Interesting thread:
On log periodics: Unless I am wrong, there are never more than two elements
in an LPY fully active, so performance approximates two element yagi on any
one frequency.
Steppir has compromise element spacing as multiband yagi, largely
compensated for by tuning individual elements for optimum performance.
F/B falls off on 10 principally because DE/ Ref spacing bit large on that
band. For a 10m fanatic would suggest fixing a dedicated 10m Refl on boom at
0.2 spacing and living with possible compromised performance on 24 mHz. All
other bands should be unaffected.
73 es gl
Barry ZL1DD
---------- Forwarded message ----------
From: Doug Turnbull <turnbull@net1.ie>
Date: 25 February 2011 09:55
Subject: Re: [TowerTalk] book Tribander comparison test
To: Gene Fuller <w2lu@rochester.rr.com>, Mike <noddy1211@sbcglobal.net>,
towertalk@contesting.com
The trouble with LP antennas and some multiband Yagis is that they have a
very high wind load. The SteppIR avoids this with fewer elements.
SteppIR, maintenance has been a problem for some and not for many others.
I have found this interesting thread and appreciate the different
viewpoints.
73 Doug EI2CN
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Gene Fuller
Sent: 25 February 2011 02:37
To: Mike; towertalk@contesting.com
Subject: Re: [TowerTalk] book Tribander comparison test
This thread is really running thin. That being said, do you really think
that given the same height and feed line loss you could tell one or two db
difference between antennas. At that point it's more a matter of operator
skill!. I would still take the simplicity of a good LP. For that matter you
could stack a pair of T-10's for the price of a single SteppIR, or even a
TH-11, including the cost of a side gate - or spend your money on getting
the T-10 higher.
Gene / W2LU
----- Original Message -----
From: "Mike" <noddy1211@sbcglobal.net>
To: <towertalk@contesting.com>
Sent: Thursday, February 24, 2011 8:52 PM
Subject: Re: [TowerTalk] book Tribander comparison test
> You are dead right it is a "tunable "monobander" and in a classification
> of
> its own really, so nothing to compare with. Even on 20 meters a three
> element Steppir has hardly has anything to compare with as most people
> putting up a monobander for that band would choose a 4 t 6 element
> antenna.
> But it does work better than a 3 element tribander on 20 meters because it
> tunes the whole band without traps, most short tri-banders are a
> compromise
> on 20 meters anyway.
>
> Mike
>
> -----Original Message-----
>
> > It would be, if they had motors to vary the distance between the
> > elements
>
> Nonsense! Some 30+ years ago W2PV showed that a monobander was a
> monobander no matter what the element spacing as long as the elements
> are properly tuned for their place in the array. Gain is a product
> of boom length as long as there are "enough" elements for the length.
>
> Tapered spacing only effects the bandwidth and feed impedance of the
> antenna and with a SteppIR bandwidth has no meaning since the antenna
> is constantly retuned for the operating frequency.
>
> SteppIR is a tunable "monobander" with a fixed length boom - other
> than the optional fixed length elements for six meters, a SteppIR
> has no traps or parasitic elements whose sole purpose is to allow
> operation on more than one frequency at a time.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2/24/2011 6:57 PM, Dick NY1E wrote:
>> " As far as the SteppIR, it's a monobander for all practical
>> purposes."
>>
>> It would be, if they had motors to vary the distance between the
> elements... otherwise its a tribander (ok 5 bander) with a good swr!
>>
>> Dick NY1E
>> www.ny1e.com
>>
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> 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
_______________________________________________
_______________________________________________
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
--
Barry Kirkwood PhD ZL1DD
barry.kirkwood@gmail.com
NZ: 021 160 8999
Thailand 081 235 1556
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|