Chattanooga TN: Got Atlanta But Few Locals - AVS Forum
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post #1 of 89 Old 11-11-2011, 05:17 PM - Thread Starter
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Hello, all:

I've moved into an apartment on the eastern slope of Missionary Ridge in Chattanooga. Not far from the top of the ridge, but on the eastern side.

http://www.tvfool.com/?option=com_wr...4bbaa60ba6c757

My Digitenna DUV-XF is out on the deck, aimed in a southeasterly direction. I get reliable reception out of:

WNGH-33 (18-1) PBS
WSB-39 (2-1) ABC/MeTV
WAGA-27 (5-1) FOX
WGCL-19 (46-1) CBS
WPXA-51 (14-1) ION

(WUPA and WATL are present as well but trampled by local analogs.)

The puzzle to me is that I don't get anything else. Now, I have some partial explanations. I know that I am slightly below the ridge, and I know that the building has some foil-backed insulation in it. I also know that I'm looking through the building at the local signals.

But what's odd is that I have tons of signal from the Chattanooga stations, but nothing decodes. I hooked up my spectrum analyzer and, for example, WELF-16 (23-1) looks pretty strong and very rectangular. Yet my HDHomeRun won't even try to decode it, nor will my analyzer, nor will any of my other tuners. With very careful placement I can often get one or two of them to pop up at a time, but then I lose everything else (except WNGH).

If I go outside and stand at the southwestern corner of the building, all the Chattanooga signals come in fine on my Silver Sensor, even though the signals look essentially the same on the analyzer as they do on the DUV-XF on the deck. On the DUV-XF, I can look at the analyzer and see WSB-39 next to WDSI-40 and see WDSI is about 10 dB stronger (HDHR: 100% strength 0% quality) but fails to decode while WSB is fine (HDHR: 90% strength 75% quality).

I'm really not sure what to do at this point. I've got my Silver Sensor sitting in my bedroom in a position where it gets WFLI, WDSI, and WYHB-LD and nothing else (except WNGH) right now. I'd really like to have the locals available to me without moving the antenna around constantly. I don't mind having a separate aim for Atlanta versus Chattanooga, I just don't want one aim for Atlanta and eight for Chattanooga.

Here's my reception: http://www.rabbitears.info/dxlocation.php?id=265

Anything noted in green I have decoded cleanly in at least one position.

Any thoughts? Any extra information needed?

- Trip

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post #2 of 89 Old 11-11-2011, 07:16 PM
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So I guess you may not be able to get WXIA 11 Alive from Atlanta, so hopefully you can get NBC from Chatanooga. Maybe set up an A/B switch for each market and try something like a Clearstream 1 or 2 for Chatanooga. What type of preamp? And I guess you're not in Virginia anymore?
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post #3 of 89 Old 11-11-2011, 07:23 PM - Thread Starter
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Quote:
Originally Posted by tylerSC View Post

So I guess you may not be able to get WXIA 11 Alive from Atlanta, so hopefully you can get NBC from Chatanooga.

I haven't had any success with it yet, but the DUV-XF isn't a great VHF antenna anyway.

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Maybe set up an A/B switch for each market and try something like a Clearstream 1 or 2 for Chatanooga. What type of preamp?

I'm using my Kitztech KT200, but I get the same results whether I have the amp in the line or not, except without it WSB becomes weaker and WAGA/WGCL stop decoding.

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And I guess you're not in Virginia anymore?

Nope. An announcement will be forthcoming.

- Trip

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post #4 of 89 Old 11-11-2011, 07:31 PM
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Does the spectrum analyzer show multipath? Sure sounds like that is your problem.

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post #5 of 89 Old 11-11-2011, 07:34 PM - Thread Starter
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No, that was my first guess. The signals look really good as far as I can tell. They just refuse to decode.

When I find my serial cable in my still-to-be-sorted pile of luggage, I'll try to get some snapshots. Maybe someone else will see something I don't. Fresh pair of eyes and all that.

- Trip

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post #6 of 89 Old 11-11-2011, 08:10 PM
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The only thing I can think of is overload. The DUV-XF is a pretty high-gain antenna, and you have it hooked up to an amplifier.

I'll go ahead and second the ClearStream recommendation. They sell a bundle with a VHF antenna add-on. That or diplex in (without an amplifier!) a separate VHF antenna.

I assume you figured out how to not get stuck with your username.

