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Hi Bouval, I currently receive the following channels outdoors: CBFT 2.1, CBMT 6.1,
CKMI 15.1, 15.2, CIVM 17.1, WNPI 18.1, 18.2, 18.3, WNYF 28.1, WWNY 28.2, WCFE 57.1, 57.2, 57.3. I receive channel 8 CJOH analog probably from a repeater located in Lancaster.
My antenna is pointed southeast. When it points southwest I receive CBOT 4.1 and lose CBMT 6.1. I seem to be receiving more channels from Montreal. This may be due to my metal roof which is located northwest of my antenna. Do you think I would receive more channels if a built an antenna using copper in place of steel?
 

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Update: I got the CM4228HD in the mail, managed to remove the 91XG from the attic and connect the 4228 in its' place. Other than removing the plastic caps protecting the whiskers and performing a bolt re-tightening procedure described in post #415 here, I left my new 4228HD bone stock (no twin balun mods for me, at least not for now).

To my big surprise, almost all the U.S. channels are watchable off the 4228HD from the attic, even the off-angle 57.1-3 channels (although I only get "poor" signal on those - 1 out of 4 bars). Channel 13 (ABC) doesn't come in at all, but I think my RCA pre-amp does a better job amplifying UHF than it does VHF, which might be the problem.... I think I can see a ChannelMaster 7777 pre-amp in my future. It can't be due to poor aiming of the antenna, as I now get Fox 44.1 at close to 80% signal strength.

I'm a little lost on how to tell whether or not CM7777's 30 dB gain on UHF/VHF will cause adverse effects on my reception. From what I understand, my current RCA pre-amp amplifies 16 dB for VHF and close to 23 dB for UHF (based on some independent tests that were conducted by members of other forums).

:confused:
 

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Do not buy a CM 7777!

If you need a pre-amp, you need the one with the lowest noise figure, not the highest gain (a point lost on many in these forums).

Check out the amplifiers thread and you will see (amongst others) that Research Communications amps are highly recommended, and Kitztech is a less-expensive alternative.

In simple terms, you are trying to achieve a maximum signal-to-noise ratio in your system, (about 16 dB minimum for receiving an ATSC signal), and the 0.5 dB of an RC or Kitztech gives you almost 3 dB advantage in this over the 3.5 dB noise factor of a CM 7777. In addition, the very high gain of the CM 7777 can cause overloading and IMD, not very desirable!

You will find more than you ever want to know about pre-amps in the thread for that topic!
 

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Allrighty, thanks! I will concentrate my information seeking in the preamp thread then... although your explanation already does a good job of summing it up. I haven't considered the preamp's noise figure so far... interesting point!
 

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OTA Reception Vaudreuil-Dorion

ChannelSeeker,

Stay away from the CM7777, I've got one that I don't even dare trying unless I put a 3 or 6 dB attenuator at the antenna. If I were you, I'd go for the Winegard HDA-200 pre-amp.

I guess what you call a combiner switch is simply a reversed splitter. You should try your CM4228HD alone, no splitter and no CM4221HD.
.
 

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The combiner is a dedicated OTA antenna combiner I mail ordered from Futureshop. It's made by a company we can't mention here (starts with "Digi..."). Model # is DGSCA201. I've ordered it because I read somewhere that a reverse splitter is not as efficient as a real combiner due to higher noise. I don't know if that's true, but my combiner works well. As for the CM4221HD, it helps pull lower signal Montreal channels such as Savoir, ICI and City through the attic roof, so it stays. It also seems to help reinforce the signal on some US stations, as the ones it used to get before adding the 4228 are now stronger than the rest (I think the signal adds up from both antennas now).

Thanks for the warning on the CM7777 and hints on what amps to use. I checked out reviews and comparisons on the Kitztech yesterday and it seems interesting. I'll check out the HDA-200 too. My biggest concern now is boosting the signal on vhf-hi for channel 13, but also uhf for off angle channels 57.1-3

Thanks! ��
 

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Specs on the Winegard:

•Gain: 24 dB.
•Noise Figure: 4.5 dB.

