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Old 13-Jan-2018, 2:41 AM   #1
oak hill
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Lost Channels

Hi,
I'm using a homemade bow tie antenna in my attic for about 5 years now in Paradise, PA 17562
During the summer months I would get about 15 channels, including grit 15.1 and comet 15.2
As the trees started to shed their leaves I would pick up a few more channels.
About 2 months ago I lost grit, comet, escape 49.?, decades 3.2 instead of gaining some channels.
Checked the antenna and wiring and all looks OK
About a week ago I got 3.1 fox? and 3.2 decades and 15.1 is now comet (not grit) and no 15.2
Still no grit.
I didn't move the antenna yet.
Any thoughts??
Thanks, Angelo
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Old 13-Jan-2018, 3:59 PM   #2
rabbit73
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Welcome to the forum, Angelo

Here is a zip code TVFool report for your area, but your actual location might be different.
http://www.tvfool.com/?option=com_wr...60ed1f6c5589cc

Please do a report based on your exact address for greater accuracy; your exact address will not show in the report. Please give us the link to the report that is in bold type near the top of the report. You can do it here:

http://www.tvfool.com/index.php?opti...pper&Itemid=29

You have given us virtual channel numbers. What we need are callsigns and real channel numbers. The problem is that the subchannels you want come and go from the main network channels. They are often hard to track down, but we will try.

An added problem is that TVFool is using a defective database, so the reports often have errors, but we can make comparisons with reports from other sites.
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Last edited by rabbit73; 13-Jan-2018 at 4:08 PM.
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Old 13-Jan-2018, 4:29 PM   #3
oak hill
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Here's a link to my report
http://www.tvfool.com/?option=com_wr...60ed71b2ba5770
And yes, stations come and go and show up at different channels. Or disappear altogether.
Angelo
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Old 13-Jan-2018, 8:20 PM   #4
rabbit73
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Thank you for the report; here is an extract:



this report is from rabbitears.info:



and for comparison, this report is from the FCC DTV map site; it uses 30' antenna height:

Attached Images
File Type: jpg oak hillTVFreportTVF3.JPG (147.3 KB, 227 views)
File Type: jpg oak hillTVFreportRE.JPG (169.9 KB, 231 views)
File Type: jpg oak hillTVFreportFCC.JPG (121.3 KB, 234 views)
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Last edited by rabbit73; 13-Jan-2018 at 8:29 PM.
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Old 13-Jan-2018, 9:27 PM   #5
rabbit73
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This is what is on WGAL real channel 8 and 49:
http://www.rabbitears.info/market.ph...&callsign=wgal
8.1 NBC
8.2 MeTV
Real channel 8 is a VHF-High channel. A UHF bowtie antenna doesn't work very well on VHF-High unless the signal is very strong. An attic location for an antenna and trees make TV signals weaker.

Are you using a preamp?

WPMT now on real channel 36:
http://www.rabbitears.info/market.ph...&callsign=wpmt
33.1 PBS
33.2 PBS Kids
43.1 Fox
43.2 Antenna TV

WXBU: Comet (WXBU) is moving to a new frequency on December 29, 2017 at noon.
http://local21news.com/features/comet-move/comet

see WHP on real channel 21, will move to real channel 32
http://www.rabbitears.info/market.ph...h&callsign=whp
15.1 Comet
21.1 CBS
21.2 MyN
21.3 CW

KJWP on real channel 2 which is a VHF-Low channel; very big antenna elements needed for it
http://www.rabbitears.info/market.ph...&callsign=kjwp
2.1 MeTV
2.2 Grit
2.3 Escape
2.4 Heroes & Icons
2.5 Retro TV

KYW real channel 26, moving to 30
http://www.rabbitears.info/market.ph...h&callsign=kyw
3.1 CBS
3.2 Decades
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Last edited by rabbit73; 13-Jan-2018 at 10:57 PM.
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Old 13-Jan-2018, 11:01 PM   #6
oak hill
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No preamp

