TV Fool  

Go Back   TV Fool > Over The Air Services > Help With Reception

Notices

Reply
 
Thread Tools
Old 30-Dec-2015, 2:20 AM   #1
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
Do i have a chance?

Hi, in need of a little advice on reception. My tvfool report:

http://www.tvfool.com/?option=com_wr...b97d569f846710

The goal is to get CHAN-DT channel 22. Seeing that is a negative 3.9 dB i just don't know if i should even bother with spending $$ on a antenna. I bought a cheap digiwave 4 bay and was able to get 21, 27, 29, 23, 35, 19 and 24 with the antenna outside leaning against my fence. When aimed 15 degrees (me holding it) i cannot get CHAN channel 22 with the digiwave. I can mount an antenna properly on my roof aprox 20 feet up and have clear line at 16-17 degrees. Some trees at 15 degrees. Coaxial cable will be 30 feet max to tuner..do i have a hope with a proper antenna like the Db8e? Or is channel 22 just to weak?

Cheers
Shaun
Shaunms is offline   Reply With Quote
Old 30-Dec-2015, 5:18 PM   #2
tonyp063
Member
 
Join Date: Dec 2013
Posts: 47
I think what is the main issue is that the 2 channels immediately either side of it (21 & 23) are ~65dB more powerful at your location & the co-channel interference would preclude it coming in.

Wiser heads than I will chime in too.
tonyp063 is offline   Reply With Quote
Old 30-Dec-2015, 7:07 PM   #3
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,633
tonyp063 is correct, 21 and 23 are causing a serious problem for 22, but it is called adjacent channel interference. Co-channel interference would be from another transmitter on channel 22, like a much weaker KCPQ Fox with a NM of -23.3 dB.

TV tuners are not required to tolerate adjacent channel interference greater than 33 dB.

The only possible solution would be a separate antenna, preamp, and a custom single channel bandpass filter for real channel 22 from Tin Lee Electronics. Even they might not be able to design a filter that would work. You could call them and email your tvfool report. The filter would be more than $100.
http://www.tinlee.com/index.php
http://www.tinlee.com/bandpass_filters.php?active=3#CF7
__________________
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; 30-Dec-2015 at 7:36 PM.
rabbit73 is offline   Reply With Quote
Old 30-Dec-2015, 7:09 PM   #4
tonyp063
Member
 
Join Date: Dec 2013
Posts: 47
Quote:
...it is called adjacent channel interference
Yeah. That's what I meant. Thanks for catching that.
tonyp063 is offline   Reply With Quote
Old 1-Jan-2016, 3:18 PM   #5
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
Thanks for the advice. I was worried it looked unlikley but at least i now know
Shaunms is offline   Reply With Quote
Old 2-Jan-2016, 6:56 PM   #6
Tower Guy
Senior Member
 
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,195
In order to reduce the interference you could select an antenna with a null at 123 degrees to reject 21 and 23. The popular DB8e is about 23 db down at 123 degrees at those channels. (the 91XG is similar) That's leaves about 14 db to filter out with a Tin Lee filter. The extra 14 db could also be achieved by placing the antenna on the side of the house so that the angle toward the stronger 21 and 23 is blocked by aluminum siding, foil backed insulation, or some other RF opaque material.

A pair of 91 XG's stacked horizontally and spaced 42" apart could also get channel 22. http://www.hdtvprimer.com/antennas/ganging.html
Tower Guy is offline   Reply With Quote
Old 5-Jan-2016, 1:12 PM   #7
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
Would there be an alternative to the 91xg? I was looking at the specs and they are over 90" long. I was planning on installing setup on my garage wall pointing to 16 degrees. The issue is the 90" 91xg would cross over into my neighbors property. Is there another antenna that might also work when ganged as you suggested?
Shaunms is offline   Reply With Quote
Old 5-Jan-2016, 2:07 PM   #8
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,633
Quote:
Would there be an alternative to the 91xg? I was looking at the specs and they are over 90" long.
As mentioned by Tower Guy, the DB8e might work as well as the 91XG, and it is a panel antenna that wouldn't stick out as far.
Quote:
I was planning on installing setup on my garage wall pointing to 16 degrees.
The separate DB8e would need to be mounted in a location that shields it from the signals from 21 and 23 and have a clear path from the 22 transmitter without trees or other buildings in the way. Both panels of the DB8e must be aimed at 15 degrees true/358 degrees magnetic.

It would help if you can show us some photos of the mounting location, or send me the coordinates of the antenna location by PM so that I can look at the green signal lines on the tvfool interactive map browser.

