The 950Q USB tuner questions and posts are now in their own thread in the HTPC forum:

http://www.digitalhome.ca/forum/showthread.php?t=120496

cheers

From my test here last summer, I've noticed that when I used a Kitz Tech amp (one input) with two antennas (CM4228 and Delhi 10Y13S) and a CM0549 UVSJ, you lose the 3-5 % gain on the TV signal meter because of the small lost from the combiner. You get the same results that if you would use a CM7777. I tried the same thing with a RC preamp and you get the same results as the Kitz.

Did you try putting pre-amps before the signal combiner to minimize the insertion loss before the first stage amp? The disadvantage is you will likely have to have separate downleads for each antenna so that you can power both amps (unless you use a combiner that will pass power on both sides and a power injector capable of powering both amps).

Did you try putting pre-amps before the signal combiner to minimize the insertion loss before the first stage amp?

Yup and I was not also impressed with the results.

I did that on the roof with a 120 volts extension cord. I put two pre-amps and I had something weird going on there. I tried several combination's and several combiners to get WVNY better and the best is one for now is the CM7777. Like I said before, this Spring I will purchase a Winegard VHF only preamp for my FM antenna and HD radio and I will the try it on the 10y13s for WVNY for fun.

On paper the best one is to have the preamp right after the balun and have one single coax running down to the TivoHD, but this is not practical for me.

intravino, I would be very interested to see your TVFool results. I suspect you are in a bad location and have both co-channel interference from CKTM-TV and adjacent channel interference from CFCF-TV when trying to receive WVNY-DT.

Regardless, there must be something about the VHF performance of the CM7777 that makes it better for you. It could be related to having separate amps for VHF and UHF, each optimized for its target band.

I would be very interested to see your TVFool results. I suspect you are in a bad location and have both co-channel interference from CKTM-TV and adjacent channel interference from CFCF-TV when trying to receive WVNY-DT

I know, It's been two years that I am trying to get a good lock on WVNY. I'm not a beginner at all, I've paid my dues. CKTM is one of the problem, CFCF not really but the biggest thing is that I get more or less 600 watts of power at my location for WVNY. August 2011 could help me also because CKTM has to change to digital.

Anyhow, I've change my location of my 10y13S and now I get it 80 % of the time, since the November at least. Still the CM7777 is the better then the other solutions. Rememeber, that I an 35 km from South East of Montreal, So I don't have the Mont-Royal tower near me. But that is an other discussion.

The problems: not only (as a Toronto resident) do I want to get CN Tower broadcasts (2 miles) but also Buffalo (50 miles). But these antenna sites are within 3 degrees of each other!!! I have a chimney antenna mount (CM 4 bay 4221) followed by 70 feet of RG6, then a 4-way splitter (and one of those outputs goes a further 30 feet to a set-top converter box which is the weakest reception of my system).

The natural but rejected solution: an antenna amp, the Winegard HDP269 handles strong signals, amplifies only 12dB, and mounts at the head end. But with some reports of static or lightning failures and the antenna being too inaccessible for DIY repairs, decided not to use it.

Solution: PCT amplified 4-way splitter with 8dB gain in place of the 4-way passive splitter with a loss of 8dB. That puts me 16dB ahead. A few dollars cheaper than the Winegard. Really a Channel Master company and the product looks very well made, some flexibility in ways to install it, packaged nicely, and with OK instructions.

PCT seems to power all the leads nicely and with good signals. No evidence of PCT overloading - but when Canada goes 100% HDTV (Aug, 2011) might see overload happening from CN Tower stations. Fair local station FM reception with the CM 4221 and this set-up, although it won't pick up as far as Buffalo.

but when Canada goes 100% HDTV (Aug, 2011) might see overload happening from CN Tower stations.

Actually the opposite is true. After the analog shutdown you will have less overload from the CN Tower. Even if the DTV stations increase their power, they will be significantly lower in power than the analog stations that will be shutting down.

Actually the opposite is true. After the analog shutdown you will have less overload from the CN Tower. Even if the DTV stations increase their power, they will be significantly lower in power than the analog stations that will be shutting down.

I read that some of the stations will have higher DTV power after the magic date of Aug 2011.

While the SDTV signals need inherently stronger power and as you indicate. But the DTV antennas aren't as sensitive at those frequencies - so more power in the air but less power coming down the cable to overload the amp. So maybe a wash.

BTW, in SDTV days, I used a CBC-Ch 5 filter so as to be able to get NBC-Buffalo-Ch 4 ("60 Minutes" on Sunday nights). Worked like a charm. But it was a major PIA to screw it in and out of the cable. If a broad lower-band SDTV filter were available, it might help some Toronto viewers but see my comments above about antenna selectivity.

