Would a discone cover all the US TV broadcast Freqs?
 

Hal Rosser wrote:
"Cecil Moore" wrote in message
...
JB wrote:
Discone is vertically polarized and TV is horizontal. Results in a 15db
or
more loss in signal.
How about a dual-discone mounted horizontally?
--
73, Cecil http://www.w5dxp.com

If I did that, the omi-directionality (if that's a word) would go away and
so would most of the compactness needed foe stealthiness.
So - does anyone know of an omni directional horizontally polarized wide
band antenna?




A "big wheel" is omni and horizontal, but not especially broadband.

Would a discone cover all the US TV broadcast Freqs?
 

As for Ed's repeated advice for paint it black (Rolling Stones?), no.
Paint it off-white or a paler shade of blue (Procol Harumish). In
experiments during WWII, they discovered that lighting targets against
the sky made them disappear - not darkening them which offered
contrast. Oxidized aluminum is probably the best coloration.


No, not Rolling Stones.... never was a fan. And I stand corrected. I
know better, but here in Oregon, most of my outside stuff has a "dark
Green" folage background and I was thinking of that instead of the sky.


Ed K7AAT

Would a discone cover all the US TV broadcast Freqs?
 

Bart Bailey wrote:
Being an omni, you're going to pick up any ghosts arriving at your
location, unlike a directional that can attempt to null them out.

"Ghosting" on a digital TV screen?
--
73, Cecil http://www.w5dxp.com

Would a discone cover all the US TV broadcast Freqs?
 

Cecil Moore wrote:

...
"Ghosting" on a digital TV screen?

Well, heck yes!

I see dead people (ghosts) on my TV screen all the time, don't you? If
not, get some old reruns of Gunsmoke on, you'll see 'em! :-|

Regards,
JS

Would a discone cover all the US TV broadcast Freqs?
 

In article ,
Jim Lux wrote:

Somewhat tricky..

Two crossed dipoles fed with the correct phasing is very close to that.

The tricky part, I believe, is maintaining the correct phasing between
dipoles over a sufficiently wide frequency range.

For narrow-band applications, using an additional quarter-wavelength
feedline phasing section would do.

For somewhat wider-band applications (say, 2:1 frequency range) a
broadband 90-degree hybrid ought to work... Minicircuits sells some
such.

I'm not at all sure how to do this for an antenna intended to cover
everything from VHF low-band up to the 700 MHz end of the new UHF
channel range. This is more than a full decade of frequencies... is
there a single broadband 90-degree hybrid that can do the job?

It feels like it might be necessary to split the signals into multiple
bands (VHF / UHF at least, possibly VHF-low / VHF-high / UHF) and then
do the phase shifting on each band individually and then recombine.
Pretty complex...

Or is there an approach I've missed?

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Would a discone cover all the US TV broadcast Freqs?
 

"Jim Lux" wrote in message
...
Hal Rosser wrote:
"Cecil Moore" wrote in message
...
JB wrote:
Discone is vertically polarized and TV is horizontal. Results in a
15db or
more loss in signal.
How about a dual-discone mounted horizontally?
--
73, Cecil http://www.w5dxp.com

If I did that, the omi-directionality (if that's a word) would go away
and so would most of the compactness needed foe stealthiness.
So - does anyone know of an omni directional horizontally polarized wide
band antenna?

Somewhat tricky..

Two crossed dipoles fed with the correct phasing is very close to that.

Check out "Lindenblad" or "turnstile"


A Lindenblad array (e.g. http://www.bbc.co.uk/rd/pubs/reports/1991-15.pdf
Page 9) can provide good circular polarisation over much of a sphere and is
a relatively complicated antenna to design if it is to match properly -
probably over the top for the stated application. But the turnstile, and
the Alford loop
(http://books.google.co.uk/books?id=1...sult#PPA123,M1
as used at DVOR stations), are simpler and can provide good omni patterns in
the horizontal plane and thereabouts for horizontal polarisation.

Chris

Would a discone cover all the US TV broadcast Freqs?
 

John Smith wrote:
Cecil Moore wrote:

...
"Ghosting" on a digital TV screen?

Well, heck yes!

I see dead people (ghosts) on my TV screen all the time, don't you? If
not, get some old reruns of Gunsmoke on, you'll see 'em! :-|

Ahh, Gunsmoke's Amanda Blake was one of my favorite "mature babes".
rowwwwrr.

- 73 de Mike N3LI -

Would a discone cover all the US TV broadcast Freqs?
 

How about a dual-discone mounted horizontally?
--
73, Cecil http://www.w5dxp.com

A biconcal dipole. I thought you wanted stealth.

Would a discone cover all the US TV broadcast Freqs?
 

"Hal Rosser" wrote in message
...
I want to put up the smallest outdoor antenna that would cover all TV
Broadcast Freqs being used after Feb 2009. The log-periodicals are too
"un-stealthy" to go unnoticed by the XYL, but I think a little discone
with
some black paint might escape her inspection as long as I do the
installation while she's out shopping.
Question is - have any of you used one for TV - and if so, how did it
perform? would it cover the TV broadcast freqs ? (I'm aware of its lack
of
gain - I'm within 5 miles of most local stations, and within 20 miles of a
couple more.)
Thanks
Hal W4PMJ

Why not just put a normal antenna up in the garage or the attic? A small
yagi should do it. You can remove the UHF reflectors if there is plenty of
signal. Even cut half of the UHF directors without much loss. Bring it up
in the rafters and spread it out. Not near as good as on the roof but you
can always put it up normally when she finds out about it anyway.

Would a discone cover all the US TV broadcast Freqs?
 

"Hal Rosser" wrote in message
...

"Cecil Moore" wrote in message
...
JB wrote:
Discone is vertically polarized and TV is horizontal. Results in a 15db
or
more loss in signal.

How about a dual-discone mounted horizontally?
--
73, Cecil http://www.w5dxp.com

If I did that, the omi-directionality (if that's a word) would go away and
so would most of the compactness needed foe stealthiness.
So - does anyone know of an omni directional horizontally polarized wide
band antenna?


As close as you are to them, anything will work and you don't need to worry
about the loss due to polarization.