The major claim to fame of this type of antenna is not "gain" or
"directivity", but coverage of all the amateur HF bands with one antenna
with a single feedline. It is a compromise to accomplish that end. I
seriously doubt it has any "gain" over a single-band properly installed and
fed 1/4-wavelength vertical radiator.
Dave - W?LEV
On Wed, Nov 13, 2024 at 12:23?PM Jim Lux via groups.io <jimlux=
[email protected]> wrote:
Indeed but modeling multiband antennas with traps and internal components
with multiple coupling mechanisms can be full of interesting challenges
Sent via the Samsung Galaxy S24, an AT&T 5G smartphone
-------- Original message --------From: "Colin McDonald via groups.io"
<colinrmcdonald@...> Date: 11/12/24 11:21 PM (GMT+00:00)
To: [email protected] Subject: Re: [nanovna-users] measuring gain
of multi band vertival antenna (GAP Titan DX) This isn't something the
NanoVNA can measure. Any free antenna modelling software can tell you
though. Just download a flavor and enter all the antenna specifications it
asks for. It'll tell you what the angle of radiation is and where the
strongest gain is theoretically.Otherwise, you can use a field strength
meter to compare a dipole or a ground mounted quarter wave with radials to
the titan.However, a field strength meter won't always give you the most
accurate results if the antenna has an angle of radiation that passes over
where you are taking the measurements. Antennas present gain at specific
angles, what are called lobes. Depending on the type of antenna, quarter
wave, half wave, 5/8s wave, full wave etc the angle will be different.
It'll change depending on whether the antenna is a ground mounted vertical,
elevated, how many ground radials you have and of course near by
objects.Antenna modelling software calculates all of this information and
spits out data that can be useful to you.#1 is usually ground radials for a
ground mounted vertical antenna regardless of the radiating elements wave
length. The more quarter wave on the lowest operating frequency ground
radials you have, up to about 128, the better the antenna will perform.A
google search will also tell you what the estimated gain over a dipole or
gain over an isotropic radiator is for the dx titan antenna. Gain is
measured as a comparison in DB to either a dipole or an isotropic radiator.
Most manufacturers use DBI because it yields a larger number which makes
people believe the antenna has more gain. The antenna isn't an amplifier,
there is no magic going on that turns your 100 watts into a KW or
something. There is effected radiated power, but that is based entirely on
lobe radiation and a direct comparison of the nulls to the strongest lobes
of a particular antenna.None of which can be measured with a
NanoVNA.Theoretical math and formulas are used in the modelling software as
apposed to direct electrical measurements.73Colin VA6GGOn 2024-11-12 2:47
p.m., Michael E Wilson Sr via groups.io wrote:> Has anyone measured or
seen the gain factors for an antenna like the Tital DX. I have used one for
16 years, moved it to 4 different locations and it has never faild. But I
am curious about its gain on the divverent bands and would like to get a
measurement. Then may be I could see what is needed to improve it
operationj. Any information as to what equipment would be needed and the
procedures to follow would be appreciagted.>> Thanks.> 73> Mike Wilson>
KE5WCT> Daingerfield, Morris County, Texas (EM23ob)>>> >>
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*Dave - W?LEV*
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Dave - W?LEV
