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TV Antennas in parallel

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user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Dec 20, 2012 8:23 am Post subject: TV Antennas in parallel

This is not aviation related, but may be of interest to electron herders.

Cable is not available at my location.  I get TV signals from antennas in the attic.  I read some place that two antennas can be connected together if the feed lines are of equal length.  I took it one step further and connected 3 antennas together using equal (â‰ˆ 8 foot) lengths of 300 ohm twin-lead TV antenna cable.  The 3 antennas point in different directions.  I was surprised to receive even more stations than I had hoped for, a total of 34 counting the sub-channels, all with digital quality.

Joe

_________________
Joe Gores

sam.marlow

Joined: 25 Feb 2006
Posts: 99

Posted: Thu Dec 20, 2012 10:46 am Post subject: TV Antennas in parallel

Where did you purchase your antennas?



user9253 wrote:

 	  Quote: 	
		   



 This is not aviation related, but may be of interest to electron herders.

 Cable is not available at my location.  I get TV signals from antennas in the attic.  I read some place that two antennas can be connected together if the feed lines are of equal length.  I took it one step further and connected 3 antennas together using equal (â‰ˆ 8 foot) lengths of 300 ohm twin-lead TV antenna cable.  The 3 antennas point in different directions.  I was surprised to receive even more stations than I had hoped for, a total of 34 counting the sub-channels, all with digital quality.

 Joe



 --------

 Joe Gores





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=390745#390745

harley(at)AgelessWings.co
Guest

Posted: Thu Dec 20, 2012 12:17 pm Post subject: TV Antennas in parallel

I did the same thing that Joe did, but with only two antennas...I     get 32 channels over the air (again, including the subchannels),     here just south of Rochester NY, most from Rochester, but some of     them from Buffalo.  

     

     I didn't buy the antennas, I made them, and mounted them in the     crawl space above my ceiling, pointing North and West (although,     unlike the instructions, I used old wire coat hangars for the wire,     didn't use screws and washers to connect but scraped the enamel off     where contact was needed and soldered them together, and bent them     so the cross wires don't touch...didn't use any shrink tubing):

     

 www.popularmechanics.com/technology/how-to/tv/build-your-own-digital-tv-antenna

     

     You can also find a number of video instructions to make these on     Youtube. And they do work better than any commercial ones I've used     in the past.  I am thinking of dropping Dish Network, as several of     the channels I receive here over the air are also on Dish (Ion for     example)!

     

     Harley

          

       On 12/20/2012 1:47 PM, Sam Marlow wrote:

     

     [quote]-->       AeroElectric-List message posted by: Sam Marlow       <sam.marlow(at)roadrunner.com> (sam.marlow(at)roadrunner.com)       

       

       Where did you purchase your antennas?       

       

       user9253 wrote:       

        	  Quote: 	
		  --> AeroElectric-List message posted         by: "user9253" <fransew(at)gmail.com> (fransew(at)gmail.com)         

         

         This is not aviation related, but may be of interest to electron         herders.         

         Cable is not available at my location.  I get TV signals from         antennas in the attic.  I read some place that two antennas can         be connected together if the feed lines are of equal length.  I         took it one step further and connected 3 antennas together using         equal (â‰ˆ 8 foot) lengths of 300 ohm twin-lead TV antenna         cable.  The 3 antennas point in different directions.  I was         surprised to receive even more stations than I had hoped for, a         total of 34 counting the sub-channels, all with digital quality.         

         Joe         

         

         --------         

         Joe Gores         

         

         

         

         

         Read this topic online here:         

         

         http://forums.matronics.com/viewtopic.php?p=390745#390745         

         

         

         

         

         

         

         

         

         

         

         

       	
       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       -----       

       No virus found in this message.       

       Checked by AVG - www.avg.com       

       12/19/12       

       

       

     [b]

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Dec 20, 2012 5:41 pm Post subject: Re: TV Antennas in parallel

 	  Quote: 	
		  Where did you purchase your antennas? 	


I do not remember where I bought them.  They have been in the attic for years.  Long ago there were 3 sets of lead-in cables connected to a RF A-B-C switch behind the TV.  Now the A-B-C switch is not needed.  There is only one lead-in cable used.

Joe

_________________
Joe Gores

john.maccallum(at)bigpond
Guest

Posted: Thu Dec 20, 2012 6:39 pm Post subject: TV Antennas in parallel

Hi Joe,



That is a good outcome but usually you just can't add antennas in parallel

like that due to Impedance and phasing mismatches.

The feedlines need to be matched to the frequency you are working at and be

either 1/4 wave or 1/2 wavelength multiples depending on 

The antenna configuration and not just be equal lengths.

The characteristic feed line impedance in your 300 ohm hook up will be way

off and it will not be 100 ohms as is suggested by simple

Mathematics and as well the impedance will also vary with frequency.

