If that splitter is installed between the PA18 and its power inserter and is not passing power to the pre-amp, you just installed a 30 dB attenuator. Make certain you didn't inadvertently do this. You must either have a straight coax run between the inserter and the pre-amp or you must use a properly-connected DC Pass splitter.

It looks like the intersection of Jane and St Clair is about 5.5 miles from the CN tower. That is far too close to strong signal sources to be using the PA18 based on what I know about it.

TVFool for Jane and St Clair @ 30': http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9c6b012ee90219

ProjectSHO89, majortom,

My setup is two 4221HDs stacked on a 10ft mast on my chimney (about 35ft total, I guess) and pointed at Buffalo from Jane and St. Clair area of Toronto. The two antennas are connected via identical length RG-6 into a high quality splitter and goes straight down about 50-60 ft of cable right into a PCI tuner card (Kworld 120).

I normally get all of Toronto and most of Buffalo solid with this, except WIVB and WKBW are iffy during sunset and sometimes even WRGZ drops out.

When I installed the pre-amp, I lost all the "iffy" channels immediately and only the strongest local stations could be tuned. it was like I installed an attenuator.
where is the amp? Up on the mast? and where is the power inserter?

You said 50-60 ft from splitter to tuner, didn't mention anything in between?

Anyway, do you know what the effects of overload look like on your tv? Does it breakup or freeze or pixelate?

But, if your close to cn tower, the overload won't be from digital stations, it will be from the megawatt analog stations. 5, 9, 19, 25, 41, 47 and 69 are all high power. Your tuner will reduce its input agc to nothing to protect itself.

ProjectSHO89,

(nothing between pre-amp and power inserter)

So, it doesn't matter that my antenna is aimed in such a way that it is barely catching the CN tower signals? I can see it overloading if I was pointed straight at the tower, but I'm not. And why would it overload on channels that are super-weak like WIVB? This makes no sense to me.

Tom.F.1,

Pre-Amp was up on the mast. Two antennas connected to splitter/joiner with equal 4' cables, then a 3' cable into the pre-amp input, then a solid run (maybe 50') of cable from the pre-amp output to the power inserter (in my basement) then a 10' run to the tuner card.

If it is overload, then it is resulting in about a 5db drop in signal on every channel (tuner compensation?). When that happens, I just lose channels. There is no pixelation or stuttering, they are just "gone". Only the strongest local stations still work. This is counterintuitive, but makes sense if the tuner is reducing its gain due to overload.

Trying to interprets your previous posts...

1. So I take that you don't have LOS of Toronto CN tower?

2. If you lock the first antenna single antenna) to Buffalo, you get all your US stations?

3. If you point second antenna (single antenna) to Toronto, do you get all Toronto stations?

4. Any possibility of mounting your antenna above the roof line?

First off, I'm concerned about using TSReader as a signal level meter. When I use it with my USB tuner, it gives me "readings" that bear no relationship to a true signal meter (I have one of those).

Unplug the PA18 power supply and see what happens. Unpowered, it will represent approximately a 30 dB attenuator and will remove "overload" from the equation. If there is no difference in your observed results, check the output of the inserter for 12-14 VDC.

Overload can also come from FM radio and cellular transmissions.

Yep, TSReader is a tool for data transport stream analysis, and it it terrific at that, but OTOH It is not in the same category of signal analyzer in the manner of these devices (http://www.digitalhome.ca/forum/showthread.php?t=96705). You need the right tool for the right job.

ProjectSHO89,

During my testing yesterday I did try unplugging the power inserter power supply . The signals increased (but not back to normal levels that I get with no pre-amp at all).

I tried this several times, plugging and unplugging the power supply. Every time plugging the power supply in resulted in a 5db drop is TS Reader's signal strength (dbm) reading (on all channels, both local and remote).

Something tells me TS reader's dbm figure is a SNR.

I suspect that overload is the issue. When the pre-amp has power, the signal spikes up and as Tom mentioned the tuner reacts by reducing it own gain (?). The weakest signals are cut off and only the strongest local signals still have enough strength to get through.

Within 30 minutes of testing I had un-installed the pre-amp, as it was coming close to Coronation Street recording time ;)

The pre-amp is now for sale, and I will explore other options.

stampeder, I cannot afford to buy a proper signal meter.

Have you tried a 4 or 8-way splitter? It might help with overload. I use a Winegard AP-4727 (22 db) with an original 4228 aimed at Buffalo. Before I added a 4-way splitter, a few stations were overloading my tuners. With the splitter I get rock-solid reception of all Toronto and Buffalo channels. Without the preamp I can't pickup 53, 65 and 66 while aiming my antenna at Buffalo. I also have a rotor on my antenna but I haven't moved it in 2 years.

The one thing about the Winegard amps is that they have a higher input threshold. I don't know if that's why mine works so well for me.

I notice you have 2 antennas. Have you tried using just the antenna pointed at Buffalo with the preamp? (disconnect the TO antenna). A single 4221 pointed at Buffalo with a preamp should get you all the channels (4221's have very good side reception). Joining 2 antennas can cause signal cancellation and may confuse the preamp. Also the the Kworld tuner isn't the best for multipath. I have one as my third tuner in my HTPC and it is by far my worst tuner.

I've searched high and low (experiments) and have been unable to find a situation where an amp makes a significant difference on an indoors antenna. The opportunity for improvement is such a small margin...unless the tuner has a particularly sucky noise figure. Signal amplitude that can be corrected by a pre-amp is rarely the problem indoors.

Agreed. Amplifiers are typically useless at best on an indoor antenna. In reality they tend to make things worse.

