[TowerTalk] TowerTalk Digest, Vol 38, Issue 41

Mon Feb 20 12:08:04 EST 2006

When you click on it there should be an option where you can select the 
progarm to open it with.  Scroll down to Wordpad and then open it.  I can 
walk you though it if you still have trouble.

----- Original Message ----- 
From: <towertalk-request at contesting.com>
To: <towertalk at contesting.com>
Sent: Monday, February 20, 2006 4:26 PM
Subject: TowerTalk Digest, Vol 38, Issue 41

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> Today's Topics:
>
>   1. Re: Hy-gain 204BA element changes... (John Wagner)
>   2. Feedline (wf3h at comcast.net)
>   3. Re: Feedline (Matt Patterson)
>   4. Quagi Optimization (Pat Barthelow)
>   5. Re: Feedline (Jim Lux)
>   6. Re: Quagi Optimization (Jim Lux)
>   7. Re: Feedline (ersmar at comcast.net)
>   8. Re: Quagi Optimization (Al Williams)
>   9. Re: Feedline (K6XN)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 20 Feb 2006 08:46:42 -0500
> From: "John Wagner" <jwagner at dxengineering.com>
> Subject: Re: [TowerTalk] Hy-gain 204BA element changes...
> To: "'Dino Darling'" <k6rix at earthlink.net>
> Cc: towertalk at contesting.com
> Message-ID:
> <4239A4FA4FF82E44AD6D215C41024B5C04CE4A60 at exchange.summit.network>
> Content-Type: text/plain; charset="us-ascii"
>
>
>> I have an older Hy-gain 4-element 20 meter mono band beam.  I
>> downloaded the LJ-204BA manual from the Hy-gain (MFJ) website.  I
>> took the antenna apart and verified that all the element lengths are
>> the same in the manual.  Other than a different style hairpin, my
>> older antenna is identical to the current version.
>>
>> Hy-gain makes use of swagged element tips.  I have a slight issue
>> with the amount of overlap with the non-swagged elements
>> closer in to the boom.
>>
>> I'm aware of the electrical characteristics of tapered elements and
>> know you just can't shove one the second element in and extra inch
>> and make up for it by pulling out the third element an inch.  The
>> diameter of the tubing effects the electrical length of that
>> half-element.
>>
>> Well, understanding, and knowing how to compensate for changes, is
>> two different things and I could use your help.
>>
>> I can download a YAG file from the ARRL website
>> (http://www.arrl.org/antmodels/), but need YO to play with it.  I
>> believe YO compensates for tapers.  I don't have a NEC file
>> of this antenna.
>>
>> So let me get specific...
>>
>> The second tube out from the boom (for all eight half-elements) is 1
>> 1/8" x 48".  The instructions call for 46" exposed.  This leaves only
>> 2" inside the 1 1/4" tube!  The 1 1/4" tube is NOT swagged.  The
>> third tube out is 7/8" x 55".  The instructions calls for 50 1/2"
>> exposed.  This leaves 4 1/2" inside the 1 1/8" swagged tube.  Here is
>> the thing though, the 1 1/8" tube is swagged for the first 2".  The
>> remainder 2 1/2" of the 7/8" tube if just floating inside the
>> 1 1/8" tube!
>>
>> What I would like to do is move the 1 1/8" tube in one additional
>> inch (3" overlap instead of 2") and compensate for the shorter
>> half-element by pulling the 7/8" out...but by how much, I don't
>> know.  I have 2 1/2" to play with since it is only floating in
>> air.  This is where I need your help!  I do know that 1" of 1 1/8
>> requires more than 1" of 7/8" to compensate.
>>
>> The rest of the elements have enough overlap per diameter.  My issue
>> is that there is a lot of weight on only 2" of the 1 1/8" tube!  It's
>> a good argument to say this is the way it's been done for years, so
>> why mess with it.  My 1 1/8" tubes are bent at the 2" mark and I'd
>> guess it would be better if there was a bit more overlap.
