recomendations for improvements

[crickey7115]

I have recently moved and I now live about 71 miles outside chicago. I currently have an Antennas direct C4 mounted 30ft up on the roof and a Winegard LNA-200 preamp. My signal analysis is

http://www.tvfool.com/?option=com_wr...8e0354b20a60e6

I am currently pulling in WFLD with minor noise but no other channels in that direction. I would like to get the major networks. Would I benefit from upgrading the antenna to something like Solid Signal HD8200XL? any advice would be welcome.

Thank you

[rabbit73]

Welcome to the forum, crickey7115:

Please do another TVFOOL report using exact address (which will not show) or coordinates. We need a more accurate report because your zip report shows a very strong signal from WWTO that might be causing overload that will interfere with your reception of weak signals. Your FMFOOL report shows the same problem.



The HD8200XL also covers VHF-Low, real channels 2-6. You don't need that big antenna unless you must have those channels 4 and 6.

[crickey7115]

Thank you for a response. This is my report with coordinates.

http://www.tvfool.com/?option=com_wr...8e037f5f83209d

I am able to get most of the channels out of Chicago (northeast) after dark with my current set up. So I think with a slight upgrade of antenna I should be able to pull it in, but there are so many options its hard to narrow it down.

[rabbit73]

Thanks for the new report. Your old report puts you in Ottawa IL near the Walmart and Goodwill N of 80. Your new report puts you near the aqueduct where it crosses the Fox River, if I did the estimate right.

The FM report looks better as interference goes, but the TVFOOL report looks a little worse because WWTO looks even stronger and your weak signals are a much weaker. The greater difference between the strongest and the weakest means that it becomes more difficult to receive the weak ones.

The strong signals will overload a preamp and create spurious signals in the preamp that will wipe out the weak signals.

WWTO has a Noise Margin of 69.9 dB, which puts it in the Possible Overload category. If you add the antenna gain of 10 dBd (12 dBi) it is now at 79.9 dB NM in the Overload category. If you then add the preamp gain, the tuner is probably overloaded.



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

Have you grounded the coax and the mast?

The coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.

Notice that I have put "to reject interference" in bold type to keep WWTO from causing any more interference than necessary. It can get directly into the TV cabinet and it can get into the plastic case of the preamp.

This is not an easy problem to solve. Are you willing to try some experiments? The experiments will tell us what is possible to tame WWTO with what you have, or if a custom filter from Tin Lee will be necessary.

[crickey7115]

I am definitely willing to experiment. I have an electronics degree and have been fiddling with various electronics since birth, I think. I will ground everything to make sure it is safe and as clean as possible. I would love to just filter that channel out I had a hard time with noise at my previous home that I never really solved it was about 5 miles from WWTO. If there is any websites you could give for more research please let me know.

[rabbit73]

I am definitely willing to experiment.

Good; I have a few ideas that might be worth trying. I'll start with the easy inexpensive ones first.

have been fiddling with various electronics

I have been doing antenna experiments since I was 8, when I built my first crystal set radio. I have been a ham radio operator since the early '50s, and built many ham antennas, especially for mobile DX operation. My call signs:
W4...
ex-W2...
ex-DL4.. when is was in the US Army in Germany

I worked with electronic equipment for the US Government. Since I retired I have helped posters with their reception problems on four forums for the past 7 years, and I'm still learning.

I am currently pulling in WFLD with minor noise but no other channels in that direction.....I had a hard time with noise at my previous home that I never really solved it

Can you tell me what you mean by noise; is it electrical interference from power line noise or something else?

I would love to just filter that channel out.....I never really solved it was about 5 miles from WWTO.

OK, let's start with that, since it is your biggest problem. What I want you to do is to insert, using the high and common ports, 1 or 2 UVSJs between the C4 and the input of the preamp. This will attenuate WWTO on real channel 10, and 4, 6, and 12 which will block CBS for the test. I want to know if limiting the C4 to UHF only (real channels 14-51) will work. The UVSJs will also block FM interference for the test.
http://www.solidsignal.com/pview.asp?p=zuvsj
http://www.3starinc.com/uvsj_uhf_vhf...or_joiner.html
http://comingsoon.radioshack.com/vhf...l#.ValMzjjbJLM very slow link
http://mjsales.net/products/tru-spec...ant=1198505857
http://www.nsccom.com/browseproducts/UVSJ.html

C4 > UVSJ (1 or 2) > preamp > coax > power inserter > TV

The reason why I think 2 UVSJs might be necessary is because WWTO is 73.0 dB stronger than WFLD Fox, your strongest Chicago channel and 82.4 dB stronger than WCPX Ion, your weakest Chicago channel. The UVSJ is rated at ~25 dB attenuation, they usually do better. It doesn't need to completely eliminate WWTO, just attenuate it.
http://www.hollandelectronics.com/ca...-Diplexers.pdf

If there is any websites you could give for more research please let me know.