8.1 NBC, 8.2 MeTV, 15.1 grit, 15.2 comet, 3.2 decades, 49.4 escape, 43.1 fox had the best reception for a couple of years. Now they're all over the place if at all.
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Old 14-Jan-2018, 3:11 AM   #7
rabbit73
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Quote:
Originally Posted by oak hill View Post
No preamp

8.1 NBC, 8.2 MeTV, 15.1 grit, 15.2 comet, 3.2 decades, 49.4 escape, 43.1 fox had the best reception for a couple of years. Now they're all over the place if at all.
Yup, a lot of changes, and even more changes to come. You will need to rescan to keep up with the changes and maybe try a preamp and a different antenna. to find what you want, Angelo.

It is the real channel number that determines what antenna is needed.

VHF-Low, real channels 2-6
VHF-High, real channels 7-13
UHF, real channels 14-51

The virtual channel number (like 5.1) is a holdover from the analog TV days to maintain the identity of the station, and is what the TV displays.
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Old 14-Jan-2018, 3:34 AM   #8
oak hill
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I can see that now.
My antenna is at around 290* but Grit is at 87*. So I'll never pick it up now.
I'll scan every once in a while and see how it goes.
I'll also get a preamp.
I'd hate to have to use an antenna with a rotator. That's a real PITA
Angelo
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Old 14-Jan-2018, 4:09 PM   #9
rabbit73
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Quote:
Originally Posted by oak hill View Post
I can see that now.
My antenna is at around 290* but Grit is at 87*. So I'll never pick it up now.
I'll scan every once in a while and see how it goes.
I'll also get a preamp.
I'd hate to have to use an antenna with a rotator. That's a real PITA
Angelo
Here is a list of stations that have Grit:
https://www.rabbitears.info/search.p...=Grit&sort=dma

Tell me more about your bowtie antenna. Maybe it can be improved.

What are its dimensions? Does it have a reflector?
Can you show us a photo?

Grit is on KJWP on real VHF-Low channel 2, that is in a different direction. You could build a simple antenna for it that could be aimed at 87 degrees to see if you can pick it up. If you connect that antenna alone to your TV and you can pick it up, it could be easily combined with your bowtie antenna with a HLSJ combiner and you wouldn't need a rotator or an A/B switch.



Channel 2 is 54 to 60 MHz. The center of the channel is 57 MHz.
5540/57 = 97 inches for a halfwave dipole

If you can't find 300 ohm twin lead, you can use some 14 gauge solid copper electrical wire for a folded dipole:



If the folded dipole for channel 2 is almost, but not quite, good enough, you can add a director and a reflector to convert it into a 3 element beam:

Attached Images
File Type: jpg folded dipole3.jpg (63.3 KB, 196 views)
File Type: jpg Channel 2 Yagi.jpg (87.6 KB, 197 views)
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Last edited by rabbit73; 14-Jan-2018 at 4:47 PM.
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Old 14-Jan-2018, 8:07 PM   #10
oak hill
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2 hooked together in attic at 280*
I have a spare I'm not using
attic1.jpg

attic2.jpg

attic3.jpg
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Old 14-Jan-2018, 11:53 PM   #11
rabbit73
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Thank you for the photos.

The dimensions are pretty close to correct, but when you fasten the wires to wood without any insulators there will be some signal loss. Also, a reflector on just one antenna would give at least as much gain as two antennas without reflectors.



How did you combine the two antennas, a splitter in reverse?

When you combine two antennas that have wire baluns, the is a 50% percent chance of getting it right, because the two antennas must be connected in phase to have any gain over just one.

