Is the elevation of the feed point (via the 2 sections of 25G plus
insulators) important or would it work the same with the feed at
ground level and the radials sloping up to their installed height?
Patrick
WA7VNI
patd@wolfenet.com
On Thursday, March 05, 1998 12:59 PM, Robert D. Edmondson
[SMTP:n4vv@greene.xtn.net] wrote:
> Tom,
> I have been reading this thread on verticals & radials, etc. This
> past
> summer I installed a Inverted L for 160. I have 2 sections of 25G,
> Antenna
> Mart insulators & then 5 more sections of 25G. Out of the top I
> have a 15
> foot aluminum pipe. This gives me approximately 65 feet vertical &
> the L
> wire runs to a tree. I use one (1) elevated radial that slopes
down
> from
> 20 to 5 feet off the ground. I have no idea what the losses are,
> but do
> know it works. Worked the ZL7, KH9, 8Q, ZK1, K7K, etc. this past
> season.
> Maybe it would work better if it was ground mounted with many
> radials, but
> I can't complain & a lot easier then burying radials.
>
> 73's Doyle/N4VV
>
> ----------
> > From: T A RUSSELL <n4kg@juno.com>
> > To: TOPBAND@contesting.com; TOWERTALK@contesting.com;
> > DX@ve7tcp.ampr.org;
> w8ji.tom@MCIONE.com
> > Subject: Re: TopBand: Elevated GP vs. Vertical Antennas
To: <topband@contesting.com>
> > Date: Thursday, March 05, 1998 9:15 AM
> >
> > N4KG response below -
> >
> > On Wed, 04 Mar 1998 04:24:48 +0000 Tom Rauch >
> >
> > >> By the way my "vertical" is a tower with raised radials, the
> > >> radials
> > >> going to the coax center conductor and the shield to the
> > >> tower..
> > >> The N4KG method...... (K9FD)
> > >
> >
> > >Not only with Beverages nearby, it also works better for
> > >transmitting. Raised resonant radials radiate like crazy and
> > >couple
> > >to EVERYTHING else in the near field (including lossy soil below
> > >the
> > >antenna) no matter how much time is wasted pruning and tuning.
> > >The
> > >fields from each radial only cancel completely hundreds of feet
> > >away,
> > >and that is where they don't cause power loss. (W8JI)
> > >
> > >You also likely give up a lot of useful RF to the loss in the
> > >tower
> > >to earth connection, which modeling programs often "think" is a
> > >zero
> > >ohm zero loss connection. In the real world, a tower stuck in
the
> > >
> > >mud is not a zero ohm lossless earth termination! (W8JI)
> > >
> > >Raised radials are a great idea if they are installed a hundred
> > >feet
> > >in the air, but place anything (including good ole dirt) within
a
> > >
> > >pretty large distance and the radials couple like crazy to
> > >whatever the other conductor is. And that's true no matter how
> > >much time is wasted "tuning and pruning" them for equal
currents.
> > >
> > >
> > >73, Tom W8JI
> > >w8ji.tom@MCIONE.com
> > >
> > ...............................................
> >
> > Hi Tom -
> >
> > I agree that my elevated GP antennas have losses due to the
> > earth
> > connection
> > and low radials, but you make it sound like such antennas are not
> > much
> > better than a dummy load and on this point I must STRONGLY
> > DISAGREE.
> >
> > (My GUESS at WORST CASE losses compared to a full size ground
> > based
> > vertical with lots of radials is 6 dB. My HUNCH is that it is
> > actually
> > much LESS.)
> >
> > My 80M elevated GP has accounted for 225 countries since I
> > started
> > tracking
> > it's performance. While I do not have direct comparison data, I
> > expect
> > that
> > it performs MUCH BETTER than a GAP or heavily loaded multiband
> > vertical
> > or base loaded vertical.
> >
> > On 160M, I have recently worked 3DA0, 5A, 5B4, H44, KH9, S7, YB,
> > ZL7,
> > Antarctica, and many JA's and Europeans with 1000W (QRP on
> > 160!)
> > feeding a 140 ft tower with 6 elevated radials at 15 ft. Signal
> > reports
> > and
> > competive "feel" in the pile-ups lead me to believe that it is
> > comparable
> > to others in the state using top loaded verticals against ground
> > radials.
> >
> > I recently installed a full size folded wire vertical (61 ft up,
2
> > ft
> > across at top,
> > 1 ft across at 3 ft up) in my woods, over very wet marshy ground,
> > with 32
> > radials (8 = 75 ft, 24 = 100 ft), fed with 450 ft of half-inch
> > CATV
> > hardline
> > and a quarter wave RG58 coaxial transformer.
> >
> > Comparisons with N4NO, 12 miles SE of me, and K4AB, 10 miles
> > west
> > of me, both indicated the N4KG elevated GP was 3 to 4 dB stronger
> > than
> > the ground mounted vertical. This was something of a surprise.
> > Perhaps
> > the fact that the vertical is near a (low) creek and the GP/tower
> > is on
> > the
> > edge of a ridge which gently slopes to the creek (about a 20 ft
> > drop over
> > 300 ft) accounts for the discrepancy when measured by ground
wave.
> >
> >
> > On RECEIVE, there is absolutely ZERO difference detected either
> > by
> > S-meter or ear (with the AGC OFF) when listening to skip signals.
> > On transmit, N4AR/8 saw zero difference. More transmit tests
need
> >
> > to be performed.
> >
> > Bottom line: Elevated GP antennas ARE effective, quick and easy
> > to
> > install, and VERY INEXPENSIVE. They utilize an existing tower
> > and
> > therefore PREVENT PARASITIC INTERATION that would exist if a
> > separate vertical antenna were installed near an existing tower.
> > (I have experienced parasitic effects on both 80 and 160M when
> > verticals were installed less than 1/4 wavelength from an
existing
> >
> > tower which happened to be self resonant near the same band .)
> >
> > The N4KG Reverse-Fed Elevated GP (June 1994 QST) may be the
> > BEST alternative for 80 and/or 160M for someone with limited
> > real estate. It also offers quick and easy access to the low
> > bands
> > by visiting DXpeditioners to existing HF stations in foreign
> > lands.
> >
> > de Tom N4KG
> >
> >
> >
> > ______________________________________________________________
_____
> > __
> > You don't need to buy Internet access to use free Internet
e-mail.
> >
> > Get completely free e-mail from Juno at http://www.juno.com
> > Or call Juno at (800) 654-JUNO [654-5866]
> >
>
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