I would like to model the Channel Master CM4228HD Antenna with EZNEC.
It looks like a good deal to me at its price.

I need screen to Bow ties distance

length of bow ties

I think the distance between the bowties will be either 1/4 or 1/2
wave (from picture)

I think the included angle in each of the bow ties is about 30 degrees
as pictured.

The phasing lines are obvious from the picture.

There is a picture at
http://www.digitalhome.ca/forum/showthread.php?t=95467

Of course I will share the model!

John Ferrell W8CCW

In article ,
John Ferrell wrote:
|
| I would like to model the Channel Master CM4228HD Antenna with EZNEC.
| It looks like a good deal to me at its price.

Ken Nist (KQ6QV) has done a lot of TV antenna modelling with EZNEC,
and many of his antenna models (*.ez) are available on this page:

http://www.hdtvprimer.com/SIMS/

However, the CM4228a.ez on that page probably is the old CM4228 rather
than the new CM4228HD. His page analyzing the new CM4228HD antenna is:

http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html

His main page comparing commercially available antennas is:

http://www.hdtvprimer.com/ANTENNAS/comparing.html

Holl_ands has done a lot of modelling (using 4nec2), including the
new CM4228HD (this page has his 4nec2 model files):

http://imageevent.com/holl_ands/mult...yrefl/cm4228hd

| http://www.digitalhome.ca/forum/showthread.php?t=95467

Also on that site is an entire forum thread for modifying the
new CM4228HD:

http://www.digitalhome.ca/forum/showthread.php?t=103749

John, further searching should turn up more information and details.
AFAIR, the reflector on the new model facilitates reception on the
VHF-hi band, which may or may not be sufficient (it is, afterall,
designed for the UHF band). Too, there are a lot of DIY options...

Best Regards,
Chuck

On Sat, 2 Oct 2010 01:23:57 +0000 (UTC),
(Charles Seeger) wrote:

In article ,
John Ferrell wrote:
|
| I would like to model the Channel Master CM4228HD Antenna with EZNEC.
| It looks like a good deal to me at its price.

Ken Nist (KQ6QV) has done a lot of TV antenna modelling with EZNEC,
and many of his antenna models (*.ez) are available on this page:

http://www.hdtvprimer.com/SIMS/

However, the CM4228a.ez on that page probably is the old CM4228 rather
than the new CM4228HD. His page analyzing the new CM4228HD antenna is:

http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html

His main page comparing commercially available antennas is:

http://www.hdtvprimer.com/ANTENNAS/comparing.html

Holl_ands has done a lot of modelling (using 4nec2), including the
new CM4228HD (this page has his 4nec2 model files):

http://imageevent.com/holl_ands/mult...yrefl/cm4228hd

| http://www.digitalhome.ca/forum/showthread.php?t=95467

Also on that site is an entire forum thread for modifying the
new CM4228HD:

http://www.digitalhome.ca/forum/showthread.php?t=103749

John, further searching should turn up more information and details.
AFAIR, the reflector on the new model facilitates reception on the
VHF-hi band, which may or may not be sufficient (it is, afterall,
designed for the UHF band). Too, there are a lot of DIY options...

Best Regards,
Chuck
Thank you!

I am going to have to spend some time with these. My EZNEC + 5 does
not like all of the .EZ files but there is plenty of meat there to be
dissected. My interests are academic in the antennas. I don't spend
much time watching TV these days.

I have not looked for .ez file examples for a while on the net. When
last I looked, most of the sites I found were only interested in
selling models. Being an old time frugal Ham I am very cautious with
my hobby dollars!


John Ferrell W8CCW

On 10/2/2010 6:38 PM, John Ferrell wrote:

...
I have not looked for .ez file examples for a while on the net. When
last I looked, most of the sites I found were only interested in
selling models. Being an old time frugal Ham I am very cautious with
my hobby dollars!


John Ferrell W8CCW

Remember the first set you made from the scavenged parts of old radios
and TV's? Remember the excitment of your first piece of old military
gear, reworked and placed into service? Remember mail ordering tuning
caps, filtering caps, tubes for that first big amp?

Good on you mate! Those were the days when amateurs were hams and men
were men--heck, even the boys back then were men by todays' standards!

Sounds like you had it right, did it right, and are still doing it
right--to me!

Regards,
JS

"John Ferrell" wrote in message
...
I would like to model the Channel Master CM4228HD Antenna with EZNEC.
It looks like a good deal to me at its price.

I need screen to Bow ties distance

length of bow ties

I think the distance between the bowties will be either 1/4 or 1/2
wave (from picture)

I think the included angle in each of the bow ties is about 30 degrees
as pictured.

The phasing lines are obvious from the picture.