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post #7 of 89 Old 11-11-2011, 09:01 PM - Thread Starter
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Quote:
Originally Posted by Davenlr View Post

Does the spectrum analyzer show multipath? Sure sounds like that is your problem.

Here's what the spectrum analyzer shows.

http://www.rabbitears.info/specan/chatt/

Out of all of those snapshots, only RF channels 19, 27, 33, 39, and 51 decode.

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Originally Posted by cgmv123 View Post

The only thing I can think of is overload. The DUV-XF is a pretty high-gain antenna, and you have it hooked up to an amplifier.

I thought about overload, but the strongest signal I have is WNGH and it's only 10 dB stronger than my strongest signal was in Virginia. Other than WDNN analog, nothing else is stronger than signals I'm used to seeing.

Quote:


I'll go ahead and second the ClearStream recommendation. They sell a bundle with a VHF antenna add-on. That or diplex in (without an amplifier!) a separate VHF antenna.

I may look into a separate VHF but I'm not really looking to spend too much money if I can help it. My VHF bowtie hasn't helped; I tried.

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I assume you figured out how to not get stuck with your username.

I have thought about it... I'm tempted to leave it alone.

- Trip

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post #8 of 89 Old 11-11-2011, 09:24 PM
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Quote:
Originally Posted by Trip in VA View Post

Here's what the spectrum analyzer shows.

http://www.rabbitears.info/specan/chatt/

Out of all of those snapshots, only RF channels 19, 27, 33, 39, and 51 decode.

I thought about overload, but the strongest signal I have is WNGH and it's only 10 dB stronger than my strongest signal was in Virginia. Other than WDNN analog, nothing else is stronger than signals I'm used to seeing.

I may look into a separate VHF but I'm not really looking to spend too much money if I can help it. My VHF bowtie hasn't helped; I tried.

Since your spectrum analyzer isn't being effective, can you ship it up to Wisconsin so I can confirm my fears about multi-path?

Jokes aside, your analysis looks solid. This is truly an enigma. Your situation screams multipath, but that's obviously not the case. I should apologize, I'm not that familiar with spectrum analyzers. Can your analyzer do it's own noise margin calculation? TVFool doesn't take buildings into account. I find it hard to believe that foil-backed insulation and other building materials would cause that much loss, but you never know.

I wonder if it's time to start thinking about defective equipment.

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post #9 of 89 Old 11-11-2011, 09:39 PM - Thread Starter
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Quote:
Originally Posted by cgmv123 View Post

Since your spectrum analyzer isn't being effective, can you ship it up to Wisconsin so I can confirm my fears about multi-path?

Hehe, keep an eye out on eBay, they pop up every now and then for a few hundred dollars.

Quote:


Jokes aside, your analysis looks solid. This is truly an enigma. Your situation screams multipath, but that's obviously not the case.

That's why I posted. I really don't get it.

Quote:


I should apologize, I'm not that familiar with spectrum analyzers. Can your analyzer do it's own noise margin calculation?

Mine will do an MER (SNR) calculation, but only if it can successfully decode the signal. So WNGH and WPXA are >36 dB, haven't checked Atlanta, and the rest don't decode so I don't have a number for them.

Quote:


TVFool doesn't take buildings into account. I find it hard to believe that foil-backed insulation and other building materials would cause that much loss, but you never know.

I would expect them to either knock the signal down a lot, create lots of multipath, or both. I don't see much multipath or much signal being knocked down. As far as the latter, I think it's less than 20 dB worth and still enough for a decode under normal conditions anyway.

Quote:


I wonder if it's time to start thinking about defective equipment.

I had the UHF section of one tuner die on one of my HDHomeRuns before and had to ship it back under warranty, but this is every tuner I've tried (HDHR both tuners, Aero-M, Pinnacle 800i, WinTV-D), every coax I've tried, and every antenna I've tried (DUV-XF, DUV Vii, Silver Sensor, VHF bowtie, paperclip); all seem to have the same issue.

- Trip

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post #10 of 89 Old 11-11-2011, 10:01 PM
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Quote:
Originally Posted by Trip in VA View Post

Hehe, keep an eye out on eBay, they pop up every now and then for a few hundred dollars.

I don't need a spectrum analyzer to figure out what to do. What I hope is the right antenna (ClearStream Convertible) is on order from Amazon. Too bad your situation isn't that easy.

Quote:


That's why I posted. I really don't get it.

