[600MRG] last nights results: fishing pole helical vertical

Sat Feb 1 10:03:12 CST 2014

Hi Graham,

Sorry for the lack of details in my last system assessment.  I had a number of plates spinning at the same time HI!

So all of these experiments have been based around a 5 gallon plastic bucket variometer with the outer coil wound with #14 and a small rotating coil of 30 turns total, same wire.  I've wound these coils before with many more turns on the rotating coil and I think after these experiments I would go back to use maybe as many as 50 turns (my main antenna ATU uses a rotating coil with 50 turns and it transitions a much larger area with sharper tuning as expected).  Taps are on the main coil about every 5 turns but I did not really count. carefully  Anyway, I wrote a document chronicling in detail the steps I went through to make my original coil and can send you that directly if you like.  While i have been unable to measure the inductance on the vario directly due to limitions with my metering, the calculated value seems to be around 1800 uH total.  My advice would be to just wind it and not worry about it.  This coil, with the help of a little
 additional series inductance was able to successfully resonate a 102" "whip" in a prior experiment so unless you are doing to load up something extremely ridiculous, you should have plenty with the bucket alone for most reasonable verticals.

That coil was used to resonate 4 different "small" antennas so far with some interesting results.  The fishing pole vertical seemed to be a pretty good performer but was by no means the best during these tests.  Perhaps under different conditions things might have been different and I will revisit the fishing pole again once the wx stabilizes again and I have fixed my analyzer and will add some top loading wires as this is the most efficient configuration.  

The fishing pole was a 15 foot long telescoping and subsequently tapering fiberglass design.  I simply wound about 30 long, tapered turns down the length of the pole using wire ties to secure the wire to the pole.  At the top, I allowed about an 8" tuft of wire to extend beyond the tip of the pole.  The antenna wire feeds the HV side of the vario.  In the case of the fishing pole and the 102" whip test, i needed slightly more series inductance to resonate so I used a smaller coil to accomplish this, connecting the smaller coil (6" diameter and about 60 uH total) on the low voltage side of the bucket and tapping with the coax feeder when I was near resonance but close enough to adjust with the vario.

using the MFJ analyzer, I measured the impedance from inside the shack and was able to get it matched in about 4 trips out to the antenna.  You want to make this adjustment far away from the antenna because you will couple to it.  

The radial system was an old existing radial system that I have not maintained in many years and it has gone unused for a long time.  These tests suggest that many of the radials are probably in tact but our average ground conditions here are above average  so its difficult to assess.  Obvious as many  radials as you can get will be good.  Anecdotally, at the site of my first test 1 mile away from my normal operating position, I used a 20m Inverted Vee fed with 25 feet of 450 ohm window line as a marconi with this coil against 4 radials, 3 were 25-30 feet long and 1 was about 50 feet long and coiled around the available space (worst case, i know).  That antenna proved to be the best of these tested so far but again, good ground conditions may make up for fewer radials.

Some have asked about decoupling the coax as with few radials, that coax tends to look like a radial and carry a lot of current sometime.  The tests here at my station have buried coax and grounding at the feed point as well as at the entrance to the shack and this seemed sufficient.  no bites or sparkies in the shack HI!  The first test with the Vee at the site a mile away had the coax laying on the ground and it definitely looked like a radial.  In fact initial tests left me with a nice tingly feeling on my finger tips.  This was fixed with a ground rod at the coax entrance tied to the shield.  Problem solved and no more RF at the rig/amp.

I'm leaving a lot out here but I am still organizing and going through information as I prepare to write a bit and also put together some presentations for this spring and summer.  As you can see, I did not get too hung up on calculated or measured values.  That was intentional.  You should be able to wind that bucket vario and find a tap to load a G5RV that you might have on your property, or 80m dipole, etc.  Obviously construction technique is important with the antenna since it will have a lot higher voltage on it potentially then normal but if you have a dipole with the feeder either in free space or coming down an insulated support I would encourage you to try and load it up.  With the dipole wires acting like a top hat, it should be more efficient than the straight fishing pole antenna alone (no toploading wires).

Performance of the fishing pole was really pretty good.  All of these compromise antennas have been excellent performers on ground wave out to at least 200 miles and there has been some skywave fun as well, with many signal levels consistent with QSO quality signal levels (Mike /12 in CO and I were just talking about this yesterday as he was receiving me in the low teens during the 2nd night of my test).

I'll be happy to send you some pics directly if you like and I will certainly keep you posted as I develop more content.  Hopefully in a week or two i will be able to continue this parade of insanity in one capacity or another.

73,

John XIQ

________________________________
 From: Graham <planophore at aei.ca>
To: 600mrg at w7ekb.com 
Sent: Saturday, February 1, 2014 7:45 AM
Subject: Re: [600MRG] last nights results: fishing pole helical vertical

John,

I must have missed some earlier posts on your fishing pole vertical.

It sounds interesting and as I have very little room for much of an 
antenna on these longer wavelengths I wonder if you could post some more 
details.

cheers, Graham ve3gtc FN25ig near Ottawa Canada

On 14-01-31 04:46 PM, John Langridge wrote:
> Good morning -
>
>
> Just getting a chance to look at last nights results and it looks pretty good.  The ground wave stayed stable and consistent all night with consistent reports from the guys up in OK.  Nothing out of the ordinary.  Signals to AA5AM across town have been consistent and loud through his listening period.
>
> Skywave had some nice surprises including WG2XKA and WE2XGR in New England all the way to N6RY on the west coast with a lot of station in between.
>
>
> Its difficult if not impossible to fairly compare to previous tests due to definite changes in conditions but this setup seems to be a solid performer under these conditions, particularly on the ground wave for pretty much any mode you want to use.  For someone casually trying out the band, there is enough wow factor with the simplicity of the setup to make it a good choice.  Again, all of this is intended to be qualitative in nature and real-world.  The casual operator will and does glaze over when you start looking at much of the math - they don't care, they just want to be able to get on the air (direct quote).  That said, I still believe the 20m inverted Vee marconi is best through these tests but some small toploading wires on the top of the flimsy fishing pole might make the fishing pole a very good competitor.  The Vee marconi was the only antenna tested to have toploading that I've looked at so far.  Nothing earth shattering or new here -
>   just a fact.
>
> I fully expect that there is coupling to surrounding objects - that is reality - and while my main antenna here is detuned at the moment, there is no doubt current flowing in that system to some degree.  I say that's probably ok.  If someone were in a limited space environment, they would have the same with their landscaping, electrical and plumbing so as long as interference is not generated, I look at re-radiation as a potential asset under those situations.  You wont get away from it in a real world compromise situation.
>
> I may continue to run through tonight if wx allows.
>
> 73 and thanks again for all the reports, comments and encouragement!
>
> John XIQ
> _______________________________________________
>

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