High Def Forum - Your High Definition Community & High Definition Resource

Go Back   High Def Forum - Your High Definition Community & High Definition Resource >
Rules HDTV Forum Gallery LINK TO US! RSS - High Def Forum AddThis Feed Button AddThis Social Bookmark Button Groups

Local HDTV Info and Reception Learn about your local HDTV stations, availability, reception issues, OTA antennas and any other local issues.

Like Tree4Likes
  • 2 Post By projectsho89
  • 2 Post By rabbit73

Twin antennas pointed different directions

Reply
AddThis Social Bookmark Button
 
Thread Tools
Old 01-06-2019, 01:31 PM   #1  
HDTV Radio Guy
Thread Starter
 

Join Date: Jan 2019
Location: Central VA
Posts: 2
Default Twin antennas pointed different directions

I am located in rural Central Virginia about 72 miles south of Washington DC and 32 miles north of Richmond. I have a 32 element Antennacraft yagi pointed at Richmond and a ~52 element Antennacraft yagi pointing at DC. Both antennas are mounted on a mast attached to the end of my one story house and are about 10 degress from being 180 degrees apart. The two antennas are joined with a 2 port joiner/splitter prior to entering twin FM traps followed by a Winegard XT preamplifier. I tried to match the lengths of the transmission lines from the antennas to minimize phase errors but they are two different antennas pointed in different directions. I installed a similar setup for a friend in a different county using a yagi and a bow tie and it's working very well for him.

Just to make things more interesting, there is a 47KW ERP FM station broadcasting from a tower 2.5 miles away and the local CW station is 15 miles away with a 1MW ERP (yes, that's 1 & 6 zeros). Fortunately, the latter will go away after "repacking" is complete in 2020.

Other than periodic weather condition interruptions the Richmond commercial stations are quite reliable, however the two PBS stations are problematic. The PBS station TVFool predicts has the stronger signal, ch 57, is never seen and the other, ch 23, is all but unwatchable during the summer due to foliage and intermittent the rest of the year. I have an old Sencore signal strength meter and can watch it and the TV at the same time. Sometimes 23 will pixelate or go away entirely without observing a change on the meter.

From DC, I get the two VHF stations periodically during the day, mostly at night. Only one of the UHF stations, ch 50, appears sporadically 2-3 times a week for a total of 2-4 hours. A couple of the other DC UHF signal levels are comparable to channel 50 but are never seen.

I've ordered a pair of 80 dB FM filters, one for each antenna and I'm planning to have separate XT preamps prior to the splitter/combiner. I'm sure the excessive FM station signals play some part in this but I'm not sure how much. Also under consideration is swapping out the no-name baluns (transformers) on the antennas because I suspect they aren't sealed as well as they could be. Another idea is to go with just the DC antenna and pick up Richmond off the back end.

I'm interested in other peoples experiences tying unlike/opposing antennas together and experiences with defective/poor quality baluns.

Regards,
George
wizardgmb is offline   Reply With Quote
Old 01-07-2019, 02:48 AM   #2  
High Definition is the definition of life.
 
Terryl3's Avatar
 

Join Date: May 2013
Location: Deep in the Duraflame National Forest
Posts: 1,498
Default

If the FM station at 2.5 miles away is affecting things then at it's power levels there would be almost nothing you could do to try and eliminate it as a possible problem, it's signal would be directly picked up by the TV's internal tuner.

The only way to keep it from getting directly into the TV set would be to put it (the TV) inside a Faraday cage, or a metal building.

Not much you can do about it.

As to the two dissimilar antennas pointing in two different directions being phased combined, all I can say is good luck and I hope you have a lot of hair to loose.

A good RF spectrum analyzer would be a big help, but the two antennas being pointing in two different directions is a big phasing problem, the spectrum analyzer would be the best tool to help with this big problem.

I would drop the use of two dissimilar antennas and go with the best high gain one, then the use of a good TV antenna rotor would keep the hair loss at a minimum.

Or an A/B switch would eliminate the phasing problems.

And yes most consumer grade baulins are a bit of a problem, I used commercial grade on all my installs, less of a chance for something to go wrong.
Terryl3 is offline   Reply With Quote
Old 01-07-2019, 06:39 AM   #3  
High Definition is the definition of life.
 

Join Date: Oct 2009
Posts: 1,234
Default

How about posting the following:

Your TVFool link (you may need to intentionally edit it to an obvious non-link as a new member).
Identifying the TV and FM radio stations explicitly by their call letters.
Identifying all components by their make and model numbers instead of by a generic description.

With specifics, we can better analyze the situation and advise you.
rabbit73 and Chiwaukee OTA like this.
projectsho89 is offline   Reply With Quote
Old 01-07-2019, 08:14 PM   #4  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default

Hello, George; welcome to the forum.
Quote:
Originally Posted by wizardgmb View Post
The two antennas are joined with a 2 port joiner/splitter prior to entering twin FM traps followed by a Winegard XT preamplifier.
That is a convenient way of combining two antennas aimed in different directions, but it doesn't always work.
If you don't have all the channels after combining that you had when the antennas were separate, that method of combining doesn't work for you.
Quote:
I tried to match the lengths of the transmission lines from the antennas to minimize phase errors but they are two different antennas pointed in different directions.
It is not necessary, and even irrelevant, to have identical length feedlines in your situation. The only time it is necessary to have identical length feedlines from each antenna is when you are combining two identical antennas aimed in the same direction for additional gain.

Now that you have us interested, may we see your TVFool signal report?
Terryl3 and Chiwaukee OTA like this.

