Interference Sources on OTA, Radio, WiFi Signals - Page 3 - Canadian TV, Computing and Home Theatre Forums
 

Go Back   Canadian TV, Computing and Home Theatre Forums > Canadian Internet, Phone, TV and Wireless Service Providers > Over-The-Air (OTA) Digital Television

Digital Home Helpful Information

Reply
 
Thread Tools Search this Thread Display Modes

Old 2010-01-03, 08:24 AM   #31
JamesK
Veteran
 
Join Date: May 2009
Location: Mississauga
Posts: 6,181
Default

I believe the issue was interference to reception. Powerling induced "hum bars" haven't been an issue for a long time and that's also why NTSC was set to have a field rate matching the powerline frequency. By doing so, the visible effect of those bars was minimized. Also, the bars were a result of deficiencies in the set's power supply, not interference received via OTA.
JamesK is online now  
Sponsored Links
Advertisement
 
Old 2010-01-07, 01:19 AM   #32
pshelston
Rookie
 
Join Date: Aug 2008
Location: Toronto, ON (Upper Beach)
Posts: 22
Default TTC Streetcar interference

Hello,

I live in Toronto on a street with streetcar service and everytime a streetcar goes by I get some loss of signal on CFTO-DT (Ch 40) and also some fuzziness on CIII-TV analog (Ch 41).

Any ideas how I can reduce the impact of this interference? It doesn't appear to be affecting other channels (at least not that I notice).
pshelston is offline  
Old 2010-01-07, 10:50 AM   #33
roger1818
Veteran
 
Join Date: Apr 2006
Location: Ottawa (Stittsville), ON, OTA (DB4e & VHF-HI folded dipole, AP-2870 pre-amp in Attic), MythTV HTPC
Posts: 6,111
Default

Quote:
Originally Posted by pshelston View Post
I live in Toronto on a street with streetcar service and everytime a streetcar goes by I get some loss of signal on CFTO-DT (Ch 40) and also some fuzziness on CIII-TV analog (Ch 41).

Any ideas how I can reduce the impact of this interference? It doesn't appear to be affecting other channels (at least not that I notice).

Looking at your previous posts I gather you have a hacked CM4221HD, Kitztech amp and a couple UVSJs to filter out VHF. Are the UVSJs between the antenna and the amp or the amp and the TV?

If the streetcar is producing RF noise directly on channels 40 and 41, there isn't much you can do about it other than move the antenna higher to get it further away from the streetcar.

More likely it is producing noise at a lower frequency and the amp is generating harmonics on UHF. That is the biggest issue with the Kitztech is I gather it only has one amp for both VHF and UHF so harmonic distortion from VHF signals can appear on UHF. Having a UVSJ before the amp should fix this problem, if you aren't already doing this.

Another option is it is generating noise on the powerline (though I would think it would be on a separate circuit). Making sure both your amp and your tuner are plugged into good RFI filtering power bars should fix it in this case.
roger1818 is offline  
Old 2010-01-07, 12:44 PM   #34
stampeder
OTA Forum Moderator
 
Join Date: Jan 2005
Location: North Delta, BC (96Av x 116St)
Posts: 23,971
Default

Just adding that you might want to ask in the Antenna R&D forum how to build a cheap, simple, small UHF Yagi antenna optimized only for channels 40 and 41, aimed right at the CN Tower with no amplification. The idea is to have an antenna that "sees" only straight forward but almost nothing from the sides or back. Mixing that in with your existing antenna is a topic we could help you with later if you want to go that route.
stampeder is offline  
Old 2010-01-07, 09:43 PM   #35
Jase88
Moderator
 
Join Date: Jan 2009
Location: Kitchener, ON
Posts: 4,555
Default

I'm getting some low-VHF interference in the Toronto direction...it only seems to hit at night, so I'm starting to suspect street lights.

I may have to do some late-night target practice with a pellet gun to confirm (just kidding).
__________________
DMX 68' tower, HyGain HAM 5 rotator, Antennas Direct 91-XG & C5, Channel Master 7777 preamp, Siemens surge protection
Jase88 is offline  
Old 2010-01-07, 09:45 PM   #36
Jase88
Moderator
 
Join Date: Jan 2009
Location: Kitchener, ON
Posts: 4,555
Default

@pshelton: You're probably close enough to the CN tower that you could angle your antenna up sharply. I wonder if this would provide enough front-back isolation to reduce/eliminate the interference?!
__________________
DMX 68' tower, HyGain HAM 5 rotator, Antennas Direct 91-XG & C5, Channel Master 7777 preamp, Siemens surge protection
Jase88 is offline  
Old 2010-01-07, 11:50 PM   #37
pshelston
Rookie
 
Join Date: Aug 2008
Location: Toronto, ON (Upper Beach)
Posts: 22
Default

Quote:
Originally Posted by roger1818 View Post
Looking at your previous posts I gather you have a hacked CM4221HD, Kitztech amp and a couple UVSJs to filter out VHF. Are the UVSJs between the antenna and the amp or the amp and the TV?

