Changing SNR
 

I put up a CM 2020 and got just about what the signal analysis stated but every now and then my SNR drops from 26 to 11 or 12 (on channel wnep) and then right back for no apparent reason. No clouds or rain, just drops out. Channed 56 (wolf wont even come in to be watchable. I know my diplexor cost me a few DBs and when I add the 4 way slpitter even more Dbs (about 8 to 10 total) but I don't understand the sudden drop off. What would be my best solution?

http://www.tvfool.com/?option=com_wr...e779c2bcd9a205

Multi-path interference usually manifests itself that way.

Is the diplexer for satellite system integration or another OTA antenna? What's the make/model of the diplexer?

How well does the system operate when only one TV is connected, with no diplexer or splitter in the cable run?

Experimentation with antenna location & aim would be the next logical step.

I'm not real clear on multipath interference but all my primary transmitters are all in one place, 22, 28, 16, 56, 44, 64, all 19 miles away. The only one not there is 38, wswb off the right side (about 90 degrees) which comes in with no issue...(only 4 miles away).

Tv Reception.
 

The following is a Teleview Tv Reception Recommendation.

Aim the CM2020 antenna at about 229 degree magnetic compass direction for the reception of ,

WOLF-DT REAL UHF channel 45 , virtual number (65.1) FOX.

WVIA-TV REAL UHF channel 41 , virtual number (44.1) PBS.

WNEP-TV REAL UHF channel 50 , virtual number (16.1) ABC.

WYOU-DT REAL VHF channel 13 , virtual number (22.1) CBS.

WBRE-DT REAL VHF channel 11 , virtual number (28.1) NBC.

W43CO-D REAL UHF channel 43 , virtual number (x) Religion.

_________________________

With the CM2020 antenna aimed at about 229 degree magnetic compass direction are these Digital Tv stations channels also received??

WQPX-DT REAL UHF channel 32 , virtual number (64.1) ION TV.

WSWB-DT REAL UHF channel 31 ,virtual number (38.1) CW.

W47DH-D REAL UHF channel 47 , virtual number (x) PBS.

W14CO-D REAL UHF channel 14 , virtual number (x) ABC and Antenna Tv.

______________________________

Connect the CM2020 antenna to the Tv with No diplexer , No splitters , and only one Tv.

Scan for Digital Broadcast Tv stations channels , what is reception like now??

As always , trees and tree leaves do a real fine job of reducing and blocking reception and so buildings and other obstructions.

The diplexors are Turk ref # BDS-p1. They are used to combine and split ATCS and Satellite signal.
When I connect the OTA antenna directly without the diplexor I get about 1 db more which equates to 1% signal on my Sony Bravio TV signal meter.
When I put the 4 way splitter in it drop down about 4 Dbs more and the second diplerxor gets it down a total of about 8 db making 56 (wolf-fox) unreceivable at 72% on the Sony meter and my sat receivers.

The antenna was pointed using information here and a protable TV. I do however have some concerns. My report says 2 edge transmitter which I'm told don't point at the transmitter point to the right or left. I'm pointed right at the transmitter b/c if I go 5 degrees left or right my signal fails all together.

This antenna is 30% smaller than the Ratshack I had at 120" boom. It was also on the front porch roof and pointed in a different direction for best signa. (about 30 degrees) The new antenna is on the back second floor fire escape with 10' mast so antenna is at the third floor level. I'm using RG6 cable about 70 to 80 feet. Any help would be good.

That's were I'm pointed. I'm just about 200 to 300 feet lower than the horizon meaning there is no direct line of site. That is why the over size antenna for transmitters only 19 miles away. There are no trees, no houses, nothing in the direct line of my antenna.

Tv Reception.
 

The following is a Teleview Recommendation for Tv Reception.

Install a Antennas Direct CPA-19 preamp , No diplexers , No splitters , connect 1 Tv only.

What is reception like now??

http://www.solidsignal.com , http://www.amazon.com.