I suspect that overload is the issue. When the pre-amp has power, the signal spikes up and as Tom mentioned the tuner reacts by reducing it own gain (?). The weakest signals are cut off and only the strongest local signals still have enough strength to get through.
Hi Cogitech, sorry to hear your experiment didn't work out. I went looking back to when you first asked about an amp and found my suggestion - "Pre-amp not recommended due to overload, but If you're splitting to feed more than 1 tuner, a distribution amp works wonders."
I think you also said you have a tree blocking your path to Buffalo? I recently did an install for people who live in a forest in Mississauga, and I warned them they wouldn't get all stations. They wanted to go ahead anyway and told me to use the best equipment. So, with two DB-8's combined and a 7777 pre-amp, they get everything except WGRZ and WIVB.
Another one I did with trees in uptown Toronto has the same problem as you, a pre-amp won't help due to overload, he's looking for a 50-60 ft tower.

No, haven't tried a splitter. I've just lent my PA-18 to my co-worker who is going to try it. If it works for him, he's going to let me try his POS Digi**** pre-amp which has an adjustable gain.

My actual TVFool is this, BTW: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9c6bfb9c811dc5

Tom,

I realize I went against the better judgement of several members, including yourself, when I decided to try the pre-amp. For some reason I assumed I'd be OK since I'm not aimed at the CN Tower. Live and learn. Hopefully I can sell this PA-18 and put the money into something else. Maybe a different tuner card, maybe a mast stand/base so I can put the mast anywhere on my (flat) roof. I might be able to sneak around that tree...

http://www.cogitech.ca/photos/chimney.jpg

http://www.cogitech.ca/photos/base.jpg

so now I got another 4228HD. stack far apart and point for 2 different signals. some what alright. but had problems. so I read that they should be a close as possible in the forum and the black plastic caps touching each other and pointing the same direction.
Hi Duesouth, from looking at the tvfool report you posted, you must be in southeast etobicoke?
You're so close to CN tower that overload from your pre-amp might be the problem. Too much signal and your tuner reduces its gain(agc) to protect itself.
If it were me, I'd try pointing one antenna (the top one) at NBC (153 degrees magnetic), and the other doesn't need to point at CN tower, you want about 1/2 way between toronto and buffalo, so that you only catch cn tower on a side lobe, try about 125 degrees magnetic.
As for spacing, I like the center of bottom bowtie 16" to center of top bowtie. Space them as if there was a bowtie missing between the two.
A more powerful pre-amp will only make overload worse.
Good Luck!!

Yep, he's at Lakeshore and Kipling: http://www.digitalhome.ca/forum/showpost.php?p=1092161&postcount=1142

1. and 3. no LOS to the cn tower. but if I had it 250 feet more south then yes I would have line of sight but I do get almost all local station. 41.1 is one that I do not get. but I get 41 in analog perfect picture.

2. yes I do get all of buffalo 2.1 comes in at 56% during daytime to 66% at nighttime. I seem to be also lock onto bativia station.

I do not see any advantage of me going above my roof line since it is to the north. I am already at 65 feet above the ground. I would then need go above 75 feet. this antenna is on non penetrating stand on my balcony with concrete blocks. I am thinking leverage. go to high and it might tip over with the wind here. it is pretty windy.

jeneral,

My 4221HDs are stacked (identical aiming) and pointed at South Buffalo. The stack works perfectly for all of Toronto and Grand Island. The trouble is (some of) the South Buffalo stations.

This tells me that the two antennas are working fine stacked like this (no cancellation, etc.). Correct me if I am wrong.

hello cogitech
I had a look at your tvfool, and am sad to relay the same things others have said regarding using a preamp in your setup. Attenuation could assist but you have a ton of high powered analog stations that will wreck havoc on the television AGC.
For example from my home here in London I introduced a channel 10 and FM trap. When I point to the Cleveland market the channel 10 (CFPL) is pretty much in the way. Before I introduced the trap the AGC would compensate for the strong signal of the CFPL tower and I would not get any Cleveland market stations in. Now all is good with the trap in place. FM stations are just as bad.
If you plan on adding more televisions to your set up like three (what I have) or four, the splitter would act as an attenuator. In this case it might actually help.

Best of luck,
Looking forward to reading your results

Mark

Thanks Mark,

So, if I installed an FM trap and traps for 5, 9, 19, 25, 41, 47 and 69, I'd be good to go with a low-power pre-amp? :D :rolleyes:

I think I am going to abandon the pre-amp idea entirely and try re-positioning my antenna to go "around" that stupid tree. The antenna is precariously mounted on my chimney as it is and if I put it on the other corner of my roof I'll have easy access to soft soil for my (yet-to-be-installed) grounding rod.

Lots of work to do. I may revisit other pre-amps or a different tuner later...

Duesouth,

Now I have better understanding of your situation and also know why 4228 helps in your location.

Digital channels requires LOS for stable reception.

The powerful beam of 4228 (compare to 4221) must have pickup most of Toronto channels (like CBC or CFTO etc) and 41.1 occasionally but you are at borderline with that channel. The RF of 41 can be picked up easily via signal 'bouncing' from nearby building - you are lucky.

One 4228 is good enough for all US/Hamilton channels, pre-amp maybe optional here.

Given that Toronto channels are broadcast from CN tower and your proximity to CN tower, here is my suggestion:

- Use a small antenna which has little wind load (e.g. CM4220, small yagi or even a home made 1 bay will do the job), extend the mast or somehow mount it in such a way to have LOS to CN tower.
- Will figure a way to combine the channels from two antennas later depending your receptions from Toronto.