[TenTec] Smaller 20M Rohmbic Question

[Don Jones]

Thank you Jerry and Steve,

I was figuring 70-ish at the feed point based upon what I could find about
vee-beams. Here in W. WA we are going to point it at 80 deg magnetic for
field day. We have a very large field and it is perfect for one of these. 

We are going to just live with what we get on the other bands.

73,

Don Jones KO7i
Arlington, WA 


-----Original Message-----
From: Steve Hunt [mailto:steve at karinya.net] 
Sent: Monday, April 11, 2011 4:03 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Smaller 20M Rohmbic Question

What Jerry said!

It models as having a gain of 8dBd and a half-power beamwidth of about 
+/- 30 degrees.
Hope you can erect it in the direction you need ;)

73,
Steve G3TXQ


-----Original Message-----
From: Dr. Gerald N. Johnson [mailto:geraldj at weather.net] 
Sent: Sunday, April 10, 2011 6:41 PM
To: tentec at contesting.com
Subject: Re: [TenTec] Smaller 20M Rohmbic Question

Chart in my 1994 edition ARRL antenna handbook says the optimum angle 
varies with the the wave angle. Between 52 degrees for zero wave angle 
to 60 degrees for 30 degree wave angle. That's the tilt angle, the angle 
between the wires and the line between the side supports. So half the 
angle at the feed would be 90 - 52 to 60 or 30 to 38 degrees, V angle at 
the feed line then would be 60 to 76 degrees depending on the desired 
wave angle. I'd shoot for 15 or 20 degrees wave angle which calls for 
tilt angle of 53 to 55 degrees or 35 to 38 half angle at the V or 70 to 
76 degrees at the feed.

73, Jerry, K0CQ

On 4/10/2011 8:31 PM, Don Jones wrote:
> I am curious if anyone has any experience with smaller sized rhombic's
using
> 2 wavelength legs? What is a proper angle for the feed point?
> Thanks,
> Don Jones KO7i
> Arlington, WA
>
>
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