Hi Guys Thanks for the notes -all noted and apppreciated.
A close up of any of the db open systems , especially the close up of a single element would be greatly appreciated. I have done many searches on repeater antennas and it seems like the vhf\uhf standard in the USA is decibel . In my past company we did use the ASP series of 2 and 4-stacks-we outshined the competition by far -I always said it were decent antennas. I have made some single antennas years ago with some success using that very same principle.By reducing the folded dipole to mast(reflector) one decreases the feed impedance so by the comments from you , the harness ends with 75 Ohm coax onto the element it now makes some sense. I did recover one db-224 from a remote site which was damaged due to water (black death) right through. With so many of Db antennas used there should be a dedicated forum to "Repeater Antennas ". Kind regards Bradley Glen ZS5WT --- Steve Grantham <[EMAIL PROTECTED]> wrote: > I think you will find that the feed point is 50-Ohms > when feeding one of these single unbalanced dipole > elements. The harness is for making the multiple > elements on the array look like one element to the > transmission line. Look at their (DB's) folded > unipole antenna for low band. It's a ground-plane > antenna with a similar radiating element that's fed > with 50-Ohm line. The difference is that it's got > radials on it instead of a mirrored counterpoise. > There may be other subtle differences, but... > > Steve, aa5sg > ----- Original Message ----- > From: Paul Guello > To: [email protected] > Sent: Thursday, April 15, 2004 1:19 PM > Subject: Re: [Repeater-Builder] Decibel repeater > antenna question-unbalanced radiating loops > > > There are not any baluns on these antennas. If I > remember right, they use 75 ohm coax on each bay > (odd multiples of quarter wave length) and 35 ohm > coax on the feed (again odd multiples) to match the > impedance to 50 ohms. This info was on the group a > while back, somebody must still have it. > > Paul, kb9wlc > > > > Mathew Quaife <[EMAIL PROTECTED]> wrote: > Would a close up pic of a DB304 work for your > needs, or I have the DB420 there as well. > > Mathew > > > bradley glen <[EMAIL PROTECTED]> wrote: > Hi > > I have been studying the db stacked array and > the > bayed array seems to use unbalanced dipoles as > the > radiators .I have tried to find a close up > view of a > single dipole so I can confirm my ideas. > > If anyone has some good tech info on these > antennas I > would appreciate the info. > > It would make sense to " by-pass " the need of > baluns > for each dipole -cost and balun loss????? > > Regards > > Brad > ZS5WT Repeater Owner > [EMAIL PROTECTED] > > > > > > > __________________________________ > Do you Yahoo!? > Yahoo! Tax Center - File online by April 15th > http://taxes.yahoo.com/filing.html > > > > > > Yahoo! Groups Links > > > > > > > > ---------------------------------------------------------------------------- > Do you Yahoo!? > Yahoo! Tax Center - File online by April 15th > > > > > > > > > ------------------------------------------------------------------------------ > Do you Yahoo!? > Yahoo! Tax Center - File online by April 15th > > > > > > > > ------------------------------------------------------------------------------ > Yahoo! Groups Links > > a.. To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > b.. To unsubscribe from this group, send an > email to: > [EMAIL PROTECTED] > > c.. Your use of Yahoo! Groups is subject to the > Yahoo! Terms of Service. > > __________________________________ Do you Yahoo!? Yahoo! Tax Center - File online by April 15th http://taxes.yahoo.com/filing.html 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/
