Indoor Omni Antenna 550-600mHz Suggestions...

[Klay Anderson]

I\'m in need of an indoor omni antenna (actually two) in the 550-600mHz range. I\'ve found a few with 5-9dBi gain from Italian manufacturers. And while we are well versed in importing, we find their pricing....well, shockingly high. Any US ideas?

 

[Peter W.]

https://en-us.sennheiser.com/a-1031-u

Like this, or am I missing something? About US$150 or so.

Peter Wieck
Melrose Park, PA

 

[Clifford Heath]

On 6/1/21 4:47 am, Klay Anderson wrote:

I\'m in need of an indoor omni antenna (actually two) in the 550-600mHz range. I\'ve found a few with 5-9dBi gain from Italian manufacturers. And while we are well versed in importing, we find their pricing....well, shockingly high. Any US ideas?

PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

Also, I doubt you have a house big enough to contain an antenna for
550-600 milli-Hertz.

 

[KenW]

On Wed, 6 Jan 2021 09:19:40 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 6/1/21 4:47 am, Klay Anderson wrote:
I\'m in need of an indoor omni antenna (actually two) in the 550-600mHz range. I\'ve found a few with 5-9dBi gain from Italian manufacturers. And while we are well versed in importing, we find their pricing....well, shockingly high. Any US ideas?


PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

Also, I doubt you have a house big enough to contain an antenna for
550-600 milli-Hertz.

For what purpose ?


KenW

 

[Phil Allison]

Clifford Heath wrote:

=======================

PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

** Wrong. Omni and isotropic are not the same.

Any vertical whip type is an omni and can have considerable gain.

Also, I doubt you have a house big enough to contain an antenna for
550-600 milli-Hertz.

 

[Phil Allison]

mailser...@gmail.com wrote:

==========================

I\'m in need of an indoor omni antenna (actually two) in the 550-600mHz range.
I\'ve found a few with 5-9dBi gain from Italian manufacturers.

** 600MHz is a common radio mic frequency.

Flexible vertical antennas with BNC connectors sell for a few dollars.

Co-linear versions with gain are harder to find.


...... Phil

 

[Dave Platt]

In article <2C5JH.27093$rY1.20704@fx40.iad>,
Clifford Heath <no.spam@please.net> wrote:

I\'m in need of an indoor omni antenna (actually two) in the 550-600mHz range. I\'ve found a few with 5-9dBi gain
from Italian manufacturers. And while we are well versed in importing, we find their pricing....well, shockingly
high. Any US ideas?


PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

In my experience, when people want to refer to an isotropic or \"0 dBi\"
antenna (which is a purely theoretical reference - no
perfectly-isotropic antenna can actually exist) they use the word
\"isotropic\".

In common usage, the term \"omni\" for an antenna usually refers an
antenna such as a monopole or dipole, which has a uniform radiation
pattern in a two-axis circular pattern, and is directional in only one
axis. I assume that\'s what the original poster is looking for.

Antenna gain is not always quoted w/r/t isotropic. Some manufacturers
quote gain that way (as dBi). Others quote it w/r/t a half-wave
dipole (as dBd).

Antenna vendors which quote antenna gain in \"dB\" (without telling you
what they\'re using as the 0 dB reference) are generally using dBi
numbers, because they\'re bigger by 2.15 and thus look better in the
ads

Now, to the original request: as to needing antennas in the 550-600
MHz range (which is what I assume you\'re looking for since you said
\"indoor\")... that\'s still part of the US UHF-TV band, I think, and so
not one for which small narrow-band antennas would have much of a
commodity market, hence not many cheap commercial antennas available
(or so I suspect). Most coverage here is probably broad-band (often
untuned) receive-only antennas.

How much gain do you need? Receive-only, or is transmission required?
Can you satisfy your needs with something as simple as a wire whip of
the correct length, soldered to a BNC or similar connector, maybe with
a counterpoise wire attached to the ground shell, or a couple of
ground radials sticking out sidewise? Does it need to be pretty, or
child-safe, or capable of surviving the landing and attack of a
hyacinthine macaw? 50 ohm, 75 ohm, or something more exotic?

