It doesn't matter if you can achieve the required element-to-element spacing
and the top of the mast extends several inches beyond the top of the top
element and the bottom of the mast extends several inches below the bottom of
the bottom element.
Chuck
WB2EDV
----- Original Message -----
From: k5in
To: Repeater-Builder@yahoogroups.com
Sent: Monday, March 23, 2009 7:46 PM
Subject: Re: [Repeater-Builder] Re: Decibel dipole array sweeps
Jeff,
Well, for that matter anybody that wants to answer. How long is the mast
supposed to be on a DB413?
I have one with a mast that is 12ft in length. Does it really matter when it
is 140ft in the air, 40 inches off the side of a tower?
Brian, k5in
----- Original Message -----
From: Jeff DePolo
To: Repeater-Builder@yahoogroups.com
Sent: Sunday, March 22, 2009 2:49 PM
Subject: RE: [Repeater-Builder] Re: Decibel dipole array sweeps
I'd be interested in seeing what you have. Back in the old days of Decibel,
they would send you good info if you were able to get to the right person.
I haven't had that kind of success since Andrew bought them out.
Just this week I came across a non-catalog Decibel antenna on a tower (the
one where this DB413 is going). It was a Decibel DB478E-JJ fiberglass omni.
I can't find it any of my catalogs, nor on the web. I'm fairly certain it's
a 220 MHz antenna based on the -JJ suffix. I also have a DB420 that has a
factory label on it that says 450-482 MHz. There's a lot of custom stuff
out there from the "old" Decibel, too bad Andrew has drastically cut back on
the special-order products...
--- Jeff WN3A
> -----Original Message-----
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tom, N6MVT
> Sent: Sunday, March 22, 2009 5:10 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Re: Decibel dipole array sweeps
>
> On a somewhat related notes...I had to do some research on
> the rare (and not currently made) down tilt models from db
> products. I have some paperwork with measurements and notes
> on them from their "archives".
>
> Not complete or easy to read (originally faxed) but it helps
> to determine if you might have a 4 or 9 degree downtilt
> harness and other related parts measurements.
>
> If someone is in need of them I can either e-mail or perhaps
> post on this site.
>
> Also, I have seen some of the dipoles get modified with short
> stainless machine screws+nuts drilled through the top &
> bottom of the dipole elements, to help get the Return Loss
> even better at lower freqs.
>
> Not sure what, if any, skewed pattern is introduced by doing
> the machine screw mod or not. Quite often it's hard to tell
> any changes in the field unless it is very drastic.
>
> Tom
>
>
>
>
>
> No virus found in this incoming message.
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> Date: 03/21/09 17:58:00
>
>
>
