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teknojnky what is your setup? I also get everything but not CJNT and no ABC. The antenna is pointing towards Mt. Mansfield. I use to get Tele Savoir 29.1 when the temperature went down, but not any more.
 

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Trying to decide on type of pre-amp for my setup

Hello everyone,

Have been around the forum for a while, but I'm still kind of a noob when it comes to all the signal gain and loss issues. This is totally out of my area of expertise and I have no clue how I'm supposed to calculate what baluns and antennas are supposed to go with what pre-amps, etc.

Anyway, I have an attic-mounted setup and I'm not going to move it to the roof for various reasons, unless I'm really stuck. I have an ANT751R pointed at my local channels (all the ones in green, except PBS) and they work great. No pixelation and all channels come in at "Good" or "Excellent" quality on my Toshiba LED TV. Even in rough snowy weather, the signal is rock solid. I will try to upgrade that antenna to a modded CM4221HD soon though to see if I can pick up the weaker local channels in yellow (currently I'm missing two).

I also have an Antennas Direct 91XG that's "kind of" pointing at PBS 57.1 (185 deg) and it's getting a decent signal too. I say kind of, because as I was trying to install it from the access hatch to my attic the other day (I have no way of getting up there completely for now), the antenna fell in between some 2x4 roof beams and jammed, pointing roughly in that direction. I intended it to point CBS, NBC and Fox, but this small accident occurred and I was not able to recuperate the antenna (I can't access the attic at this time to free and reposition the antenna, I have to wait till spring). I connected it to my ANT751R using a combiner switch. There are no other splitters for now and my total coax length is about 100 feet... maybe even a little less (I'm using the pre-existing coax network of my house, which is an early 2000's construction and is wired with RG6).

Anyhow, I was wondering what kind of a pre-amp would be best in my situation to get the American channels I want on my 91XG and perhaps also reinforce the signal on my locals. I get the current PBS at "Average" or "Good" signal strength, but that's not very telling since the antenna is not actually pointing right at it and it's not even the tower I want (I'm roughly pointing at 180 deg now and I need to point at 149 deg to get the desired channels). The channels I do want, however, are really weak according to TV Fool (Fox is at around 21 db, for example).

Also, I currently have an RCA TVPRAMP1R pre-amp that's not installed, but I fear I'll probably need a stronger pre-amp once I re-aim the 91XG at the other stations anyhow, plus I'm not even sure if the RCA pre-amp will be compatible and not detrimental to signal gain (I've read many posts here of experienced users actually losing gain by using the wrong pre-amp). I was toying with the idea of getting the CM7777 due to it's high 30 db gain for maximum results, but first I want to be sure it will be compatible with my kind of a setup.

Thanks in advance for your help!

Here's my TV Fool report:


 

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Definitely try your RCA TVPRAMP1R preamp first since you already have it on hand. Also when you are testing a strong preamp it is always good to have some attenuators handy, especially with the strong local stations you are getting. I used to carry around 2 x 3dB and 1 x 6dB so that I could combine them for a variety of levels, swapping them in and out from no attenuation to highest total attenuation to get the signal just right. It involves a lot of rescanning, but you can do the attenuation testing right down at your TV.

We'll keep discussing your particular situation here in this thread but you'll find everything you will ever need to know about preamps in the following thread: Signal Amplifiers (Amps, Preamps, Distro Amps)
 

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Thanks for the info, Stampeder. I don't have any attenuators yet, so I guess that's my next thing to get for testing. The reason I posted the question is because I didn't quite understand the various technical issues discussed in the other thread. There are many variables, it would seem... and many possibilities.

Anyway, I'll try the RCA first and see what happens. I'll report back with news at a later time. Thanks again!
 

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OTA reception Vaudreuil-Dorion

ChannelSeeker,

You wont need any attenuators as long as you stay away from the CM7777 pre-amp.

So try your RCA TVPRAMP1R and come back with your reception results.

The channels I do want, however, are really weak according to TV Fool (Fox is at around 21 db, for example).
21 NM(dB) is not weak for FOX, but it could be with an attic mount setup.
.
 

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Thanks Bouval, that's good info there. I was very surprised how good the signal is for my locals on the ANT751R with no preamp and a combiner on the line. I thought the attic reception would be choppy, but it's rock solid and strong even when it snows. Perhaps the fact that my street is higher than the surroundings (and the new construction type of my roof) have something to do with it.

Another question: I have a CM4221HD inbound that I'm going to mod. Do you think I could potentially get the channels in yellow with it if I connect it in lieu of the 91XG? The setup will be amplified by the RCA preamp, of course...

