ON - Barrie, Muskoka, Sault Ste. Marie, Northern Ontario - OTA - Page 51 - Canadian TV, Computing and Home Theatre Forums

 4Likes
Reply
LinkBack Thread Tools Search this Thread Display Modes

post #751 of 758 (permalink) Unread 2019-09-09, 03:57 PM
DHC Supporter
 
Join Date: May 2010
Location: S.E. VA
Posts: 985
Quote:
Originally Posted by John67 View Post
I have a cottage on the north west side of the Georgian Bay Penninsule, near Lafontaine Beach.

My struggle is the CHCH repeater which sits on the same tower as the Global TV antenna.
Hello, John

Here is a signal report from rabbitears.info based on my estimate of your location:
https://www.rabbitears.info/searchma...&study_id=9947

This is an extract from that report:



This terrain profile shows the hill that you are behind:



The CHCH coverage in your area is weak because they are using a directional antenna that sends only about 1/3 of their power in your direction:





Quote:
Doing some googling, I found some sites where it shows CHCH-DT-3 as having a virtual channel of 67.1. Is that just old and now replaced by 23.1?
The rabbitears.info report shows CHCH with real channel 23 and virtual channel 67.1

Quote:
Both antennas feed into a combiner and then CM7778.
What type of combiner are you using, a UVSJ UHF-VHF combiner or a splitter in reverse.

Quote:
I thought I would register something for CHCH. Would an antenna with a different frequency profile be a better choice?
CHCH is transmitting on real UHF channel 23, so the best antenna for it would be a UHF antenna that has good gain at the low end of the UHF band. It must be aimed at the CHCH transmitter.

They are scheduled to move to channel 28:
https://www.rabbitears.info/market.p...208903#station

It might be worth the trouble to try different locations for the antenna to find a hot spot.

Trees block TV signals, especially UHF signals.

Some users behind a hill have found that tilting the front end of the antenna UP helps, but it doesn't always work. The Antennas Direct 91XG and the Solid Signal HDB91X have a tilt adjustment.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; 2019-09-09 at 04:30 PM.
rabbit73 is online now  
Sponsored Links
Advertisement
 
post #752 of 758 (permalink) Unread 2019-09-10, 11:28 AM
Rookie
 
Join Date: Nov 2011
Location: Cambridge, ON (Clemens Mill)
Posts: 12
Rabbit73 thanks for the reply and info you provided.

I am using a splitter in reverse to combine the two antennas ahead of the cm7778.

I had thought about tilting the antenna, but will have to rig something up.
John67 is offline  
post #753 of 758 (permalink) Unread 2019-09-10, 01:07 PM
DHC Supporter
 
Join Date: May 2010
Location: S.E. VA
Posts: 985
Quote:
Originally Posted by John67 View Post
I am using a splitter in reverse to combine the two antennas ahead of the cm7778.
Using a splitter in reverse can sometime cause a reception problem. In your case, the VHF antenna and the UHF antenna are both picking up CHCH. The CHCH signal from the VHF antenna will interfere with the CHCH signal from the UHF antenna if it isn't perfectly in phase. To test the theory, connect just the UHF antenna directly to the 7778 without the splitter and see if it makes CHCH better. It it doesn't, then you need a better antenna for CHCH.

A UVSJ is designed to combine a UHF antenna with a VHF antenna without the same signals from each antenna causing interference to each other.


If you can not measure it, you can not improve it.
Lord Kelvin, 1883
rabbit73 is online now  
 
post #754 of 758 (permalink) Unread 2019-09-10, 02:45 PM
Rookie
 
Join Date: Nov 2011
Location: Cambridge, ON (Clemens Mill)
Posts: 12
Again, thanks for the info.

I'd be surprised if the vhf antenna is picking up as it is a folded dipole tuned to CKVR and pointed 90 degrees relative to the uhf antenna. Anything is worth a shot, but it is a matter of finding a combined.
John67 is offline  
post #755 of 758 (permalink) Unread 2019-09-10, 03:36 PM
DHC Supporter
 
Join Date: May 2010
Location: S.E. VA
Posts: 985
Quote:
Originally Posted by John67 View Post
I'd be surprised if the vhf antenna is picking up as it is a folded dipole tuned to CKVR and pointed 90 degrees relative to the uhf antenna. Anything is worth a shot, but it is a matter of finding a combined.
It is true that the folded dipole isn't picking up much from CHCH, but it doesn't take much out of phase signal to mess up a good signal. My crystal ball isn't good enough to predict the results of the test. You just have to try it before you can eliminate that possibility, otherwise you will never know. You need to do it before going to another antenna for CHCH or another method of combining. But, it's your antenna system and your decision.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
rabbit73 is online now  
post #756 of 758 (permalink) Unread 2019-09-13, 06:37 PM
Veteran
 
Join Date: Jan 2009
Posts: 4,614
Must have been some odd tropo last night, picked up that CHCH RF 23 from Muskoka for about a 1/2hr or so down here, just south of Buffalo, but nothing else out of range from the usual direction. Have never seen that down here before that I recall.


CHCH-3
Muskoka, ON
RF channel 23
Virtual channel 67.00000000
ERP 63 kW
RCASML 1673 ft.
Distance 155.5 miles
9/13 4:32:06 AM

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
majortom is online now  
post #757 of 758 (permalink) Unread 2019-09-14, 10:06 AM
Moderator
 
Join Date: Aug 2005
Location: Winnipeg, MB
Posts: 15,319
Dr.Dave is offline  
post #758 of 758 (permalink) Unread Today, 10:01 AM
DHC Supporter
 
Join Date: May 2010
Location: S.E. VA
Posts: 985
Using an SDR Dongle to Look at the Noise Level for Channels 2 and 4

Quote:
Originally Posted by cyclist44 View Post
Here is a photo of my setup. Window is facing North. I am able to get 100l% on channel 9 and 27% on channels 2 and 4.

Quote:
27% is just not quite enough to view channels 2 and 4. Signal is trying to come through. Screen is mostly black but you can see some color trying to come through.
There is a test that you can do that is very inexpensive. You can buy an RTLSDR dongle and learn to use the free spectrum analyzer software for it to see what your channels 2 and 4 look like at your location.

The dongle is only about $20 US. It plugs into a USB port on your computer. It doesn't come with the software; it will be necessary for you to assemble the software in a folder. If you have trouble assembling the software, there is a tutorial thread that will help you.

Forum member lenlab was able to do it so that he could see what was causing interference to his reception of VHF channels 7-13. This is his thread:
https://www.digitalhome.ca/forum/186...ml#post3091165

This is his scan that shows noise interference on VHF 7-13:



For comparison, this is what my channels 7-13 look like; 7 and 13 are OK but 9 is marginal:



This is the SDR dongle with an antenna adapter cable:



I did a test scan for channel 3 that shows a very high noise level from electrical interference on VHF:



The signal had just enough SNR above that high noise level for good reception:



If your channels 2 and 4 don't have more than 15 dB SNR above your noise level, try to find a location for the antenna where the noise isn't as strong.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; Today at 11:15 AM.
rabbit73 is online now  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Canadian TV, Computing and Home Theatre Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in













Posting Rules  
You may not post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome