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
> >
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|
