I have 4 stack of JP 2000 tribanders on one of my towers. Those are interlaced
10 element beams (3/3/4 elements respectively on 20/15/10) with single feedline
and boom of about 7.5 meters.
I find them pretty equivalent to respective monobanders with 3/3/4 elements and
I find 9m stacking distance almost optimal on all bands (yes I have done
The antennas are at 45/36/27/18m (150/120/90/60 feet).
I have been able to switch them in any configuration and in 99% of the time the
full stack is as good or best. The cases with closer stations when lower 2
prevail are not important in contest. They hear me with the stack as well. So I
have quit switching it.
The 4-stack BEATS HANDS DOWN my 5 over 5 on 20m (42/22m), 5 over 5 on 15
(29/15m) and 6 over 6 on 10 (26/19m). It simply perfect combination on all
bands. It also beats the same JP 2000 3-stack on 35/26/17m.
[mailto:email@example.com] On Behalf Of GALE STEWARD
Sent: Wednesday, February 24, 2010 10:39 PM
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] 3-Stack Tribander Issues
K3WW has a stack of three Skyhawks at 30/60/90 ft and it works great.
--- On Wed, 2/24/10, Bill Conwell <firstname.lastname@example.org> wrote:
> From: Bill Conwell <email@example.com>
> Subject: [TowerTalk] 3-Stack Tribander Issues
> To: firstname.lastname@example.org
> Date: Wednesday, February 24, 2010, 1:30 AM
> I’m thinking of building a 3-stack
> of tribanders. Folks who are familiar
> with stacked monobanders give me doubtful looks.
> I’m wondering who on the
> list has actual experience stacking tribanders, and what
> observations they can offer.
> By way of background, I was an EE in a past life, with a
> bit of professional
> experience with phased arrays for VHF/UHF and shortwave
> broadcast, and
> radar. So I appreciate the phased array concept.
> My contemplated stack has 8.6m spacing between antennas
> (with the top
> antenna at 130’). I recognize that half wave
> spacing has certain desirable
> attributes, and that my spacing is a bit large for 15m and
> a bit short for
> 20m. But modeling suggests that’s not a big
> deal. (I may cover 10m
> I expect to turn the top two antennas in tandem, and have
> the bottom antenna
> independently rotatable.
> I recognize that tribanders are, themselves,
> compromises. However, current
> designs seem a vast improvement over the designs of 30
> years ago. (I’m
> thinking of using one of the interlaced models, e.g., with
> 2 or 3 full sized
> elements per band.)
> I’m not interested in longer boom yagis – narrow in
> azimuth and broad in
> elevation pattern (e.g., beaming Europe only to put a null
> on Africa, or
> beaming Japan only to put a null on NZ/Australia).
> I’d rather have a
> broader azimuthal pattern, and a selection of different
> elevation patterns –
> depending on whether I drive antennas #1+#2+#3, or #1+#2,
> or # 2+#3, or
> #1+#3, or #1, or # 2 or# 3.
> What issues/observations can folks with experience relate?
> Bill, K2PO/7
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