Hey guys ,
Last month I worked my first EmE contact t with a big gun DL7APV , really good signals And was speaker copy at one time , I build a 4 x 15 elel DG7YBN yagis on a H frame , also made the power splitter . At the time I had a LDMOS 70cm in build but made my first also with just 30 watts !.
The next few days I could not even copy DL7APV at all , what was going on ? .
We’ll rotation was the problem and since it switched to vertical we had like -20 db loss so no chance .
This got me thinking of polarity switching , looking at how this was done Involved extrA yagis or crossed yagis , since other guys even rotated the whole array ,.
I sat down and thought about it , then I came to me , a way to get pol rotation , with no switching , no losses and using the same array !.
I got to works and built a prototype , using one of the DG7YBN yagis , 25 element .
Then one night when it was ready and a temp lash up to manually point it at the moon I waited till a big fan was available , then Bernd DL7APV came on and we started a test . Initially I was setting the Yagi horizontal , and on his CQ calls go nothing at all, that dreaded -20dm loss again or a factor of 100 ! No chance, so the I said to Bernd to Arsenal. Where I operated the rotation command ( takes 30 seconds ) , so we now had vertical polarisation with the same Yagi , no switching , no losses , and then tested again , this time we had a solid copy and decode it was speaker copy , I could hear his tones even!. This proved the concept worked very, very well , so. Next I’ll build and array of 4 x 25 ele yagis and apply the new GW4LWD DPS to the array ( Dynamic Polarity System ) .
This will make a pretty potent EME array , and any Yagi can.be used.
Here is an image link of the setup
https://www.dropbox.com/s/1gmr1wulpjpb1dp/IMG_1123.JPG?dl=0And here is a video clip of its operation.
https://www.dropbox.com/s/8jzshf9y1411n2f/IMG_1132.mov?dl=0This is a look what a full setup would look like.
https://www.dropbox.com/s/vhtvt9r05h3zypp/DA331C8A-8A80-4ECB-919E-108A59ABE849.jpeg?d l=0The actual setup in the test.
https://www.dropbox.com/s/i8hjcf62bq279wm/1C1891F4-5FAA-4303-BAAD-C525670D6FB0.jpeg?d l=0All the best guys
William
GW4LWD