>>
>> One of these days I may get a copy of YO and learn to use it, or
>> build a NEC file for use in Eznec, but for now, I'm useless!  :-)
>>
>> Dino...k6rix at earthlink.net
>>
>
> Dino, I'm with the folks who suggested that making these changes to the 
> 'BA
> Is probably not necessary. I have an older (25+ year old) 204BA, bought it
> used
> Other than changing the hairpin to the new style, cleaned it up and put it
> back up
> On my 55' tower. It has been through heavy winds, ice, etc. no problem at
> all and works
> Very well. I might suggest a balun upgrade to a good current balun rather
> than the Hygain
> Bn series.
>
> 73 John W8JJW
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 20 Feb 2006 14:07:28 +0000
> From: wf3h at comcast.net
> Subject: [TowerTalk] Feedline
> To: <TOWERTALK at contesting.com>
> Message-ID:
> <022020061407.16800.43F9CD2000008596000041A0220075115008CC0099 at comcast.net>
>
> Content-Type: text/plain
>
> OK I know this has the potential to open a can of worms, but I'm going to 
> put up a nice tower about 100-200' from the station.  I need a good 
> feedline that is low loss and easy to work with. Hardline is not an 
> option.
>
> I will be feeding both HF and VHF antennas.
>
> Also, I'll be putting in a rotator (Ham IV). Any good rotator cable?
>
> THanks all you experts! Appreciate it.
>
> Bob/WF3H
>
> ------------------------------
>
> Message: 3
> Date: Mon, 20 Feb 2006 08:38:42 -0600
> From: "Matt Patterson" <mattpatt at 1starnet.com>
> Subject: Re: [TowerTalk] Feedline
> To: <TOWERTALK at contesting.com>
> Message-ID: <000e01c6362b$5bc700e0$ab17460a at jsmisc06>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> When you say HF and VHF what VHF bands are you talking about specifically?
>
>
> 73 Matt
> W5LL
> ----- Original Message ----- 
> From: <wf3h at comcast.net>
> To: <TOWERTALK at contesting.com>
> Sent: Monday, February 20, 2006 8:07 AM
> Subject: [TowerTalk] Feedline
>
>
>> OK I know this has the potential to open a can of worms, but I'm going to
>> put up a nice tower about 100-200' from the station.  I need a good
>> feedline that is low loss and easy to work with. Hardline is not an
>> option.
>>
>> I will be feeding both HF and VHF antennas.
>>
>> Also, I'll be putting in a rotator (Ham IV). Any good rotator cable?
>>
>> THanks all you experts! Appreciate it.
>>
>> Bob/WF3H
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 20 Feb 2006 07:13:59 -0800
> From: "Pat Barthelow" <aa6eg at hotmail.com>
> Subject: [TowerTalk] Quagi Optimization
> To: towertalk at contesting.com
> Message-ID: <BAY114-F19A6093C864CE8276CA897FBFF0 at phx.gbl>
> Content-Type: text/plain; format=flowed
>
> Sorry for the slightly off topic query, and please guide me to the best
> antenna discussion group....I am at a remote location, (Sierra Foothills
> above Auburn CA,) and built Wayne Oberbecks Late 70's version, 16 el Quagi
> for 440 to try to hit the hometown repeater, ( Monterey CA) some 160 miles
> away, driven with 5 watts.  I can hear the repeater sometimes,  but cant
> quite key it.
> I want to know what the most sensitive dimensions are that affect gain. 
> My
> aluminum welding rod/wood boom/copper quad loop quagi, probably has some
> dimesnional inaccuracies of up to 1/2 ", probably the driven loop size or
> flatness, and some of the director element spacing  vary from the Oberbeck
> model, vary in spacing while lengths conform pretty tight.  They may also
> vary in perpendicularity to the boom  (some slightly bent, or not 90 deg 
> to
> the flat boom, so their tips may be out of whack, say by 1/2  to 3/4
> inch.... With only rough tools, what dimensions do I have to pay attention
> to most, to get the best gain out of this antenna?  How about  the not
> having a balun problem?
> 73, DX, de Pat AA6EG aa6eg at hotmail.coim
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 20 Feb 2006 07:22:56 -0800
> From: Jim Lux <jimlux at earthlink.net>
> Subject: Re: [TowerTalk] Feedline
> To: wf3h at comcast.net, <TOWERTALK at contesting.com>
> Message-ID: <6.1.1.1.2.20060220071907.01fcc520 at mail.earthlink.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> At 06:07 AM 2/20/2006, wf3h at comcast.net wrote:
>>OK I know this has the potential to open a can of worms, but I'm going to
>>put up a nice tower about 100-200' from the station.  I need a good
>>feedline that is low loss and easy to work with. Hardline is not an 
>>option.
