I've received word that the Dropbox link was requiring sign-ups to Dropbox, so I have created a link to the Smith chart using a different image upload service:
http://imgur.com/a/RmE1Q 73, Matt NQ6N On Thu, Mar 9, 2017 at 1:04 PM, Matt Murphy <[email protected]> wrote: > I realized the attached Smith chart image did not come through on the > reflector so I posted it on the web, here is the chart: > > https://www.dropbox.com/s/nwfqr6xhsfdgjjb/Screenshot% > 202017-03-09%2013.03.33.png?dl=0 > > 73, Matt NQ6N > > On Thu, Mar 9, 2017 at 12:46 PM, Matt Murphy <[email protected]> wrote: > >> In preparation for the Stew I'm thinking of setting up a two element >> end-fire array aimed at Europe, and possibly another one aimed south. >> >> I've done some reading about these types of arrays and I think I >> understand >> the approach taken by W8JI in his design of the short verticals he uses, >> as >> well as the design of the YCCC short vertical. >> >> Just for kicks I decided to model a short vertical that used matching >> stubs >> made with RG-59. >> >> I'd like to ask for advice on this approach. I would use the array on >> 160m >> only, and the objective is for it to have better RDF than my inverted L, >> so >> even a few dB would be helpful. >> >> I modeled a 6' vertical element in CocoaNEC and designed a matching >> network >> using SimSmith.I have attached the Smith chart of the matching stubs. >> >> In my CocoaNEC model, the feed point impedance does not change much if I >> increase the length of the element to 30', and the matching network is not >> sensitive to changes in the feed point impedance. I wonder if this >> matching network might just be equivalent to matching the coax with no >> antenna connected (and if so what that means for the antenna's >> performance) >> >> Any advice on the antenna, matching network, etc., would be much >> appreciated. My next step is to build one and verify that my real world >> results for a single element match the model's prediction, and if so, to >> subsequently build a second one and connect them with a phasing line to >> achieve end-fire directivity over the bottom end of 160m. >> >> Advice much appreciated. >> >> 73, Matt NQ6N >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