I think the Kitztech KT-200 would be a better option, as the noise is rated at 0.4 dB and gain is the same. Price is about the same too, all in.

Every decibel extra is worth its' weight in gold!

��
 

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ChannelSeeker your DGSCA201 combiner is such a low quality product that most OTA enthusiast reading your posts would not touch with a ten foot pole. It is no different from the one sold at a dollar store. Having said that the antenna I am using is in the same category, no one here would touch.
With OTA it's a trial and error. What works for one will not work for the other. Reading noise figure specs on pre-amps in my opinion is pointless. The best you can do is to get your equipment from a place where you can return it. Combining CM4221 for Montreal with CM4228 for US from our location is a wise choice. They are both quality antennas which will give satisfactory results. Adding a third antenna for WCFE 57 in my opinion is overkill and totally unnecessary. If you want to get an antenna for every channel out there why not use your CM4228HD alone withe a rotor. Every combiner, amplifier, pre-amp, poor cable, cheap connector introduces a signal loss. Amplifiers amplify everything the noise and the signal. You want the best results without the amp or pre-amp and then to boost the signal using them. Asking ten people here for there opinion on amps or pre-amps will give you ten different answers. It's almost like asking which oil is better for your car. Creating a heated debate. Keep it simple. Get the most channels possible without spending to much time and money. Since you already have RCA pre-amp I would not spent another dime for a different one. Have fun.
 

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Thanks Ogorek. I understand that mileage can vary depending on many factors, but I am still trying to achieve the optimal configuration for my setup. In essence, I'm after a solid and stable reception of all of TVFool's green and yellow channels for my location, weather permitting of course. Once I manage to get that, I'll call it.

The RCA preamp is not satisfactory, because it only amplifies 16dB on VHF and so I don't get channel 13 at all. Plus yesterday, after returning home from work, I have also noticed that my 57.1-3 PBS channels started losing the 1 bar of signal they had (out of 4 possible bars in total) and have become pixelated/unwatchable. I haven't touched the setup at all and yet these channels were mostly all gone today. I thought that perhaps it was due to weather conditions along the signal path, but it hasn't really improved all day even as I type this (and the weather seems pretty stable, according to radar readings). I've got no clue what happened: these channels used to be OK and perfectly watchable with the CM4228HD for the first few days and now things are getting ugly.

In any case, I have pulled the trigger on a Kitztech KT-200 and am patiently awaiting its' arrival. You only live once, after all... and if it helps stabilize these channels and gets me channel 13 as a bonus, I'll be a happy camper. That being said, if you have any suggestions on what better combiner I could use for both antennas in lieu of the DGSCA201, I'd be more than happy to listen... so far it appears to work OK, but nothing says that particular component of my setup can't be improved upon. As stated before, my goal is to stabilize reception as much as possible without moving anything to the roof, which would be a total PITA.

This is the technical description of the combiner I have now:

DGSCA201 is a 2 way power divider/combiner that covers .2-1000MHz.It is 50 ohms impedance and 1 watt power input rating. Insertion loss is .6 dB. Isolation is 25 dB. SMA(f) connectors.
Could you please tell me what gives it such a bad reputation for being "dollar store quality"? I don't mind paying again and perhaps more if there's any real improvement to be had reception-wise, but I'd hate paying just for the brand name printed on the combiner, lol. Thanks!

;)
 

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That combiner would be bad for you on at least two counts: first the impedance is 50 ohms - it should be 75 ohms - and will cause signal loss because of the mid-match to 75 ohm coax; secondly, unless it contains diodes - of which there is no indication - the voltage from the power inserted will appear on the second output, which may be detrimental to the equipment connected to that port. You would need a DC blocker on that port (which is harder to find than a splitter with power pass on only one side).

You should be able to find the latter from any of the online stores selling satellite gear. For a bricks-and-mortar store, there is one in Vaudreuil - RPS Satellite - that might be near you.

