Is there a way for me to use 2 CM4228 and combine them for better gain to pull in WB 49 from Buffalo.


I was thinking if the CM4228 is basically two CM4221 put side by side can I then stack two CM4228 on top of each other or beside each other?

Too bad I can only get this channel os those days the DXing is good. :(

Now we are talking. I spoke to Ron Morgan, Technical Consultant Andrew Corp. North Carolina Channel Master Brand Products.

They don't any any actual test but had said a few customers had tried it with success.

Ron said just make sure on the second antenna that the bow are evenily spaced between the first and second antenna.

As you can see the antenna slightly over lap to have the bow evenly spaced.

http://pic5.picturetrail.com/VOL83/536944/4741575/105344401.jpg

Since my cowoker has two CM4228 mounted I will ask him to try it. :) If you drive south of 16th Ave on Mccowan on the west side before the cop station you can see his dual CM4228.

Here's a DHCer who already uses a stacked CM4228:

http://www.digitalhomecanada.com/forum/showpost.php?p=207838&postcount=19

so maybe you could PM him for some info.

check out http://www.hdtvprimer.com/ISSUES/erecting_antenna.html


See....
Antenna Projects -- For Do-It-Yourselfers in very weak signal areas

A 16-Bay UHF antenna
A 32-Bay UHF antenna

http://www.hdtvprimer.com/ANTENNAS/16bayA.jpg

http://www.hdtvprimer.com/ANTENNAS/32bay.jpg

I just received a Channel Master 4228 by UPS today and I noticed that the right side (if looking at the front of the antenna) appears tilted slightly inwards. If I lay the antenna flat on the ground, almost all the left side bowties are horizontal but the right side is all over the place. Am I correct in assuming that this unit is supposed to be symmetrical? Should I whip out a set of pliers and try to fix this unit (I'm a little scared of snapping something off)? Can anyone let me know if their 4228 is symmetrical?

A friend has a CM4228 that he has not instaleld yet so I lent him a CM4221 that I was going to install at my office to see what it can pull in. He just leaned it up on a wall outside his balcony. :)

He lives around Markham Rd and 16th Ave.

Damm by the way is today a good dx day :) The reason is he is pulling in all Buffalo except Wb at 10 out of 10 on his Samsung SIR T451. :)

Then he is pulling in the 2 station from Rochester Fox and Pbs but also Wham(Abc) at 5 to 6 bars.

All Toronto station are at 10 except Toronto 1 at 8 bars.

He just has the antenna leaned up against the wall and he lost WHAM it was leaning back. He then tilted it forward and the signal came back. :)

I think Iam going to have to play with the tilt angle on my antenna to see if I can get more gain. Now its level and vertical.

Yaamon the morning today was a good day for Rochester and Erie stations.How high of the ground is his Balcony

Its on the second floor of his house, a standard house my guess 15 or 16' from the ground ?

After speaking to him I realise that his antenna is point almost dead south and mine pointed 15' or a little more off towards west.

Looking on the antenna specs the 4221 does have a wider angle of coverage.

I will ask him when my Rochester drops off and see if he can still get them. If he does then I am going to install one and point my cm4228 more south and use a 4221 south west.

Cm4228 & Cm4221.

I would like to install these two antenna like what Tom F1 did and since I will be on the roof I was wondering what HDTV primer was saying would make a difference.

To replace and use two baluns. Is this the same thing as a coax 300ohm to 75ohm matching transformer ?

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

I just realise I can test the antenna at my office, so I just ordered a bunch of matching 300 to 75ohm transformer and a few CM4221 for sale should get it before the end of the week.

For those who need I have CM4228 in stock and should have the cm4221 in stock by Thursday.

I guess the author is talking about replacing/disconnecting the two steel wires that mount to the center connector where it joins the two antenna. Where the one balun is conencted.

Guy's I was wondering if anybody has thought about this ? Maybe I'am out to lunch not making any sense.

