[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: The crossed yagis on the Dayton AO-40 demo station



Wayne,

Is there a simple way to explain which yagi goes in front
of the other to get RHCP or LHCP?

Jack, K2BMI



On Tue, 21 May 2002, Estes Wayne-W10191 wrote:

> Tom Busch wrote:
>
> I'm fired up about Cheap Yagi arrays.
> I had one comment/observation.  I noticed that the Cheap Yagis mounted on
> Howard's umbrella dish for the AO-40 demo station did not appear to use
> the 17 inch, 72-ohm coax power divider described in the article in CQ-VHF.
>
> So, I guess I'm asking what the phasing harness does, if I'm feeding them
> in phase anyway.
>
>
> Wayne replies:
>
> My 7x7 Arrow CP yagi uses identical matching as Howard's CP "cheap yagi".  The two planes are physically offset by a quarter wavelength, so there is no "phase shift" section on one side of the Tee.  The 75 Ohm coax connections on each side of the Tee merely match the two 50 Ohm antenna feedpoints to the 50 Ohm feedline.
>
> The "top" of the Tee is about 11 inches long.  I suppose it would be about 17 inches long if a quarter wave phasing section was added.  But that would only be needed if the two antenna planes were NOT physically offset by a quarter wavelength.
>
> Wayne Estes W9AE
> Mundelein, IL, USA
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home