There is a picture at
http://www.digitalhome.ca/forum/showthread.php?t=95467

Of course I will share the model!

John Ferrell W8CCW

The following NEC code is for a measured 2 bay bow-tie. Should be the
same as an 8 bay model.

Frank (VE6CB)


CM UHF TV Antenna (Measured dimensions).
CE
GW 1 12 0 1 0.25 0 7 1.5 0.081
GM 1 1 0 180 0 0 0 0
GM 2 1 0 0 180 0 0 0
GM 4 1 0 0 0 0 0 8 ! End of two dipole array.
GW 9 17 0 1 -0.25 0 1 8.25 0.081 ! Parallel transmission line.
GW 10 17 0 -1 -0.25 0 -1 8.25 0.081 ! Parallel transmission line.
GW 11 4 0 -1 4.25 0 1 4.25 0.081 ! Feedpoint segment.
GW 12 36 -8 -9 -2 -8 9 -2 0.081 ! First horizontal grid element
GM 1 12 0 0 0 0 0 1 12 1 12 36 ! Creats 12 horizontal grid elements
GW 25 24 -8 -9 -2 -8 -9 10 0.081 ! First vertical grid element
GM 1 9 0 0 0 0 2 0 25 1 25 24 ! Creats 9 vertical grid elements
GM 0 0 0 0 0 0 0 120 ! Moves entire structure 10 ft high
GS 0 0 0.025400
GE 1 -1 0
GN 2 0 0 0 13.0000 0.0050
FR 0 1 0 0 635 1
EX 0 11 2 0 1 0
LD 5 0 0 0 2.5E7
RP 0 1801 1 1000 -90 0 0.10000 1.00000
EN

I enjoy making my antennas also

But this 8bay hd antenna is pretty cheap. I see it for pick up at 69 dollars
in Toronto. Plus some taxes of course but looks like a pretty solid antenna
for that price. I cannot imagine how much time one would spend getting all
the parts then assembling. I think just too easy to buy today.

Good luck with the build.
I am going to buy two tomorrow, throw them on the tower and be done with it.







"Frank" wrote in message
news:k2_po.1159$u9.578@edtnps82...

"John Ferrell" wrote in message
...
I would like to model the Channel Master CM4228HD Antenna with EZNEC.
It looks like a good deal to me at its price.

I need screen to Bow ties distance

length of bow ties

I think the distance between the bowties will be either 1/4 or 1/2
wave (from picture)

I think the included angle in each of the bow ties is about 30 degrees
as pictured.

The phasing lines are obvious from the picture.

There is a picture at
http://www.digitalhome.ca/forum/showthread.php?t=95467

Of course I will share the model!

John Ferrell W8CCW

The following NEC code is for a measured 2 bay bow-tie. Should be the
same as an 8 bay model.

Frank (VE6CB)


CM UHF TV Antenna (Measured dimensions).
CE
GW 1 12 0 1 0.25 0 7 1.5 0.081
GM 1 1 0 180 0 0 0 0
GM 2 1 0 0 180 0 0 0
GM 4 1 0 0 0 0 0 8 ! End of two dipole array.
GW 9 17 0 1 -0.25 0 1 8.25 0.081 ! Parallel transmission line.
GW 10 17 0 -1 -0.25 0 -1 8.25 0.081 ! Parallel transmission line.
GW 11 4 0 -1 4.25 0 1 4.25 0.081 ! Feedpoint segment.
GW 12 36 -8 -9 -2 -8 9 -2 0.081 ! First horizontal grid element
GM 1 12 0 0 0 0 0 1 12 1 12 36 ! Creats 12 horizontal grid elements
GW 25 24 -8 -9 -2 -8 -9 10 0.081 ! First vertical grid element
GM 1 9 0 0 0 0 2 0 25 1 25 24 ! Creats 9 vertical grid elements
GM 0 0 0 0 0 0 0 120 ! Moves entire structure 10 ft high
GS 0 0 0.025400
GE 1 -1 0
GN 2 0 0 0 13.0000 0.0050
FR 0 1 0 0 635 1
EX 0 11 2 0 1 0
LD 5 0 0 0 2.5E7
RP 0 1801 1 1000 -90 0 0.10000 1.00000
EN

On Sun, 3 Oct 2010 08:26:19 -0400, "Cannuck" wrote:

I enjoy making my antennas also

But this 8bay hd antenna is pretty cheap. I see it for pick up at 69 dollars
in Toronto. Plus some taxes of course but looks like a pretty solid antenna
for that price. I cannot imagine how much time one would spend getting all
the parts then assembling. I think just too easy to buy today.

Good luck with the build.
I am going to buy two tomorrow, throw them on the tower and be done with it.

