On Wed, 19 Nov 2008 15:20:13 -0800, Dave Platt wrote:
In article , Rich Grise
wrote:

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Most of the wideband TV antennas I've seen, seem to be log-periodic in the
VHF range, but to use a reflector and a bunch of auxiliary elements (which
don't appear to stick to the L-P taper schedule) for the UHF.

You might want to consider a different approach - have you seen this one?

http://www.digitalhome.ca/ota/superantenna/index.htm

Thanks, but that thing's HUGE! I was thinking something more along the
lines of 1' square. (or a 1' cube)

Thanks,
Rich

On Wed, 19 Nov 2008 17:52:01 -0600, David G. Nagel wrote:

You don't really need a new antenna. If your current antenna is working
such that you get a good picture then it should work as a digital tv
antenna.

I've heard that there's no "signal strength" meter or anything - it's
either there, or not. With my analog, I can zero in on the proper tuning
(I just futz around with the clip lead until it's "good enough") so
I need something I don't have to screw around with.

Thanks,
Rich

"Rich Grise" wrote in message
news
My current UHF antenna is a 14" Radio Shack clip lead clipped from the
center of my coax to the venetian blind. I have to hand-adjust it
for the channel, weather conditions, phase of the moon, etc. I can
do this because I can _see_ an indication of signal strength.

Well, with this new Fascist "No More Free TV" crap, I'm gonna need
a real UHF antenna. My budget is exceedingly limited, but I have
a supply of materials (GTAW filler rod, with some coppery-colored
coating, so it solders like a dream, and is as stiff as piano wire)
to build an antenna with.

But I've been searching the web for some weeks now, and I can't
seem to find any kind of formula, except there was this program
I downloaded - LPDA.EXE, which runs on DOS. Unfortunately, it's
in Russian or Polish or Uzbekistani - one of those East Yurp
languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif

Which I went through pretty much by-guess-and-by-gosh - can
anybody read that stuff?

There are a lot of factors I don't know about, like "Tau", and
all of the specific designs on the web are flat - something is
telling me I want one of those pyramid-shaped ones, but I really
don't know the difference (between that and flat) - it's probably
something to do with bandwidth or F/B ratio or whatever.

My local library has no ARRL Antenna Book (!), and did I mention
I have a seriously limited budget?

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to
send myself to Log-Periodic School, where should I start?

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Thanks,
Rich


You probably don't need a program, just a decent text book that covers the
topic adequately, which, undoubtedly is what the program writers worked
from, and they might not have got it right! 'Antennas' by John Kraus
contains enough detail to make a start and it's probably more general than
someone's program which might involve specific choices of some parameter
values. So my recommendation would be to find a technical library that
offers access to non-members and send yourself to Log-Periodic School as you
put it. The IET library in London does this, for free. Do you have an
equivalent institution (e.g. IEEE), or a local university that covers
electronic engineering? You might be surprised how much access you can gain
to libraries to which you have contributed through taxes, or which need to
maintain an 'altruistic' public appearance.

The pyramidal form has greater aperture in the vertical plane for all but
the highest frequencies. It behaves like a vertically-stacked pair of
Log-Periodic Dipole Arrays and achieves a bit more gain. Its pattern in the
vertical plane is consistently sharper over a range of frequencies because
of the vertical taper, but it is a bit more difficult to design. Not all
'wideband' UHF antennas are based on the LPDA - some are Yagi-Uda arrays
designed using NEC and its derivatives, achieving a useful compromise
between bandwidth, gain, and pattern shapes. But if you want to include
channels below 21 as well as the UHF band, with consistent directivity, then
LPDA is probably the only way to go.

Chris

This won't do at all! Two of my favorite stations are ch. 56 & ch. 58.
=:-O

Not after The Big Day. Their frequencies will be changing. Channels
which are broadcasting NTSC in channels 52 and above will be moving
down to a lower frequency.

I've got 2-13 covered by my external VHF folded dipole. (It's an RV).

Are the channel frequencies going to be all changed around? I suppose
I should email those two stations. I don't know much about DTV, other
than I have to buy a damn box and I need a "better" antenna.

A lot of them will be.

Take a look at:

http://hraunfoss.fcc.gov/edocs_publi...C-06-150A1.pdf

I don't think it's the latest set of assignments but it's pretty well
up to date.


--
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!

On Nov 20, 12:03 pm, Rich Grise wrote:
On Wed, 19 Nov 2008 17:52:01 -0600, David G. Nagel wrote:

You don't really need a new antenna. If your current antenna is working
such that you get a good picture then it should work as a digital tv
antenna.

I've heard that there's no "signal strength" meter or anything

Most digital STB's have a "signal strength" indicator on screen for
each channel.

it's either there, or not.

