I have a Firestick No Ground Plane antenna on order that I'm going to install for a friend. Reading through the reviews there are comments that you cannot use an external SWR meter to tune it. That you use the radio's internal SWR meter. I'm not sure why this would be or if that also means I cannot use either my NanoVNA or MFJ259. Does anyone have any background with these?

Thanks again,
/A

Sure sounds like the length of coax is part of the antenna matching.Especially true for an antenna without radials or a ground plane.
So that extra length of coax between the radio and the SWR meterchanges the tuning of the antenna 'system'.

Good luck with your tweaking.  Kent

Its a proprietary cable and not just something like a make shift sleeve dipole. The shield isn't connected at the antenna side. Maybe it's somehow a J-pole using the coax?? I fail to understand why there was the statement about high SWR using an external meter. Re-thinking this I can still tune for best resonance using an external regardless of SWR and recheck the SWR seen by the radio's meter.

/a

These "No Ground" antennas use the coax feeding it or the ground connections to the radio as the counterpoise to the radiating element hence the recommendation to use the radio's SWR meter. I would stay away form these antennas if your don't want RF in your shack..

All of these "no ground" antenna are descendants of the Gotham Antennas sold when I was young:

<https://www.w8ji.com/gotham.htm>

Mike N2MS

On 11/10/2024 7:12 AM EST Andrew Harman via groups.io <nexus9d9@...> wrote:


I have a Firestick No Ground Plane antenna on order that I'm going to install for a friend. Reading through the reviews there are comments that you cannot use an external SWR meter to tune it. That you use the radio's internal SWR meter. I'm not sure why this would be or if that also means I cannot use either my NanoVNA or MFJ259. Does anyone have any background with these?

Thanks again,
/A

in the following forum areas:

Documentation & Update Files: https://groups.io/g/nanovna-users/files
Knowledge-based Wiki: https://groups.io/g/nanovna-users/wiki
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Unsubscribe: https://groups.io/g/nanovna-users/leave/11823847/89811/742747392/xyzzy [mstangelo@...]
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I'm using a NGP antenna in a camper for reasons. While an in-line SWR
meter can cause issues, the VNA is the perfect tool for tuning. Got mine
tuned to over 30dB return loss.

Chris Smith
NK9W

On Sun, Nov 10, 2024 at 7:39 AM Mike N2MS via groups.io <mstangelo=
comcast.net@groups.io> wrote:

These "No Ground" antennas use the coax feeding it or the ground
connections to the radio as the counterpoise to the radiating element hence
the recommendation to use the radio's SWR meter. I would stay away form
these antennas if your don't want RF in your shack..

All of these "no ground" antenna are descendants of the Gotham Antennas
sold when I was young:

<https://www.w8ji.com/gotham.htm>

Mike N2MS

On 11/10/2024 7:12 AM EST Andrew Harman via groups.io <nexus9d9=

gmail.com@groups.io> wrote:

I have a Firestick No Ground Plane antenna on order that I'm going to

install for a friend. Reading through the reviews there are comments that
you cannot use an external SWR meter to tune it. That you use the radio's
internal SWR meter. I'm not sure why this would be or if that also means
I cannot use either my NanoVNA or MFJ259. Does anyone have any background
with these?

Thanks again,
/A

in the following forum areas:

Documentation & Update Files: https://groups.io/g/nanovna-users/files

Knowledge-based Wiki: https://groups.io/g/nanovna-users/wiki
-=-=-
Group Owner: nanovna-users+owner@groups.io
Unsubscribe:

https://groups.io/g/nanovna-users/leave/11823847/89811/742747392/xyzzy [
mstangelo@...]

Hello,
The Firestick NGP is a mobile CB antenna designed to be mounted on a
vehicle. That is why it has NO radials.
The vehicle is supposed to make up the ground plane, not the coaxial lead.
Without knowing where, to what or how the antenna is going to be mounted,
the worry of RF on the coaxial lead may not be a concern unless, it is used
as a fixed station antenna or one does not properly ground the antenna
mount to the vehicle.
In my 60 years of civilian, military and commercial, mobile communications
installations, I have never had a problem of using an external SWR meter to
tune a antenna installed between the coaxial lead and radio. NOT at the
antenna feed point.
You DO NOT tune the antenna itself.