If the streetcar is producing RF noise directly on channels 40 and 41, there isn't much you can do about it other than move the antenna higher to get it further away from the streetcar.

More likely it is producing noise at a lower frequency and the amp is generating harmonics on UHF. That is the biggest issue with the Kitztech is I gather it only has one amp for both VHF and UHF so harmonic distortion from VHF signals can appear on UHF. Having a UVSJ before the amp should fix this problem, if you aren't already doing this.

Another option is it is generating noise on the powerline (though I would think it would be on a separate circuit). Making sure both your amp and your tuner are plugged into good RFI filtering power bars should fix it in this case.
Actually, I didn't get any better results with the Kitztech or with the UVSJ so I removed everything to simplify.

All I have now is the 4221HD (mild hacks) -> ~40' -> grounding block (ground to water faucet) + surge suppressor -> 8' -> TV.

Is there any way to tell if I'm getting noise on the powerline? On analog ch 37 & 41 the interference manifests itself as a rapid flickering/dimming.

Quote:
Originally Posted by stampeder
Just adding that you might want to ask in the Antenna R&D forum how to build a cheap, simple, small UHF Yagi antenna optimized only for channels 40 and 41, aimed right at the CN Tower with no amplification. The idea is to have an antenna that "sees" only straight forward but almost nothing from the sides or back. Mixing that in with your existing antenna is a topic we could help you with later if you want to go that route.
That's an idea... I'd hate to have to deal with this during the olympics. The only part I'm wouldn't be looking forward to is the mixing

Quote:
Originally Posted by jase88
@pshelton: You're probably close enough to the CN tower that you could angle your antenna up sharply. I wonder if this would provide enough front-back isolation to reduce/eliminate the interference?!
Wouldn't that affect my Buffalo reception, though? Right now the CN Tower is on the right side of my antenna and Buffalo is straight ahead. The street car line is right between me and Buffalo.
pshelston is offline  
Old 2011-07-25, 10:47 PM   #38
Yroc
 
Join Date: Jan 2011
Location: Ottawa (Overbrook)
Posts: 174
Question OTA TV Interference From My Blender? (& Various Other Devices)

Can anyone explain why I end up with interference on the TV reception when I run my blender (27.1 and 17.1 only)?
Yroc is offline  
Old 2011-07-26, 12:16 AM   #39
FunkyTown
 
Join Date: May 2006
Location: Gatineau, QC
Posts: 1,277
Default

The blender is creating radio frequency at those channels. I remember my mother mixing a cake in the late 1960s and our tv would go haywire until she turned the mixer off. I used to think it was the electricity in the wall getting scrambled, but it's actually radio wave interference.
FunkyTown is offline  
Old 2011-07-26, 10:37 AM   #40
Yroc
 
Join Date: Jan 2011
Location: Ottawa (Overbrook)
Posts: 174
Default

Anyway to stop it?
Yroc is offline  
Old 2011-07-26, 10:47 AM   #41
flavoie
 
Join Date: May 2007
Location: Orleans, ON
Posts: 1,248
Default

hum... tinfoil hat for your blender or TV ?
Your question is its own answer: how do you block these frequecies from your blender to get to your TV ? Attenuation. How? that is the tricky part.
All IMHO.
flavoie is offline  
Old 2011-07-26, 10:54 AM   #42
tvlurker
Veteran
 
Join Date: Jul 2005
Location: Craig Henry (Greenbank/Hunt Club), Nepean, ON
Posts: 3,002
Default

You can't block the frequencies, since it's the component within the desired channel that is affecting you.

What you need is a very directional antenna, above the house and pointed directly at the desired station.

The blender noise will still exist around the house, but the antenna won't be picking it up.

changing from an indoor loop or other low gain antenna to an outdoor directional antenna is the way to go, if local electrical noise is interfering with your reception.

That's why 60's-era directional antennas were advertised as being "noise-immune".
tvlurker is online now  
Old 2011-07-26, 11:10 AM   #43
flavoie
 
Join Date: May 2007
Location: Orleans, ON
Posts: 1,248
Default

By using an outside antenna, you're also using your house as an attenuator for the blender frequencies
flavoie is offline  
Old 2011-07-26, 11:11 AM   #44
mike infinity
 
Join Date: Oct 2004
Posts: 462
Default

Quote:
Originally Posted by Yroc View Post
Anyway to stop it?
You could always put your blender in a Faraday cage (edit: ie a FANCY tinfoil hat). Not sure about the acceptance factor of other blender-users you may live with though. You could always schedule blender usage outside important broadcast time.

There can be line interference as well BTW (ie ground loops, etc)....I used to get horizontal bars with my old component connections. Switching to a digital connection has largely resolved the issue.
mike infinity is offline  
Old 2011-07-27, 04:12 PM   #45
Moosebox
 
Join Date: Feb 2007
Location: Burlington
Posts: 28
Default

My shredder does this too.
Moosebox is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 -4. The time now is 01:08 AM.

OTA Forum Sponsor


Search Digital Home

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.