I read that some of the stations will have higher DTV power after the magic date of Aug 2011.

True, but they will be lower than the analog broadcasts.

While the SDTV signals need inherently stronger power and as you indicate. But the DTV antennas aren't as sensitive at those frequencies - so more power in the air but less power coming down the cable to overload the amp. So maybe a wash.

There is no such thing as a DTV antenna (despite what the antenna marketing folks would like you to believe). Both analog and digital TV use the same VHF (channels 2-13) and UHF (channels 14-69) frequencies. After the analog shutdown, UHF channels 52-69 will no longer be used. Also VHF-LO (channels 2-6) will only be used by a few stations in select locations. Currently most DTV broadcasts in Canada use UHF but many of them are scheduled to revert to VHF so if you have a UHF only antenna, you may not be able to receive them after the analog shutdown.

BTW, in SDTV days, I used a CBC-Ch 5 filter so as to be able to get NBC-Buffalo-Ch 4 ("60 Minutes" on Sunday nights). Worked like a charm. But it was a major PIA to screw it in and out of the cable.

That worked because there is a small gap between channels 4 and 5. There is also a large gap between 6 and 7 as well as 13 and 14.

If a broad lower-band SDTV filter were available, it might help some Toronto viewers but see my comments above about antenna selectivity.

You can get a filter to take out all of VHF, but it won't touch any of the analog stations on UHF. It will also block the DTV station that revert to VHF after the analog shutdown.

@ManBOOYA: Barrie's CKVR (/A\ Network) will be moving from channel 3 to 10; I'm sure GTA'ers will want that station as well on VHF.

@Marbles_00: CBLFT Toronto (CBC Francais) currently is rated for 2500 watts (the same projected ERP for CTV 9) on channel 24, and I receive it just fine here in Kitchener. Of course there is more noise and propagation in the VHF band (which contributes to noise)--so only time will tell if CTV will be receivable outside of the GTA.

Why not keep all the DTV stations in the same band? Why would some Toronto stations want to be VHF?

Can you elaborate?I would, but not in this thread as it is waaaaaaaay off topic. :)

Here's where to follow up on what is purely a corporate and public policy issue:

http://www.digitalhome.ca/forum/showthread.php?t=120638

Back to discussing Signal Amplifiers, etc. in this thread. :)

I know I hear about the channel master Titan pre amp as one
of the best and it is pricey. But is this pre amp any good
CHANNEL MASTER 3041DSB Spartan 3. I ask because it is
on sale for a unbelievable price, was wondering if anyone had
problems with it or if it's any good.

It has 17db VHF gain and 23 db UHF gain but doesn't have noise
figure.

Keep in mind that the 3041 (now discontinued) has 300 ohm inputs for use with twin-lead to the antenna.

Summintsource's description says NF on UHF is 2.2 dB and 3.0 d on VHF.

One thing to consider when looking at pre-amps with 300ohm inputs is not requiring a Balun will improve the effective noise factor (or more accurately, when looking at pre-amps with 75ohm inputs, the need for a Balun will degrade the effective noise factor).

This is assuming the antenna you are using has 300ohm terminals. Antennas with a Balun built in don't have the option of using a pre-amp with 300ohm inputs without modifying the antenna (or using a second Balun and thus further degrading the performance).

it says the amp is 75 ohms on the website and my antenna is the cm4221hd.

it says the amp is 75 ohms on the website and my antenna is the cm4221hd.
I am not sure which website you are looking at, but a major online vendor I checked says it has a 300 ohm input and 75 ohm output. For the CM4221HD you will want a pre-amp with a 75 ohm input.

IIRC, most 300ohm input amplifiers have built-in baluns, so unfortunately the balun isn't eliminated.

IIRC, most 300ohm input amplifiers have built-in baluns, so unfortunately the balun isn't eliminated.
It is not eliminated, but the loss through the balun is included when they calculate the noise factor, so when comparing amps, you need to take that into account. Having it built in also saves an extra connection.

It is not eliminated, but the loss through the balun is included when they calculate the noise factor, so when comparing amps, you need to take that into account. Having it built in also saves an extra connection.
The previous time this was discussed here, with reverse-engineered circuit diagrams and the like, the conclusion was that the built-in balun was not taken into account in the pre-amp manufacturer's quoted NF value.

Or at least that's how I remember it, without actually taking the time to search backwards here for the specific posts. ;)

Cheers

Here's my post re which Preamps "APPEAR" to include the Balun loss and which don't:
http://www.digitalhome.ca/forum/showthread.php?p=874273