I see a lot of trees in your area.
Attached Images
File Type: jpg ShaunmsTVFtrees.JPG (100.4 KB, 299 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; 5-Jan-2016 at 2:55 PM.
rabbit73 is offline   Reply With Quote
Old 5-Jan-2016, 5:09 PM   #9
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
thanks for the reply. I do have a few trees around! I have attached a copy of your pic with some details that may help. When standing on a ladder next to my planned location I get a clear line of sight above roof lines etc of neighbors sheds and roofs. At work right now but will try to snap a pic from the ladder pointing towards channel 22
Attached Images
File Type: jpg ShaunmsTVFtrees.JPG (170.3 KB, 312 views)
Shaunms is offline   Reply With Quote
Old 5-Jan-2016, 7:06 PM   #10
Tower Guy
Senior Member
 
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,195
Would a pair of 43 XG antennas stacked 42 inches apart hang over your neighbors?
Tower Guy is offline   Reply With Quote
Old 5-Jan-2016, 7:23 PM   #11
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
they would just cross over. The advantage I have is the neighbor in question has a shed that would block their view of the antenna's. So if it hangs over a few inches I am not worried so much. with the 91xg's they would hang over a couple feet.
Shaunms is offline   Reply With Quote
Old 5-Jan-2016, 7:32 PM   #12
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,633
Thanks for the image with the notes. This is what I wanted to do:



I deleted the numbers after the decimal point in the coordinates for your protection and increased the height to make the CH22 green line easier to see.

You ARE on the CH22 fringe, but a -3.9 NM can be compensated for by antenna gain. The biggest problem is interference from strong local signals. The FB/FR ratios of the antenna can attenuate the strong locals to some extent, but there will still be reflections from the strong locals off objects in front of the CH22 antenna.

The terrain causes a lot of interference to the signal.
http://www.tvfool.com/?option=com_wr...ALLTV%26n%3d12
Attached Images
File Type: jpg ShaunmsTVFgreenlines3.JPG (154.1 KB, 675 views)
File Type: jpg ShaunmsTVFcovCHAN.JPG (90.5 KB, 290 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; 5-Jan-2016 at 8:11 PM.
rabbit73 is offline   Reply With Quote
Old 5-Jan-2016, 7:58 PM   #13
Shaunms
Junior Member
 
Join Date: Dec 2015
Location: Victoria, bc
Posts: 6
very helpful info thank you all. So I am summarizing here but it looks like a potential long shot to get this to work. If I go with 2 - 43XG's and a tin lee filter I am in for about $250. 2 - 91XG's and the tin lee filter put my at $300. I know there is lots of variables but in your opinion is this cost worth the risk of spending the cash and not getting the signal strength needed? and if it worth the risk should I go with the 91XG's vs 43XG? would the bigger antenna really make a big impact given this scenario?

again, really appreciate all your thoughts and help
Shaunms is offline   Reply With Quote
Old 5-Jan-2016, 8:24 PM   #14
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,633
Only you can decide if the gamble is worth it.

The tvfool report is only a computer simulation, and is often not too accurate with 1Edge and 2Edge signals.

If you talk to a Tin Lee engineer and email your tvfool report to him he can give you an idea of the odds.

As a test you could try your present antenna in the new location. The signal wavefront is rarely uniform, and a small change in antenna location can make a big difference. Antenna installers call it "walking the roof." To say it another way, the best location for the antenna isn't always where you wanted to put it.
__________________
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; 5-Jan-2016 at 8:26 PM.
rabbit73 is offline   Reply With Quote
Old 6-Jan-2016, 11:57 AM   #15
Tower Guy
Senior Member
 
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,195
I'd try the pair of 43XG antennas without the TinLee filter first and then add the filter if necessary. However, Rabbit73 is right, reflections may minimize the interference advantages of the stacked antennas, but the actual amount of the interference is hard to predict.
Tower Guy is offline   Reply With Quote
Old 6-Jan-2016, 1:13 PM   #16
ADTech
Antennas Direct Tech Supp
 
Join Date: Jan 2010
Posts: 2,941
FYI, the 43XG has been discontinued and we are out of stock. All remaining inventory is out there in the distributor's warehouses and, when they're gone, they're gone.
__________________
Antennas Direct Tech Support

For support and recommendations regarding our products, please contact us directly at https://www.antennasdirect.com/customer-service.html

Sorry, I'm not a mod and cannot assist with your site registration.
ADTech is offline   Reply With Quote
Reply

Bookmarks

Go Back   TV Fool > Over The Air Services > Help With Reception


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT. The time now is 2:49 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Copyright © TV Fool, LLC