on 8/19/03 10:28 AM, towertalk-request@contesting.com at
towertalk-request@contesting.com wrote:
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> Today's Topics:
>
> 1. Brake wedges for Tailtwister (Tree)
> 2. MA type towers (Terry Dunlap)
> 3. Re: Need info & manual on 20 meter beam (AA6DX)
> 4. Re: Towers on Rock Ledge (Geoff)
> 5. Re: MA type towers
> 6. AEA HF Analyst Manual?
> (Mandell, Thomas W (N-Superior Technical Resources Inc.))
> 7. Re: W0IYH Feed line Choke Performance (Tim Duffy K3LR)
> 8. Re: W0IYH Feed line Choke Performance (Tim Duffy K3LR)
> 9. Re: W0IYH Feed line Choke Performance (Jim White, K4OJ)
> 10. RE: W0IYH Feed line Choke Performance (Joe Subich, K4IK)
>
>
> ----------------------------------------------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 11:39:18 -0500
> From: Tree <tree@kkn.net>
> To: towertalk@contesting.com
> Subject: [TowerTalk] Brake wedges for Tailtwister
> Message-ID: <20030819163917.GA11116@kkn.net>
> Content-Type: text/plain; charset=us-ascii
> MIME-Version: 1.0
> Precedence: list
> Message: 1
>
>
> I bought a couple of brake wedges at Dayton from the HyGain booth. I have
> to replace the one in my Tailtwister that has a 3 element 40 on it after
> most any storm (which happens about once every two years). I noticed
> that the slot that is drilled in the middle was slightly off - about 150
> mils or so. I put it together, but it isn't locking down.
>
> I have asked HyGain about this and really not received much useful
> information about it. I have now ordered a new one and hopefully it
> will have the correct dimensions, and I will send the other ones back.
>
> Anyone else have this problem?
>
> Tree N6TR
> tree@kkn.net
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 09:29:25 -0700
> From: Terry Dunlap <kk6t@pacbell.net>
> To: towertalk@contesting.com
> Subject: [TowerTalk] MA type towers
> Message-ID: <5.1.0.14.2.20030819092919.0411bb08@postoffice.pacbell.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
> MIME-Version: 1.0
> Precedence: list
> Message: 2
>
> While we're on the subject of MA type towers.......
>
> With the rotor at the top and any mast being held by only the
> top clamp of the rotor, how can people be using 5'-10' masts?
>
> Even with minimal loads on the top of these masts, I would think
> that would be a huge strain on the rotor clamp.
>
> 73 de Terry KK6T
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 10:02:13 -0700
> From: "AA6DX" <aa6dx@pacbell.net>
> To: "Arne Gjerning" <gjerning@flash.net>, "Bob Nielsen" <nielsen@oz.net>,
> <towertalk@contesting.com>, "Pete Smith" <n4zr@contesting.com>
> Subject: Re: [TowerTalk] Need info & manual on 20 meter beam
> Message-ID: <037801c36673$a2d3d650$7662ce3f@desk>
> References: <000e01c36599$b3c8f880$3042f60c@attbi.com>
> <20030819034827.GA10084@n7xy.net>
> <5.2.0.9.2.20030819030057.01b788d0@mail.adelphia.net>
> Content-Type: text/plain;
> charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 3
>
> Bob, NA6T, and I, have the 15M version of the original LONG JOHN ... it is a
> MONDO beam!
> Unfortunately, it is stored in the horizontally grounded position .. Boy,
> did it play at my Redding, CA contest station in the late 70s. 73, Y'all
> Mark AA6DX
> ----- Original Message -----
> From: "Pete Smith" <n4zr@contesting.com>
> To: "Arne Gjerning" <gjerning@flash.net>; "Bob Nielsen" <nielsen@oz.net>;
> <towertalk@contesting.com>
> Sent: Tuesday, August 19, 2003 12:01 AM
> Subject: Re: [TowerTalk] Need info & manual on 20 meter beam
>
>
>> At 11:01 PM 8/18/03 -0600, Arne Gjerning wrote:
>>> The LJ-205CA is NOT anywhere near the same antenna. What Chuck, N6PSN,
> has
>>> is the ORIGINAL LONG JOHN series 20M yagi from late 50s/early 60s. He
>>> described the yagi correctly as having a 46 ft boom; whereas the LJ-205CA
>>> has ONLY a 34ft boom. His antenna is built like a "MACK TRUCK" compared
> to
>>> the LJ-205CA.