I can give you links for further information if you tell me the topic you are interested in. I can also bore you with several long posts about overload, from what I have learned.

I now live about 71 miles outside Chicago.

The curvature of the earth starts to affect TV signals at about 70 miles. You can see the black arc, below the gray, at the bottom of the transmitter profile; see attachment. If you click on a callsign in your tvfool report, it will show you the profile. The transmitter is at the left end, your location is at the right.

[crickey7115]

I have the USVJs on order and I will keep you updated with the results. I am very grateful for your experience and your help, thank you. I should have paid a little more attention in my antennas class in college .

[crickey7115]

I have installed the USJVs. The quality improved slightly but during the day the signal is still pretty low. I do still receive wwto even with the attenuation. I found out I don't even need an antenna to pull in wwto. I had the cable disconnected and the signal still came through perfectly, I thought that was a little strange. Do you think a large yagi style antenna might pull in the signal better?

[rabbit73]

Thanks for the report.

I do still receive wwto even with the attenuation.

You don't need to eliminate it completely, just weaken it a lot. How much attenuation did you use and with what attenuators?

Is this the setup you used?

C4 > UVSJ > UVSJ > attenuator > LNA-200 > coax > power inserter > TV

I found out I don't even need an antenna to pull in wwto. I had the cable disconnected and the signal still came through perfectly, I thought that was a little strange.

That's not strange, it's normal. If the coax is not connected to the TV, then the TV tuner isn't grounded, and WWTO can get directly into the TV cabinet.

In order to keep the very strong WWTO from interfering with the reception of your weak signals the coax must be grounded with a grounding block that is connected to the house electrical system ground, and the coax must be connected to the TV. In other words, there must be a continuous shield from the antenna all the way down to the TV.

Do you think a large yagi style antenna might pull in the signal better?

It might make the weak 2Edge signals from 62 degrees magnetic a little stronger, but it might also make WWTO a little stronger.

You not only need to make the weak signals stronger, you also need to make WWTO weaker to reduce the difference between the two.

WWTO is in the opposite direction from your weak desired signals. If a yagi had a better front-to-back ratio than the C4, it would help.
for UHF only, but will pick up strong VHF
https://www.antennasdirect.com/cmss_...-sellsheet.pdf
https://www.antennasdirect.com/store...V-Antenna.html
https://www.antennasdirect.com/cmss_...y/91XG-TDS.pdf
for UHF and VHF
http://www.winegard.com/kbase/uploads/HD7698P.pdf

If you substituted an Antennas Direct Juice preamp, which is highly resistant to overload and has a metal case, for the LNA-200 preamp, it might tolerate WWTO better.

It is possible to order a special filter to make WWTO a lot weaker without making your weak signals too weak from its insertion loss, but if the two UVSJs don't make it weak enough during the test with the coax grounded, I doubt that the custom filter would do any better.

If WWTO still gets into the TV with the coax grounded, the only thing left to try is exotic measures like the TV in a screened enclosure (Faraday Cage) that is grounded, with a small viewing opening in the front. The antenna coming in the rear with an F-81 feed thru adapter, and the AC power coming thru with a chassis RF filter. If the viewing opening still lets in too much WWTO, you could insert a piece of low-E glass which would block interference from WWTO but let you see the TV screen.

Originally Posted by rabbit73

Extreme measures are sometimes necessary, even if your equipment is operating properly, if you have very strong EMI.

John Stanley, K4ERO, was able to operate a ham station when he was living at the transmitter site of HCJB in Quito, Ecuador. A 40 meter dipole collected enough RF to light a 100 watt bulb. See Front-End Overload, A Worst Case Example on p214 of The ARRL Antenna Compendium, Vol. 3.

This is where the quad loop antenna was invented (patent no. 2,537,191) by Clarence C. Moore, W9LZX, because of problems with corona discharges from the previous four-element antennas that were fed by high power transmitters located at 10,000 feet altitude in the Andes. The aluminum elements got so hot that pieces melted and fell to ground.
Quad antenna - Wikipedia, the free encyclopedia

http://www.digitalhome.ca/forum/186-...ml#post1307146

Did you aim the C4 at 62 degrees magnetic for the test?

Was the coax grounded to the house electrical system ground with a grounding block for the test?

Before I suggest a different antenna with more gain and maybe better front-to-back ratio, a different preamp that is more resistant to overload, or a special filter, I want to be sure about your test setup.