Nor do I. 'Nuff said.

Quote:


Mine will do an MER (SNR) calculation, but only if it can successfully decode the signal. So WNGH and WPXA are >36 dB, haven't checked Atlanta, and the rest don't decode so I don't have a number for them.

I would expect them to either knock the signal down a lot, create lots of multipath, or both. I don't see much multipath or much signal being knocked down. As far as the latter, I think it's less than 20 dB worth and still enough for a decode under normal conditions anyway.


That sounds like it might be interference. I don't know from what, though, since I'm about 600 miles away from you. I know the spectrum analyzer is supposed to show that and of course, you already ruled that out, but I'm just trying to keep hope in this thread. Keep it from blowing our minds. This is becoming increasingly frustrating.

Quote:


...paperclip...

Well, there's your problem! I do have a story about paperclip antennas, but since I don't think it will help you, I'll keep it to myself.

Quote:


I had the UHF section of one tuner die on one of my HDHomeRuns before and had to ship it back under warranty, but this is every tuner I've tried (HDHR both tuners, Aero-M, Pinnacle 800i, WinTV-D), every coax I've tried, and every antenna I've tried (DUV-XF, DUV Vii, Silver Sensor, VHF bowtie, paperclip); all seem to have the same issue.

Let's see, is that 3 of my ideas that haven't worked now?

I'm going to go sleep on this now. Hopefully, I'll wake up and you'll have perfect ATSC reception. Wishful thinking.

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post #11 of 89 Old 11-11-2011, 10:35 PM - Thread Starter
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Quote:
Originally Posted by cgmv123 View Post

I don't need a spectrum analyzer to figure out what to do. What I hope is the right antenna (ClearStream Convertible) is on order from Amazon. Too bad your situation isn't that easy.

Haha, indeed.

Quote:


That sounds like it might be interference. I don't know from what, though, since I'm about 600 miles away from you. I know the spectrum analyzer is supposed to show that and of course, you already ruled that out, but I'm just trying to keep hope in this thread. Keep it from blowing our minds. This is becoming increasingly frustrating.

I thought about interference as well and I couldn't figure out what would impact stations from one direction but not another. I thought about cable leaks but I don't see anything on the spectrum analyzer that would indicate cable leaks.

Quote:


Let's see, is that 3 of my ideas that haven't worked now?

Nothing wrong with covering every possibility, particularly with something this puzzling.

Quote:


I'm going to go sleep on this now. Hopefully, I'll wake up and you'll have perfect ATSC reception. Wishful thinking.

Hehe, nothing wrong with that. I will hope for the same!

The more I think about it, the more I think it has to be something related to the building. I've changed everything else. I'd just like to know what it could be; maybe there's something I could do about it.

I'm considering trying to find a way to run coax to the front porch right near where I tested earlier today and got good reception. I could hide the antenna under the porch perhaps, just not sure what I'd want to put there that could get muddy or whatnot.

- Trip

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post #12 of 89 Old 11-12-2011, 06:34 AM - Thread Starter
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I left my HDHR sitting on channel 10 while I slept last night and at some point, WXIA did decode. So since it did decode, I'm guessing that might be feasible with the right antenna at some point. Of course, since I watch nothing on NBC, it's down the priority list at the moment.

- Trip
LL

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post #13 of 89 Old 11-12-2011, 08:44 AM
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If it's related to the building, see if any of your neighbors know what a TV antenna is. They may be having similar issues.

Try leaving your HDHR on 13 and seeing if WRCB is able to decode. If you have time on your hands, just move down the list.

If you have a laptop, take your antennas and HDHR up on the roof and see if that helps. That should confirm if it's the building or not.

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post #14 of 89 Old 11-12-2011, 09:11 AM
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Quote:
Originally Posted by Trip in VA View Post


But what's odd is that I have tons of signal from the Chattanooga stations, but nothing decodes. I hooked up my spectrum analyzer and, for example, WELF-16 (23-1) looks pretty strong and very rectangular.

Any thoughts?

- Trip

With that DC to light spectrum analyzer , how far have you scanned? Could there be narrow band noise hitting those channels only, either by harmonics or intermod.

Is there a MATV in your building leaking ... yeah, the analyzer should determine that ... but ... have you scanned with a whip of simple loop rather than a real antenna?
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post #15 of 89 Old 11-12-2011, 09:29 AM
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Quote:
Originally Posted by gbynum View Post

With that DC to light spectrum analyzer , how far have you scanned? Could there be narrow band noise hitting those channels only, either by harmonics or intermod.