Attached Images
File Type: jpg 4-BayAnt.jpg (102.2 KB, 173 views)
File Type: jpg Combine4-Bays.jpg (225.9 KB, 171 views)
__________________
If you can not measure it, you can not improve it.
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Last edited by rabbit73; 15-Jan-2018 at 12:38 AM.
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Old 15-Jan-2018, 12:48 AM   #12
oak hill
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''How did you combine the two antennas, a splitter in reverse?''
Yes
What do I use for a reflector?
Do I need to use the dipole or can I put reflectors on the two in the attic, face one at 280*, the other at 87*and join them with a combiner?
Can I use small pieces of wood as insulators?
I don't have any test equipment.

Off Topic......Going to hospital tomorrow for pre-op tests for total knee replacement
Feb 6. Got denied this surgery last year because of heart problems.
Now have defibrillator.

Last edited by oak hill; 15-Jan-2018 at 12:54 AM.
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Old 15-Jan-2018, 1:30 AM   #13
rabbit73
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Quote:
Originally Posted by oak hill View Post
''How did you combine the two antennas, a splitter in reverse?''
Yes
Did you make the two coax lines exactly the same length?

Did you try reversing the leads on just one balun to see which way gives the most gain? When the baluns are not connected in phase the main lobe of the combined antennas splits in two:



Quote:
What do I use for a reflector?
Outdoors you would use 1" x 2" wire fencing, but indoors you can use aluminum foil glued to cardboard.
Quote:
Do I need to use the dipole or can I put reflectors on the two in the attic, face one at 280*, the other at 87*and join them with a combiner?
No, that would not get Grit on channel 2. Leave the bowtie antennas aimed at 280 and use a separate antenna for 87.

Antenna elements must be a certain length for each channel frequency for best results. It's like organ pipes; short pipes are for the high frequency notes and the pipes are long for the low frequency notes.
Quote:
Can I use small pieces of wood as insulators?
No, that wouldn't be any better; it should be plastic like a PVC coupling:







http://m4antenna.eastmasonvilleweather.com/index.html

http://m4antenna.eastmasonvilleweath...0Drawings.html

https://sites.google.com/site/maycre...setup/mclapp-4

Quote:
I don't have any test equipment.
Does your TV have a relative signal strength indicator?
Quote:
Off Topic......Going to hospital tomorrow for pre-op tests for total knee replacement
Feb 6. Got denied this surgery last year because of heart problems.
Now have defibrillator.
Sorry to hear you are having health problems. I hope the operation and the rehab go well.
Attached Images
File Type: jpg Example 3 TATOut (2)_1.jpg (44.4 KB, 167 views)
File Type: jpg mclapp PVC coupling2.jpg (101.4 KB, 166 views)
File Type: jpg mclappPVCstandoff1.jpg (41.9 KB, 165 views)
File Type: jpg mclappPVCstandoff3.jpg (39.3 KB, 160 views)
__________________
If you can not measure it, you can not improve it.
Lord Kelvin, 1883
http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 15-Jan-2018 at 2:02 AM.
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Old 15-Jan-2018, 11:30 AM   #14
oak hill
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Great info.
I can do all you mentioned but not for a few days.
Is the reflector the same height and width as the antenna?
Angelo
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Old 15-Jan-2018, 6:29 PM   #15
rabbit73
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Quote:
Originally Posted by oak hill View Post
Is the reflector the same height and width as the antenna?
Angelo
A little bigger, like this:



I modified one for a friend to make it safer to handle in his attic. I put wood molding corner strips on the edges of the 1" x 2" wire mesh reflector:



and black heat shrink tubing and thread protector caps on the ends of the whisker elements to keep from getting scratched:

Attached Images
File Type: jpg CM 4221-3021 Original2.jpg (66.2 KB, 145 views)
File Type: jpg CM 4221 Mod.jpg (74.5 KB, 140 views)
File Type: jpg CM 4221 Mod2.jpg (84.8 KB, 140 views)
__________________
If you can not measure it, you can not improve it.
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http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 15-Jan-2018 at 7:07 PM.
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Old 16-Jan-2018, 5:49 PM   #16
oak hill
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Nice Work!!
I'll start on this in a few days.
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