>
> Are you cost limited? How many feedlines? Will the feedline be 
> underground,
> and if so, in conduit or direct burial?
>
>
>>I will be feeding both HF and VHF antennas.
>>
>>Also, I'll be putting in a rotator (Ham IV). Any good rotator cable?
> Same sort of questions.  For example, 14/3 Romex is often available very
> inexpensively in 100ft boxes.  A couple runs gives you 6 wires.
>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 20 Feb 2006 07:28:32 -0800
> From: Jim Lux <jimlux at earthlink.net>
> Subject: Re: [TowerTalk] Quagi Optimization
> To: "Pat Barthelow" <aa6eg at hotmail.com>, towertalk at contesting.com
> Message-ID: <6.1.1.1.2.20060220072356.01fcf090 at mail.earthlink.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> At 07:13 AM 2/20/2006, Pat Barthelow wrote:
>>Sorry for the slightly off topic query, and please guide me to the best
>>antenna discussion group....I am at a remote location, (Sierra Foothills
>>above Auburn CA,) and built Wayne Oberbecks Late 70's version, 16 el Quagi
>>for 440 to try to hit the hometown repeater, ( Monterey CA) some 160 miles
>>away, driven with 5 watts.  I can hear the repeater sometimes,  but cant
>>quite key it.
>>I want to know what the most sensitive dimensions are that affect gain. 
>>My
>>aluminum welding rod/wood boom/copper quad loop quagi, probably has some
>>dimesnional inaccuracies of up to 1/2 ", probably the driven loop size or
>>flatness, and some of the director element spacing  vary from the Oberbeck
>>model, vary in spacing while lengths conform pretty tight.  They may also
>>vary in perpendicularity to the boom  (some slightly bent, or not 90 deg 
>>to
>>the flat boom, so their tips may be out of whack, say by 1/2  to 3/4
>>inch.... With only rough tools, what dimensions do I have to pay attention
>>to most, to get the best gain out of this antenna?  How about  the not
>>having a balun problem?
>>73, DX, de Pat AA6EG aa6eg at hotmail.coim
>
> Can you send me the dimensions (or point me to an online source of them, 
> or
> if they're in the ARRL antenna book).  I can run a model pretty quickly 
> and
> tell you what's the most sensitive.
>
> In general, elements closer to the driven element are more critical (they
> have more current). Length is more critical than orientation, since the
> length sets the phase of the current in the element (1% change in length
> results in a couple degree change in phase). Spacing is also fairly
> important (1/2" is about 6 degrees of phase) Small changes in orientation
> aren't all that big a deal: the coupling is, to a first order, 
> proportional
> to the cosine of the angle,and the difference between cosine(0) and
> cosine(5 degrees) is pretty small)
>
> Jim
>
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 20 Feb 2006 16:00:58 +0000
> From: ersmar at comcast.net
> Subject: Re: [TowerTalk] Feedline
> To: wf3h at comcast.net, <TOWERTALK at contesting.com>
> Message-ID:
> <022020061600.20138.43F9E7BA00006E7B00004EAA22007601809D0E039C9D0A at comcast.net>
>
>
> Bob:
>
>     A while back (ca 1995!) W3LPL compiled a table of coax cables vs loss. 
> You can find one source here: 
> http://www.k1ttt.net/technote/coaxloss.html#tables .
>
>     Frank recommended (elsewhere) that coax should be selected to keep the 
> loss below 1 dB for the highest freq the coax run will carry.  So for 28 
> MHz and 200 feet of coax the conventional cable designs (RG-213, -8X and 
> 9913) would be too lossy.  You'd more or less be forced to go with some 
> sort of Andrew cable design such as Superflex (FXA12-50J).
>
>     Of course, you could accept greater losses in your coax runs and 
> select one of the more common cable designs.  These tables will let you 
> calculate the loss impact for each design you might consider.
