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Old 25-Apr-2016, 9:20 AM   #41
chris1379
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Quote:
Originally Posted by rabbit73 View Post
That's normal; you are getting a reflection from the car. It's called dynamic multipath.
Thanks. I didn't know it was normal to get this from objects below the antenna
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Originally Posted by rabbit73 View Post
Yes, you are geting reflections off metal objects like the gutter, awning, and fence that can interfere with or enhance the direct signals. It's called static multipath.
Thanks. I had this one right.
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Originally Posted by rabbit73 View Post
There is no sense in trying another antenna yet until you have done the things needed with this antenna like grounding, filters, and another antenna location.
I tried a water pipe with no changes. I also drove a 4 ft. ground rod next to the antenna. It is connected to the ground block. This still doesn't make a difference in signal but it may have reduced the picture breakup on very weak signals.

The filters are homemade but are definitely working. The RCA converter can't detect the weak stations at all without one. I made one more 5-pole just to try it.

I am limited in location options but I have moved it all around the area shown. It is about 3 ft. closer to the metal pipe.

Quote:
Originally Posted by rabbit73 View Post
What is your present connection system?

Ant > grounding block > HLSJ > tuner ? You should get WOWK with that.
I do but that is the station most sensitive to positioning. I can manage a 35% signal and still get dropouts. My best most effective connection is Ant > grounding block > FM trap > amplifier > 160MHz High pass > tuner. The amplifier is actually the power supply part of the Radio Shack preamp mentioned earlier. If you look inside, there is low noise 10dB adjustable amp that is meant to supplement the outdoor part, which I don't have.

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Originally Posted by rabbit73 View Post
Once you have that you can try some experiments with an antenna with more gain, another filter, and a preamp for WCHS.

Ant > UVSJ > NF-471 > preamp > grounding block > power inserter > tuner

The antenna would be a UHF antenna with more gain like the 91XG

The UVSJ blocks FM and VHF-High but passes UHF

The NF-471 Notch Filter blocks UHF channels 24-29 to make 26 much weaker to keep the preamp from being overloaded by 26
I see. Level the signals as much as possible. I don't think 26 will be a problem. I only have a 60% signal because I am pointed away by 55 degrees. I think I will get a quality HLSJ and matching transformer, just for peace of mind.
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Old 7-May-2016, 11:10 PM   #42
chris1379
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Quote:
Originally Posted by rabbit73 View Post
Ant > grounding block > HLSJ > tuner ? You should get WOWK with that.

Once you have that you can try some experiments with an antenna with more gain, another filter, and a preamp for WCHS.

Ant > UVSJ > NF-471 > preamp > grounding block > power inserter > tuner

The antenna would be a UHF antenna with more gain like the 91XG

The UVSJ blocks FM and VHF-High but passes UHF

The NF-471 Notch Filter blocks UHF channels 24-29 to make 26 much weaker to keep the preamp from being overloaded by 26
I believe I can get WOWK reliably with the VU-75XR if I optimize its position for that channel. That means I need a UHF only antenna. You mentioned the 91XG. Would a 4 or 8 bay bowtie work also? If I need a preamp for UHF but not VHF, where is the best place to join them or should I amplify both? I do need to block FM from the VHF antenna. I don't think the NF-471 is needed on UHF and could hurt CH 23.

When I was looking around, I came across this In-line amplifier. Could this be used as a preamp if the antenna is much better than what I have?
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Old 8-May-2016, 2:06 AM   #43
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Quote:
You mentioned the 91XG. Would a 4 or 8 bay bowtie work also?
Probably, but WCHS is weak
Quote:
If I need a preamp for UHF but not VHF, where is the best place to join them or should I amplify both?
You can't amplify UHF for WCHS yet until you attenuate 26, because it will overload the preamp.
http://www.tvfool.com/?option=com_wr...f1f05778a90214
Quote:
I don't think the NF-471 is needed on UHF and could hurt CH 23.
It probably would hurt 23. That was ONLY for a test to see if WCHS was possible if you made 26 weaker before spending a lot more money on a Tin Lee custom bandstop filter to make ONLY 26 weaker.
Quote:
When I was looking around, I came across this In-line amplifier. Could this be used as a preamp if the antenna is much better than what I have?
That amp is not for you. You would need the Pico Macom PS10 Power Inserter/Power Supply, a DC block to keep the antenna from shorting the DC coming out of the input, and it would be overloaded by 26 with a signal power of -27.5 dBm even before adding antenna gain.
-27.5 dBm = 21.5 dBmV