Is there a MATV in your building leaking ... yeah, the analyzer should determine that ... but ... have you scanned with a whip of simple loop rather than a real antenna?

I was thinking of a building broadcast when I mentioned interference. I think certain stations are paying his landlord to interfere out their competitors. CONSPIRACY ALERT!!!!

This is another situation where asking around would help tremendously.

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post #16 of 89 Old 11-12-2011, 11:54 AM
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Quote:
Originally Posted by Trip in VA View Post

Here's what the spectrum analyzer shows.

http://www.rabbitears.info/specan/chatt/

Out of all of those snapshots, only RF channels 19, 27, 33, 39, and 51 decode.

- Trip

I lose most of my TV channels when my neighbor runs his dirty (electrically) lawn mower. You may have interference due to impulse noises similar to sparking. Is it possible for you to set up your spectrum analyzer to a single frequency without any TV signals, then monitor the noise level as you move your antenna about the room?
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post #17 of 89 Old 11-12-2011, 04:34 PM
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Hi Trip!
Hope that you are doing OK.
Looking forward to reading about your latest adventures.

+1
I also suspect broadband RF interference being radiated inside the building.

Time to try a VHF rcvr with AM again.

Did you ground the coax?

73,
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post #18 of 89 Old 11-13-2011, 03:49 AM - Thread Starter
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Hey folks,

Sorry for my delayed response. Burned myself out moving furniture and continued unpacking yesterday. More to do today, including additional grocery shopping.

Quote:
Originally Posted by cgmv123 View Post

If it's related to the building, see if any of your neighbors know what a TV antenna is. They may be having similar issues.

The ones I've met are all on cable. According to the landlord, everyone in the building but me is on Comcast.

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Try leaving your HDHR on 13 and seeing if WRCB is able to decode. If you have time on your hands, just move down the list.

I left it on 13 part of the day and 16 part of the day. Nothing decoded on either one.

Meanwhile, I'm looking at WXIA and WUVG right this moment, and WUPA is clean as well. The missing Atlanta stations cannot be that far below decoding if they're this usable before the sun rises.

Quote:


If you have a laptop, take your antennas and HDHR up on the roof and see if that helps. That should confirm if it's the building or not.

I didn't have to take it that far, not that I have roof access to do so. If I take it outside to the corner of the building, all of the UHF signals suddenly start decoding. (Silver Sensor, which I used for testing, isn't a VHF antenna.)

Quote:
Originally Posted by gbynum View Post

With that DC to light spectrum analyzer , how far have you scanned? Could there be narrow band noise hitting those channels only, either by harmonics or intermod.

Is there a MATV in your building leaking ... yeah, the analyzer should determine that ... but ... have you scanned with a whip of simple loop rather than a real antenna?

The analyzer hasn't shown anything out of place whatever I use. I tested with the paper clip in addition to the actual antennas and haven't observed any odd-looking interference on vacant channels or outside the TV band. Doesn't mean there isn't something there, just that I haven't seen it.

Quote:
Originally Posted by retiredengineer View Post

I lose most of my TV channels when my neighbor runs his dirty (electrically) lawn mower. You may have interference due to impulse noises similar to sparking. Is it possible for you to set up your spectrum analyzer to a single frequency without any TV signals, then monitor the noise level as you move your antenna about the room?

I've done it with a tuner rather than the analyzer. I'll give it a look when I get the chance.

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Originally Posted by rabbit73 View Post

Hi Trip!
Hope that you are doing OK.
Looking forward to reading about your latest adventures.

Hello!

I am doing well, and a full update will be forthcoming. I hope that you are also doing well!

Quote:


+1
I also suspect broadband RF interference being radiated inside the building.

Time to try a VHF rcvr with AM again.

Other than my HT, which is stone deaf on AM, I'm not even sure I have a portable AM receiver with me. Not a bad idea though.

Quote:


Did you ground the coax?

73,
rabbit

I've never personally grounded any coax because I've never had something outside. Might it help with this issue?

73!

