Jim, you already know this but will mention as a reminder: In addition to
open and short, you can also terminate the shack end of the coax in a + or -
reactance to achieve whatever reactance needed at the feedpoint of the
parasitic element.
It sounds like you might be using a 45 degree or multiple coax length with
open or short termination to generate a + or - 50 ohm reactance at the
feedpoint. That seems a clever method of switching the parasitic dipole from
reflector to director if the dipole is tuned to the operating frequency.
Also, since both feed lines are available in the shack, you could drive
both dipoles at such a phase relationship as needed to achieve various
forward, reverse or even squint patterns. This would constitute a 2-el driven
array. Isn't the HB9CV style antenna like that?
73,
Gerald K5GW
In a message dated 2/22/2015 2:43:13 A.M. Central Standard Time,
jim@audiosystemsgroup.com writes:
On Sun,2/22/2015 12:09 AM, Jim Thomson wrote:
> another option is to cut the parasitic ele as a DIR.
Thanks for the suggestions, but thanks to limitations of the
installation, I'm stuck with what I've got up in the air. What I have is
simply two dipoles cut for the middle of the band, fed with RG11. I'm
driving one and tuning the reflector by varying the length of the coax
to an open or closed termination. In its half-done form, it's a three
position switch. Eventually it will be relays. :)
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|