 

[Ralph Mowery]

In article <4bdfch-84d.ln1@coop.radagast.org>, dplatt@coop.radagast.org
says...

In common usage, the term \"omni\" for an antenna usually refers an
antenna such as a monopole or dipole, which has a uniform radiation
pattern in a two-axis circular pattern, and is directional in only one
axis. I assume that\'s what the original poster is looking for.

Antenna gain is not always quoted w/r/t isotropic. Some manufacturers
quote gain that way (as dBi). Others quote it w/r/t a half-wave
dipole (as dBd).

Antenna vendors which quote antenna gain in \"dB\" (without telling you
what they\'re using as the 0 dB reference) are generally using dBi
numbers, because they\'re bigger by 2.15 and thus look better in the
ads

There seem to be many ways to state antenna gain. Some refference to a
1/2 wave dipole, some to a 1/4 wave vertical, and some to a wet noodle.

I never look at the gain given, but to the physical size of an antenna.
This is one case where bigger is usually better.

 

[Phil Allison]

Dave Platt wrote:

------------------------------

In common usage, the term \"omni\" for an antenna usually refers an
antenna such as a monopole or dipole, which has a uniform radiation
pattern in a two-axis circular pattern, and is directional in only one
axis.

** Dipoles are directional - the radiation or pick up pattern is in the shape of a figure 8.

Only if used vertically is it omni.

..... Phil

 

[J.B. Wood]

On 1/5/2021 5:19 PM, Clifford Heath wrote:

On 6/1/21 4:47 am, Klay Anderson wrote:


PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

Please look up what \"isotropic\" means and how it applies in antenna
theory. Then you\'ll be better informed. Sincerely,


--
J. B. Wood e-mail: arl_123234@hotmail.com

 

[Clifford Heath]

On 6/1/21 11:30 pm, J.B. Wood wrote:

On 1/5/2021 5:19 PM, Clifford Heath wrote:
On 6/1/21 4:47 am, Klay Anderson wrote:


PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

Please look up what \"isotropic\" means and how it applies in antenna
theory.  Then you\'ll be better informed.  Sincerely,

Smart-arses trying to explain why omni doesn\'t actually mean omni...
sigh. Some people are just born to be d*ckheads

 

[J.B. Wood]

On 1/6/2021 10:15 PM, Clifford Heath wrote:

Smart-arses trying to explain why omni doesn\'t actually mean omni...
sigh. Some people are just born to be d*ckheads

An antenna is termed omni-directional if it possesses a circular
radiation pattern in the azimuthal plane. The same pattern in the
elevation plane can be doughnut-shaped or something else. An isotropic
antenna is a theoretical construct with a spherical pattern in 3-space.
As its pattern is spherical, it\'s useful as a basis for comparison of
antenna gain (azimuth & elevation). Gain expressed in \"dBi\" designates
the units for this comparison. An isotropic antenna can be approached
in practice using 3 orthogonal electrically-small (in terms of a
wavelength) dipoles or loops (often called \"magnetic\" loops by ham radio
operators). Sincerely,

--
J. B. Wood e-mail: arl_123234@hotmail.com

 

[Rob]

Clifford Heath <no.spam@please.net> wrote:

On 6/1/21 11:30 pm, J.B. Wood wrote:
On 1/5/2021 5:19 PM, Clifford Heath wrote:
On 6/1/21 4:47 am, Klay Anderson wrote:


PSA: omni antennae do not have gain, because gain is always quoted wrt
an omni (isotropic) antenna having gain of 0dB.

Please look up what \"isotropic\" means and how it applies in antenna
theory.  Then you\'ll be better informed.  Sincerely,

Smart-arses trying to explain why omni doesn\'t actually mean omni...
sigh. Some people are just born to be d*ckheads

Like you.