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measuring gain of multi band vertival antenna (GAP Titan DX)

 

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)
 

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.


73

Colin VA6GG

On 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)
 

Modeling wont work. This antenna uses multi coax sections folded and placed inside the tube, with the feed point at the mid point, and section dropping below the tube with the coax connector. So far I have found no one that has the spects for all of the bands. It covers 80 thru 10 meters (less 160 and 60 meters). It is a great antenna, I would just like to know more about it.

Hope someone out there has de-structed one and figured how it is put togethere and has some written data stored away somewhere.

73
Mike, KE5WCT
 

Why not contact the manufacturer and ask?
https://gapantenna.com/shop/titan-dx/
 

A co-linear vertical dipole design. Using coax as the elements to linearly load the element.

Fed like a dipole in the middle instead of an end fed like most vertical antennas.

Sure you can put that into modelling software. Though perhaps not the free ones.

Also, an educated guess suggests gain would be the same as a dipole, or a DB or two more in the strong lobes at particular direction and angle.

The manual for these is online.

I am unaware of any equipment other than field strength equipment used to compare a known antenna like a dipole, that can provide a gain measurement.

How do they determine that a particular antenna has gain? Well, it's theoretical for the most part, but antenna makers also measure the field strength of the antenna to determine how much RF energy is being sent out and in what direction and at what angle.

Or they should. I suspect most just provide standard estimates based on the physical design of the antenna and don't really test anything beyond the stuff you can check on a NanoVNA.


73

Colin, VA6GG

On 2024-11-12 8:26 p.m., Michael E Wilson Sr via groups.io wrote:
Modeling wont work. This antenna uses multi coax sections folded and placed inside the tube, with the feed point at the mid point, and section dropping below the tube with the coax connector. So far I have found no one that has the spects for all of the bands. It covers 80 thru 10 meters (less 160 and 60 meters). It is a great antenna, I would just like to know more about it.

Hope someone out there has de-structed one and figured how it is put togethere and has some written data stored away somewhere.

73
Mike, KE5WCT
 

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: nanovna-users@groups.io 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)>>> >>
 

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 - WØLEV

On Wed, Nov 13, 2024 at 12:23 PM Jim Lux via groups.io <jimlux=
earthlink.net@groups.io> 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: nanovna-users@groups.io 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)>>> >>




--

*Dave - WØLEV*


--
Dave - WØLEV
 

To measure the loss/gain of an antenna, both in transmission and reception, you will have to do it by comparing it with another one. For this, a field strength meter will be useful; the nanoVNA is a vector network analyzer, it is not designed for that purpose.
--
ALVARO, EA8ARX
 

its just several dipoles in parallel on the higher bands fed on the gap (almost similar to a fan dipole)

except on 10m where it is 3 quarterwave ... on 40m it is a quarterwave against bent radial (the gap is "bridged" with the folded coax stup inside)... on 80m its a loaded vertical where the cap on the top is transformed to a coil via the folded coax inside ... so it is NOT a colinear design

dg9bfc sigi

Am 13.11.2024 um 07:48 schrieb Colin McDonald via groups.io:

A co-linear vertical dipole design. Using coax as the elements to linearly load the element.

Fed like a dipole in the middle instead of an end fed like most vertical antennas.

Sure you can put that into modelling software. Though perhaps not the free ones.

Also, an educated guess suggests gain would be the same as a dipole, or a DB or two more in the strong lobes at particular direction and angle.

The manual for these is online.

I am unaware of any equipment other than field strength equipment used to compare a known antenna like a dipole, that can provide a gain measurement.

How do they determine that a particular antenna has gain? Well, it's theoretical for the most part, but antenna makers also measure the field strength of the antenna to determine how much RF energy is being sent out and in what direction and at what angle.

Or they should. I suspect most just provide standard estimates based on the physical design of the antenna and don't really test anything beyond the stuff you can check on a NanoVNA.


73

Colin, VA6GG


On 2024-11-12 8:26 p.m., Michael E Wilson Sr via groups.io wrote:
Modeling wont work. This antenna uses multi coax sections folded and placed inside the tube, with the feed point at the mid point, and section dropping below the tube with the coax connector. So far I have found no one that has the spects for all of the bands. It covers 80 thru 10 meters (less 160 and 60 meters). It is a great antenna, I would just like to know more about it.

Hope someone out there has de-structed one and figured how it is put togethere and has some written data stored away somewhere.

73
Mike, KE5WCT

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