Mike, do a Bing or Google search "rebuilding Cushcraft A3S" or "tuning
Cushcraft A3S" and you will find the resonant trap frequencies and cap values
on a site where a guy has some rebuilding info for that tribander -- at least
that will get you started.
Another place to search is for the fellow that rebuilds the Cushcraft R-5 --
R-7 verticals -- some good info there also.
John NA6L
-----Original Message-----
From: Mike Baker <k7dd@cox.net>
To: 'Ed Haggerty' <himself@edhaggerty.com>
Cc: TowerTalk <TowerTalk@contesting.com>
Sent: Wed, Mar 7, 2012 5:22 pm
Subject: Re: [TowerTalk] Hustler 6BTV Question
I guess I need to clarify my real needs here.
I am not putting together a 6BTV. I have one and it works fine.
I am looking to build a trap tribander Yagi. My question was really about
what the resonant frequency of the trap is in ANY trapped antenna. I read
someplace it shouldn't be in the band of trapping but outside the band a bit
because the series losses of the trap on to the next lowest trap inline
would be higher if they were in band. That raises the question: below the
band of desired trapping or above the band. Ad how much off band should they
be? 1% above the top or 1% below the bottom? What? I see lots of traps made
of coax but I was thinking more about using a coil over a solid former (like
the Hustler traps are made) with a piece of coax as the tuning capacitor.
(Much like what the ATB-34 Cushcraft Yagi used.)
So, my real question is how far off band center should the trap be?
Oh, and I know how many turns for each trap in a Hustler but what I don't
know is the capacitor value and I can't calculate that without knowing the
resonant frequency. A catch 22 sort of...
Mike Baker K7DD
K7dd@cox.net
All QSO's are uploaded to LOTW and EQSL.
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Ed Haggerty
Sent: Wednesday, March 07, 2012 10:23 AM
To: Mike Baker
Cc: TowerTalk@contesting.com
Subject: Re: [TowerTalk] Hustler 6BTV Question
Mike
The resonant frequency of the trap is not a fixed value. The primary
component to the value is the number of turns. (what Hustler said with out
saying).
The next component is the depth of insertion of the bottom section of
aluminum tubing. Do a googel search on:
Hustler BTV Series Trap Calibration Resonance Adjustment Procedure
This will give you a better understanding.
On 7 Mar, 2012, at 9:20 AM, Mike Baker wrote:
> Hi Guys,
>
> Does anyone on this forum know what the self-resonant frequency of
> each of the traps is for a Hustler 6BTV? I have asked this question of
> the manufacturer a few times and they give me tuning info for the
> antenna but not what I was requesting.
> Yes, I know this is a bit off topic but this does seem to be a
> well-informed forum.
>
> Thanks in advance.
>
> Mike Baker K7DD
> K7dd@cox.net
>
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
73
Ed KB3TOX OMISS-8168
Grid square FM29bs
AIM -- kb3tox@mac.com
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