 450 lighthouses and Lightships in some 50 countries around the world are participating in the event each year.

The event is always held on the 3rd full weekend in August starting at 0001 UTC on Saturday and finishing at 2359 UTC on Sunday.

VE3FCT will be QRV on 7.250; 21.350; 14.250-14.260; and 50.125, for SSB depending on the band conditions.  All frequencies will be +/- 10 Kc or so.

Radios for VE3FCT, for both events, will be an FT-857D, and the antennas will be an 80m OCF Dipole and 31' homebrew vertical.  A Buddipole 6m antenna will also be used.