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Old May 31st 09, 05:04 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

On May 30, 8:28*pm, Usual Suspect wrote:
WInegard makes an antenna-in-a-box, the SS-1000 which lists ~4 db gain over
the UHF TV range:

http://tinyurl.com/nqpzm2

I must say at the outset that I am hesitant to buy an antenna based on its
form-factor, but I'm forced by the local code to not display bare-element
type antennae on the mast.

I do like the panel style for the reason that I can arrange 3 around a common
mast, aimed at remote cities, and join the outputs for increased coverage..

Has anyone experience with the SS-1000? Or can recommend a similar style
antenna?

Thanks.
--
Al, the usual


Hey OM
This si just a rehash of another post awhile back in this here forum.
But DTV will never go away so:

I seen one on youtube, there are a tonne of them, but this, to the
best of my recollection, one used:

1pc 1x2 2ft long board
5 steel wire coat hangers
dry wall screws
and a 75 ohm to 300 ohm balun

to make a 4 bay bowtie antenna

Ideally that's 6 db over, just a single bowtie.

And an 8 bay bowtie would be 9db.

I the real world it would be slightly less

Capture area of stacked antennas is greater, so less UHF fading. Like
when the wind blows trees branches around and when cars and trucks go
by.

But nothing like watching a pixelated picture. Unless you got a good
memory in that set box.

73 OM
de n8zu
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Old June 1st 09, 06:00 AM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?


"Gordon" wrote in message
...
raypsi wrote in news:eedf031f-c023-4a15-abea-
:



Then there is mine...

http://mysite.verizon.net/g_reeder/C...V_antenna.html

Hi, Gordon,

I recall when you introduced your neat handiwork to the group. I meant
to ask a question:

Did you ever try connecting each of the antennas' twin lead to its own
separate balun and combine the 75-ohm sides of the baluns into a single
coax? A passive splitter, connected backwards, performs this function
nicely.

I ask because, as you have your antenna wired (two antennas in parallel
to a single balun) looks like an impedance mismatch; the balun wants a
300-ohm connection to the two screws and two 300-ohm antennas at the same
time would be 150-ohms. I think you previously said you are not a techie,
so forgive me if I'm using terms you don't know.

Not being one to argue with success, if you tried it and it wasn't any
better, then more power to you. Rock on!

"Sal"

PS: For my fellow techies: Yes, I realize the 300-ohm figure for a bowtie
is nominal and the actual impedance will differ from that figure.
Paralleling the two antennas could be superior.



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Old June 1st 09, 06:46 AM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

"Sal M. Onella" wrote in
:


"Gordon" wrote in message
...
raypsi wrote in news:eedf031f-c023-4a15-abea-
:



Then there is mine...

http://mysite.verizon.net/g_reeder/C...V_antenna.html

Hi, Gordon,

I recall when you introduced your neat handiwork to the group. I
meant
to ask a question:

Did you ever try connecting each of the antennas' twin lead to its
own
separate balun and combine the 75-ohm sides of the baluns into a
single coax? A passive splitter, connected backwards, performs this
function nicely.



No, I didn't think to try that. I could give it a shot, I have all
the necessary parts. I am concerned about loss, and thought that
the extra hardware would introduce too much extra loss.


I ask because, as you have your antenna wired (two antennas in
parallel
to a single balun) looks like an impedance mismatch; the balun wants
a 300-ohm connection to the two screws and two 300-ohm antennas at the
same time would be 150-ohms. I think you previously said you are not
a techie, so forgive me if I'm using terms you don't know.


I'm following you.

Hmmm... Yes. I can see how there could be a mismatch. But I
thought that only applied to simple things like resistance in DC
and AC circuits. RF is not one of my forte`s.

Anyway, I was trying to mimic the Channelmaster two and 4 bay
bowtie designs, that seem to have a 300 ohm feed.

Maybe someone could explain that.


Not being one to argue with success, if you tried it and it wasn't
any
better, then more power to you. Rock on!


Well, I got an improvement, probably in spite of myself. The
setup gives better signal strength, and is less suseptable to
interfearence (people walking aroung the room) than just a
single bowtie.


"Sal"

PS: For my fellow techies: Yes, I realize the 300-ohm figure for a
bowtie is nominal and the actual impedance will differ from that
figure. Paralleling the two antennas could be superior.




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Old June 1st 09, 12:49 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

Gordon wrote:
Well, I got an improvement, probably in spite of myself. The
setup gives better signal strength, and is less suseptable to
interfearence (people walking aroung the room) than just a
single bowtie.


A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com


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Old June 1st 09, 01:31 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

Cecil Moore wrote:
Gordon wrote:
Well, I got an improvement, probably in spite of myself. The
setup gives better signal strength, and is less suseptable to
interfearence (people walking aroung the room) than just a single bowtie.


A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?


If its bad enough it will wreck the reception. But the latest
processors can tolerate multipath that is only 1 db down.

They are getting better as they try to debug HDTV for mobile reception.

-Bill
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Old June 1st 09, 04:26 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

On Jun 1, 4:49*am, Cecil Moore wrote:
Gordon wrote:
Well, I got an improvement, probably in spite of myself. *The
setup gives better signal strength, and is less suseptable to
interfearence (people walking aroung the room) than just a
single bowtie.


A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?
--
73, Cecil, IEEE, OOTC, *http://www.w5dxp.com


It puts 'ripples' into the passband. The ripples happen because of
phase cancelations. The ATI HDTV Wonder cards can handle variations to
around 8-10 dB. After that it just freezes up.

Near the bottom of the page in the link there is an example of the
ATSC spectrum. Add random dips into it.

http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html


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Old June 1st 09, 05:11 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

On Mon, 01 Jun 2009 06:49:20 -0500, Cecil Moore
wrote:

A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?


Your worst nightmare. From 10 years ago:
http://www.businessweek.com/bwdaily/dnflash/aug1999/nf90826b.htm
(Note the sales predictions, which were totally wrong).
All DTV chipsets now have ghost elimination circuitry, which does a
good job of reducing multipath problems. There's a spec for it but
I'm too lazy to look. Here's the patent:
http://www.google.com/patents?id=XNp3AAAAEBAJ&dq=7038732
with references to others in citations. I won't pretend to understand
how it works.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old June 1st 09, 09:27 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?

On Mon, 01 Jun 2009 06:49:20 -0500, Cecil Moore
wrote:

Gordon wrote:
Well, I got an improvement, probably in spite of myself. The
setup gives better signal strength, and is less suseptable to
interfearence (people walking aroung the room) than just a
single bowtie.


A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?


In countries using COFDM (DVB-T), the symbol time is about 1000 us
(8k) or 250 us (2k), so in the worst case with minimal guard
intervals, you can still use mismatched coaxial cables longer than 1
km without problems :-).

With ATSC 8VSB it depends how well the equalizer is capable of
detecting the characteristics of the radio and coaxial path with a
known signal pattern.

Paul OH3LWR

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Old June 10th 09, 02:21 AM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew,alt.tv.tech.hdtv
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Default "Panel" style UHF DTV antenna?



A mismatch can cause ghosting in an analog TV.
What does ghosting do to a digital TV signal?


Just as a point of interest (to me at least) I grew up within 3 blocks of
an airport, it
was a several times a day occurance to have the picture flutter as an
airplane flew by.
Mike




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