:confused:
 

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Cornwall Area Reception

I recently built a SBGH without reflector using 12 gauge steel wire usually used for suspended ceilings. The reception was certainly better than I had been expecting. The antenna is located on the south west corner of a second floor bedroom. I've tried different rooms in the house and this is by far the best location. Within the next few weeks I plan to build a DBGH using 6 gauge copper wire. This antenna will be located outside on the roof. Currently, we receive the following channels: CJOH -8, WNPI - 18.1,2,3, WNYF - 28.1, WWNY - 28.2, CBFT - 2.1, CBOT - 4.1, WCFE - 57.1,2. Hopefully, the new antenna will be able to receive even more. I tried to insert the report from TVFool but it doesn't appear to work with my IPad.
 

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Awesome news!

I received my CM4221HD earlier this week and modded it as suggested on this forum. The thing is amazing! It's rated as a "65 mile" antenna, but picks up stations 85 miles away! :eek: I pointed it at my locals (84 deg) and I scanned for channels... to my surprise, a few came in at 149 deg, no pre-amp! (those were the American channels, 85 miles away) So... I moved the antenna a bit to the west to find more of a "middle ground" between my locals and the distant American tower and added my RCA TVPRAMP1R pre-amp to the setup. Lo and behold: from my previous 12 channels with the old RCA ANT751R antenna (rated at 45 miles), I now had 24 channels! :D

Still no FOX, but CBS, PBS and NBC are coming in right now, with a watchable signal strength... and I'm not even close to aiming at 149 degrees. I'd say I'm aiming at approx. 100 deg. right now. The locals are still rock solid, even with the antenna off point. Pretty good stuff, that Channel Master hardware! Sure as heck beats the RCA ANT751R antenna I had there previously.

(Oh, and it's an attic installation by the way... which makes it even more impressive)




Question: As I am still new at this, I don't fully understand the concept of "multipath". I plan on aiming an Antennas Direct 91XG at 149 deg to get the full spectrum of the American channels (of which I get a few now with the modded CM4221HD and a pre-amp), but I'm concerned that both antennas getting some of the same channels might create problems and "cancel each other out", as some members have stated in other threads. Should I be concerned or is multipath only a problem in specific situations? Even if I re-aim my CM4221HD at my locals, it still picks up the American channels from the side... so no matter what, it will still get at least some of them.
 

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ChannelSeeker Antennas Direct 91XG is an excellent antenna but it is only UHF so WVNY 22 most likely will be no go. You should have purchased CM4228HD. Just with CM4228HD pointed at Mount Mansfield you would have got most Montreal and US channels including FOX 44. With this antenna some people also reported pulling in ABC 22 from our area. I think buying CM4221HD and Antennas Direct 91XD for our area is waist of money and overkill. In my opinion from this area one CM4228HD attached to a pre-amp or an amp will produce excellent results.
I have a cheap 8 bay "junk" antenna pointed at Mount Mansfield 25' above ground attached to GE amp from CTire and with this setup I have excellent reception of 2.1, 3.1-2, 5.1-3, 6.1, 8, 10.1, 12.1, 15.1, 17.1, 33.1-4, 35.1, 44.1, 57.1-3.
Eventually I would like to get CM4228HD attached to a pre-amp and try my luck with catching WVNY 22.
 

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I don't think multhipath will be your problem. My cheap 8 bay antenna is multidirectional and at one point I had one half pointed to Montreal and the other to US. From Montreal I gained Tele Savoir 29 and few extra bars on Global but the signal from the States was a bit lower. Now I have the whole antenna pointing to the states. I lost channel 29, but this gives the best results. CBS, NBC, and PBS 33 come in at 100%.
Digital television is very similar to satellite, the antenna has to be precisely pointed for best results. Sometimes a few degrees will make all the difference. Unlike satellite height of the antenna from the ground also matters.
If you are set on two antennas configuration, I would point 91XG by it self to US, find the best signal for US channels only and mount the antenna. then I would point CM4221HD by itself to Montreal, find the best signal for Montreal channels only and mount it. I would join the two antennas with a good 1GHz combiner from Regal or Channel Plus and then run them to my pre-amp and tv. We are far from any transmitter so you can use any pre-amp you like. You will not overload the signal a specially that your antennas are located in the attic. Your setup is as good as your weakest link so don't forget about good quality RG6 coax cable and connections. With this setup you will get the most possible UHF channels. I am not sure if the 91XG will be able to pull in ABC 22 (VHF 13). It would be nice. Have fun and let us know of your results.
 

