Hello Joe,

Thanks for the reply, appreciate it.

Yes, the phasing harness is different, but my guess was that this shouldn't make a lot of difference as long as you get the 90 degree phase and the impedance right. If you look at the radiation patterns for both then they are nearly identical, hence my question if they are not one and the same thing.

It came up here because I have two DCAs right now, one for 2m, one for 70cm, both RHCP, no pre-amps. I do hear some birds, but signals are very weak. The 2m one works fine when receiving the NOAA wx sats, so I was wondering if the 30 degree angle of the Lindenblad would be better for amateur sats. I lack the knowledge to understand the difference between, what you say, the geosynchronous orbit of NOAA sats and the LEO orbits of our sats. NOAA wx sats are also LEO sats, not? I'll see if Google turns up something there.

It's easy for me to change the tilt of my DCAs to 30 degrees, so I'll try that this week. Should be a nice experiment.

73 de Hans BX2ABT

Hans,

Here are links with antenna patterns for the DCA:

https://drive.google.com/file/d/0B0Dkk87YYl-xX2gzLXk5MHZKVU0/view

and the EZ-Lindenblad:

http://www.amsat.org/wordpress/wp-content/uploads/2015/08/An-EZ-Lindenblad-A...

The difference is in the lengths of the "RG-59 (75ohm) phasing harness" and dipoles to achieve a 50 ohm impedance at the required frequency.

The angle of the crossbooms affects the directivity of the antenna, in the examples given, 60 degrees for a NOAA satellite in a geosynchronous orbit and 30 degrees for a LEO orbit.

The only differences I see are the 50 ohm load feedpoint and the Lindenblad dipoles are not exactly in the same plane as the DCA.

-73, Joe Spier, K6WAO President, AMSAT