That's true of the displayed picture, but not the signal.
Poor (or even too much) signal strength can lead to "drop outs" or
"freezing" of the video image.

Dave.

On Nov 20, 11:55 am, Rich Grise wrote:
On Wed, 19 Nov 2008 18:14:27 -0500, Tam wrote:
"Rich Grise" wrote in message
news
My current UHF antenna is a 14" Radio Shack clip lead clipped from the
center of my coax to the venetian blind. I have to hand-adjust it for
the channel, weather conditions, phase of the moon, etc. I can do this
because I can _see_ an indication of signal strength.

Well, with this new Fascist "No More Free TV" crap, I'm gonna need a
real UHF antenna. My budget is exceedingly limited, but I have a supply
of materials (GTAW filler rod, with some coppery-colored coating, so it
solders like a dream, and is as stiff as piano wire) to build an antenna
with.

But I've been searching the web for some weeks now, and I can't seem to
find any kind of formula, except there was this program I downloaded -
LPDA.EXE, which runs on DOS. Unfortunately, it's in Russian or Polish or
Uzbekistani - one of those East Yurp languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif

Which I went through pretty much by-guess-and-by-gosh - can anybody read
that stuff?

There are a lot of factors I don't know about, like "Tau", and all of
the specific designs on the web are flat - something is telling me I
want one of those pyramid-shaped ones, but I really don't know the
difference (between that and flat) - it's probably something to do with
bandwidth or F/B ratio or whatever.

My local library has no ARRL Antenna Book (!), and did I mention I have
a seriously limited budget?

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to send
myself to Log-Periodic School, where should I start?

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Before you get too far, be sure you know what you need. This is based on
post 2/09 channel assignments. You will need to cover either a) CH2 - CH51
b)CH7 - CH51
c) CH14 - CH51

This won't do at all! Two of my favorite stations are ch. 56 & ch. 58.
=:-O

I've got 2-13 covered by my external VHF folded dipole. (It's an RV).

Are the channel frequencies going to be all changed around?

Yes.
Channels will vary depending upon your country and location. You
should have some sort of official digital TV website for your country
that lists and explains all this stuff.
Australia for instance is:
http://www.dba.org.au/
(server down?)

Dave.

On Nov 19, 6:14�pm, "Tam" wrote:
"Rich Grise" wrote in message

news


My current UHF antenna is a 14" Radio Shack clip lead clipped from the
center of my coax to the venetian blind. I have to hand-adjust it
for the channel, weather conditions, phase of the moon, etc. I can
do this because I can _see_ an indication of signal strength.

Well, with this new Fascist "No More Free TV" crap, I'm gonna need
a real UHF antenna. My budget is exceedingly limited, but I have
a supply of materials (GTAW filler rod, with some coppery-colored
coating, so it solders like a dream, and is as stiff as piano wire)
to build an antenna with.

But I've been searching the web for some weeks now, and I can't
seem to find any kind of formula, except there was this program
I downloaded - LPDA.EXE, which runs on DOS. Unfortunately, it's
in Russian or Polish or Uzbekistani - one of those East Yurp
languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif

Which I went through pretty much by-guess-and-by-gosh - can
anybody read that stuff?

There are a lot of factors I don't know about, like "Tau", and
all of the specific designs on the web are flat - something is
telling me I want one of those pyramid-shaped ones, but I really
don't know the difference (between that and flat) - it's probably
something to do with bandwidth or F/B ratio or whatever.

My local library has no ARRL Antenna Book (!), and did I mention
I have a seriously limited budget?

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to
send myself to Log-Periodic School, where should I start?

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Thanks,
Rich

Before you get too far, be sure you know what you need. This is based on
post 2/09 channel assignments. You will need to cover either
a) CH2 - CH51
b)CH7 - CH51
c) CH14 - CH51

Tam- Hide quoted text -

- Show quoted text -

I agree. How much can a coat hanger cost?
If you are really rubbing pennies together, I would ditch the log-
periodic approach and go with something simpler, like a monopole or
folded unipole antenna. (All you need is wire.)

I just want to mention (again) here that: Hopefully, we'll be able to
knock out Ch-5 and Ch-6 from this antenna scenario very soon (and move
them to the FM Band, as the FCC is presently considering. I'm a huge
proponent of this possibility!

I will try to find the Comments link at the FCC web site so those of
you who agree can chime in....

This idea has been floated before, of course. This time it seems to
have "legs".
I don't know how much you can read into it, but... the FCC has yet to
explain how Non-Commercial Educational (NCE) vertical only stations
can obtain authorization for horiz/vertical operation once this DTV
transition occurs - which is now less than 90 days away.