>
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 13:29:11 -0400
> From: "Geoff" <geoffrey@jeremy.mv.com>
> To: "Martin Ewing AA6E" <aa6e@arrl.net>, <towertalk@contesting.com>
> Subject: Re: [TowerTalk] Towers on Rock Ledge
> Message-ID: <024001c36677$75cb3960$6501a8c0@Carl>
> References: <3F41042A.5020003@arrl.net>
> Content-Type: text/plain;
> charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 4
>
> I dug down to the ledge and then had 2" diameter holes drilled down 8' at
> the guy angle.
> Installed power company rock anchors, locked in place and filled the rest of
> the hole with "Pour Rock" to seal.
> That was 11 years ago and no problems whatsoever with a total of 4 towers.
>
> The anchors are 3/4" diameter with heavy galvanizing; easy to attach Rohn 3
> and 5 level equalizing plates.
>
> G
>
>
> ----- Original Message -----
> From: "Martin Ewing AA6E" <aa6e@arrl.net>
> To: <towertalk@contesting.com>
> Sent: Monday, August 18, 2003 12:51 PM
> Subject: [TowerTalk] Towers on Rock Ledge
>
>
>> Folks,
>>
>> Is there any general information available on siting towers on rock? I
> have
>> granite ledge just a foot or less down, so digging the big hole in the
> ground
>> won't do the trick here.
>>
>> I suppose one needs "local engineering", but maybe there is some design
> info to
>> help get me oriented.
>>
>> Tnx / 73, Martin, AA6E
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 13:35:40 EDT
> From: K7LXC@aol.com
> To: kk6t@pacbell.net, towertalk@contesting.com
> Subject: Re: [TowerTalk] MA type towers
> Message-ID: <ae.4605bb1e.2c73b9ec@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 5
>
> In a message dated 8/19/03 9:33:31 AM Pacific Daylight Time, kk6t@pacbell.net
> writes:
>
>> With the rotor at the top and any mast being held by only the
>> top clamp of the rotor, how can people be using 5'-10' masts?
>
> There are 2 configurations: 1) rotator on the top of the tower and 2)
> rotator at the bottom of the tower as part of the MARB rotating tower system.
> It's obviously easier with the rotator at the bottom to have a loaded mast.
>>
>> Even with minimal loads on the top of these masts, I would think
>> that would be a huge strain on the rotor clamp.
>
> Well, yes but sometimes the rotator will take it. When I was at Hy-Gain
> in the 90's we destruction tested a TailTwister and the force required was
> something like 3,000 foot/pounds before the neck broke off. Pretty strong!
>
> Cheers,
> Steve K7LXC
> TOWER TECH
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 10:49:31 -0400
> From: "Mandell, Thomas W (N-Superior Technical Resources Inc.)"
> <thomas.w.mandell@lmco.com>
> To: towertalk@contesting.com
> Subject: [TowerTalk] AEA HF Analyst Manual?
> Message-ID: <F74C419E9D6FCD448BE5B4DDF904ED78047B109D@EMSS04M06.us.lmco.com>
> Content-Type: text/plain; charset=iso-8859-1
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7BIT
> Precedence: list
> Message: 6
>
> If your looking for the AEA CIA HF analyzer manual it's available on the AEA
> web site.
>
> Tom W3FRG
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Mon, 18 Aug 2003 18:09:06 -0500
> From: Tim Duffy K3LR <k3lr@k3lr.com>
> To: "Paul Christensen, Esq." <w9ac@arrl.net>,
> Towertalk <towertalk@contesting.com>
> Subject: Re: [TowerTalk] W0IYH Feed line Choke Performance
> Message-ID: <3F415C92.E09543D6@k3lr.com>
> References: <3F410FD4.186A29FC@k3lr.com>
> <009501c365c7$1116a5a0$6401a8c0@se1.client2.attbi.com>
> Content-Type: text/plain; charset=us-ascii
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 7
>
> HI Paul!