A 4228 is basically two 4221 stacked side by side. If you look at the angle of coverage the 4221 is almost twice the amount.

Because the 4228 combines, two 4221 side by side the antenna becomes more directional.

What if you were to stack on top two 4221, the angle of coverage would be the same and would the gain not be the same as a single 4228.

There is a diagram using 2 4228 in a side by side stacked compared to over head a example.
Side by Side
http://pic5.picturetrail.com/VOL83/536944/4741575/108803118.jpg

Overhead stacked.
http://pic5.picturetrail.com/VOL83/536944/4741575/108803142.jpg [/IMG]

I am hoping that with the wider coverage of stacking two 4221 would pull in more stations then a single 4228.

My reason is my friend still can pull in the Rochester stations when my signal is gone. The 4221 that I loaned him points almost dead south and he live a little north and 3km east of me.

I just got a confirmation from Channel Master that by stacking the two 4221 I should still get the gain of the single 4228 but with the same directivity of a single cm4221.

Which is what some us need if you live north and east of say 404 to get Toronto and all Buffalo at max signals.

This will allow me to then point my antenna more south to pulling in the Rochester stations better.

I just ordered 3, 4221 from my distributor and will remove my single 4228 and replace it with dual stacked over head 4221. :)

Will let you guys know how it goes.

Here is the angle of coverage on a single CM4228.
http://pic5.picturetrail.com/VOL83/536944/4741575/108804680.jpg

A single Cm4221.
http://pic5.picturetrail.com/VOL83/536944/4741575/108804710.jpg

Hi Yeamon. Please post your results with the two 4221's.

You're pretty far north at 14th Ave, it would be very interesting to see how well the 4221's work compared to the 4228.

What equipment were you going to use to combine the signal from the two antennas?

BTW, roughly where does your friend live? Is he able to pull in the Rochestor stations all the time with just the 4221, or does the signal drop out every now and then?

Someone here on DHC mentioned being able to receive the Rochestor channels using the big Weingard yagi antenna, it would be interesting if the much smaller 4221 were able to also reliably receive those channels.

weblurker Iam just one light south of 14th Ave and east of McCowan.

My friend is on the north side of 16th and just west of Markham Road.

He moved the antenna in his house and lost the Rochester channels except PBS.

Last night at times when I lost Rochester signals he still got the PBS from his bedroom. Once he moved it back outside and with the antenna vertical they were back, this was last night.

On comparsion he is pulling in the NBC with the same Samsung SIR T451 10 out of 10 while I get 6 to 7 in the day and 8 at that time.

Iam getting stock of the cm4221 on Thursday and I will remove my Cm4228 and stack two cm4221 overhead.

I will post the results so we all can learn from it.

Apparently when manufactures are designing antenna they want more directivity and want to reject signals from the sides and rear. They want you to use a rotor to position it for best signal.

When they combined two 4221/3021 for more gain, they also wanted better directivity and better rejection of from the sides and rear, so my guess is to combine them side by side rather than stacking it on top.

Because of where we are located(Hdtv from CN Tower) and using it only for HDTV signals we want a wider coverage to get Toronto and Buffalo at max signals from the direction we are pointing from.

I will be using a regular tv splitter in reverse to combine the signals.

My coworker if you drive north on McCowan north of the cop station Carlton Rd and south of 16th you will see his stacked Cm4228.

After my install and if it works out, I wil tell him to disassemble one of his Cm4228 and stack them to get the same gain but a wider angle.

Right now from his location he found out by turning one more west towards CN Tower the Toronto ones have more gain. He might be able to get Toronto and Buffalo with the antenna stacked.

I would also be very interested in your results. i live in welland so buffalo is not a challenge for me but Toronto stations are .I cannot receive any Toronto stations . I used to receive cbc when it was a test pattern but lost it as soon as they started broadcasting, hopefully stacking 2 4221 in each direction will solve my problem

weblurker Iam just one light south of 14th Ave and east of McCowan.

My friend is on the north side of 16th and just west of Markham Road.