>
> 73 de
> Gene Smar  AD3F
>
>
> -------------- Original message ----------------------
> From: wf3h at comcast.net
>> OK I know this has the potential to open a can of worms, but I'm going to 
>> put up
>> a nice tower about 100-200' from the station.  I need a good feedline 
>> that is
>> low loss and easy to work with. Hardline is not an option.
>>
>> I will be feeding both HF and VHF antennas.
>>
>> Also, I'll be putting in a rotator (Ham IV). Any good rotator cable?
>>
>> THanks all you experts! Appreciate it.
>>
>> Bob/WF3H
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 20 Feb 2006 08:05:35 -0800
> From: "Al Williams" <alwilliams at olywa.net>
> Subject: Re: [TowerTalk] Quagi Optimization
> To: <towertalk at contesting.com>, "Jim Lux" <jimlux at earthlink.net>
> Message-ID: <001801c63637$80a117a0$25daadd8 at PAPASDELL>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
>
> ----- Original Message ----- 
> From: "Jim Lux" <jimlux at earthlink.net>
> To: "Pat Barthelow" <aa6eg at hotmail.com>; <towertalk at contesting.com>
>> In general, elements closer to the driven element are more critical (they
>> have more current).
>
> For a REGULAR YAGI do the parasitic element's induced voltages cause
> radiation which then cause currents in the neighboring elements and so on?
> I am pretty sure that this is true but do these SECONDARY currents have 
> the
> amplitude and phase to have much effect on the total pattern?
>
> Do antenna modelling programs take these secondary currents and radiation
> into account when summing up the segments and elements?
>
> K7PUC
>
>
>
> ------------------------------
>
> Message: 9
> Date: Mon, 20 Feb 2006 08:05:36 -0800
> From: "K6XN" <k6xn at comcast.net>
> Subject: Re: [TowerTalk] Feedline
> To: <wf3h at comcast.net>, <TOWERTALK at contesting.com>
> Message-ID: <20060220160548.BC1B13192CB at dayton.akorn.net>
> Content-Type: text/plain; charset="us-ascii"
>
> Team
>
> This summer we installed an 11 element 70 foot boom length M2 6 meter yagi
> on an 85 foot tower at an elevation of 5000 feet located about 200 feet 
> from
> my summer QTH in CM99 in the Sierras. I used a single 300 foot length of
> Times Microwave LMR-600 low loss coax for the run from the radio room to 
> the
> antenna and it has worked out *great*. Be sure to also get the Times
> Microwave TC-600-NMC special "N" connectors. I was able to get everything
> from Texas Towers and the coax arrived OK on its own wooden spool. Make 
> sure
> you invite some friends to help you though with the antenna assembly and
> raising party and for laying out the LMR-600  :-)
>
> I am *very* pleased with LMR-600 and I am changing over all of my VHF feed
> lines for VHF to LMR-600.
>
> Good luck and 73, Ted, K6XN
>
> Ps Yes..we can bounce our 6 meter SSB signals off the moon with this 
> antenna
> and feed line and we can hear our own signals come back to us after about 
> 2
> seconds when we run the 6 meter modified Heathkit SB 220 linear (thank you
> KM1H for the 1200 watts on 6 meters). We can also usually work just about
> any one on earth that we can hear on 6 meters with only 10 watts to the 11
> element beam....we are in a wilderness area at the summer QTH in CM99 with
> no commercial power (no neighbors and no QRN or TVs either) and we usually
> run QRP on solar power and batteries but we do have a back up 20 KW diesel
> generator for running the well pump, back up...and contests. :-)
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of wf3h at comcast.net
> Sent: Monday, February 20, 2006 6:07 AM
> To: TOWERTALK at contesting.com
> Subject: [TowerTalk] Feedline
>
> OK I know this has the potential to open a can of worms, but I'm going to
> put up a nice tower about 100-200' from the station.  I need a good 
> feedline
> that is low loss and easy to work with. Hardline is not an option.
>
> I will be feeding both HF and VHF antennas.
>
> Also, I'll be putting in a rotator (Ham IV). Any good rotator cable?
>
> THanks all you experts! Appreciate it.
>
> Bob/WF3H
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> End of TowerTalk Digest, Vol 38, Issue 41
> *****************************************
> 