Clyde Lambert KC7BJE
Retired Electronics Manufactureing Engineer
U.S. Army Signal Corps Veteran

Actually the firestick NGP does indeed time at the antenna, and it does use
the coax as a counterpoise. It does not use the vehicle as ground plane.
I have one on a fiberglass bodied vehicle and used a VNA to time the tip of
the antenna for best return loss at center operating frequency.

30dB return loss on CB channel 20 is as good as it gets.. and yes,
extending the coax made it un-tunable on CB freqs.

On Sun, Nov 10, 2024, 12:43 PM Clyde Lambert via groups.io <clyde.lambert=
gmail.com@groups.io> wrote:

Hello,
The Firestick NGP is a mobile CB antenna designed to be mounted on a
vehicle. That is why it has NO radials.
The vehicle is supposed to make up the ground plane, not the coaxial lead.
Without knowing where, to what or how the antenna is going to be mounted,
the worry of RF on the coaxial lead may not be a concern unless, it is used
as a fixed station antenna or one does not properly ground the antenna
mount to the vehicle.
In my 60 years of civilian, military and commercial, mobile communications
installations, I have never had a problem of using an external SWR meter to
tune a antenna installed between the coaxial lead and radio. NOT at the
antenna feed point.
You DO NOT tune the antenna itself.

Clyde Lambert KC7BJE
Retired Electronics Manufactureing Engineer
U.S. Army Signal Corps Veteran

Perhaps my ignorance is showing, but It occurred to me that the linked "documentation", http://www.firestik.com/Catalog/NGP_3-Way.htm, makes it fairly clear why the Firestick NGP is named as such, why a customized feedline length, and the propriety of an swr tuning procedure with a NanoVNA or MFJ259, at the transmitter end of that customized length.

The Ol' Dog

Yes, the coax is understood to be part of the antenna so an external meter would have to be at the coax end and not the antenna feed point. Also, Firestik says not to trim the length as it is factory matched. They do say you can add coax but only in 9ft increments and on the radio side. They specify it is resonant through 30mhz, my target will be 10m at 28.4. (fingers crossed). So, it's being said that a VNA will work to "time" the antenna leaves me wondering what the commenter was talking about in his review. Another thought is that if this is like a sleeve dipole that the SWR will vary if the coax is run horizontal, vertical or diagonal. Diagonal runs tend to require a longer length - so the placement during testing is critical.
But.....contrary to what was just said: You DO tune the antenna at the tip; You DO NOT ground the antenna mount. You should normally isolate the bracket from a metallic mast if used. You can ground the remainder of the mast for lightning protection if that's your choice. In this app the shield is not bonded to the mounting bracket and it will be attached to PVC pipe, there is no need to add a ground wire from the bracket.

Regards,
/a

On Nov 11, 2024, at 8:21 AM, Andrew Harman via groups.io <Nexus9d9@...> wrote:

Yes, the coax is understood to be part of the antenna so an external meter would have to be at the coax end and not the antenna feed point. Also, Firestik says not to trim the length as it is factory matched. They do say you can add coax but only in 9ft increments and on the radio side. They specify it is resonant through 30mhz, my target will be 10m at 28.4. (fingers crossed). So, it's being said that a VNA will work to "time" the antenna leaves me wondering what the commenter was talking about in his review. Another thought is that if this is like a sleeve dipole that the SWR will vary if the coax is run horizontal, vertical or diagonal. Diagonal runs tend to require a longer length - so the placement during testing is critical.
But.....contrary to what was just said: You DO tune the antenna at the tip; You DO NOT ground the antenna mount. You should normally isolate the bracket from a metallic mast if used. You can ground the remainder of the mast for lightning protection if that's your choice. In this app the shield is not bonded to the mounting bracket and it will be attached to PVC pipe, there is no need to add a ground wire from the bracket.

Would be marginally interested (as in probably not enough to go buy one of these ham-stick clones for myself) to see what happens if you tried running the antenna against a ground plane with and without the OEM feed line. My un-educated guess is it will be fine, maybe even better than the magic feed line - though highly dependent on both the overall installation, as well as the adjustment of the tuning stud. I used a set of Hamsticks for a while - they’re similar - fiberglass blank, wrapped with a loading coil, adjusted by a stinger at the top end. Worked best against a decent ground plane - I used 4 radials with the ’stick on the end of a painters pole. The whole setup was very frequency dependent since there is a very high “Q” factor with these types of dummy loads… errrr antennas.






--

Daniel Brown
daniel.h.brown@...

Good morning, y'all.

There is a fundamental feature of the physics involved in this particular
antenna installation. No ground plane indicates a colinear antenna. But,
the issue is, from the radio, through the SWR meter, to the antenna feed
point requires specific lengths of coaxial feed line. That length can be
any number of *electrical* half-wavelengths of coax from radio (or SWR
meter with a very short jumper coax) to the antenna feed point. The point
is to make each end of the feed system at zero volts! Essentially, using
RG-58 (50 ohms) at multiple half-wavelengths with zero volts at each end
removes the coax from the equation allowing for maximum power transfer from
source to load minus the resistive losses within the lumped constants of
the feed line.

Just voicing my experiences; take it for what it is worth.

Best Regards,

Michael L Robinson, KC0TA

“In the beginning of a change the Patriot is a scarce man, and brave, and
hated and scorned. When his cause succeeds, the timid join him, for then it
costs nothing to be a Patriot.” ― Mark Twain

When Tyranny becomes Law, Revolution becomes Duty!






On Mon, Nov 11, 2024 at 7:42 AM Daniel Brown via groups.io <daniel.h.brown=
gmail.com@groups.io> wrote:

On Nov 11, 2024, at 8:21 AM, Andrew Harman via groups.io <Nexus9d9=

gmail.com@groups.io> wrote:

Yes, the coax is understood to be part of the antenna so an external

meter would have to be at the coax end and not the antenna feed point.
Also, Firestik says not to trim the length as it is factory matched.
They do say you can add coax but only in 9ft increments and on the radio
side. They specify it is resonant through 30mhz, my target will be 10m
at 28.4. (fingers crossed). So, it's being said that a VNA will work to
"time" the antenna leaves me wondering what the commenter was talking about
in his review. Another thought is that if this is like a sleeve dipole
that the SWR will vary if the coax is run horizontal, vertical or
diagonal. Diagonal runs tend to require a longer length - so the
placement during testing is critical.

But.....contrary to what was just said: You DO tune the antenna at the

tip; You DO NOT ground the antenna mount. You should normally isolate the
bracket from a metallic mast if used. You can ground the remainder of the
mast for lightning protection if that's your choice. In this app the
shield is not bonded to the mounting bracket and it will be attached to PVC
pipe, there is no need to add a ground wire from the bracket.

Would be marginally interested (as in probably not enough to go buy one of
these ham-stick clones for myself) to see what happens if you tried running
the antenna against a ground plane with and without the OEM feed line. My
un-educated guess is it will be fine, maybe even better than the magic feed
line - though highly dependent on both the overall installation, as well as
the adjustment of the tuning stud. I used a set of Hamsticks for a while -
they’re similar - fiberglass blank, wrapped with a loading coil, adjusted
by a stinger at the top end. Worked best against a decent ground plane - I
used 4 radials with the ’stick on the end of a painters pole. The whole
setup was very frequency dependent since there is a very high “Q” factor
with these types of dummy loads… errrr antennas.






--

Daniel Brown
daniel.h.brown@...

On Mon, Nov 11, 2024 at 12:06 PM, Michael Robinson wrote:

Essentially, using
RG-58 (50 ohms) at multiple half-wavelengths with zero volts at each end
removes the coax from the equation

ODD half-wavelengths of ANY impedance transmission line will repeat the impedance presented at the far end. It is not confined to RG-58 or to 50Ω line.
73, Don N2VGU