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Transmitting thru a 4:1 balun

 
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Transmitting thru a 4:1 balun
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9YCH-FM
New registered user
New registered user


Joined: 01 Jun 2003
Posts: 5
Location: Vermont, USA

Post Transmitting thru a 4:1 balun Reply with quote
Hi all!
I'm using a homebrew folded dipole that is tacked to the wall above
this table- the computer, music and radio systems are all together. Using
75 ohm coax and needed a way to feed the (theoretically) 300 ohm
antenna.
I tried an ordinary recption-type balun. Screw terminals and a
female F-connector. Popped the plastic cover off and watched carefully to
see if it fried at 5 watts. No, but after about 30 seconds the ferrite
core was HOT. Ran 30 minutes no problem and shut down. Mounted a
Socket7 CPU fan just below it and ran for 10 hours. Barely warm to the
touch:-))
A hot transformer core means that it is waaay saturated. Histeresis
losses are high and the inductance is less than nominal. No
problem, tho- it is a voltage-type design and all that matters are the
ratio of turns. I'm located between two villages. This system provides
spotty coverage over hilly terrain to the farther village (7 miles) and fine
coverage to the nearer village (3 miles).

I'm going to have to break down and make a proper 6:1 balun at some
point. That, and an off-the-shelf FM Yagi (Channel Master Stereo Probe 9)
ought to extend solid coverage out to the farther village with the
on-axis ERP somewhere around 25-35 watts (after cable losses).
Tue Jun 03, 2003 4:00 am View user's profile Send private message Visit poster's website
Bill O. Rights
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Post Reply with quote
Your main problem is you've got it "tacked to the wall". No antenna is going to function properly, no matter what ratio of balun you use, "tacked to the wall".

Couple of things you need to include. Type of coax and length. Length of antenna. And elevation of your location.

You'd be better off running your sig into an omni FM antenna from the center of your room, than what you have posted.

Good luck

Bill O. Rights
Sat Oct 25, 2003 9:19 am
Black_Hawk
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Joined: 15 Mar 2004
Posts: 112
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Post Re: Transmitting thru a 4:1 balun Reply with quote


_________________
If they can get you asking the wrong questions, they don't have to worry about the answers. - Thomas Pynchon..If you make people think they're thinking, they'll love you; but if you really make them think they'll hate you. - Don Marquis..
Sat May 29, 2004 8:20 am View user's profile Send private message
Black_Hawk
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Joined: 15 Mar 2004
Posts: 112
Location: Entering The Flags...but simply an arm wielding a sword signifying power

Post PERSONALLY I PREFER A 1 TO 1 BALUN Reply with quote


Greetings,
There are Antenna designs that i would implement wherby if i need a Balun,then a 1 to 1 BAZOOKA TYPE IS MY PERSONAL CHOICE FOR EFFECTING A MATCH POINT..HAS ALWAYS WORKED FOR ME.

_________________
If they can get you asking the wrong questions, they don't have to worry about the answers. - Thomas Pynchon..If you make people think they're thinking, they'll love you; but if you really make them think they'll hate you. - Don Marquis..
Sat May 29, 2004 8:26 am View user's profile Send private message
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