Rick, this is true, but even the 450 ohm ladder line stuff is certainly better
than a long run of coax.
73
Scott
---------- Original Message ----------------------------------
From: "NJ0IP" <Rick@DJ0IP.de>
Reply-To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 19 Jan 2006 12:05:34 -0800
>Scott, this is true if and only if people recognize that Maxwell was talking
>about openwire in the classical form, and not ladderline which most people
>use now days.
>
>73
>Rick
>
>-----Original Message-----
>From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
>On Behalf Of Scott Harwood
>Sent: Thursday, January 19, 2006 7:35 AM
>To: Discussion of Ten-Tec Equipment
>Subject: Re: [TenTec] What makes the 238 good or any other tuner good?
>
>
>Hey guys:
>
>In his book, "Reflections", Maxwell states that all power fed into the
>transmission line (minus line loss) is absorbed by the load, regardless of
>the mismatch. Secondly, with open-wire tuned feed lines, we can ignore this
>mismatch at the junction of the feed line and the antenna, and all matching
>can be done at the transmitter itself. Put another way, if an antenna tuner
>can properly match the impedance of the input of the feed line, using open
>wire line we can transfer just about all power to the antenna.
>
>Thus, the case for open wire line and a tuner.
>
>Scott K4VWK
>
>---------- Original Message ----------------------------------
>From: Randy Russe3ll <lord_russell53@yahoo.com>
>Reply-To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
>Date: Wed, 18 Jan 2006 18:57:09 -0800 (PST)
>
>>Even if you have a finely tuned resonant dipole, and
>>it is actually 50 ohms at your feedpoint heighth,
>>you're losing more db in 100 feet of coax than I am on
>>a mismatched 4:1 swr. If you put your loading coils
>>on to "fool the transmitter" your using even more. If
>>you try to use your coax on any kind of mismatch, your
>>losses skyrocket. This includes feeding a 35 ohm or
>>say 80 ohm feedpoint with 50 ohm coax. Those are both
>>Z's attained on dipoles between 20 feet in the air and
>>a full wave high. The purpose of coax is convienence
>>swapped for performance. A link coupled tuner is more
>>of an Antenna impedance transformer. You've already
>>got a few of those in your rig anyway. I didn't see
>>anything supporting your theory about transmission
>>lines in the ARRL Antenna book. In fact, if you go
>>back and read it, you will understand what I'm saying
>>about losses in coax, and the reasons for the
>>superiority of balanced feedlines. In a multi band
>>system, it's an absolute must. Oh, and resonance is
>>NOT a requirement for radiation efficiency. 73s
>>--- Roger Borowski <K9RB@bellsouth.net> wrote:
>>
>>> After more than 45 years of continual hamming on all
>>> bands and modes, I can
>>> honestly say that I never have used an antenna tuner
>>> and never found any
>>> system that will outperform a resonant antenna fed
>>> with coaxial cable, which
>>> I've always used since the early 60's. If the
>>> antenna isn't resonant on the
>>> desired frequency of operation, many people think an
>>> antenna tuner is the
>>> fix. While an antenna tuner will allow you to use
>>> most anything metallic as
>>> a radiator of RF, the most efficient power transfer
>>> is to a 50 ohm resonant
>>> load via 50 ohm coaxial feedline. In all cases where
>>> an antenna tuner is
>>> used with a coaxial fed antenna, all it does is
>>> further complicate a system
>>> with an added piece of equipment that only fools the
>>> transmitter into seeing
>>> the match it is looking for, while creating losses
>>> in itself and further
>>> losses in the coaxial feedline due to the mismatch
>>> that still remains
>>> between the antenna tuner and the antenna.
>>> Fortunately I've never been
>>> forced to use anything other than resonant antennas
>>> fed with good quality 50
>>> ohm coaxial cable. If you're bound and determined to
>>> use open wire feeders
>>> to one of the many non-resonant antenna designs of
>>> yesteryear, that would
>>> require an antenna tuner. Why anyone who understands
>>> antennas would want to
>>> do that 50-60 years after coaxial cable became
>>> common place is beyond my
>>> comprehension. It's an easy chore to adjust antenna
>>> lengths for resonance
>>> and where available space doesn't permit, it's also
>>> easy to use loading
>>> coils or linear loading configurations on the
>>> antenna. If you haven't a clue
>>> as to what I'm saying, pick up a book on antennas,
>>> such as the ARRL Antenna
>>> Book and read the entire section on the theory of
>>> antennas. As a Ham, you
>>> really need to know this. An antenna tuner is a band
>>> aid approach that
>>> allows one to use an inefficient antenna, whatever
>>> it may actually be, with
>>> some degree of success. You see 1:1 SWR on the tuner
>>> meter and you and your
>>> rig are happy, but in actuality, put another SWR
>>> meter after the antenna
>>> tuner and you'll see the real mismatch, why you are
>>> generating RFI, and
>>> experiencing far less performance, both transmitting
>>> and receiving, than you
>>> could be.
>>> 73, -=Rog-K9RB=-
>>> FCC First Class Commercial License first attained in
>>> 1967, Ham Radio license
>>> first attained 1961.
>>> A-1 Operator Club, ARRL Life Member, DXCC #1 Honor
>>> Roll (350) Mixed, Phone,
>>> CW (since '92) and presently need 11 more on RTTY
>>> for H.R. Need (4) more
>>> zones on 160M. for all (9) HF band "Worked All
>>> Zones". At present 160 Meter
>>> DXCC - 211 + 36 zones. Former member NIDXA No.Ill.DX
>>> Assn., 9th area
>>> incoming QSL bureau sorter for many years, Charter
>>> Member Metro DX Club,
>>> Life member / former Trustee W9AA Hamfesters ARC.,
>>> CP-40 in 1963 at 14 years
>>> of age, former ARRL OO, & NCS, active 160M through
>>> V.H.F. / U.H.F. for 45
>>> years. 1st place CQWPX-CW 15M in 1981. 1st place
>>> CQWW-CW 40M in both 1980 &
>>> 1988. (Ancient history now!) Also KG4RB -GTMO Cuba,
>>> Bio and photos available
>>> at www.qrz.com Reply direct to; K9RB@arrl.net
>>>
>>> ----- Original Message -----
>>> From: "Richard Williams" <richardw@mho.com>
>>> To: "Discussion of Ten-Tec Equipment"
>>> <tentec@contesting.com>
>>> Sent: Wednesday, January 18, 2006 5:43 PM
>>> Subject: Re: [TenTec] What makes the 238 good or any
>>> other tuner good?
>>>
>>>
>>> Rich,
>>>
>>> Quite a number of answers I see on the board. My
>>> personal opinion is the
>>> best tuner out there is the XMatch tuner
>>> manufactured by Paul Schrader
>>> (N4XM). This is pretty well backed up by the ARRL
>>> when they did a review
>>> of this one and three others back in Mar of 97. You
>>> can read it by signing
>>> on to the ARRL home page and search for XMatch
>>> tuner.
>>>
>>> I don't think anything comes even close to it specs
>>> when operating on 160
>>> Mtrs. I believe he still makes them as I see his
>>> ads in EST..
>>>
>>> Maybe someone else out there has the Match and will
>>> put there "two cents"
>>> worth in.
>>>
>>> Dick KHZ
>>>
>>>
>>> _______________________________________________
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>>> TenTec@contesting.com
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>>>
>>> _______________________________________________
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>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
>>
>>
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>
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