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Re: [TowerTalk] Stacking tribanders (SteppIRs)

To: terry@ab5k.net
Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)
From: "Howard Klein" <howk2@hotmail.com>
Reply-to: rf@xemaps.com
Date: Mon, 31 Jul 2006 14:31:25 +0000
List-post: <mailto:towertalk@contesting.com>
Terry,
I have  both the Comtek and Stackmatch. I used the Stackmatch first and 
found the same thing I am seeing now with the Comtek. I stayed with the 
Comtek because the Array solutions did not have the two stack switch at that 
time and I only have the two anrtennas. Makes switching easier. Bottom line 
for me not much difference. I do find the same situation on 20 that you do. 
Wants to kick off my Acom unless I do some massaging of the elements. I can 
get the SWR to near flat but clearly reducing gain. This only happens on 20. 
The other bands work as expected. Still playing around.
Howard..K2HK

----Original Message Follows----
From: Terry Gerdes <terry@ab5k.net>
To: rf@xemaps.com
CC: TOWERTALK@contesting.com
Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)
Date: Mon, 31 Jul 2006 09:04:51 -0500

Hi Howard,

Thanks for the replay.  Does the Comtek switch work better than the
Stackmatch?  What I see here is the lower and mid antennas have flat SWR
when running standalone but when I put them into a stack, the SWR jumps high
enough to get close to dumping the Alpha amp off-line.  Does the Comtek
switch provide a better match?

Terry

----- Original Message -----
From: "Howard Klein" <howk2@hotmail.com>
To: <terry@ab5k.net>
Cc: <TOWERTALK@contesting.com>
Sent: Monday, July 31, 2006 8:56 AM
Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)


 > Terry,
 > I have two 4 El's. One at ~85 and the other at ~45 ft. I do much what you
 > do. I tune individual antennas for best SWR and then switch to both. Woks
 > well on all bands but 20. My top antenna is turned with an Alfa Spid and
 > the lower with a Tic Ring. I tried the Stackmatch but now am using the
 > Comtek switch.
 > Howard..K2HK
 >
 > ----Original Message Follows----
 > From: Terry Gerdes <terry@ab5k.net>
 > To: Cqtestk4xs@aol.com, TOWERTALK@contesting.com
 > Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)
 > Date: Mon, 31 Jul 2006 08:27:51 -0500
 >
 > > I'd like to hear from the guys who have used the Stackmatch to phase
 > their
 > > SteppIRs.
 >
 > Bill,
 >
 > I have been using a three stack of SteppIR's for one year in 
configuration
 > close to what you plan on planning.  Mine are stacked at 33, 66 and 100
 > feet
 > on a 100 foot R55 rotating tower.  The top MonstIR antenna is on a
 > AlphaSpid
 > rotor and can be turned separately.  Pic at:
 > http://www.ab5k.net/images/Monstir2.jpg
 >
 > The antennas are feed with equal lengths of coax into a StackMatch as
 > recommended by the SteppIR folks.   The StackMatch  is the one that goes
 > thru six meters.   There are some SWR issues that I do see in that the
 > antennas have low SWR individually but the SWR rises when in the stack.
 > My
 > current approach is to tune each antenna up or down in frequency until I
 > get
 > a reasonable SWR on the stack.   That seems to work well.  A better
 > approach
 > would be to adjust only the driven elements for a better SWR match.  I
 > have
 > not had time to do that.
 >
 > Also there are times when the top MonstIR does not seem to offer as much
 > contribution as it should while the bottom two play as expected.  This 
may
 > be due to the fact that the top antenna is on a 2 foot longer boom and 
its
 > driven element is in a different place so there may not be an exact phase
 > match between it and the lower two antennas.    If there is a phase
 > difference in the MonstIR and the other SteppIR, it would be easy to add 
a
 > short piece of coax to adjust this out.
 >
 > Despite the observations noted, the array works well and it was used in a
 > North America first place win in the CQWW RTTY contest last year.
 >
 > 73 Terry - AB5K
 >
 >
 >
 > ----- Original Message -----
 > From: <Cqtestk4xs@aol.com>
 > To: <TOWERTALK@contesting.com>
 > Sent: Monday, July 31, 2006 6:04 AM
 > Subject: Re: [TowerTalk] Stacking tribanders (SteppIRs)
 >
 >
 > >
 > > In a message dated 7/31/2006 4:19:30 A.M. Greenwich Standard Time,
 > > w7ce@curtiss.net writes:
 > >
 > > In my  models, I've also noticed that the F/R suffers when the antennas
 > > are
 > > stacked.  However, I've been able to re-optimize the element  lengths
 > > based
 > > on the stacking distance and height above ground and can get  F/R
 > > numbers
 > > that meet or exceed those of a single antenna.  In some  cases, the
 > change
 > > in
 > >
 > >
 > >
 > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 > >
 > > This is not only the case with SteppIRs, I had the same thing with my
 > > KLM
 > > monobanders.  However, living in FL, giving up some F/B to get the
 > > benefits  of
 > > stacking was worth it.
 > >
 > > Most of the stacks I had used around .75 for spacing....pretty much
 > > what
 > > the
 > > master W2PV recommended.
 > >
 > > Plans for KH6 include three SteppIRs...the MonstIR at 90, a 4 el at 60,
 > > and
 > > another at 30, all phasable with a Stackmatch on Rohn 65.
 > >
 > > Over the last 20 years I used Ameritron boxes for switching the
 > > stacks...BIP/BOP/TOP/BOT, and will miss the second one, BOP, since I
 > > will
 > > be  using the
 > > Stackmatch  which has no provision for BOP.  Yes, I know I  can use the
 > > lower
 > > single antennas to achieve that, but I have always been a fan  of using
 > > all
 > > antennas to get the maximum gain for the higher angle  radiation.
 > >
 > > Spacing on the antennas for 90/60/30 should be a bit close on 20, but
 > with
 > > the middle one switched out it should be close to the killer stack W2PV
 > > spoke
 > > of  for 20. The three high should scream on 15 and 10, since I have 
used
 > > stacks
 > > at  this height before for those bands.
 > >
 > > I'd like to hear from the guys who have used the Stackmatch to phase
 > their
 > > SteppIRs.
 > >
 > > Bill K4XS
 > > _______________________________________________
 > >
 > >
 > >
 > > _______________________________________________
 > > TowerTalk mailing list
 > > TowerTalk@contesting.com
 > > http://lists.contesting.com/mailman/listinfo/towertalk
 > >
 >
 > _______________________________________________
 >
 >
 >
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 >
 >
 >

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