Login  Register

Re: 75ohm Impedance question K3S and Antenna side.

Posted by John K9UWA-2 on Apr 01, 2020; 12:28pm
URL: http://elecraft.85.s1.nabble.com/75ohm-Impedance-question-K3S-and-Antenna-side-tp7659364p7659411.html

Ah YES I noticed it is for a multi band antenna.

2 wavelengths 3540 = 265'
4 wavelengths 7080 = 265'
6 wavelengths 10600 = 265'
8 wavelengths 14160 = 265'
12 wavelngths 21240 = 265'
16 wavelengths 28320 = 265'

Multiply the 265' by velocity factor of the coax and you will be someplace just a bit
over 200 feet.

the 10mhz band is off a bit. So OK... other than that 80, 40, 20, 15,10 are all
harmonically related.   As I said 50 in and 50 out. If the OP runs this vertical on 17
and 12m then yes he will have maybe a 1.5 / 1 mismatch caused by the coax. But
the antenna isn't designed for 17 and 12.

I cut all the 3/4" CATV in my system with a Hewlett Packard HP 4815A Vector
Impedance Meter. Any 1/2 wave mult the the SWR is the same in as out.  Any
ODD 1/4 wavelength multiple creates a transformation With Multiple 4 hi stacks of
yagi's I have many of those in the system as well. 75 ohm cable works well to put
pairs or quads of yagi's together.

The only thing that maybe won't be perfect is the actual vertical itself may not be a
50 ohm input.  His vertical is a  Hustler 6BTV.  
73
John k9uwa

On 31 Mar 2020 at 22:39, Jim Brown wrote:

> On 3/31/2020 8:52 PM, John K9UWA wrote:
> > Cut the hardline to multiples of 1/2 wavelength and the swr will be 1 to 1 on
> > both ends. 50 in 50 out.
>
> Did you notice that this is for an all-band antenna?
>
> 73, Jim K9YC
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

John Goller, K9UWA & Jean Goller, N9PXF
Antique Radio Restorations
[hidden email]
Visit our Web Site at:
http://www.JohnJeanAntiqueRadio.com
4836 Ranch Road
Leo, IN 46765
USA
1-260-637-6426

______________________________________________________________
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
Message delivered to [hidden email]