[TenTec] OT: Openwire Balanced Antenna Tuners (QST Test)

[Bob McGraw - K4TAX]

Agreed, the term "antenna tuner" doesn't really tune the antenna but more 
correctly matches the load, being a combination of antenna and feedline, to 
a suitable impedance to which the radio can deliver power.  There is no 
"fooling" involved except to the operator.  Regardless, at the output of the 
tuner, feedline loss will always remain the same.  The idea of using open 
wire line is the fact the loss per unit/frequency with a given SWR is always 
less than coaxial cable for the same SWR, length and frequency.

Regarding "antenna tuners" in actuality every AM broadcast station in the 
world correctly uses a matching network, i.e. antenna tuner, at the base of 
the antenna.  These are typically referred to as "tuning networks" with most 
being T networks having fixed values of L and C components.  There's no 
substitute for a proper antenna with a correct matching network that 
provides a good impedance match to the feedline and the use of a low loss 
feedline.

On the topic of SWR and feedline loss, I suggest one should investigate the 
actual loss in the tuner being used.  A recent report shows some tuners can 
have as much as 30% or more power loss under certain conditions.  That is a 
lot more loss than dealing with a 3:1 SWR at the radio and no tuner. 
Today's radios and amplifiers typically will operate satisfactorily with a 
3:1 SWR or less.

With regard to the recent QST article, March 2013,  on balanced tuners, I 
was astonished at some of the loss values reported with one brand in 
particular.  In all likely hood, the typical ham installation might not see 
the low impedance values where the test were conducted.  I would have 
preferred a test sequence of higher impedance values as opposed to the very 
low impedance values.


73
Bob, K4TAX


DISCLOSURE:
This is to inform all persons, I am a Tentec Ambassador and I receive
compensation according to the Tentec Ambassador program.  In addition, I
serve as a volunteer beta test person to Tentec for the Omni VII, Eagle
and Argonaut VI radios.  I hold no employment relationship, no financial
interests nor do I conduct any commercial business, direct or indirect,
with Tentec.






----- Original Message ----- 
From: "bob barnes" <k0wtz at yahoo.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Friday, February 15, 2013 9:59 PM
Subject: Re: [TenTec] OT: Openwire Balanced Antenna Tuners (QST Test)


my thoughts on antenna tuners is they will not change an antenna but they 
will fool your rig into seeing a load. not matter what that swr if it is 
high with the tuner the swr will still be high behind that tuner no matter 
what!


that tuner is still seeing all the bad things about your antenn best bet 
trim the ant to a acceptable low swr and save your cash.

i know that may not be believable but that is the way it is.

bob k0wtz

all things are possible in Christ Jesus our savior

--- On Fri, 2/15/13, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:


From: Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de>
Subject: [TenTec] OT: Openwire Balanced Antenna Tuners (QST Test)
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>, 
Ten-Tec-Omni-VII at yahoogroups.com, TenTec_Eagle at yahoogroups.com
Date: Friday, February 15, 2013, 9:48 AM


The March 2013 issue of QST has another Antenna Tuner test by Joel, W1ZR.

This article is a good read because it also describes the ARRL's newest test
method for antenna tuners.

ONE OF THE BIGGEST MISTAKES I find people make in their thinking is, they
believe that if their ATU can match the antenna, that's goodness. NOT!
In addition to whatever losses the antenna itself may have, there may also
be SIGNIFICANT matchbox losses. as this article points out on one of the
boxes.

The two Matchboxes tested here are the MFJ-976 and Palstar BT-1500A.
<> What are their matching ranges?
<> MORE IMPORTANT, how much power is lost in the matchbox when matching the
various impedances?

BTW, I have added these results to my "MATCHBOX SHOOT-OUT Spreadsheet" on my
web site.
It compares these tuners to others which the ARRL has previously tested.
LINK: http://www.dj0ip.de/antenna-matchboxes/matchbox-shoot-out/

A HUGE THANK YOU TO JOEL and his colleagues for reporting on this
interesting topic.

73
Rick, DJ0IP


_______________________________________________
TenTec mailing list
TenTec at contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec at contesting.com
http://lists.contesting.com/mailman/listinfo/tentec