A system I used that worked very well was four 81' elevated (up 20') radials
after a single coil. The antenna was a tree supported inverted L. This is
straight from the ON4UN handbook. Another ham neighbor used four 67' elevated
radials after a single coil, also from the same section in the ON4UN hand book
... 4th Edition page 9-25 ... It was very easy resonating the system with that
single coil but the best SWR was about 2.5. That problem was solved with a
hairpin match. At the time I was living near Sewanee, TN on a sandstone plateau
with the worst possible ground conductivity, about a "2" according to the map.
I don't think I can attach a photo of the feed point and send it to the group
but can sure send to anyone interested in seeing what it looks like.
73, Mike WA5POK
On Monday, July 2, 2018 12:05 PM, Grant Saviers <grants2@pacbell.net> wrote:
I agree that resonating 8 elevated radials would be a aggravating task.
I have 8 10' elevated 125' +/- radials for my T loaded vertical. I
made no effort to resonate them. OTOH, for one or two radials,
resonating them is important. N6LF covered this in his papers on
elevated radials. antennasbyn6lf.com also a two part series in QEX 2012
My installation has significant imbalance in radial currents, as much as
3.4:1 highest to lowest as measured with an MFJ854 RF current meter that
I calibrated. The causes are proximity to a steel building and a tower
for two of them. The others are intermittently in forest and over grass.
With the 13ga aluminum wire I use for elevated radials the excess RF
power loss from unbalance is less than 1% I^2*R using skin depth
resistances. I modeled (EZNEC Pro4) the antenna with 8 current sources
of the actual values in each radial. The azimuth pattern distortion is
1db. The gain is 0.05db lower . The two highest current radials are
adjacent.
This leads me to believe that for 8 or more elevated radials there is
small benefit to pattern uniformity or efficiency with resonated radials
or for finding some no loss means to equalize the radial currents. N6LF
concludes that for his recommended 10 elevated radials, efficiency and
pattern sensitivity to length and current asymmetry is low.
I've had good results mechanically with 13ga aluminum electric fence
wire. There is no skin depth problem on 160m which may happen with
cheap copperweld steel. Aluminum is also available 9ga which is tough
stuff. As noted the very little stretch doesn't matter.
Grant KZ1W
On 7/1/2018 16:14 PM, Charles Moizeau wrote:
> With in-ground, which optimally should be be so shallow as to be on-ground,
> radials there's no thought or effort needed to think about them as being
> anything close to the intended radiation frequency.
>
>
> But with elevated radials my understanding, and it is more nonexistent than
> limited because I've never tried them, is that all have to be physically
> matched to one another yet tuned to the radiation frequency, and this
> requirement is an extremely fiddly undertaking because there will be nearby
> objects, e.g., trees, varying ground slopes, etc. that will differently
> affect radials of identical physical length.
>
>
> Charles, W2SH
>
> ________________________________
> From: Topband <topband-bounces@contesting.com> on behalf of N2TK, Tony
> <tony.kaz@verizon.net>
> Sent: Sunday, July 1, 2018 5:01 PM
> To: 'Carl'; topband@contesting.com
> Subject: Re: Topband: Radial plate
>
> Hi Carl,
> One advantages of going underground. No more wires hanging up in the air. It
> will look cleaner. But I do not have any idea if my signal will degrade
> going with buried radials over the 5 elevated radials at each feedpoint. The
> ice was brutal this past winter.
> Why do you say there will be a large signal loss going from elevated to
> ground radials? You got my attentions with that statement.
> N2TK, Tony
>
> -----Original Message-----
> From: Carl [mailto:km1h@jeremy.qozzy.com]
> Sent: Sunday, July 01, 2018 3:51 PM
> To: N2TK, Tony <tony.kaz@verizon.net>; topband@contesting.com
> Subject: Re: Topband: Radial plate
>
> Since the change to on ground radials can result in a large loss of signal
> in some areas why not just invest in stronger elevated radials?
>
> I use scrapped deep well wire from well shops which is available in #12 to 6
> in this area in 2 and 3 wire insulated styles and is often free. . For the
> 16 160M radials up 12-15' they run over tree branches and also over fairly
> open areas.
>
> Since I live on top of the tallest hill in the area of Southern NH Im
> exposed to everything Mother Nature can throw at me from all
> directions.....ice included. Back when I used #18 & 16 it was regularly
> needing repair, amd now nothing in about 12 years. It acts/handles like a
> cross between soft drawn house wire and hard drawn.
>
> #16 to12 copper clad steel is available also with and without a strong
> jacket and stranded or solid..
>
> Carl
>
>
> ----- Original Message -----
> From: "N2TK, Tony" <tony.kaz@verizon.net>
> To: <topband@contesting.com>
> Sent: Wednesday, June 27, 2018 9:08 AM
> Subject: Topband: Radial plate
>
>
> Planning on changing from elevated radials to ground mounted radials for my
> 80 M 4-sq. After twice having to rebuild the elevated radials this past
> winter from the snow/ice storms it is time to go to the ground. I plan on
> having the feedpoints on 4x4 posts with the feedpoints 3' up from the ground
> so they don't get snow covered often.
>
> Looking at the DXEngineering Radial plates. It looks like an easy way to tie
> the radials together on the ground then run a ground wire up to a box at the
> feedpoint. Any comments or issues with using these radial plates?
>
>
>
> Also going to use buried feedlines - RG6, � wave with 8 turns through #31
> big clamp-on core at the feedpoint.
>
> 73,
>
> N2TK, Tony
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
>
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>
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