: ON - Hamilton, Stoney Creek, Brantford, Haldimand
2010-01-11, 01:01 PM
A proper match is when you tape one end of both coax strands together at the exact same length and then slide your hand up the cables all the way to the other end, where you cut/crimp those ends at exactly the same length.
2010-01-11, 02:21 PM
So I can improve signal from what I have now, by equaling the 2 cable lengths before the combiner?
2010-01-11, 02:34 PM
Please read Post #16 in the OTA FAQ to understand better what the combining issues are:
2010-01-11, 04:02 PM
I was not aware that those 2 lengths of RG6 need to be the same. I know for a fact that they were not cut to be the same.
2010-01-11, 04:37 PM
I have had some situations here where it didn't seem to have an adverse effect on phasing, but for the novice approach, it's best to be safe and keep them as equal as possible. When you're balancing between three of four antennas, sometimes it's just not feasible to have exact equal lengths of cable.
2010-01-11, 04:39 PM
I would still test the 4220 on its own, just to verify that it can get more TO stations than just CBC. That way you will know if it is even worth trying to go through combining it with your 4228. Though you want to keep the coax from antenna to combiner as short as possible, if you do find a location for the 4220 a distance away from the combiner, then cut a matching length of coax for the 4228.
Do you have a post (or website) which outlines your setup? You have long lengths of coax from the antenna to combiner...are you using a pre-amp, or distribution amp, or both? If a pre-amp, are you driving one of the antennas with it or is it at the combiner output? Curious, as I'm going to be dropping multiple lines at around 60', just trying to get an ideal hookup to try. I have a plan already, but I'm open for changes and ideas. Or PM me if you want.
2010-01-11, 08:46 PM
Marbles: I've tried 3 different pre-amps- CM 7778, Winegard HDP-269, and Kitztech. The best one, for my location was the Winegard, probably because it has great input tolerance, less chance for overload. I regulary got Erie PA channels and the extra gain was only 12db. I would probably continue to use it, but it is very fragile to lightning or near lightning. It popped on me after a storm. It might be better for an attic instal. The CM and Kitztech were just too strong- major overload.
So currently my set-up consists of a hacked and stacked 4221HDs and a hacked 4228HD. The stack is joined on the tower with a reverse splitter and joined with the 4228HD in the house, then fed into a CM 3414 distribution amp for three TVs, one port is capped. I'm very impressed with the distribution amp- got me a better lock on a couple stations. I also have a CM rotor to rotate the stack, but rarely need to; more of a summer thing when tropo brings in more channels. I get all TO stations in digital, that are available, plus most of Buffalo, except WNYO and ION which come in the summer more regularly.
As I mentioned previously, I will probably get the monster, the 91XG- I think it's most appropriate for my location, very close to the CHCH tower, but I might need to use the rotor more since it is very directional.
2010-01-13, 01:31 PM
The 4220 must be helping out, because I was not getting CBLT when the 4228 was on its own.
I just picked up 2 identical CM4221's (the older ones). What I would like to do is replace the 4220 that I have on the mast with these 2.
Just wondering if I should expect better results if I stack these 2 vertically , or should I set them up side by side?
The 4228 that I have is at the very top of the mast. Below it is where I am thinking of putting the twin 4221's. I can get about 14" of separation between the bottom of the 4228 to the top of the 4221's.
2010-01-13, 01:53 PM
Not too sure if horizontal is better than vertical, but I did the vertical and got good results. Putting them horizontally might be a little more complicated, since the vertical can go on the one mast.
You could with 14, but 25 inches (at least) is recommended. That doesnít mean you canít try it. I would try maybe with just one 4221 to start- might give you more separation.
2010-01-13, 05:19 PM
I think you have misunderstood....
I dont want to put them horizontally, but rather stand them side by side. The clamps on the back of them are set up that way. In other words, when put together, they will look like the shape of the 4228.
Either that, or stand them up one on top of the other.
2010-01-13, 05:53 PM
side by side is horizontal [like the 4228]
one stacked over the other is vertical.
As goforit said, try just one 4221 toward your closest local broadcast tower.
I would recommend using only one of the 4221's pointed to your closest broadcast towers and the 4228 toward your furthest broadcast towers.
2010-01-13, 06:13 PM
I have attached a pic that I found on the net that looks just like the 4221's that I have. Maybe they are not true 4221's, I am not sure, but they look like this one.
Stand them up, side by side and you will have almost 1 complete square shaped like the 8 bay one that I have at the top of the mast.
2010-01-13, 06:46 PM
Do those antenna have that little element sitting in front of each whisker pair as the photo shows? I don't have a 4221, but all the images I've seen of it don't have that little element. What is that? Is that to aid in picking up VHF? like a frontal NAROD? Anyone?
Anyways, for TO, you may not need both of them, unless all the hardware is there, and they are already mounted and ganged in a horizontal fashion.
2010-01-13, 09:07 PM
Mine do not have the front short horizontal element. But that was the closest pic I found of the ones that I have.
Like I mentioned before, maybe they are not true Channel Masters.
This is what I have and I hope that 2 of these will get me more than just CBLT and SUN TV from Toronto.
2010-01-13, 09:52 PM
This is the old style Channel Master CM4221 antenna that was replaced by the current CM4221HD model.
2010-01-13, 11:41 PM
giovanni, see Post #16 in the OTA FAQ before replying. The concept and terminology of combining antennas is all there.
2010-01-14, 08:49 AM
Mine look very much like your picture, only difference I see is that the back mesh on the ones I have has more of a curved feature to it. That's all.
And thank you stampeder, I have read post #16.
Sometimes it helps to get opinions and results from people in your area.
2010-01-14, 12:05 PM
That is exactly the success of these local threads. :)
BTW many people have tried to build CM4228 clones out of 2 CM4221 clones and not had much luck. The reason is that an underperforming antenna is still poor even if mounted side-by-side with a second underperforming antenna. For example, using numbers I'm just throwing in here but which are realistic, if 2 clones are each measured at 9dB gain on a certain channel, stacking them will only get you a total of about 11.5-to-12dB gain on that channel afterwards, but if a real CM4221 was getting 12dB in the first place you would either not need to stack a second one or else a second stacked one would now get you about 15dB!
The moral of the story is to use the best antenna from the beginning and if you stack them your results will be much better.
2010-01-14, 01:48 PM
Assuming you looked at giovanni's picture, what would those little elements mounted in front of each whisker be used for? Any ideas?
2010-01-14, 02:38 PM
Nope, not sure what they're for but I know that they have been discussed somewhere in the Antenna R&D forum some time in the past - can't remember where or when.