I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?


Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike

amdx wrote:
I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?


Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike



I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are
commercial, could you please point me at a web site? I'd love to see
why they made these.

tom
K0TAR

On 12 Jun, 18:16, Tom Ring wrote:
amdx wrote:
I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?

Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike

I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are
commercial, could you please point me at a web site? I'd love to see
why they made these.

tom
K0TAR

I would imagine he is checking for cross polarisation

"Tom Ring" wrote in message
. ..
amdx wrote:
I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?


Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike



I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are commercial,
could you please point me at a web site? I'd love to see why they made
these.

tom
K0TAR

Very broadbanded.

Jimmie D wrote:

I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are commercial,
could you please point me at a web site? I'd love to see why they made
these.

tom
K0TAR

Very broadbanded.



Ridiculous.

tom
K0TAR

"Tom Ring" wrote in message
. ..
amdx wrote:
I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?


Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike



I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are commercial,
could you please point me at a web site? I'd love to see why they made
these.

tom
K0TAR

but 0dBi would be perfectly omnidirectional by definition. either he is
reading the scale wrong or is looking at f/b ratio instead of gain, or maybe
looking at depth of a null or sidelobes.

"Dave" wrote in message
news:muPbi.10807$Ar5.10317@trndny01...

"Tom Ring" wrote in message
. ..
amdx wrote:
I'm comparing elevation plots of an antenna. They have different
forward gains, this makes it difficult to compare the lobe shape.

Is there a way to equalize the gains to do a comparison?


Example: I have an antenna that is -19dbi and one that is -23dbi.
Can I add 4db of gain to one to make the comparison easier?
Mike



I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are commercial,
could you please point me at a web site? I'd love to see why they made
these.

tom
K0TAR

but 0dBi would be perfectly omnidirectional by definition.
Yes.
either he is reading the scale wrong
No.
or is looking at f/b ratio instead of gain,
No.
or maybe looking at depth of a null or sidelobes.
No.
Mike

Dave wrote:
I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are commercial,
could you please point me at a web site? I'd love to see why they made
these.

tom
K0TAR

but 0dBi would be perfectly omnidirectional by definition. either he is
reading the scale wrong or is looking at f/b ratio instead of gain, or maybe
looking at depth of a null or sidelobes.



Actually they could have gain that low and still be directional. It
would probably be silly to do so, but with nice lossy components, quite
possible.

Heck, I bet someone here may have even done something like it for some
reasonable engineering design.

tom
K0TAR

"Tom Ring" wrote in message
. ..
Dave wrote:
I am wondering what type of antenna has -19 or -23 dBi gain. I would
speculate that they are quite omnidirectional, and the patterns wouldn't
be significantly different.

It's tough to get gain that low unintentionally. If they are
commercial, could you please point me at a web site? I'd love to see
why they made these.

tom
K0TAR

but 0dBi would be perfectly omnidirectional by definition. either he is
reading the scale wrong or is looking at f/b ratio instead of gain, or
maybe looking at depth of a null or sidelobes.

Actually they could have gain that low and still be directional. It would
probably be silly to do so, but with nice lossy components, quite
possible.

Heck, I bet someone here may have even done something like it for some
reasonable engineering design.

tom
K0TAR

Do a little research on the Flag or pennant antenna.
It's a rotatable antenna that has a good f/b ratio at low
frequencies. I've measured 40db f/b at 1430khz.
I have a variable termination.
Mike

On Wed, 13 Jun 2007 19:45:35 -0500, Tom Ring
wrote:

Actually they could have gain that low and still be directional.
....
Heck, I bet someone here may have even done something like it for some
reasonable engineering design.

.... tsk, tsk, tsk. Such a fall from grace for the fractal antenna.
Gone, and long forgotten.

73's
Richard Clark, KB7QHC