Outdoor 300-75ohm matching transformer?

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digitalanalog

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I am looking for the Best (of course) 300-75 ohm matching transformer, waterproof.

Wire ends on one end and "F" type connection on the other.

For wide band coverage 25-1300mhz. to be used on an omni directional scanner antenna.

Suggestions and why it's the best choice.

Just the simple facts, review(s) or your experience please.

Thanks
 

buddrousa

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If I remember it was a Channel master brand that came with the ST2's.
 

digitalanalog

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Has anyone ever done any comparison testing on different models and would like to share their results?

I can buy abunch of different name brands anywhere from $.99 - $ 8.99 and up but I was hoping someone has been through the brands and has some results.

I will also be buying in bulk so they need to be available.

I guess this is more then likly my best option unless anyone else has any ideas.

Just because it $19.00, That does not mean it's the best. That just means its not cheap.
Channel Master CM-3203
 

ArloG

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Has anyone ever done any comparison testing on different models and would like to share their results?

I can buy abunch of different name brands anywhere from $.99 - $ 8.99 and up but I was hoping someone has been through the brands and has some results.

I will also be buying in bulk so they need to be available.

I guess this is more then likly my best option unless anyone else has any ideas.

Just because it $19.00, That does not mean it's the best. That just means its not cheap.
Channel Master CM-3203
Google is your friend:

 

Ubbe

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I believe that the material that the balun are made of do not exists for a 25-900MHz range. You have to compromise to focus on either end of the frequency spectrum. It will have low effecience on low frequencies, too few windings and the transformer loss would be high, and the material will saturate at high frequencies that makes it attenuate the signals. The television baluns are probably only designed for 170-700Mhz and outside of that range they will be less efficient with some loss, probably cutting the signal levels in half, or more, at 35MHz and 900Mhz.

/Ubbe
 

Schwartzm9039

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Since the coverage range of the antenna is 25 to 1300MHZ, my suggestion is to not introduce a balun at all, and opt for a proper antenna rig with a Belden low-loss cable and proper termination. If that is not an option, then I would use a hand made 4:1 coaxial balun as documented here: The Creative Science Centre. I would also solder the twin lead to the coax directly, no balun, since this is receive only, to see if acceptable performance is achieved at the center of your wide range bandwidth. This would then be used to compare handmade, or commercial units. Give it a try.
 

Ubbe

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The coaxial balun you suggest are highly frequency dependent and would not be useable for a wide frequency range antenna.
A 300-75 ohm 4:1 balun will reduce the signal levels equal amount, 25% left. It has to be compared to what signal levels are at the other end of a coax when the impedances doesn't match but you have no loss in any impedance matching network. Practical tests will show what would be the best solution for scanner monitoring.

/Ubbe
 
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