He moved the antenna in his house and lost the Rochester channels except PBS.


That's amazing, getting the Rochester signals from 16th Ave, almost in Richmond Hill.

It sounds like he's able to get those channels almost all the time, so it's likely not just due to the warm weather effect.


Last night at times when I lost Rochester signals he still got the PBS from his bedroom. Once he moved it back outside and with the antenna vertical they were back, this was last night.

On comparsion he is pulling in the NBC with the same Samsung SIR T451 10 out of 10 while I get 6 to 7 in the day and 8 at that time.

Apparently when manufactures are designing antenna they want more directivity and want to reject signals from the sides and rear. They want you to use a rotor to position it for best signal.


For me, this was one of those forehead slapping moments. I think you're right, the 4228 was designed to be used with a rotor, perhaps the 4221 was designed for mast mount.

So if you're using a 4228 without a rotor, the 4228's directionality may actually be a detriment. The 4221 loses a bit of sensitivity to the 4228 but because it's not as directional, when you put both of them on a static mast mount, the 4221 picks up more signal compared to a 4228. The 4228 will definitely not be pointed in the right direction for some transmitters.



I will be using a regular tv splitter in reverse to combine the signals.



I think there was a thread on DHC about using a diplexor to combine satellite and UHF antenna signals. IIRC, someone said you could buy them from Sayal at Victoria Park and Steeles. Do you think that would be any better than a TV splitter in reverse?



I am getting stock of the cm4221 on Thursday and I will remove my Cm4228 and stack two cm4221 overhead.

I will post the results so we all can learn from it.


Yes, please post your results. What you're doing is extremely interesting.

I had thought that you could only get the Rochester channels intermittently during hot weather with a rotated yagi antenna.

weblurker I think we might be right that a stacked 4221 does give us a wider coverage area compared to a cm4228 and the same gain as a 4228 when stacked.

If you look on the diagram you can see that at a 30' angle the 4228 is almost down -12 to -15db of signal.

The 4221 at 30' is down only 3 to 5db.

So for most of us who are using it to get signal from the CN Tower and Buffalo the wider coverage of the 4221 is nice.

I will also setup at my office a 4221 to demo. :)

I live in welland so buffalo is not a challenge for me but Toronto stations are .I cannot receive any Toronto stations .

Do you use a rotator? I can get CBC with a stationary antenna in the attic but, unless I turn the antenna toward Toronto, CTV is non existent. When I do, I lose WGRZ Buffalo, and CTV isn't stable anyway.
It seems a rotator is imperative in Niagara because of dealing with opposite directions. A 30 ft tower is going up with a CM 4228 and rotator. I hope it's worth it.

Update on my friend 4221 reception, I got a text message from my friend that last night he lost the Rochester stations. :(

He can still get all the Buffalo stations at max except WB no signal.

All of his Toronto is max except Toronto 1 at 7 bars out out 10.

jbracing24,


I get all channels except for CTV and City using a Square Shooter SS-2000 pointed at Pennsylvania.

Crispy

weblurker I think we might be right that a stacked 4221 does give us a wider coverage area compared to a cm4228 and the same gain as a 4228 when stacked.

If you look on the diagram you can see that at a 30' angle the 4228 is almost down -11 to -12db of signal.

The 4221 at 30' is down only 3 to 5db.



Hi Yaamon. What's this "we" business? :->

Seriously, I think all the credit goes to you for trying out this idea, contacting Channel Master for their opinion, buying the 4221's and installing them and posting the results here at DHC.


Update on my friend 4221 reception, I got a text message from my friend that last night he lost the Rochester stations.



Ack, maybe the Rochester reception was due to the summertime warm weather effect. What your friend experienced seems to be the usual pattern, reception during the day that disappears as the temperature falls.

BTW, are you able to receive WB with the 4228 at the same time that your friend wasn't able to receive that channel with the 4221?

I received my stock of antenna in today and my coworker will bring over his ladder on Sat to help me install the cm4221 stacked. :)