I built a 4 bay antenna for my daughter and it seems to work, I
received 21 channels at my home, which according to TVFOOL is about right.
But it got me looking at other antennas, I found a 2 bay fractal that
is simple, in that you just print the pdf, glue it to aluminum flashing
and cut it out.
https://docs.google.com/file/d/0B5qw...ZINFhZS28/edit

So why not phase four together? What I see is some frequencies add and
some subtract. Also with a reflector, some frequencies add and some
subtract.
So I'm a bit confused, how does Channel master handle that on the
CM4228? Two phased 4 bays.

Opps, just found this need to read it.

http://www.hdtvprimer.com/antennas/cm4228.html

Anyway looking for general discussion about combining 4 of the above
fractals, maybe optimized for channels below 50.

Mikek

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amdx wrote:
I built a 4 bay antenna for my daughter and it seems to work, I
received 21 channels at my home, which according to TVFOOL is about right.
But it got me looking at other antennas, I found a 2 bay fractal that
is simple, in that you just print the pdf, glue it to aluminum flashing
and cut it out.
https://docs.google.com/file/d/0B5qw...ZINFhZS28/edit

So why not phase four together? What I see is some frequencies add and
some subtract. Also with a reflector, some frequencies add and some
subtract.
So I'm a bit confused, how does Channel master handle that on the
CM4228? Two phased 4 bays.

Opps, just found this need to read it.

http://www.hdtvprimer.com/antennas/cm4228.html

Anyway looking for general discussion about combining 4 of the above
fractals, maybe optimized for channels below 50.

Mikek

Instead of wondering and guessing, why don't you model the thing and then
know what will happen?


--
Jim Pennino

On Mon, 16 Mar 2015, amdx wrote:

I built a 4 bay antenna for my daughter and it seems to work, I received 21
channels at my home, which according to TVFOOL is about right.
But it got me looking at other antennas, I found a 2 bay fractal that
is simple, in that you just print the pdf, glue it to aluminum flashing and
cut it out.
https://docs.google.com/file/d/0B5qw...ZINFhZS28/edit

So why not phase four together? What I see is some frequencies add and some
subtract. Also with a reflector, some frequencies add and some subtract.
So I'm a bit confused, how does Channel master handle that on the CM4228?
Two phased 4 bays.

Opps, just found this need to read it.

http://www.hdtvprimer.com/antennas/cm4228.html

Anyway looking for general discussion about combining 4 of the above
fractals, maybe optimized for channels below 50.

YOu do see larger arrays of bowties, which is what you built.

A basic bowtie is a dipole, with the elements in a v shape, I always
assumed to broaden bandwidth.

You can stack two, you double the gain. Stack two of those, you get
four dipoles, and four times the gain of the single bowtie.

I think the bowtie nature confuses things. These are like collinear
antennas, often seen as large arrays for VHF and especially UHF work.
You don't start off with the same gain as a yagi, but since doubling gain
requires doubling what you have, it's simpler to start with a dipole and
reflector and make a lot of them than start with a yagi and keep adding
to get more gain.

A lot of those moonbounce arrays use a dipole ("driven element") and
reflector, but in the tv world, that screen often seen behind the bowtie
acts as the reflector.

Of course, the larger the array, the more directional it will become. SO
yo may need a rotator. Some have fiddled with bowties for TV, running an
array but shifting one half so it points a different way, so you get gain
in two directions. That will often be good enough for many users, the tv
stations coming in from two directions.

Of course, the real trick is combining the elements properly.

Fractals are just a way of making the elements shorter. So theoretically
they should act just like bowties, and combining them is the same thing.

The biggest problem I have with DTV is that with distant signals coming
from more than one direction (but just a bit) and different from local
signals, I can't get all the stations scanned with a higher gain antenna.
I actually took a UHF loop, stuck it on some bamboo garden stakes so it
gets up high, and stuck that out a top floor window. That lets me scan
the tv sets and get all the "local" stations I can get (except for ABC
that everyone has problems with, they moved lower in frequency and lower
power, and are now on a channel adjacent to one used locally). SO I have
them in memory, since the tv sets don't have a means of entering channels
without scanning. It's much easier fiddling with directional antennas once
you have all the available channels in memory. Then you can play with
orientation that gets the most channels without having to move the
directional array.

Michael

On 3/16/2015 2:43 PM, Michael Black wrote:
On Mon, 16 Mar 2015, amdx wrote:

I built a 4 bay antenna for my daughter and it seems to work, I
received 21 channels at my home, which according to TVFOOL is about
right.
But it got me looking at other antennas, I found a 2 bay fractal that
is simple, in that you just print the pdf, glue it to aluminum
flashing and cut it out.
https://docs.google.com/file/d/0B5qw...ZINFhZS28/edit

So why not phase four together? What I see is some frequencies add and
some subtract. Also with a reflector, some frequencies add and some
subtract.
So I'm a bit confused, how does Channel master handle that on the
CM4228? Two phased 4 bays.

Opps, just found this need to read it.

http://www.hdtvprimer.com/antennas/cm4228.html

Anyway looking for general discussion about combining 4 of the above
fractals, maybe optimized for channels below 50.

YOu do see larger arrays of bowties, which is what you built.

A basic bowtie is a dipole, with the elements in a v shape, I always
assumed to broaden bandwidth.

You can stack two, you double the gain. Stack two of those, you get
four dipoles, and four times the gain of the single bowtie.

I think the bowtie nature confuses things. These are like collinear
antennas, often seen as large arrays for VHF and especially UHF work.
You don't start off with the same gain as a yagi, but since doubling
gain requires doubling what you have, it's simpler to start with a
dipole and reflector and make a lot of them than start with a yagi and
keep adding to get more gain.

A lot of those moonbounce arrays use a dipole ("driven element") and
reflector, but in the tv world, that screen often seen behind the bowtie
acts as the reflector.

Of course, the larger the array, the more directional it will become.
SO yo may need a rotator. Some have fiddled with bowties for TV,
running an array but shifting one half so it points a different way, so
you get gain in two directions. That will often be good enough for many
users, the tv stations coming in from two directions.

Of course, the real trick is combining the elements properly.

That's where I saw the problem, after looking at the HDTVPrimer site I
posted, I could see in the graphs the ripple, but it was not a complete
cancellation.


Fractals are just a way of making the elements shorter. So theoretically
they should act just like bowties, and combining them is the same thing.

Ya, I think you lose just a little gain with the fractal, but the size
reduction helps. People are making the printable one decorative, as a
wall hanging.


The biggest problem I have with DTV is that with distant signals coming
from more than one direction (but just a bit) and different from local
signals, I can't get all the stations scanned with a higher gain
antenna. I actually took a UHF loop, stuck it on some bamboo garden
stakes so it gets up high, and stuck that out a top floor window. That
lets me scan the tv sets and get all the "local" stations I can get
(except for ABC that everyone has problems with, they moved lower in
frequency and lower power, and are now on a channel adjacent to one used
locally). SO I have them in memory, since the tv sets don't have a
means of entering channels without scanning. It's much easier fiddling
with directional antennas once you have all the available channels in
memory. Then you can play with orientation that gets the most channels
without having to move the directional array.

Michael

I like your method to program channels (I hoping there's another
way), but that's what I ran into, I get all the channels North, but some
that are SSW and SSW aren't programed.



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