OK, but I'm not sure if the "first element" is the top or the bottom. The more popular coaxail types use a freespace 1/4 wave radiator at the top. The bottom 1/4 radiator is used to decouple the feed line (prevent feed line radiation).
You also have to pay attention to the coax type and specs for proper lengths. One project version I've seen in the Brown Cover (older) ARRL Antenna Handbook has a nice project detailed. Of specific note is the testing during construction of shorter sections, before the entire antenna is constructed. The mentioned version has both the top and bottom 1/4 sections as detailed above. If you're really into this, maybe one of us (including myself) would be able to scan & Email the ARRL project antenna for you. cheers skipp --- In [email protected], bradley glen <[EMAIL PROTECTED]> wrote: > Hi Skipp > > Using coaxial-type and have tried both the coax and > solid screen by way of solid copper sleeving over > centerwith dielectric from rg-213. > > My question is that there seems to be very different > thoughts on the first element-some use 1/4 and others > use 1/2. > Every article-design seems to state that there antenna > works well or better than antenna X or Y. > Of all the designs none have substantiated the design > with an analyser of any kind -all are going on only > VSWR readings.Good VSWR does not mean good antenna . > > Kind regards > > Bradley Glen ZS5WT > --- zip14225 <[EMAIL PROTECTED]> wrote: > > Bradley, > > > > I'm not sure what type of the many collinear > > antennas you're trying to match. Are you working > > on a coaxial type or an aluminum tube type. > > > > Many collinear type antennas can be broken into > > sections and matched at each section. You give > > us a bit more info, we'll give you a few more > > thoughts. > > > > cheers > > skipp > > > > > bradley glen <[EMAIL PROTECTED]> wrote: > > > Hi > > > > > > Anyone had further development with a decent > > matching > > > design that is constant . > > > > > > I have made several designs of which none seem to > > be > > > consistant and reliable in matching .The designs > > on > > > the web are : feed straight onto the first > > halfwave > > > element-others have a quarter wave section before > > the > > > first half wave element.one feeding a high Z-other > > one > > > feeding a low Z.??????????? > > > > > > I am using a sitemaster-Anritsu s331-c and not a > > > simple vswr meter. > > > > > > Regards > > > > > > Bradley Glen ZS5WT Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
