Re: [Repeater-Builder] DB-224 problem
I once inherited a DB-224 that the shop had discovered was not performing as it should. A new antenna fixed the coverage problem the first antenna had. When I got the antenna, I discovered that one of the elements had been inverted. When I installed the antenna I turned that element back to match the other elements and it worked just fine. As an aside, I helped a buddy build a couple of six meter four element beams and when he installed them, the performance was miserable. When I got a look at the installation I could tell that the gamma feed on one antenna was on one side of the boom and the other side on the other boom. When the lower antenna was flipped over to match the upper antenna the stacked beams worked fine. For the pattern of the individual elements to sum properly at a remote site for these types of antennas, the elements must all be fed in phase. Inverting an element or reversing the gamma feed causes the elements involved to be out of phase with the other elements in the antenna. 73 - Jim W5ZIT "R. K. Brumback" <[EMAIL PROTECTED]> wrote: After a day of work putting together and putting up a DB224E in the 138-150 range I found the thing to be resonate at 150 MHZ center. After a few colorful metaphors, I find I turned one of the elements upside down with the feed at the bottom. Would this be enough to throw the antenna off balance or should I look for problems somewhere else also? I get a 2.0 SWR at 146.000. I dont mind a second trip up the tower to turn the element around (its the lower element), but that third trip would do me in! Randy B. W4CPT __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Re: [Repeater-Builder] DB-224 problem
They are fed in phase, but if one is upside down, that element is out of phase with the others. Chuck WB2EDV - Original Message - From: "MCH" <[EMAIL PROTECTED]> To: Sent: Sunday, April 13, 2008 12:56 AM Subject: Re: [Repeater-Builder] DB-224 problem >I thought all the elements were fed in phase... > > Joe M. > > Eric Lemmon wrote: >> And yes, one element fed out-of-phase will screw up the pattern. > > > > > > Yahoo! Groups Links > > > >
Re: [Repeater-Builder] DB-224 problem
I thought all the elements were fed in phase... Joe M. Eric Lemmon wrote: > And yes, one element fed out-of-phase will screw up the pattern.
Re: [Repeater-Builder] DB-224 problem
To me, I wouldn't have expected it to have thrown things that far out of whack - except for what it's doing to the pattern. But these things can fool you. Is it top mounted or side mounted? Configuration - omni or other? Any guy wires near it? In any event, report back with results after you correct the upside-down element.. Chuck WB2EDV - Original Message - From: R. K. Brumback To: [EMAIL PROTECTED] com Sent: Saturday, April 12, 2008 8:05 PM Subject: [Repeater-Builder] DB-224 problem After a day of work putting together and putting up a DB224E in the 138-150 range I found the thing to be resonate at 150 MHZ center. After a few colorful metaphors, I find I turned one of the elements upside down with the feed at the bottom. Would this be enough to throw the antenna off balance or should I look for problems somewhere else also? I get a 2.0 SWR at 146.000. I don’t mind a second trip up the tower to turn the element around (it’s the lower element), but that third trip would do me in! Randy B. W4CPT
RE: [Repeater-Builder] DB-224 problem
Randy, I have been down that road myself, so I feel your pain! Unless you are willing to let this one incident haunt you for the rest of your life, you should fix the problem now. And yes, one element fed out-of-phase will screw up the pattern. Look at the bright side: Fresh air, good exercise, proper antenna pattern. You can't ask for more! 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of R. K. Brumback Sent: Saturday, April 12, 2008 5:05 PM To: [EMAIL PROTECTED] com Subject: [Repeater-Builder] DB-224 problem After a day of work putting together and putting up a DB224E in the 138-150 range I found the thing to be resonant at 150 MHZ center. After a few colorful metaphors, I find I turned one of the elements upside down with the feed at the bottom. Would this be enough to throw the antenna off balance or should I look for problems somewhere else also? I get a 2.0 SWR at 146.000. I don't mind a second trip up the tower to turn the element around (it's the lower element), but that third trip would do me in! Randy B. W4CPT
[Repeater-Builder] DB-224 problem
After a day of work putting together and putting up a DB224E in the 138-150 range I found the thing to be resonate at 150 MHZ center. After a few colorful metaphors, I find I turned one of the elements upside down with the feed at the bottom. Would this be enough to throw the antenna off balance or should I look for problems somewhere else also? I get a 2.0 SWR at 146.000. I don’t mind a second trip up the tower to turn the element around (it’s the lower element), but that third trip would do me in! Randy B. W4CPT No virus found in this outgoing message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.12 - Release Date: 4/10/2008 12:00 AM