Good choice on the Kitztech! You might need to block the FM band from it if you have powerful FM transmitters near you if you see evidence of overload in the pre-amp. Best way to do that would be to put a HLSJ before the pre-amp (with the unused 'L' port terminated with a 75 ohm terminator).

P.S. I've never seen a splitter like yours in a dollar store 😊
 

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Good info there, thanks! Despite it's obvious shortcomings, the combiner appears to do a decent job, but perhaps that's only because there's nothing else I can compare it to. So maybe that's the cause of some signals fluctuating... Also, I don't quite understand the AC/DC passive on one side thing... doesn't the preamp need to amplify the signal from BOTH antennas?

After some searching, I believe I found a combiner that satisfies the conditions you outlined. Would a Winegard CC-7870 (about $40 shipped) be a good choice for coupling a CM4228HD and a CM4221HD, along with the KT-200 preamp I'll soon be installing? After reading the technical specs on the Wiengard, I still don't quite understand what port I'd connect which antenna to (AC/DC passive or not).

Thanks!
 

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ChannelSeeker.

I've reviewed all your recent posts to get an accurate picture of what you're trying to do.

You need to run the signal from the 4228 through the Kitztech pre-amp before combining it with the 4221, or else you will likely overload the pre-amp with the Mount Royal signals. To do this, you need a power-passing splitter/combiner with power passing on only ONE side if you want the power supply to be in the basement. If you have power passing on both sides (unless diode-protected), the power for the pre-amp will appear on the second port (where you will connect the 4221), and as antennas present a short-circuit at DC between the core and shield of the coax, you will in effect be short-circuiting your power supply (which isn't good!). Thus the two you illustrated in the amplifiers thread will NOT do! (and it was to those I was referring in post 1030, not to your Digi* combiner).

I have in my hand two suitable splitters: one is a Perfect Vision PV23402, and the other is a PV22-233 (which is reported in another forum to have the lowest -loss of any that writer tested). Google those for a supplier (they're about $3 each - no need to go spending $40!).

By the way, the description of the DGSCA201 from the Digi* web site combiner you posted earlier is laughable ("DGSCA201 is a 2 way power divider/combiner that covers .2-1000MHz.It is 50 ohms impedance and 1 watt power input rating. Insertion loss is .6 dB. Isolation is 25 dB. SMA(f) connectors.")! To start with, it does NOT have SMA connectors (rather it has F connectors), and is very unlikely to be 50 ohms impedance (as F connectors have 75 ohm impedance). Amazing they can't even get it right on their own site!

I hope this clarifies things for you.
 

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Thank you very much for this detailed explanation! I understand what needs to be done a lot better now... glad I didn't get the Winegard combiner yet!

As for the description, I got that off the walmart dot com site, as I couldn't find one elsewhere. No doubt it's the specs provided by the manufacturer though.

Thanks once again, I'll now look for the combiners you mentioned! :)


EDIT: Well, after some serious googling, I was not able to locate the splitters/combiners you mentioned. The closest "quality" splitter with power pass on one side I could find was this one:



(costs a bit more than $3, but hopefully it would perform better to stabilize the signals than the current Digi**** combiner I've got)
 

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I just put the serial numbers into Google and came up with loads of hits!

You'll find that the Monster brand is not one of those widely spoken-of in these OTA forums. Blonder-Tongue, Perfect Vision, Pico-Macom and Holland are among the "professional" brands.

I'll post some links later.
 

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You can also buy DC-Block barrel connectors should you find yourself with a combiner with DC pass on both ports when you only want DC pass on one.
 

