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Re: [TowerTalk] TowerTalk Digest, Vol 55, Issue 138

To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] TowerTalk Digest, Vol 55, Issue 138
From: "Mike Sweeley" <kl7ar@mtaonline.net>
Date: Fri, 27 Jul 2007 13:05:42 -0800
List-post: <mailto:towertalk@contesting.com>
This is a test

-----Original Message-----
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Sent: Friday, July 27, 2007 12:42 PM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 55, Issue 138

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Today's Topics:

   1. Re: Grounding Standard (John Santillo)
   2. Re: Grounding Standards (Jim Lux)
   3. Re: Wanted: KLM Insulator for 2M Yagi 144-148-13LB or     theLike
      (Roger (K8RI))
   4. What rebar is made is (Rick Karlquist)
   5. Re: Current choke beads (Joe Reisert, W1JR)
   6. Re: What rebar is made is (Bill Turner)
   7. m2 6M7   SWR change with rain (Hector Garcia XE2K)


----------------------------------------------------------------------

Message: 1
Date: Fri, 27 Jul 2007 14:57:31 -0400
From: "John Santillo" <u1004467@warwick.net>
Subject: Re: [TowerTalk] Grounding Standard
To: "Gene Smar" <ersmar@verizon.net>, "Jim Brown"
        <jim@audiosystemsgroup.com>,    "jeremy-ca" <km1h@jeremy.mv.com>,
        <towertalk@contesting.com>
Message-ID: <011b01c7d07f$fc8a6220$6a01a8c0@warwick.net>
Content-Type: text/plain;       charset="iso-8859-1"

In the defense industry we do "successful approximation's" all the time.  If
we went for perfection we'd price ourselves right out of the competition.
But, we always provide options and detail the scope of work.

73,

John
N2HMM



----- Original Message ----- 
From: "Gene Smar" <ersmar@verizon.net>
To: "Jim Brown" <jim@audiosystemsgroup.com>; "jeremy-ca"
<km1h@jeremy.mv.com>; <towertalk@contesting.com>
Sent: Friday, July 27, 2007 14:38 PM
Subject: Re: [TowerTalk] Grounding Standard


> From: jeremy-ca <km1h@jeremy.mv.com>
> Date: 2007/07/27 Fri AM 09:32:07 CDT
> To: Jim Brown <jim@audiosystemsgroup.com>, towertalk@contesting.com
> Subject: Re: [TowerTalk] Grounding Standard
>
>
>
>
> The problem with some engineers is that they strive for 100% perfection
and
> accept nothing else. Ive seen many of that type come and go over my almost
> 50 years in the RF industry. They never get a product to market or have
one
> that is not manufacturable.
> The successful ones know when to quit computing and hand the product to
the
> manufacturing engineers.
>
> Carl
> KM1H
>
>
> TT:
>
>      I once heard engineering described as the art of successful
approximation.
>
> 73 de
> Gene Smar  AD3F, P.E.
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>



------------------------------

Message: 2
Date: Fri, 27 Jul 2007 12:04:11 -0700
From: Jim Lux <jimlux@earthlink.net>
Subject: Re: [TowerTalk] Grounding Standards
To: "Jim Brown" <jim@audiosystemsgroup.com>,    "towertalk reflector"
        <towertalk@contesting.com>
Message-ID: <6.2.3.4.2.20070727114927.02c8fdd8@mail.earthlink.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 08:32 AM 7/27/2007, Jim Brown wrote:
>On Fri, 27 Jul 2007 11:04:26 -0400, Alan NV8A wrote:
>
>The grounding requirements of NEC are not terribly demanding, so
>the stuff I'm seeing quoted here re: tower grounding seems a bit
>suspect. I'd like to see citations of the numbered paragraphs that
>call for the large conductors being discussed before I take it as
>gospel.


I think there's some conflation of the NEC grounding requirements 
(easy to meet for most cases) and NFPA lightning ground requirements 
(NFPA 780) and various manufacturer (e.g. Polyphaser) recommendations.