>
> You are correct, it would be interesting experiment and some day I will take
> my
> own measurements on coax single layer chokes and I will post my findings here.
> However, in the mean time there are two excellent sources that have good
> information on the subject. W7EL has some suggested single layer coax chokes
> in
> the ARRL Antenna Book. WA2SRQ had a TowerTalk post some years back (should be
> in the archives) where Ed gave a very detailed account of his tests related to
> coax chokes.
>
> 73,
> Tim K3LR
> http://www.k3lr.com
>
> "Paul Christensen, Esq." wrote:
>
>> Tim,
>>
>> By chance, did you happen to measure the impedance of an air-wound choke
>> consisting of many tight turns? On the low bands, it would be an
>> interesting exercise to determine the equivalent number of air-wound turns
>> needed on a given diameter in order to approximate the same impedance
>> effectiveness as either the W2DU or W0IYH types.
>>
>> -Paul, W9AC
>>
>> ----- Original Message -----
>> From: "Tim Duffy K3LR" <k3lr@k3lr.com>
>> To: "Towertalk" <towertalk@contesting.com>
>> Sent: Monday, August 18, 2003 1:41 PM
>> Subject: [TowerTalk] W0IYH Feed line Choke Performance
>>
>>> I posted some of my experience concerning the W2DU type choke
>>> performance a few weeks ago.
>>> There were several requests for the test data.
>>> I retrieved my lab notes taken from my HP Network Analyzer on October
>>> 15, 2001.
>>>
>>> The W0IYH choke is made from 100 type FB-5622-43 beads on RG-142 with
>>> silver plated PL-259's on each end.
>>> The list is test frequency followed by impedance
>>> 1.8 MHz 1152 ohms
>>> 3.7 MHz 3483 ohms
>>> 7.1 MHz 4115 ohms
>>> 14.2 MHz 1783 ohms
>>> 21.2 MHz 1280 ohms
>>> 28.5 MHz 1234 ohms
>>>
>>> My tests with the W2DU choke:
>>> 1.8 MHz 984 ohms
>>> 3.7 MHz 1733 ohms
>>> 7.1 MHz 1921 ohms
>>> 14.2 MHz 1432 ohms
>>> 21.2 MHz 905 ohms
>>> 28.5 MHZ 423 ohms
>>>
>>> In 100% key down CW tests into a 50 ohm dummy load for 10 minutes I
>>> found the W2DU to overheat (individual bead temperature exceeded
>>> manufactures ratings) at 500 watts on every band. The W0IYH choke passed
>>> the same test at 2000 watts and was well within the temperature
>>> specification for each bead. I believe the W0IYH choke has adequate
>>> safety factor for 1500 watt stations as long as the VSWR does not exceed
>>> 3:1.
>>>
>>> There are lots of W2DU chokes in service and as you can see they will
>>> work well. The W0IYH design is an improved version. As I indicated in my
>>> September 1998 CQ Contest magazine article, I use the W0IYH design at my
>>> station. They are on every feed point of every antenna, at the tower
>>> mounted stacked antenna RF switch box and at the end of each antenna
>>> feed line where it connects to the RF amplifier in the radio room. They
>>> keep RF from flowing on the outside shields of the feed lines very well.
>>>
>>>
>>>
>>> If you are interested in ready to go chokes, completed W0IYH chokes are
>>> available from Comtek Systems. Please contact them for price and
>>> availability.
>>> http://www.comteksystems.com
>>>
>>>
>>> 73,
>>> Tim K3LR
>>> http://www.k3lr.com
>>>
>>>
>>> _______________________________________________
>>>
>>> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
>> questions and ask for Sherman, W2FLA.
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Mon, 18 Aug 2003 18:12:41 -0500
> From: Tim Duffy K3LR <k3lr@k3lr.com>
> To: K3vw@aol.com, Towertalk <towertalk@contesting.com>
> Subject: Re: [TowerTalk] W0IYH Feed line Choke Performance
> Message-ID: <3F415D69.BB2CDA98@k3lr.com>
> References: <108.25e39718.2c7292e6@aol.com>
> Content-Type: text/plain; charset=us-ascii
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 8
>
> Hi Willy!
