AE4PB@carolinaheli.com

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AE4PB@carolinaheli.com

John Kosko
The response from K4TAX was fine if you’re willing to settle for >2:1 SWR at the antenna.  If you want a better match, consult the book, “Understanding, Building and Using Baluns and Ununs” – Jerry Sevick W2FMI, which is/was available at the ARRL store.  I have a copy and found page 92 talks about building a 2:1 Unun for 32Ohms to 50Ohms and the same design can also match 50Ohms to 75Ohms.  Note that the ratio 32 Ohms to 75 Ohms is not quite what this Unun is supposed to perform…but it’s close.  Efficiency into 50Ohms is purported to be 97-99% over 1 to 30 MHz.   Also note that baluns like to work into a non-reactive load.  73

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Re: AE4PB@carolinaheli.com

Bob McGraw - K4TAX
Yes correct.  However as one will reduce the loss in the CATV coax and
will likely increase the loss in the matching network at the base of the
antenna.  The mismatch loss in the CATV coax is 0.205 dB, based on
earlier calculations.   I would question the loss in a broadband network
to be less.

73

Bob, K4TAX


On 3/31/2020 2:21 PM, John Kosko wrote:

> The response from K4TAX was fine if you’re willing to settle for >2:1 SWR at the antenna.  If you want a better match, consult the book, “Understanding, Building and Using Baluns and Ununs” – Jerry Sevick W2FMI, which is/was available at the ARRL store.  I have a copy and found page 92 talks about building a 2:1 Unun for 32Ohms to 50Ohms and the same design can also match 50Ohms to 75Ohms.  Note that the ratio 32 Ohms to 75 Ohms is not quite what this Unun is supposed to perform…but it’s close.  Efficiency into 50Ohms is purported to be 97-99% over 1 to 30 MHz.   Also note that baluns like to work into a non-reactive load.  73
>
> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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