Maxwell used to be a contributor to the ARRL Antenna Book and his book
?Reflections? sold through the ARRL. Now neither is true. As to the reason
why, depends on who you want to believe; Maxwell or the ARRL!
I prefer Maxwell.
Scott K4VWK
---------- Original Message ----------------------------------
From: Randy Russe3ll <lord_russell53@yahoo.com>
Reply-To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 19 Jan 2006 10:49:27 -0800 (PST)
>Sounds to me like Maxwell needs to go back and read
>the ARRL Antenna Handbook.
>
>--- JOHN <ku3g@yahoo.com> wrote:
>
>> Thank You Scott finbally somebody has it correct.
>> 73 john ku3g
>> ps interestinmg subject
>>
>> Scott Harwood <scotth@hsc.edu> wrote:
>>
>> 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
>> Reply-To: Discussion of Ten-Tec Equipment
>> 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 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"
>> >> To: "Discussion of Ten-Tec Equipment"
>> >>
>> >> 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..
>> >>
>>
>=== message truncated ===
>
>
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