>
> Jim may have not had time to post the new information. Give him a call at
> 704-542-4808. Jim's up early, so anytime after 7 AM eastern time.
>
> 73,
> Tim K3LR
> http://www.k3lr.com
>
> K3vw@aol.com wrote:
>
>> Tim, I went to their site but there was W0iyh Balun there, just W2DU types.
>> Did I miss something? I've been building my own baluns and 9: to 1 beverage
>> impedence transformers for over 22 years now. Some of the big gun's on 160
>> still
>> have mine in use after all that time & RF!! Willy K3VW
>
>
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 15:03:15 -0400
> From: "Jim White, K4OJ" <k4oj@tampabay.rr.com>
> To: Tim Duffy K3LR <k3lr@k3lr.com>
> Cc: Towertalk <towertalk@contesting.com>
> Cc: "Paul Christensen, Esq." <w9ac@arrl.net>
> Subject: Re: [TowerTalk] W0IYH Feed line Choke Performance
> Message-ID: <3F427473.2010802@tampabay.rr.com>
> References: <3F410FD4.186A29FC@k3lr.com>
> <009501c365c7$1116a5a0$6401a8c0@se1.client2.attbi.com>
> <3F415C92.E09543D6@k3lr.com>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Reply-To: k4oj@tampabay.rr.com
> Message: 9
>
> ...the WA2SRQ studies are on several places on the net including K1TTT's
> most excellent web site
>
> http://www.k1ttt.net/technote/airbalun.html
>
> I have toyed with the idea of making these as a side business... as a
> happy user of "WA2SRQ baluns" for years... and no bugs!
>
> I would be interested to know if there is a market for these... I am
> looking for a small business, have a few mechanical tweaks W1CW and I
> added to the basic design - probably would sell them on eBay or in the
> ham classifieds...
>
> Please reply direct to me on this one!
>
> Thanks,
>
> Jim, K4OJ
>
>
>
>
> Tim Duffy K3LR wrote:
>> HI Paul!
>>
>> You are correct, it would be interesting experiment and some day I will take
>> my
>> own measurements on coax single layer chokes and I will post my findings
>> here.
>> However, in the mean time there are two excellent sources that have good
>> information on the subject. W7EL has some suggested single layer coax chokes
>> in
>> the ARRL Antenna Book. WA2SRQ had a TowerTalk post some years back (should be
>> in the archives) where Ed gave a very detailed account of his tests related
>> to
>> coax chokes.
>>
>> 73,
>> Tim K3LR
>> http://www.k3lr.com
>>
>> "Paul Christensen, Esq." wrote:
>>
>>
>>> Tim,
>>>
>>> By chance, did you happen to measure the impedance of an air-wound choke
>>> consisting of many tight turns? On the low bands, it would be an
>>> interesting exercise to determine the equivalent number of air-wound turns
>>> needed on a given diameter in order to approximate the same impedance
>>> effectiveness as either the W2DU or W0IYH types.
>>>
>>> -Paul, W9AC
>>>
>>> ----- Original Message -----
>>> From: "Tim Duffy K3LR" <k3lr@k3lr.com>
>>> To: "Towertalk" <towertalk@contesting.com>
>>> Sent: Monday, August 18, 2003 1:41 PM
>>> Subject: [TowerTalk] W0IYH Feed line Choke Performance
>>>
>>>
>>>> I posted some of my experience concerning the W2DU type choke
>>>> performance a few weeks ago.
>>>> There were several requests for the test data.
>>>> I retrieved my lab notes taken from my HP Network Analyzer on October
>>>> 15, 2001.
>>>>
>>>> The W0IYH choke is made from 100 type FB-5622-43 beads on RG-142 with
>>>> silver plated PL-259's on each end.