I am inclined to agree with you. I expect this to be my recomendation
for the folks around me who are looking for an antenna for HD.

However, there is this young fellow who is bent on building his own.
Given that he just might execute this project and then move on to more
antenna projects, I think I owe it to my early mentors to cultivate
his curiousity.

Perhaps acquiring this antenna and using it's performance as an
objective for diy models will fit well.

I am a Channel Master fan. I don't think you can beat their
price/perfomance in any of their products.
John Ferrell W8CCW

On Sun, 03 Oct 2010 11:46:24 GMT, "Frank"
wrote:


"John Ferrell" wrote in message
.. .
I would like to model the Channel Master CM4228HD Antenna with EZNEC.
It looks like a good deal to me at its price.

I need screen to Bow ties distance

length of bow ties

I think the distance between the bowties will be either 1/4 or 1/2
wave (from picture)

I think the included angle in each of the bow ties is about 30 degrees
as pictured.

The phasing lines are obvious from the picture.

There is a picture at
http://www.digitalhome.ca/forum/showthread.php?t=95467

Of course I will share the model!

John Ferrell W8CCW

The following NEC code is for a measured 2 bay bow-tie. Should be the
same as an 8 bay model.

Frank (VE6CB)


CM UHF TV Antenna (Measured dimensions).
CE
GW 1 12 0 1 0.25 0 7 1.5 0.081
GM 1 1 0 180 0 0 0 0
GM 2 1 0 0 180 0 0 0
GM 4 1 0 0 0 0 0 8 ! End of two dipole array.
GW 9 17 0 1 -0.25 0 1 8.25 0.081 ! Parallel transmission line.
GW 10 17 0 -1 -0.25 0 -1 8.25 0.081 ! Parallel transmission line.
GW 11 4 0 -1 4.25 0 1 4.25 0.081 ! Feedpoint segment.
GW 12 36 -8 -9 -2 -8 9 -2 0.081 ! First horizontal grid element
GM 1 12 0 0 0 0 0 1 12 1 12 36 ! Creats 12 horizontal grid elements
GW 25 24 -8 -9 -2 -8 -9 10 0.081 ! First vertical grid element
GM 1 9 0 0 0 0 2 0 25 1 25 24 ! Creats 9 vertical grid elements
GM 0 0 0 0 0 0 0 120 ! Moves entire structure 10 ft high
GS 0 0 0.025400
GE 1 -1 0
GN 2 0 0 0 13.0000 0.0050
FR 0 1 0 0 635 1
EX 0 11 2 0 1 0
LD 5 0 0 0 2.5E7
RP 0 1801 1 1000 -90 0 0.10000 1.00000
EN


This example may be what it takes to get me to get onboard with NEC.
EZNEC has me spoiled!

So little time and so many projects...

I love my busy, cluttered life and all the puzzles to solve!
John Ferrell W8CCW

Dear John: Well said.
Last year, a colleague (also a radio amateur) had his EE class design a UHF
(14-52) antenna using EZNEC, then construct the antenna, and then he took
the resulting antennas to an antenna range for testing (he had a grant to
cover the cost including cost of EZNEC).
The design of an antenna to cover not only 14-52, but also 7-13 is more of a
challenge. In this area, we have one station in the 7-13 range. I use a
Wineguard HD1080, which is a two bay with extensions on each fat dipole. A
second colleague with an antenna that was in bad shape after 30 years, just
replaced the old antenna with an Antenna Craft HBU33 with a huge jump in
signal and significant reduction in wind load.
Channel Master is good too. Much discussion exists - as has been observed -
about the 4228.

Obviously, it is improbable to have an eight bay antenna realize its
theoretical gain over the BW needed. I would stop with four.
73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home:
"John Ferrell" wrote in message
...
On Sun, 3 Oct 2010 08:26:19 -0400, "Cannuck" wrote:

I enjoy making my antennas also

But this 8bay hd antenna is pretty cheap. I see it for pick up at 69
dollars
in Toronto. Plus some taxes of course but looks like a pretty solid
antenna
for that price. I cannot imagine how much time one would spend getting all
the parts then assembling. I think just too easy to buy today.

Good luck with the build.
I am going to buy two tomorrow, throw them on the tower and be done with
it.

I am inclined to agree with you. I expect this to be my recomendation
for the folks around me who are looking for an antenna for HD.

However, there is this young fellow who is bent on building his own.
Given that he just might execute this project and then move on to more
antenna projects, I think I owe it to my early mentors to cultivate
his curiousity.

Perhaps acquiring this antenna and using it's performance as an
objective for diy models will fit well.

I am a Channel Master fan. I don't think you can beat their
price/perfomance in any of their products.
John Ferrell W8CCW