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Many thanks for the long and complete explanation, much appreciated! I actually was wondering, with my 91XG being very directional, if I won't need three antennas so that I don't lose 57.1, 57.2 and 57.3 when I reposition my 91XG to point at Mount Mansfield (those PBS channels have different content than the 33.1-3 PBS stations and have a stronger signal, so I'd like to keep them). I figured that worst come to worst, I'll just point my RCA ANT751R at the 57.1-3 tower and put in a second combiner switch, for a total of 3 antennas on the line (I have the RCA lying around as a spare anyway). Determining best cable lengths for each antenna would probably be tricky though... :eek:

That being said, it's nice to see that your 8 bay antenna actually picks those up along with the rest of the American channels, ogorek! Thanks for the info! :)


As for the antennas I have on the line now, I already have them joined by equal length cables (RG6) and the combiner switch is a Digi*cough* brand switch I got from FutureSh*p's online store for $5 a piece. It seems to be doing a very decent job so far. I wanted something of higher quality, but couldn't really find it locally... and didn't want to pay exorbitant eBay prices + shipping from the US for a name brand combiner switch. After many years of messing around with satellite equipment, I figure all these switches are probably made/shielded the same on the inside anyway... unless I'm wrong, of course. That, plus my attic installation will certainly be very easy on the equipment (nothing will be exposed to the elements), so getting the extra heavy duty stuff is indeed overkill. Good antennas and proper cables is where I invested my modest budget on my OTA setup. ;)

Also, thank you Stampeder for the link to multipath. I think I understand now that two antennas getting bits of the same signal is no big deal, as multipath seems to only refer to obstructions in the signal wave's continuity.
 

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If I have to go to a 3 antenna setup so I don't lose the WCFE PBS channels, this is most likely what I'll do (along with what I figure would be proper cable lengths) :

 

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Make no mistake, combining multiple antennas is a big deal! Read the Stacking and Ganging thread to learn why. Even if you don't have multipath (which is almost always present to some degree), you have the issue of the same signal being received by more than one antenna, and the being combined out-of-phase in the combiner, resulting in amplitude degradation.

Using equal lengths of coax before the combiner is only necessary when stacking antennas i.e. two or more identical antennas pointed in exactly the same direction. What you are proposing to do is called ganging.

Ganging two antennas can work - it very much depends on individual circumstances. I was able to achieve success with two by using a signal analyzer to finely adjust to pointing angles to minimize signal cancellation (I also had strong multipath to contend with).

Best practice is to use as few antennas as you can. Although the 91 XG is an excellent antenna (I have two), it is rather narrow-beam. You might find an 8-bay like the CM4228 is able to pick up both Lyon Mountain (WCFE) and Mt. Mansfield (UHF only).

If you do use a VHF antenna, then be aware that there are special combines that combine a UHF antenna with a VHF antenna called a UVSJ. That effectively eliminates phase cancellation between the two antennas because the two bands are filtered separately before being combined.
 

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Thank you DXer, that sheds a quite a bit of light on my theoretical 3 antenna farm. I knew there would probably be issues with this... and since I don't have a signal analyzer, it's kind of a futile attempt. I'm sure I'd run into some kind of a problem...

I slept on it a bit and I might actually resort to getting a cm4228 for all US stations and combine it with my cm4221 for local channels. That way I'd still be at 2 antennas like I am now, not 3.

That being said, does anyone want to trade a CM4228 for a 91XG in the coming months? ;)
 

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OTA reception Cornwall area

Mcgillivray,

What are the real channel numbers you're getting now with your antenna being outdoors ?

If you hit [Pending* All channels] on your TV Fool report, you'll add 4 more channels having a positive NM(dB).

Is CJOH channel 8 still analog? I was getting it once in a while last summer from Laval.

Your next step will be a pre-amplifier to get a few more channels, but stay away from the Channel Master CM7777, channel 8 being close would overload it.

Are you receiving more channels from Montreal than Ottawa ?

Thank you.
.
 

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Bouval,

I'm getting the same channel 8 on my modded CM4221HD in the attic and it is indeed analog (comes in from behind the antenna). It is the analog version of CTV's channel 12.1, as far as I can tell by comparing content.
 

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Also, as a follow-up to my earlier posts about my setup, I decided to say "to heck with it" and ordered a CM4228HD that I found on sale for $99. I decided I'm not going to mess around with a dubious 3 antenna setup.

As ogorek and DXer suggested earlier, I'll point it at Mount Mansfield and see what happens, but as a twist, I'll also gang it with my CM4221HD through a combiner switch and point at Mount Royal to continue getting my locals. My poorly aimed Antennas Direct 91XG I currently use for PBS will be going up for sale if everything works as expected. I hope it does... (fingers crossed!)

I'll report back with results as soon as I complete the installation. Should be a few weeks, maybe sooner. Can't wait...

:D
 
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