Help Receiving Jacksonville Stations

[Frank.Mondo]

Looking for help or answers with Jacksonville Reception.


I have a Winegard HD8200U atop a 41 foot Channel Master mast connected to a Channel Master CM-777 preamplifier. This antenna points South from my location. I also have an Antennacraft HBU55 on the same mast pointed towards Savannah. Both antenna feed one line and connect to a EDA-FT Signal Booster/Amplifier in the house.

The Winegard gives reliable reception of most southerly channels (Jacksonville) as the sun sets until the next morning but then no reception during the day. Can anyone tell me why this day time loss occurs and also advise on how to continue to get the channels that I have at night and lose again each morning?

My TV Fool report is as follows:
http://www.tvfool.com/?option=com_wr...8e03a56b5ee15b

Thanks for any insight Frank

[rabbit73]

Welcome to the forum, Frank:

Both antenna feed one line

How are you combining the two antennas?

With two amps and strong signals there might be some overload which would create IMD spurious products that would wipe out weak signals.

Channel Master CM-777 preamplifier

Which 7777 is it, the old one with 2 antenna inputs, or the new one with one combined input for UHF and VHF?

The Winegard gives reliable reception of most southerly channels (Jacksonville) as the sun sets until the next morning but then no reception during the day. Can anyone tell me why this day time loss occurs and also advise on how to continue to get the channels that I have at night and lose again each morning?

Which channels in particular by callsign?

[Tim]

You are very lucky to be getting signals out of Jacksonville at all due to the curvature of the earth. That must be about 100 miles south of "Speed Trap City". You must be receiving those Jax stations via tropospheric ducting.

[Frank.Mondo]

Thanks for the reply, here are answers to your questions:

Both antenna are connected to a splitter via lines that are equal in length. The combined signal feeds the CM-7777.

The CM-777 is the newer one, has one input and one output.

The following channels we would like to receive all the time are WJXT, 4.1; WJXX, 25.1; WFDX, 30.1. These and others come in fairly good at night.

Frank

[Frank.Mondo]

Tim

I looked up tropospheric ducting and you may be on to some of the problem.
We have had this setup since January. As the weather warmed up we have been getting better reception at night. Winds from the south also help reception. According to the weathermen, our weather will be dominated by a high pressure system bring winds from the N and NE. I'll monitor night time reception and get back to you.

Frank

[rabbit73]

Both antenna are connected to a splitter via lines that are equal in length. The combined signal feeds the CM-7777.

Not a good idea, because when the same signals arrive at the combining point, they will interfere with each other if they are not in phase. But it gets even worse: if you have two different transmitters on the same channel because of co-channel assignment, they will interfere with each because they are bypassing the F to B ratio of your two antennas aimed in different directions.

Equal length lines are only required when you have two identical antennas aimed in the same direction for more gain. It's irrelevant in your setup.

Tim is correct. The curvature of the earth begins to block signals at about 70 miles, and Tropo signals will never be reliable.

The following channels we would like to receive all the time are WJXT, 4.1; WJXX, 25.1; WFDX, 30.1. These and others come in fairly good at night.

WJXT, real channel 42, virtual channel 4.1, NM -14.1 dB, 174 degrees true; co-channel interference from WJBF, real channel 42, virtual channel 6.1, NM -14.7 dB, 357 degrees true
WJXX, real channel 10, virtual channel 25.1, NM -14.9, 174 degrees true; co-channel interference from WALB, real channel 10, virtual channel 10.1, NM -20.5 dB, 259 degrees true
WFDX, real channel ? I don't see that. If you mean WFOX, it has the same problem with WPGA.

A signal must have a Noise Margin of at least 0 dB to be received. You can add the antenna gain to the NM figure on the TVFOOL report, and you can also add the gain of your preamp, but must subtract the NF of the preamp because it adds its own noise that reduces the SNR of the weak signal.



Interpreting Noise Margin in the TV Fool Report
http://www.aa6g.org/DTV/Reception/tvfool_nm.html

The NM of your strongest signal WTGS is 56.5 dB. If you add the preamp gain of 30 dB, that brings you up to 86.5 dB before adding DA gain and subtracting distribution losses; clearly overload territory for the preamp and tuner.

Two or more of your strongest signals can create spurious signals from Intermodulation Distortion (IMD) that can wipe out your weakest signals.

You have some strong local FM signals that might interfere with TV reception. See attachment 2. The FM trap in the 7777 probably will take care of them if they aren't too strong. FMFOOL reports don't link like TVFOOL reports. You can run your own FMFOOL report using your exact address here:
http://www.fmfool.com/

[Frank.Mondo]

Rabbit73,

I climbed up and my antenna tower and rewired so that my Jacksonville Antenna connects to the CM-777 and then connects to one leg of the splitter. The Savannah Antenna connects to the other leg of the splitter. The combined signal connects to the house.

Currently, we lost all Jacksonville stations and ION out of Brunswick GA. Signal strength of Savannah stations which were in the high 80's to mid 90's are now in the mid 50's and less.

Frank

[rabbit73]

That doesn't sound very good.
It sounds like the power for the preamp can't get through the splitter.
I would need to see a diagram.

[rabbit73]

Is this the setup you have been using?

8200U >
       \
        splitter > 7777 > coax > power inserter > EDA-FT Amp > ?
       /
HBU55 >

[Frank.Mondo]

Yes, that was prior to last night.

Frank

[Frank.Mondo]

Now its:

8200U > 7777 >
\
Splitter > EDA-FT AMP
/
HBU55 >

Frank

[rabbit73]

Is this the way it is now?

8200U > 7777 > 
              \
               Splitter > coax > power inserter > EDA-FT AMP > TV
              /
       HBU55 >

You have lost amplification for the HBU55.

Is the splitter that you are using as a combiner an ordinary splitter, or a power passing splitter?

[Frank.Mondo]

Rabbit73

Yes

Frank

[Frank.Mondo]

Rabbit73

Just an ordinary splitter

Frank

[rabbit73]

Sorry I didn't answer sooner, my wife isn't well and I had to get the nurse.

Your preamp isn't getting any power, and you might have created a short for the power supply and power inserter.

The best setup to prevent interaction between the two antennas is to keep them separate, each with its own preamp, coax downlead, power inserter, and power supply. You would then select which antenna to use with an A/B switch. Your tuner would need to be able to add a new channel after scan, like a Sony, so that you wouldn't have to rescan after each change of antenna.

If your TV is not able to add a channel after scan, you could connect the primary antenna to the antenna input of the TV, and the secondary antenna to a separate tuner. The output of the tuner would connect to the A/V or HDMI input of the TV.