Max input of the Tru-Spec LA-10 10 dB Coaxial IN-Line Amplifier = 14 dBmV

http://www.atvresearch.com/specinfo/la-10.pdf
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Last edited by rabbit73; 8-May-2016 at 11:32 AM.
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Old 16-May-2016, 12:35 AM   #44
chris1379
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I just wanted to post a quick update. I ordered a USB software defined radio so I can compare all of the signals at once. I'll also see if there's anything else I may not know about that could cause interference. I am also going to try a coat hanger antenna without a reflector just to see what happens. In the meantime, we have been watching WLPX-ION, CH39 which is 46th on my TV fool report at NM -39dB. Go figure.
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Old 27-May-2016, 5:09 PM   #45
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Well, since I have multiple threads going, I'm not sure where to post this. I got the SDR configured with RTLSDR scanner and found a surprise, but not a good one. It's a land mobile radio service on the same tower. Note, the FM stations are attenuated by 2 filters and a small amplifier is inline. I think I have to rethink my high pass filter. The calculated cutoff is 160MHz. I'm also including the FM band with no filters for comparison.




Attached Images
File Type: jpg landmobile.jpg (144.7 KB, 807 views)
File Type: jpg FM no filter.jpg (151.7 KB, 791 views)

Last edited by chris1379; 27-May-2016 at 5:13 PM.
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Old 5-Jun-2016, 9:26 PM   #46
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I'm back with an update. I now have a 4-bay M4 10x9.5 with a flat reflector. I have monitored my reception for a few days and it is much better with this antenna. One thing that still puzzles me is the fact that traffic and parked cars affect my reception. That means part of my signal is reflected from the street surface, right? I also have the huge hill that prevents LOS reception. I'm wondering if a slight tilt toward the top of the hill would help? By the way, here is what I am receiving on UHF. Note that CH26 is not the strongest channel because the antenna is not pointed that direction but that is constantly varying.
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File Type: jpg uhf w reflector 1024.jpg (168.8 KB, 326 views)

Last edited by chris1379; 5-Jun-2016 at 9:34 PM.
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Old 6-Jun-2016, 12:11 AM   #47
rabbit73
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Thanks for the updates, Chris. Your SDR is almost as good as a spectrum analyzer at finding interference to your TV reception. Is that signal at 152.48 MHz the land mobile? You do need to rethink a high pass filter, because a HLSJ isn't going to take it out. Maybe a coax stub and a "T" adapter can attenuate it enough.

I think you should also post your images on your AVS thread:
http://www.avsforum.com/forum/25-hdt...nton-ohio.html

Quote:
One thing that still puzzles me is the fact that traffic and parked cars affect my reception. That means part of my signal is reflected from the street surface, right?
Yes, you would notice it most with the moving vehicles.

Attached Images
File Type: jpg CarMP_1.jpg (84.8 KB, 733 views)
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Last edited by rabbit73; 6-Jun-2016 at 12:27 AM.
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Old 7-Jun-2016, 7:15 PM   #48
chris1379
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Quote:
Originally Posted by rabbit73 View Post
Thanks for the updates, Chris. Your SDR is almost as good as a spectrum analyzer at finding interference to your TV reception. Is that signal at 152.48 MHz the land mobile? You do need to rethink a high pass filter, because a HLSJ isn't going to take it out. Maybe a coax stub and a "T" adapter can attenuate it enough.

I think you should also post your images on your AVS thread:
http://www.avsforum.com/forum/25-hdt...nton-ohio.html

Yes, you would notice it most with the moving vehicles.

Interesting but I think some of my usable signal is from ground reflection. Could be wrong. But moving the antenna to a position as shown would require longer cable and possibly put the antenna more in the shadow of the tall college building across the street. It is pointed to the right of it now. At least with the SDR, I can try it with a laptop instead of moving a TV, lol. I wonder if there is a point at which the antenna height brings in better signals. 25 ft is the highest I had the other antenna and there was no sign of my weak channels between 17 and 25 ft.
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Old 10-Jun-2016, 2:54 PM   #49
chris1379
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I was looking at this site and the section on Ground Reflection explains a lot. Sometimes the ground reflections help and sometimes they hurt. They also vary with frequency. This graph shows what CH 41 (red arrow) looks like when I can't receive it.
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File Type: png Scan 470.0-650.0MHzCH8 CH13 bad arrow.png (147.3 KB, 323 views)
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Old 10-Jun-2016, 5:39 PM   #50
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Quote:
This graph shows what CH 41 (red arrow) looks like when I can't receive it.
Yep, that severe notch is going to be due to multipath due to one of its several forms, which is always due to having a blocked signal path and having to rely instead on various reflections which may arrive at the antenna in either and additive or a subtractive manner. That one is "subtractive" in the middle of that channel's bandwidth. Move the antenna a couple of feet in any direction and the received signals will change.
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