>>>> The list is test frequency followed by impedance
>>>> 1.8 MHz 1152 ohms
>>>> 3.7 MHz 3483 ohms
>>>> 7.1 MHz 4115 ohms
>>>> 14.2 MHz 1783 ohms
>>>> 21.2 MHz 1280 ohms
>>>> 28.5 MHz 1234 ohms
>>>>
>>>> My tests with the W2DU choke:
>>>> 1.8 MHz 984 ohms
>>>> 3.7 MHz 1733 ohms
>>>> 7.1 MHz 1921 ohms
>>>> 14.2 MHz 1432 ohms
>>>> 21.2 MHz 905 ohms
>>>> 28.5 MHZ 423 ohms
>>>>
>>>> In 100% key down CW tests into a 50 ohm dummy load for 10 minutes I
>>>> found the W2DU to overheat (individual bead temperature exceeded
>>>> manufactures ratings) at 500 watts on every band. The W0IYH choke passed
>>>> the same test at 2000 watts and was well within the temperature
>>>> specification for each bead. I believe the W0IYH choke has adequate
>>>> safety factor for 1500 watt stations as long as the VSWR does not exceed
>>>> 3:1.
>>>>
>>>> There are lots of W2DU chokes in service and as you can see they will
>>>> work well. The W0IYH design is an improved version. As I indicated in my
>>>> September 1998 CQ Contest magazine article, I use the W0IYH design at my
>>>> station. They are on every feed point of every antenna, at the tower
>>>> mounted stacked antenna RF switch box and at the end of each antenna
>>>> feed line where it connects to the RF amplifier in the radio room. They
>>>> keep RF from flowing on the outside shields of the feed lines very well.
>>>>
>>>>
>>>>
>>>> If you are interested in ready to go chokes, completed W0IYH chokes are
>>>> available from Comtek Systems. Please contact them for price and
>>>> availability.
>>>> http://www.comteksystems.com
>>>>
>>>>
>>>> 73,
>>>> Tim K3LR
>>>> http://www.k3lr.com
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>>>
>>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
>>> questions and ask for Sherman, W2FLA.
>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>
>>
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
>> questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
>
> ------------------------------
>
To: <towertalk@contesting.com>
> Date: Tue, 19 Aug 2003 15:20:04 -0400
> From: "Joe Subich, K4IK" <k4ik@subich.com>
> To: "'Tim Duffy K3LR'" <k3lr@k3lr.com>,
> "'Towertalk'" <towertalk@contesting.com>
> Subject: RE: [TowerTalk] W0IYH Feed line Choke Performance
> Message-ID: <002a01c36686$e56d4420$c080a8c0@laptop>
> In-Reply-To: <3F415C92.E09543D6@k3lr.com>
> Content-Type: text/plain;
> charset="us-ascii"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Message: 10
>
>
> Here is the WA2SRQ data from my personal archive ...
>
> ---------------------------------------------------------------------
>
> Having access to a Hewlett-Packard 4193A vector impedance meter at work,
> I have made measurements on a number of baluns, coaxial and otherwise.
> For my beams I was particularly interested how many turns and on what
> diameter are optimum for air core coaxial baluns, and what the effect of
> bunching the turns was (formless). Using the remote programming capability
> of the HP4193A along with an instrument controller, I measured the magnitude
>
> and phase of each balun's winding impedance at 1 MHz intervals from 1 to 35
> MHz. For comparison, I also made measurements on a commercial balun which
> consists of a number of ferrite beads slipped over a short length of coax.
> I've appended some of these measurements so you can draw your own
> conclusions.
>
> PVC pipe was used for coil forms. The 4-1/4 inch diameter baluns were wound
>
> on thin-walled PVC labeled "4 inch sewer pipe". This material makes an
> excellent balun form. It's very light weight and easy to work with, and I
> obtained a 10 foot length at the local Home Depot for about 3 dollars. The
> 6-5/8 inch diameter forms are 6 inch schedule 40 PVC pipe which is much
> thicker, heavier, and more expensive.
>
> Each test choke was close-wound on a form as a single-layer solenoid using
> RG-213 and taped to hold the turns in place. The lengths of cable were cut
> so there was about 2 inches excess at each end. This allowed just enough
> wire at the ends for connections to the HP4193A's probe tip. After data was
>
> collected for each single-layer configuration, the PVC form was removed, the
>
> turns were bunched together and taped formless, and another set of
> measurements
> was taken. I have only included the "bunched" measurements in the table for
>
> one of the baluns, but the trend was the same in each case. When compared
> to
> the single-layer version of the same diameter and number of turns, the
> bunched
> baluns show a large downward shift in parallel self-resonance frequency and
> poor choking reactance at the higher frequencies.
