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[TowerTalk] Verticals vs. Tribanders; some data (Long)

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Subject: [TowerTalk] Verticals vs. Tribanders; some data (Long)
From: (Jim Reid)
Date: Wed, 17 Jun 1998 14:23:18 -0900

Aloha from the Garden Island of Kauai,

This morning I have begun a series of signal measurements.
I will be comparing the performance of
my Mosley triband antenna,  a TA-34-XL to my Gladiator
1/4 wave vertical element 20 meter elevated antenna
which is using,  now,  four elevated radials.  In the near
future,  I will double the number of elevated radials
three times; i.e.,  first to eight,  then to 16 and at last
to 32 radials,  all elevated and all exactly resonant at
14100 mHz the NCDXF beacon frequency.  At present the
vertical is elevated about 12 feet above a very wet,  vine
and bush overgrowth of rain forest vegetation,  which
is very dense with a lot of shell ginger plants scattered
about the area;  some short wild guava tress also in the
area.  For anyone interested,  I can email (as attachments)
.jpg images of the antenna set up; images taken with
a Sony digital camera.  These would be private email;
not a great idea to post images as attachments to 
reflector posts.

Antenna particulars:

Mosley TA-34-XL;  trapped, with 4 elements each band.  
One trap on each of the four elements.  Mosley evidently 
uses the outer sleeve of the trap as a conductor for 15 
meters,  can't figure how else they get three bands on 
one element using only one trap on each side of the 
boom!  The boom is 21 feet long.  The antenna
is at about the  opt height for daytime 20 meter 
operation,  that  is,  at 45 feet above the gentle sloping 
ground behind the house.

The Gladiator Single Band 20 meter vertical, by R. Myers 
Communications, is mounted atop a Radio Shack push 
up pole.  Myers' model number is FL20M MKII Vertical.  
The antenna is elevated about  12 feet now, or only 
about 0.17 wave elevation.  The radiator element is
17feet, 7 inches long,  resonating at 14100 mHz (vswr at
this  freq.  is 1.0:1).  The elevated radials are exactly 
16 feet, 8 inches in length,  as they are closer to the 
ground,  the 1/4 wave electrical  length is physically 
shorter than the up-reaching vertical element.
The radials  slope slightly down,  and tie off about 
4 feet above the  ground.  The top of the vertical is 
therefore up around 30 feet high.  It is almost exactly 
75 feet South of the US Tower MA-550  supporting 
the TA-34.

Today,  between 2015 and 2030 UTC I took comparative 
"readings" of  several of the NCDXF beacons scattered 
about the globe.  Signals were  heard from both the
Mosley and the Gladiator from the following beacons:  
W6WX,  California;  ZL6B, New Zealand;  JA2IGY, Honshu, 
Japan;  4X6TU, Tel Aviv, Israel;  OH2B, Finland; and CS3B, 
Island of Madeira,  off the  West Coast of Morocco.  
>From none of the beacons was the signal strength
sufficient to move the S meter needle of my FT-1000D
transceiver.  I conclude then,  that the AGC level was the
same for all signals heard and reported here.

I would like to report the data as a table,  but that seems
difficult by e-mail,  so will use a by-beacon text format.

My QTH is at  21.92 N,  159.49 W; elevation about 450' ASL,
about 2 miles inland from the South shore of the
Island of Kauai;  just North of the Lawai,  Poipu Beach
area for those of you who know the island.  So most
of the 23 mile diameter of the island is to my North
horizon.  In all cases below, when using the TA-34,  the
beam was directed exactly to the short path azimuth
to the beacon,  as reported by Beacon Wizard 1.1,  by
Kangaroo Tabor software (freeware software).

All data readings within 30 minutes of the Penticton
Observatory report at 2000 UTC of a solar flux of 100.8.
"A" index,  via Solar Terrestrial Dispatch, was A sub p= 5;
A sub Bolder= 4;  K=1.  Background X-ray flux at the
time was at the B 1.38 level,  essentially of no influence.
MUF in most directions from Hawaii was around 20 mHz,
as reported by STD.  This seemed confirmed as the signals
from all the beacons listed here were stronger on 18110
mHz than those on 14100. This is usually the case that
signals will be stronger on frequencies near the MUF.
However,  I do not now have a 17 meter vertical up,
(it is on order!) only a 17 meter dipole.  At the time I
took this information the Sun was directly overhead
at 23.3 N and about 125 W.

1.  W6WX,  in California,  3959 km,  or 2450 miles distant,  at
a short path azimuth of 57 degrees from my QTH.
Readings:  With both antennas the 0.1 watt signal level
was easily heard.  Time was 2015 UTC;  HST 10:15 AM; 
in California, 1:15 PM,  PDT.

2.  ZL6B,  New Zealand,  7069 km,  or  4660 miles distant, at
a short path azimuth of 203 degrees.  With both antennas
the 0.1 watt signal levels were easily heard.  Time in New
Zealand was about  8:17 AM.

3.  JA2IGY, South central Honshu,  Japan,  6010 km,  or  about
3900 miles distant, at a short path azimuth of 299 degrees.
With the TA-34,  the 0.1 watt signal was heard;  on the
vertical only down to the 1 watt signal could be heard.  Time
in  Honshu at the time was about  05:18 AM,  sunrise in that
area of Japan had been about one hour earlier.

4.  4X6TU,  Tel Aviv,  Israel,  13,820 km,  or  8585 miles distant
at an azimuth of 345 degrees.  With the TA-34,  the 10 watt
signal level could be heard;  on the vertical,  only the
transmission text and signal at the 100 watt level was
audible.  Tel Aviv time was 11:23 PM.

5.  OH2B,  Finland,  10,870 km,  or  5630 miles distant,  at
an azimuth of 358 degrees,  practically directly over the
North Pole from my QTH.  With the TA-34,  the 1 watt
signal was  heard,  with the vertical the 10 watt
signal could  be heard,  just!

6.  CS3B,  Island of  Madeira,  12,588 km,  or  7950 miles
distant, at an azimuth of 25 degrees.  With the TA-34,
the 10 watt signal was just audible;  with the vertical,
only the 100 watt level could be heard.


It appears that around a 10 dB or so difference exists between
the two antenna set ups.  I suppose the Mosely is around 6
or 7 dBi of gain on 20 meters,  and the vertical should be
right around 0 dBi.  It is possible that these are the actual
differences,  but without signals strong enough to move
the S meter needle,  all I can do is report what I heard with
assured 10 dB differences in signal strength radiated every
few seconds by the various beacons. See 

for complete info about the NCDXF beacon network,  and
the status of each beacon.

When I have the elevated radial count increased to eight,
the test will be repeated and reported.

73,  Jim,  KH7M
On the Garden Island of Kauai

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