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Thanks, DXer. I did find most of those, but the shipping from US was ridiculous. Summit wanted over $32 to ship to Canada! Their eBay store commands the same shipping charges.... and for that much, they'd have to be located on Mars to justify the freight cost on something that fits in the smallest bubble envelope! (damn robbers, I tells ya) :eek: :eek: :eek:


Satellite Shop:


Summitsource:



Looks like for whatever reason, the satellite/OTA outlets in the United States have gone insane with shipping costs (maybe there's something in their water?). In essence, it'd be cheaper to get the Winegard locally from where I stand. Other places don't seem to carry the PV22-233 in stock or shipping cost is just as bad. Besides, it appears as though it is discontinued, based on what I was able to read on some websites...

Anyway, I'll drop by a local electronics store and see what they have. Thanks for all the tips, gentlemen!


EDIT: Local electronics store didn't have much at all... I was able to pick up a coax double grounding block, coax couplers and 75-300 ohm indoor transformers (baluns) for $0.99 a piece, but that's about it. The only splitters available were power pass on both sides and they all were the no-brand types and contained no specs. No F terminators either.

I guess that's where it's all heading: online shopping. It would help if the online stores that carry the necessary gear didn't charge and arm, a leg and a rib in shipping though! (which I'll always refuse to pay out of principle). Oh well, I'll have to make due with what I've got already on hand. My Digi**** combiner will have to stay and I'll just amplify both antennas with the Kitztech, same as I'm doing now with the RCA... so far, no signs of any overload or short circuits (that I can tell).
 

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Come to think of it, I might ask an Ameri-friend of mine to lend me a hand and be the middle man for this... a hassle, but sure beats paying $40 CDN in shipping!

;)
 

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(Replying to your last message in the other thread in this, the correct thread :D)

Your lack of success with channel 13 may be due to a number of factors:

It is thought by some in these forums that the TVFool signal strength calculations for the VHF band are off by quite a bit (in reality they are somewhat lower than TVFool calculates).

Secondly, your CM 4228 is a UHF antenna. It does have some capability at VHF, but it will have much lower gain than a dedicated VHF-Hi antenna.

The experts here claim that attic installs suffer from 10 to 20 dB signal strength attenuation compared to a roof-mounted antenna, so you're handicapped before you start when chasing weak signals.

You no doubt have some of that white stuff on the outside of your roof at the moment. Although it doesn't attenuate signals very much when it is dry and fluffy, the wetter it gets, the more it attenuates. We're just at the start of the thaw, so you may lose signal strength for a week or two until it's all gone.

Don't let all this discourage you. Based on other accounts in these forums, it can take a long while and much effort to bring in those cross-border stations reliably. You need to be prepared to try many configurations. Without expensive test equipment you have to use the trial-and-error method to achieve best results :) The point about eliminating your local antenna temporarily from the mix is to determine whether that has a negative effect on the reception of the US stations. If you do manage to receive them without it in the circuit, then we have to look for an alternative to your default set-up to enable you to get the weak Montreal stations as well.
 

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ChannelSeeker,

You might consider www.mcmelectronics.com. They have a Holland Electronics GHS-2P splitter in stock for $2.59. It looks close to the PV22233 unit you described. They also have a reasonable selection of other useful OTA stuff as well. Look under the SATV and CATV section. I am not specifically recommending this unit. I am just identifying a possible source.

I ordered some FM traps (and other odds and ends) from them last week. The total order came to just under $20. However the key point here is that shipping was $15, which is a lot better than what you are seeing elsewhere. Just MAKE SURE that you specify USPS (U.S. Postal Service) for shipping. Apparently the (total) shipping cost charged by UPS (ground) is so ridiculous that many Canadian customers are refusing delivery. I had originally specified UPS ground shipping for my order. I phoned them on Saturday to change to USPS. Their service rep. told me they were automatically changing to USPS because of the problems Canadian customers were having with UPS. I received the shipping notification yesterday. It shows $15 for USPS delivery. I haven`t received the package yet so I don`t know if it will come straight through with no problems. I hope this helps. By the way, the FM traps cover the entire FM band (i.e. including channel 6) and were on sale for $1.49. If you are interested, search for "FM trap SDR" on Youtube for some performance videos.

Regards,

Hugh
 
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