>
>
>
> Interpreting the Measurements
> -----------------------------
> All the baluns start out looking inductive at low frequencies, as indicated
> by
> the positive phase angles. As the frequency is increased, a point is
> reached
> where the capacitance between the windings forms a parallel resonance with
> the
> coil's inductance. Above this frequency, the winding reactance is reduced
> by
> this capacitance. The interwinding capacitance increases with the number of
> turns and the diameter of the turns, so "more is not always better".
>
> The effects of a large increase in interwinding capacitance is evident in
> the
> measurements on the balun with the bunched turns. This is probably a result
> of the first and last turns of the coil being much closer together than the
> single-layer coil.
>
> An important requirement of these baluns is that the magnitude of the
> winding
> reactance be much greater than the load impedance. In the case of a 50 ohm
> balanced antenna, the balun's winding impedance is effectively shunted
> across
> one half the 50 ohm load impedance, or 25 ohms. A reasonable critera for
> the
> balun's winding impedance for negligible common mode current in the shield
> is
> that it be at least 20 times this, or 500 ohms. The measurements show, for
> example, that 6 turns 4-1/4 inches in diameter meet this criteria from 14 to
> 35 MHz.
>
> The measurement data also reveals the power loss these baluns will exhibit.
> Each of the measurement points can be transformed from the polar format of
> the
> table to a parallel equivalent real and reactive shunt impedance. The power
> dissipated in the balun is then the square of the voltage across it divided
> by
> the real parallel equivalent shunt impedance. While this calculation can be
> made for each measurement point, an approximate number can be taken directly
> from the tables at the parallel resonance points. At 0 degrees phase angle
> the magnitude numbers are pure resistive. I didn't record the exact
> resonance
> points, but it can be seen from the tables that the four single-layer baluns
> are all above 15K ohms, while the ferrite bead balun read about 1.4K. These
> baluns see half the load voltage, so at 1500 watts to a 50 ohm load, the
> power
> dissipated in the coaxial baluns will be less than 1.3 watts, and the
> ferrite
> bead balun will dissipate about 13.4 watts (neglecting possible core
> saturation and other non-linear effects). These losses are certainly
> negligible. At 200 ohms load impedance, the losses are under 5 watts for
> the
> coaxial baluns and 53.6 watts for the ferrite beads.
>
>
>
> Conclusions
> -----------
> - A 1:1 coaxial balun with excellent choking reactance for 10 through 20
> meters can be made by winding 6 turns of RG-213 on inexpensive 4 inch PVC
> sewer pipe.
>
> - For 40 or 30 meters, use 12 turns of RG-213 on 4 inch PVC sewer pipe.
>
> - Don't bunch the turns together. Wind them as a single layer on a form.
> Bunching the turns kills the choking effect at higher
> frequencies.
>
> - Don't use too many turns. For example, the HyGain manuals for my 10 and
> 15
> meter yagis both recommend 12 turns 6 inches in diameter. At the very least
> this is about 3 times as much coax as is needed, and these dimensions
> actually
> give less than the desired choking impedance on 10 and 15 meters.
>
>
>
> Measurements
> ------------
> Magnitude in ohms, phase angle in degrees, as a function of frequency in Hz,
> for various baluns.