Last edited by rabbit73; 01-07-2019 at 08:19 PM..
rabbit73 is offline   Reply With Quote
Old 01-19-2019, 01:51 PM   #5  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default

Quote:
Originally Posted by Terryl3 View Post
And yes most consumer grade baulins are a bit of a problem, I used commercial grade on all my installs, less of a chance for something to go wrong.
Who makes commercial grade baluns, and where will I find them?
rabbit73 is offline   Reply With Quote
Old 01-19-2019, 04:30 PM   #6  
High Definition is the definition of life.
 
Terryl3's Avatar
 

Join Date: May 2013
Location: Deep in the Duraflame National Forest
Posts: 1,498
Default

Wow, your asking me to go back about 40 years or so with this old brain....Hummm... I think I got them bulk from Pico-Macom...But I don't think they do that type of line anymore, they make good splitters but I don't think they do the baluns anymore.

I mostly got my stuff from a MATV supplier, but they have gone out of business many years ago, satellite TV and cable took them down.
Terryl3 is offline   Reply With Quote
Old 01-19-2019, 08:06 PM   #7  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default

Quote:
Originally Posted by Terryl3 View Post
Wow, your asking me to go back about 40 years or so with this old brain....Hummm...
Thank you for your reply. I got a request today that reminded me of what you had said about commercial baluns.

Quote:
Originally Posted by PenolaCross
I'm looking at two additional upgrades to improve the signal. Baluns are often problematic so I'm planning to replace them; it was recommended to me to use "commercial" quality baluns but I have been unable to find any designated as such. I would appreciate any recommendations for a commercial quality balun, otherwise I will be using the standard Channel Master 94444.
I think it might be the same guy as the OP because he says:

Quote:
Originally Posted by PenolaCross
Complicating matters is a 47KW FM station and Sprint cell site 2.5 miles away. I have two 80 dB FM filters and Channel Master CM-3201 LTE filters enroute to deal with them.
and doesn't want to give his report there either.

and his name is also George.

So, what city in rural Central Virginia has
Quote:
CW station is 15 miles away with a 1MW ERP

Last edited by rabbit73; 01-19-2019 at 08:30 PM..
rabbit73 is offline   Reply With Quote
Old 01-19-2019, 08:47 PM   #8  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default

WUPV in Ashland has a 1000 kW CW transmitter, and it's moving from 47 to 8.

WUPV doesn't show on a TVFool report because they are using a defective database to generate reports, but it does show on a rabbitears.info report.

My assumption is that George doesn't want to give a report or location because it would compromise his identity, which is his right.

Last edited by rabbit73; 01-19-2019 at 10:06 PM..
rabbit73 is offline   Reply With Quote
Old 01-20-2019, 07:48 AM   #9  
High Definition is the definition of life.
 

Join Date: Aug 2017
Location: Maine
Posts: 33
Default

I heard the best baluns for television is if you can find the really old Channel Master 94444's. They have the solid core wire. What do you guys think of those? Is there something better? Do these make a difference?
Mogoamerica is offline   Reply With Quote
Old 01-21-2019, 09:40 AM   #10  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default

Quote:
Originally Posted by Mogoamerica View Post
I heard the best baluns for television is if you can find the really old Channel Master 94444's. They have the solid core wire. What do you guys think of those?
The original 94444 is very good, but it is now almost impossible to find. Some dealers are using a photo of the original 94444, but sending the redesigned version that has the SAME model number.





I made some comparison tests by measuring the loss of two in series and dividing by 2:





I noticed that the loss readings for the new 94444 were not consistent when I moved the leads, so I made them shorter. The very long leads form a transmission line of indefinite impedance.







Quote:
Is there something better?
Channel Master claims that their new CM-3203 is better, but I haven't seen any measurements to prove that.
https://www.channelmaster.com/TV_Ant..._p/cm-3203.htm



Quote:
Do these make a difference?
It might make a slight difference on a marginal signal, but it will not make a 50% signal 100% reliable, because OTA signals constantly vary in strength, sometimes as much as 10 dB in 30 minutes.

The lowest loss balun is a half-wave coaxial balun, but it is a DIY device.

Last edited by rabbit73; 01-21-2019 at 01:55 PM..
rabbit73 is offline   Reply With Quote
Old 01-27-2019, 04:07 AM   #11  
Go to a movie tonight
 

Join Date: Sep 2008
Location: Gettysburg, PA
Posts: 161
Default

I picked up some Philmore MT47 baluns from Full Compass about a year ago because they have the solid wire leads like the original CM94444 and they do look well built but I have not used them yet.

https://www.fullcompass.com/prod/015...hoC85UQAvD_BwE
Pamajestic is offline   Reply With Quote
Old 01-27-2019, 08:51 AM   #12  
It's the Antenna!
 

Join Date: Apr 2010
Posts: 975
Default



Quote:
Originally Posted by Pamajestic View Post
I picked up some Philmore MT47 baluns from Full Compass about a year ago because they have the solid wire leads like the original CM94444 and they do look well built but I have not used them yet.

https://www.fullcompass.com/prod/015...hoC85UQAvD_BwE
Looks promising; testing would tell how good it is. Thanks.

Last edited by rabbit73; 01-27-2019 at 11:49 AM..
rabbit73 is offline   Reply With Quote
Sponsored Links
Go Back   High Def Forum - Your High Definition Community & High Definition Resource >
AddThis Social Bookmark Button
Reply

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 09:11 PM.



Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004 - 2018, MH Sub I, LLC dba Internet Brands