Hello,

Would like to compare link budget between
portable-radio with typical small rubber whip antenna and
vehicular-radio with 1/4-wave or 5/8 antenna or vertical dipole on the
roof

Gain difference between vertical ground plane and dipole is about 2dB.

What I'm looking for is the gain difference between

portable whip
1/4-wave on car roof
5/8 on car roof
Vertical dipole

Does anybody have more info?

Thanks in advance

Pierre
ON7CIP

On Tue, 11 Dec 2007 02:40:41 -0800 (PST), wrote:

Hello,

Would like to compare link budget between
portable-radio with typical small rubber whip antenna and
vehicular-radio with 1/4-wave or 5/8 antenna or vertical dipole on the
roof

Gain difference between vertical ground plane and dipole is about 2dB.

What I'm looking for is the gain difference between

portable whip

It's a NO-NO. Don't call it "antenna".

1/4-wave on car roof

THE standard.

5/8 on car roof

Definitely bad on 2 meters.
Whip is elastic and moves and wiggles and causes additional QSB.

Vertical dipole

Not on a car roof.


Does anybody have more info?
You do. What's your operating frequency range.
Why do you keep it top secret?


w.

On Tue, 11 Dec 2007 11:55:16 +0100, Helmut Wabnig hwabnig@ .- --- -.
DOT .- t wrote:


Does anybody have more info?
You do. What's your operating frequency range.
Why do you keep it top secret?

Ahhh...it's in the subject line!
Whip on portable vs Dipole Gain for 2m or 70cm

WhoonEarthreadssubjectlines?

sorry,
w.

On Dec 11, 12:02 pm, Helmut Wabnig hwabnig@ .- --- -. DOT .- t
wrote:
On Tue, 11 Dec 2007 11:55:16 +0100, Helmut Wabnig hwabnig@ .- --- -.

DOT .- t wrote:

Does anybody have more info?
You do. What's your operating frequency range.
Why do you keep it top secret?

Ahhh...it's in the subject line!

Whip on portable vs Dipole Gain for 2m or 70cm

WhoonEarthreadssubjectlines?

sorry,
w.

Thank you for this tentative...
So lets keep on 2m for the simplicity.
I know that you do not put a vertical dipole on a roof.
You put it on a mast, and this mast (if small) can be on (side of) car
when on halt...
The link budget will change by the fact that the dipole will be
higher. (easy to take in account in a formula like Eggli-Mod for
example). But there should be also a difference in Antenna Gain.
That's what I'm looking for!

Pierre

On Wed, 12 Dec 2007 01:34:16 -0800 (PST), ON7CIP - Pierre
wrote:


example). But there should be also a difference in Antenna Gain.
That's what I'm looking for!

Pierre

When mounting an 2 m antenna on a car you do not care for gain.
Care for good SWR on 2 m and 70 cm which is difficult enough
to obtain with a combined radial.
The direction characteristic of the antenna + car assembly is
totally unpredictable. Just try to have good horizontal radiation,
else you will only heat up the atmosphere.

The best place is in the center of the roof for a metal case car.
If you bought a plastic car, well, then you bought plastic.

w.

On Tue, 11 Dec 2007 02:40:41 -0800 (PST), wrote:

Would like to compare link budget between
portable-radio with typical small rubber whip antenna and
vehicular-radio with 1/4-wave or 5/8 antenna or vertical dipole on the
roof

Hi OM,

Rubber Ducky performance is an unknown quantity, but certainly can be
improved.

Gain difference between vertical ground plane and dipole is about 2dB.

What I'm looking for is the gain difference between

portable whip
bad, maybe
1/4-wave on car roof
OK, maybe
5/8 on car roof
better, maybe
Vertical dipole
OK, maybe

All such valuations vary a lot with height. With enough height, you
could use a rubber ducky anywhere.

Does anybody have more info?

It would be simpler if you examine exactly your situation using EZNEC.
The free version should be capable of doing a lot of this.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
All such valuations vary a lot with height. With enough height, you
could use a rubber ducky anywhere.

The ducky that came with my DJ-580 was an abomination.
I replaced it with a long Diamond ducky and a Tiger
Tail and gained about 6 dB if memory serves me right.
--
73, Cecil http://www.w5dxp.com