Thanks teleview, groundurmat and adtech for your help and advice. The preamp with only 1 tv and no diplexors was out f the question for 2 reasons. I need all my stuff connected and It wasn't I was not getting these channels but the sudden drop out. They all played most of the time clearly but every now an then would drop from 80% to 29% and right back..My weakest channel Fox 56 uhf 45 had the lowest signal @ 72 to 75 % but played with less distortion than wnep @ uhf 50. So I disconnected everything and tweeked the antenna pointing coming up with 78% on Fox 56 but losing 2% on wnep. Even thought I lost 2% it played better...less pixelation and freezing....a lot less. wyou also lost signal but just a small amount. I'm re pointed to the far left of center. It took about 3 hrs moving the antenna 1/4 " on the mast about an " on the element. Also when I added the diplexors back in I checked at every step and ended up replacing the Turk's with RCA's and saving more DB's. Now with everything in place including the cheap arse ratshack slpitter I have steady signal for now. Further testing is needed but I beleive at this point a powered distibution module will be good. CM makes a 4 port with 8db gain that should work...Thnaks again for your feed back.

The CM-3414 and the CM-3410 which it's based on are very good distribution amplifiers. As with any amplifier, they can't compensate for the negative effect on SNR caused by cable, diplexer and splitter losses on the input side of the amplifier.

In other words, the CPA-19 preamp installed at the antenna would be the best option. An amplifier installed down stream of the second diplexer will not overcome the SNR hit of the cable or diplexer losses from the antenna to the input of the amplifier.

Thanks for the feed back. I have 1 question on the preamp side vs the distribution amp side. I Rent and have a set # of holes/cables coming into the apartment. The distribution amp can be added inside with just 1 diplexor before it. Using existing cabling the preamp would still have to share that diplexor (being the power amp would be inside) and I'm not sure how removing the DC blocker from the Turk diplexor would affect my satelite LNB power and or the TV preamp power being they are sharing 1 cable for a time. The RCA diplexors are built in DC block and cannot be changed were as the Turk diplexors have an additional adaptor to block DC power. Once I remove them I don't know what power (LNB or preamp) will go where or affect what. I agree the preamp is the better solution but to do it right I would need to drill another hole in the Landlords house and then split my TV signal 4 ways inside.

Does this affect what you recommend?

Tv Reception.
 

http://The following is Teleview Rec... Tv Reception..

Here are distribution amplifiers , CM3410 , CM3412 , CM3414 , http://www.channelmasterstore.com.

You can decide what will work the best.

Does anyone know if the CM 3414 will work with a preamp if needed?

Only if you are careful to avoid over driving the second amplifier in line and also avoid over driving the tuners.

A general rule of thumb is: One amplifier can be too many, Two amplifiers are too many.

It's rare to find a home installation that has enough legitimate* distribution losses to justify two amplifiers. However, there are times when more than one amplifier is needed. For example, if all signals are weak to begin with and you are distributing to more than eight TVs, you may need to use a preamp feeding a passive splitter which then feeds multiple distributions amplifiers.

In your case, the 17 dB gain of the CPA-19 is more than enough to overcome the cable, diplexer & splitter losses and still provide help with tuners that have poor noise figures.

I would install the CPA-19 at the antenna and try running with only a passive splitter.

But... you have the problem of getting power to the preamp... that may well force you to settle for using only a CM-341X. With this option you are at least dealing with the loss of the splitter and cables between the splitter and TVs. (Of course, remove any existing passive splitters and use the integral splitter in the CM-341X.)

* There are plenty of improperly wired installations that have more loss than necessary. In some cases the real problems may be masked by the addition of an extra amplifier, but the overall system performance could be improved if the wiring problems were corrected and the extra amplifier was removed.

Tv Reception.
 

The following is a Teleview Recommendation for Reception of Broadcast Tv.

I was and am not recommending using a preamp and distribution amp at the same time.

I am thinking there are some wiring issues that require correcting.

If using the preamp , install All parts of the preamp (the preamp , the power supply , the power injector) before any diplexers or splitters or anything else that can block the signal or power.

If using the CM3410 distribution amp , install it before any diplexers or splitters or etc.