- Trip

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post #19 of 89 Old 11-13-2011, 08:40 AM
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If there are any cable outlets, put terminations on them, in case they are leaking energy into your apartment. Based on your responses, you most likely do have unwanted RF leakage.
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post #20 of 89 Old 11-13-2011, 11:49 AM - Thread Starter
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Quote:
Originally Posted by retiredengineer View Post

If there are any cable outlets, put terminations on them, in case they are leaking energy into your apartment. Based on your responses, you most likely do have unwanted RF leakage.

I don't have terminations but I will attach devices to them which I hope will serve the same purpose.

With some fidgeting on the balcony, I was able to get a call sign out of WGTV-8 (22 kW at 104 miles), and WKSY-LD 21 (0.6 kW at 37 miles). I also managed to get decodes on WTCI, WELF, and WYHB-LD. Brief hints of signal on WDSI and WFLI. All of these were in different positions.

Nothing seems to make WTVC, WDEF, or WRCB decode on the balcony, despite tons and tons of signal. Fought with those for a while.

- Trip
LL

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post #21 of 89 Old 11-13-2011, 01:19 PM
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Quote:


I've never personally grounded any coax because I've never had something outside. Might it help with this issue?

Yes, it might.
Normally, you would think that grounding the coax is only needed for an outdoor antenna to drain the buildup of static charge, or for electical safety from the normal leakage current from the AC connected equipment with 2-wire cords.

But that is not the issue that I have in mind.

The outside of the ungrounded coax shield acts as an antenna to pick up noise interference (or any strong local RF signals). Noise will look just like the digital signal on your display. This common mode current will be shunted to ground if your coax is grounded. Meanwhile, the normal differential mode of the desired signal exists on the center conductor of the coax and the inside of the shield.

Member balm on DHC was trying to receive a very weak WVNY CH13 at his location in Saint-Anicet but he has a very strong local CH8 analog signal that was causing a problem. Before he grounded the coax it took over 150 dB of attenuation to drop out CH8, but when he grounded the coax it only took about 50 dB of attenuation to drop it out which is what would be expected based on its signal power.

Before the coax was grounded, the strong local was getting into the tuner AFTER the attenuator.

Discussion here on page 9:
Which VHF-Hi ONLY antenna or other solution?
www.digitalhome.ca/forum/showthread.php?t=128429&page=9

balm mentions attenuator in post 126:
www.digitalhome.ca/forum/showpost.php?p=1303730&postcount=126

And then holl_ands suggests grounding in post 128.

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post #22 of 89 Old 11-13-2011, 01:46 PM - Thread Starter
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Quote:
Originally Posted by rabbit73 View Post

The outside of the ungrounded coax shield acts as an antenna to pick up noise interference (or any strong local RF signals). Noise will look just like the digital signal on your display. This common mode current will be shunted to ground if your coax is grounded. Meanwhile, the normal differential mode of the desired signal exists on the center conductor of the coax and the inside of the shield.

[...]

Before the coax was grounded, the strong local was getting into the tuner AFTER the attenuator.

Fascinating. I will definitely investigate this possibility. Where in the chain should I ground it, between the amp and the antenna, or between the amp and the tuner?

- Trip

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Where in the chain should I ground it, between the amp and the antenna, or between the amp and the tuner?

If the coax jumper between the antenna and the amp is short, then grounding the coax between the amp and the tuner should be just as effective and probably more convenient if you have a known good ground inside.

A little trial-and-error experimenting is called for here.

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Originally Posted by rabbit73 View Post

If the coax jumper between the antenna and the amp is short, then grounding the coax between the amp and the tuner should be just as effective and probably more convenient if you have a known good ground inside.

A little trial-and-error experimenting is called for here.

The line runs from the antenna through about 20 feet of RG-6 to my amp and then there's about 3 feet to the receiver.

Is there an easy way to ground it short of ordering a grounding block?

- Trip

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post #25 of 89 Old 11-13-2011, 06:33 PM
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Trip, as Rabbit hints, and as a ham you know too, grounding shielded cable is part art and part science.

The rule of thumb is to connect the "sensitive end" to ground. That would normally be at the receiver.

If I were you, my trusty Fluke VOM would be used to see what is interconnected ... the shell of the cables to the threaded F connector ___TO THE RECEIVER CHASSIS___??? 30 years ago, that was a 100% thing ... now I don't think it is as true.

Then I'd check each cable to be sure the connector is making connection to the other end via the cable shield. Then I'd be sure the shield was connected across the amp.