There are many pending Construction Permits (CP's) and NCE facilities
that proposed Vertical-Only operation in order to protect local ANALOG
TV-6 stations. These new NCE facilities will undoubtedly delay
construction until a decision is made how to obtain dual polarization
licensing. (Due to increased transmitter power requirements and/or RF
Safety exposure issues, tower height requirements, etc..)

To date, the FCC has yet to adopt ANY relaxed TV-6 digital protection
criteria for NCE FM stations. Instead, these stations must use the
old Analog standard - which is MUCH stricter than is necessary to
fully protect a Digital TV operation!

And of course, there are only (8) full service TV's on digital channel
6. (Which is a really, really good reason to move TV-6, and possibly
TV-5 to the FM band!! -- What a huge waste of spectrum!!) Yes,
there are some low-power DTV 6's out there (translators, boosters,
LPTV's). Not very many, and all of which are in locations where other
spectrum is, or will be, avaialble after the DTV transition...

Anyway, any NCE or CP not near a digital-6 would obviously qualify for
dual-polarization. It remains to be seen what the FCC will do about
this. Hopefully, they will grow a brain and shift this "un-used"
spectrum to alleviate the very crowded FM band.

I don't know if I should hold my breath or not.?

-mpm

On Nov 19, 9:13*pm, mpm wrote:

I don't know if I should hold my breath or not.?


Oops. that post was directed at Rich.
My apologies for responding at the wrong thread entry point...

Rich Grise wrote:
My current UHF antenna is a 14" Radio Shack clip lead clipped from the
center of my coax to the venetian blind. I have to hand-adjust it
for the channel, weather conditions, phase of the moon, etc. I can
do this because I can _see_ an indication of signal strength.


LOL ... talk about trolls! That HAS TO BE THE BEST TROLL OPENING LINE I
HAVE EVER SEEN!

Well, with this new Fascist "No More Free TV" crap, I'm gonna need
a real UHF antenna. My budget is exceedingly limited, but I have
a supply of materials (GTAW filler rod, with some coppery-colored
coating, so it solders like a dream, and is as stiff as piano wire)
to build an antenna with.


Well, that is the second best ...

But I've been searching the web for some weeks now, and I can't
seem to find any kind of formula, except there was this program
I downloaded - LPDA.EXE, which runs on DOS. Unfortunately, it's
in Russian or Polish or Uzbekistani - one of those East Yurp
languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif


hmmm ....

Which I went through pretty much by-guess-and-by-gosh - can
anybody read that stuff?

There are a lot of factors I don't know about, like "Tau", and
all of the specific designs on the web are flat - something is
telling me I want one of those pyramid-shaped ones, but I really
don't know the difference (between that and flat) - it's probably
something to do with bandwidth or F/B ratio or whatever.

My local library has no ARRL Antenna Book (!), and did I mention
I have a seriously limited budget?

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to
send myself to Log-Periodic School, where should I start?

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Thanks,
Rich


Ever heard of amplifed rabbit ears?

Regards,
JS

Try a bowtie (like the one that came with sets) 5 inches in front of a piece
of hardware cloth. Most of the boxes (which are almost free after the FCC
rebate) have a signal strength bar (although with a 3-5 sec. delay)

Years ago they used to make one as a magazine rack that you could pick up
and move around.


"Rich Grise" wrote in message
news
My current UHF antenna is a 14" Radio Shack clip lead clipped from the
center of my coax to the venetian blind. I have to hand-adjust it
for the channel, weather conditions, phase of the moon, etc. I can
do this because I can _see_ an indication of signal strength.

Well, with this new Fascist "No More Free TV" crap, I'm gonna need
a real UHF antenna. My budget is exceedingly limited, but I have
a supply of materials (GTAW filler rod, with some coppery-colored
coating, so it solders like a dream, and is as stiff as piano wire)
to build an antenna with.

But I've been searching the web for some weeks now, and I can't
seem to find any kind of formula, except there was this program
I downloaded - LPDA.EXE, which runs on DOS. Unfortunately, it's
in Russian or Polish or Uzbekistani - one of those East Yurp
languages. Here's a screen snap:
http://mysite.verizon.net/richgrise/...rog-Output.gif

Which I went through pretty much by-guess-and-by-gosh - can
anybody read that stuff?

There are a lot of factors I don't know about, like "Tau", and
all of the specific designs on the web are flat - something is
telling me I want one of those pyramid-shaped ones, but I really
don't know the difference (between that and flat) - it's probably
something to do with bandwidth or F/B ratio or whatever.

My local library has no ARRL Antenna Book (!), and did I mention
I have a seriously limited budget?

So, how do I pursue this? It'd be nice to have a program that will
calculate the whole thing for me, but am I dreaming? If I want to
send myself to Log-Periodic School, where should I start?

Or, does anyone have a UHF-TV log-periodic design that they'd share? :-)

Thanks,
Rich