Multipath will cause issues with such a setup and the antennas will have

multiple

lobes and nulls. Being in the attic instead of outside is less than ideal to

boot.



But if it works it works! Just don't expect it to work at other locations

with the same degree of success.



Cheers

John MacCallum

VH-DUU

RV 10 # 41016



VK2GCN





--

mrspudandcompany(at)veriz
Guest

Posted: Fri Dec 21, 2012 10:12 am Post subject: TV Antennas in parallel

I did the same thing that Joe did, but with only two antennas...I get 32 channels over the air (again, including the subchannels), here just south of Rochester NY, most from Rochester, but some of them from Buffalo.  

  

 Harley  [quote]  How did you connect the 2 antennas together?  Did you use an impedance match transformer at the antennas?  A picture or a simple sketch would be interesting. Roger[b]

harley(at)AgelessWings.co
Guest

Posted: Fri Dec 21, 2012 11:15 am Post subject: TV Antennas in parallel

How           did you connect the 2 antennas together?  

     

 www.amazon.com/CHANNEL-2512-Passing-Splitter-Combiner/dp/B00006JPEA/ref=pd_cp_e_0

      [quote][b]

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Fri Dec 21, 2012 11:29 am Post subject: Re: TV Antennas in parallel

 	  user9253 wrote: 	
		  snip...  I was surprised to receive even more stations than I had hoped for, a total of 34 counting the sub-channels, all with digital quality.

Joe 	




 Except for TV, nature abhors a vacuum.

 My condolences, Joe.

mrspudandcompany(at)veriz
Guest

Posted: Fri Dec 21, 2012 12:05 pm Post subject: TV Antennas in parallel

How did you connect the 2 antennas together?        

  



 www.amazon.com/CHANNEL-2512-Passing-Splitter-Combiner/dp/B00006JPEA/ref=pd_cp_e_0  [quote]   OK, the above is one piece of the puzzle!  I am assuming that you connected an impedance matching transformer to each of the antennas then went through the above combiner with the outputinto a 75 ohm cable to the TV. Roger[b]

harley(at)AgelessWings.co
Guest

Posted: Fri Dec 21, 2012 12:21 pm Post subject: TV Antennas in parallel

Yeah...I didn't mention them because as far as I'm concerned they     are part of the antenna themselves... as part of the construction.

     

      

     On 12/21/2012 3:05 PM, Roger & Jean       Curtis wrote:

     

     [quote]                

How did you connect the 2 antennas                 together?                                       

         



               www.amazon.com/CHANNEL-2512-Passing-Splitter-Combiner/dp/B00006JPEA/ref=pd_cp_e_0          	  Quote: 	
		     OK, the above is one piece of the puzzle!  I am assuming that you connected an impedance matching transformer to each of the antennas then went through the above combiner with the outputinto a 75 ohm cable to the TV. Roger 	
       

     [b]

ceengland7(at)gmail.com
Guest

Posted: Fri Dec 21, 2012 12:37 pm Post subject: TV Antennas in parallel

On 12/21/2012 2:05 PM, Roger & Jean Curtis wrote:      	  Quote: 	
		                                         

          

How did you connect the 2 antennas                 together?                                       

         



               www.amazon.com/CHANNEL-2512-Passing-Splitter-Combiner/dp/B00006JPEA/ref=pd_cp_e_0          	  Quote: 	
		      	  Quote: 	
		  http://www.google.com/search?q=tv+balun&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a 	
OK, the above is one piece of the puzzle!  I am assuming that you connected an impedance matching transformer to each of the antennas then went through the above combiner with the outputinto a 75 ohm cable to the TV. Roger 	
       

       

     	
     TV balun for converting 300 ohm balanced             (antenna) to 75 ohm unbalanced (coax):

             

              	  Quote: 	
		  http://www.google.com/search?q=tv+balun&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a 	
             

             A regular 75 ohm splitter can be turned around & used as             a combiner for a lot less money than the one shown with the             DC pass-through (assuming you don't need the pass-through):

              	  Quote: 	
		  http://www.google.com/search?q=4+way+splitter&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a 	
             The only need for a DC pass-through is if you're using some             type of remotely powered RF amp.

             

             You can buy frequency selective filters that will reduce             interference from 2 antennas seeing the same station, but as             others have demonstrated, you often don't need them. 

             

             Charlie

             

             

                 [quote][b]

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Sat Dec 22, 2012 7:34 pm Post subject: Re: TV Antennas in parallel

http://www.hdtvprimer.com/ANTENNAS/ganging.html

There is a drawing on this website that is similar to the way that I connected my antennas together, except that my 3 antennas are all connected in parallel.  Another 300 ohm cable connects that junction to a balun for conversion to 75 ohms.  After reading this article, I realize that I am lucky to have good reception.

Joe

_________________
Joe Gores

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