If your building is new (after 1975 or so) and has a equipment ground in the power system, a screw holding a receptacle should connect to that path; it is a good choice. If it is old and has metal plumbing, a cold water pipe is a good path. With most street runs now in plastic, and many interiors in plastic, that is not a reliable option, however.

Do NOT use the "neutral" wire on a 2 prong receptacle.

Lots depends on the wiring practices in your building. The "breaker box" will almost certainly be bonded to earth ground.

My guess ... still ingression, maybe from a loose cable fitting. Is your 2 meter repeater running in the spare bedroom.
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post #26 of 89 Old 11-13-2011, 09:19 PM
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gbynum covered it well.

When I had a lot of equipment set up on the kitchen counter to compare the sensitivity of tuners, I felt a mild shock when I touched the metal equipment cases or the coax. I had 2 Apex DT502s, 2 8-inch TVs used a monitors, a SLM with its AC adapter, a SONY KDL22L5000 TV, and a preamp power supply. This setup was connected to a temporary outdoor antenna that was not grounded.

I was using a 4-way splitter, and when I touched any of the coax shield and ground I felt a mild shock. Each piece of equipment (all of them only had 2-wire AC cords) had its own normal leakage current that was within normal limits, but when they were interconnected the leakage currents added together, which is what I felt.

When I grounded the splitter to either the copper cold water pipe (also used by the AC breaker panel) or the grounding pin of a 3-wire receptacle, the leakage current went to zero as measured by my Simpson 229 Leakage Current Tester.
www.avsforum.com/avs-vb/showthread.php?p=18772087#post18772087

Here is another case where grounding solved an interference problem:
OTA TV Interference From My Blender? (Solved)
www.digitalhome.ca/forum/showthread.php?t=143031

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Alright, thanks guys. I have a grounding block on the way. I hope it arrives in the next few days.

In the mean time, I think I only need WAGA (House) and WNGH (Nova), so I'll be okay.

- Trip

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post #28 of 89 Old 11-13-2011, 09:54 PM
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Quote:
Originally Posted by Trip in VA View Post

Alright, thanks guys. I have a grounding block on the way. I hope it arrives in the next few days.

In the mean time, I think I only need WAGA (House) and WNGH (Nova), so I'll be okay.

http://www.hulu.com/nova & http://www.hulu.com/house if you run into any problems. I know it's not as good as OTA, but it should do the trick if you need it. Have you gone interference hunting yet?

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.....and I know that the building has some foil-backed insulation in it. I also know that I'm looking through the building at the local signals.

I also have-foil backed insulation in the outer walls. I used to be able to get a few local analog channels on a portable battery operated TV (see attachment) during a power failure. No reception now with digital; an outdoor antenna is mandatory. And, my cell phone doesn't connect unless I'm close to one particular window.
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But what's odd is that I have tons of signal from the Chattanooga stations, but nothing decodes. I hooked up my spectrum analyzer and, for example, WELF-16 (23-1) looks pretty strong and very rectangular. Yet my HDHomeRun won't even try to decode it, nor will my analyzer, nor will any of my other tuners. With very careful placement I can often get one or two of them to pop up at a time, but then I lose everything else (except WNGH).

The signal strength reading might be misleading if RF noise or multipath reflections indoors are contributing to the reading. This would then indicate, at the same time, poor quality because of many errors and reduced actual SNR. That might explain how you can have what looks like a strong but poor quality signal and why the antenna placement is critical.

Switchmode power supplies (SMPS) are becoming more common because of their higher efficiency, but they can radiate noise that will affect reception with indoor antennas.
LL

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post #30 of 89 Old 11-14-2011, 04:42 AM - Thread Starter
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Quote:
Originally Posted by cgmv123 View Post

http://www.hulu.com/nova & http://www.hulu.com/house if you run into any problems. I know it's not as good as OTA, but it should do the trick if you need it. Have you gone interference hunting yet?

Thanks for the links. As far as Nova goes, WNGH is the strongest signal here. I can get it with a paper clip. WAGA is a little more iffy, but I think I found a position that keeps it stable now.

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The signal strength reading might be misleading if RF noise or multipath reflections indoors are contributing to the reading. This would then indicate, at the same time, poor quality because of many errors and reduced actual SNR. That might explain how you can have what looks like a strong but poor quality signal and why the antenna placement is critical.

But the signals look good on the spectrum analyzer; I don't see a lot of multipath. Doesn't rule out noise though. http://www.rabbitears.info/specan/chatt/

- Trip

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