>
> 6 Turns 12 Turns 4 Turns 8 Turns 8 Turns
> Ferrite
> 4-1/4 in 4-1/4 in 6-5/8 in 6-5/8 in 6-5/8 in
> beads
> sngl layer sngl layer sngl layer sngl layer bunched
> (Aztec)
> ---------- ---------- ---------- ---------- ----------
> ----------
> Frequency Mag Phase Mag Phase Mag Phase Mag Phase Mag Phase Mag
> Phase
> 1.00E+06 26 88.1 65 89.2 26 88.3 74 89.2 94 89.3 416
> 78.1
> 2.00E+06 51 88.7 131 89.3 52 88.8 150 89.3 202 89.2 795
> 56.1
> 3.00E+06 77 88.9 200 89.4 79 89.1 232 89.3 355 88.9 1046
> 39.8
> 4.00E+06 103 89.1 273 89.5 106 89.3 324 89.4 620 88.3 1217
> 26.6
> 5.00E+06 131 89.1 356 89.4 136 89.2 436 89.3 1300 86.2 1334
> 14.7
> 6.00E+06 160 89.3 451 89.5 167 89.3 576 89.1 8530 59.9 1387
> 3.6
> 7.00E+06 190 89.4 561 89.5 201 89.4 759 89.1 2120 -81.9 1404
> -5.9
> 8.00E+06 222 89.4 696 89.6 239 89.4 1033 88.8 1019 -85.7 1369
> -15.4
> 9.00E+06 258 89.4 869 89.5 283 89.4 1514 87.3 681 -86.5 1295
> -23.7
> 1.00E+07 298 89.3 1103 89.3 333 89.2 2300 83.1 518 -86.9 1210
> -29.8
> 1.10E+07 340 89.3 1440 89.1 393 89.2 4700 73.1 418 -87.1 1123
> -35.2
> 1.20E+07 390 89.3 1983 88.7 467 88.9 15840 -5.2 350 -87.2 1043
> -39.9
> 1.30E+07 447 89.2 3010 87.7 556 88.3 4470 -62.6 300 -86.9 954
> -42.7
> 1.40E+07 514 89.3 5850 85.6 675 88.3 2830 -71.6 262 -86.9 901
> -45.2
> 1.50E+07 594 88.9 42000 44.0 834 87.5 1910 -79.9 231 -87.0 847
> -48.1
> 1.60E+07 694 88.8 7210 -81.5 1098 86.9 1375 -84.1 203 -87.2 778
> -51.8
> 1.70E+07 830 88.1 3250 -82.0 1651 81.8 991 -82.4 180 -86.9 684
> -54.4
> 1.80E+07 955 86.0 2720 -76.1 1796 70.3 986 -67.2 164 -84.9 623
> -45.9
> 1.90E+07 1203 85.4 1860 -80.1 3260 44.6 742 -71.0 145 -85.1 568
> -51.2
> 2.00E+07 1419 85.2 1738 -83.8 3710 59.0 1123 -67.7 138 -84.5 654
> -34.0
> 2.10E+07 1955 85.7 1368 -87.2 12940 -31.3 859 -84.3 122 -86.1 696
> -49.9
> 2.20E+07 3010 83.9 1133 -87.8 3620 -77.5 708 -86.1 107 -85.9 631
> -54.8
> 2.30E+07 6380 76.8 955 -88.0 2050 -83.0 613 -86.9 94 -85.5 584
> -57.4
> 2.40E+07 15980 -29.6 807 -86.3 1440 -84.6 535 -86.3 82 -85.0 536
> -58.8
> 2.50E+07 5230 -56.7 754 -82.2 1099 -84.1 466 -84.1 70 -84.3 485
> -59.2
> 2.60E+07 3210 -78.9 682 -86.4 967 -83.4 467 -81.6 60 -82.7 481
> -56.2
> 2.70E+07 2000 -84.4 578 -87.3 809 -86.5 419 -85.5 49 -81.7 463
> -60.5
> 2.80E+07 1426 -85.6 483 -86.5 685 -87.1 364 -86.2 38 -79.6 425
> -62.5
> 2.90E+07 1074 -85.1 383 -84.1 590 -87.3 308 -85.6 28 -75.2 387
> -63.8
> 3.00E+07 840 -83.2 287 -75.0 508 -87.0 244 -82.1 18 -66.3 346
> -64.4
> 3.10E+07 661 -81.7 188 -52.3 442 -85.7 174 -69.9 9 -34.3 305
> -64.3
> 3.20E+07 484 -78.2 258 20.4 385 -83.6 155 -18.0 11 37.2 263
> -63.2
> 3.30E+07 335 -41.4 1162 -13.5 326 -78.2 569 -0.3 21 63.6 212
> -58.0
> 3.40E+07 607 -32.2 839 -45.9 316 -63.4 716 -57.6 32 71.4 183
> -40.5
> 3.50E+07 705 -58.2 564 -56.3 379 -69.5 513 -72.5 46 76.0 235
> -29.6
>
>
> ------------------------------
>
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>
> End of TowerTalk Digest, Vol 8, Issue 77
> ****************************************
>
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