(FWIW, NFPA 780 in the year 2000 revision started to recommend the 
use of radial ground conductors below ground level ot distribute 
lightning charge)

There's also an IEC standard IEC62305 for lightning protection.

one might want to look at http://www.lightningsafety.com/ which has a 
lot of info on their website.


Jim, W6RMK 




------------------------------

Message: 3
Date: Fri, 27 Jul 2007 15:07:32 -0400
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Subject: Re: [TowerTalk] Wanted: KLM Insulator for 2M Yagi
        144-148-13LB or theLike
To: <towertalk@contesting.com>
Message-ID: <001001c7d081$68c79f60$6400a8c0@shop32>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
        reply-type=original




> I'm trying resurrect an old KLM Yagi and need one insulator for a
> director element.  These are T-shaped and have a groove to fit along the
> 1-1/2" boom and a 3/8" hole through which the element passes.  I can

You may find the design of these has changed a bit.  The last ones I 
purchased had a grove for the element so the element fitted on top in the 
same manner as the insulator fits on the boom. Even though they use 
insulators mine ground the reflector and directors to the boom with the 
mounting screw. Only the 4 driven elements are insulated from the boom on my

14 L KLMs
Sadtip has already given a link to a possible source.

Good Luck,

Roger (K8RI)

> fabricate an alternate arrangement, but would prefer to use one of the
> original insulators if someone has one available.
>
> Thanks.
>
> 73, Joe
> K2XX
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk 



------------------------------

Message: 4
Date: Fri, 27 Jul 2007 12:39:15 -0700 (PDT)
From: "Rick Karlquist" <richard@karlquist.com>
Subject: [TowerTalk] What rebar is made is
To: towertalk@contesting.com
Message-ID:
        <5141.192.25.142.225.1185565155.squirrel@webmail.sonic.net>
Content-Type: text/plain;charset=iso-8859-1

Answer:  guns :-)

All the recent discussion on rebar came to mind yesterday while
I was watching a show on the History Channel about what happens
to guns confiscated by the police.  It turns out that the LA police
take seized guns no longer needed for legal purposes and send
them by the truckload to a nearby foundry.  There they go into
an arc furnace where they are melted down, and after a series of
steps explained on the TV show, eventually emerge as REBAR.
The TV show has the foundry owner proudly listing some of the
famous structures that are rebarred courtesy of his foundry,
and the LA police.  I guess the specification on rebar must
go something like:  mostly iron, with some other stuff.  Kind of
like sausage; don't ask too many questions.

Rick N6RK




------------------------------

Message: 5
Date: Fri, 27 Jul 2007 16:03:43 -0400
From: "Joe Reisert, W1JR" <W1JR@arrl.net>
Subject: Re: [TowerTalk] Current choke beads
To: n7ka@comcast.net, towertalk@contesting.com (TowerTalk)
Message-ID: <0JLU00LFCT28F351@vms040.mailsrvcs.net>
Content-Type: text/plain; charset=us-ascii; format=flowed

Hi Arnie,

I guess there has been a discussion on baluns going on. Let me add a 
few comments on the subject.

First off, there are alternatives or choices on transmission line 
types used in coax baluns. RG58 is fine for low power (100-200 Watts) 
but for higher power, you need larger and higher power coax such as 
RG213 or teflon dielectric coax. When I wrote the first current 
amateur balun article (Simple and efficient broadband balun by W1JR 
in Ham Radio Magazine, September 1978) I used RG141 since it was the 
only high power coax available at that time that could be fairly 
easily wound on a 2.4" OD toroid. However, for the last 15 or so 
years I have been using the newer RG303 coax since it is less costly 
(than RG141), smaller in outside diameter, easier to use especially 
on toroids and will handle full amateur power levels.

In 1989 I helped develop a low cost PTFE coax for the Cushcraft 
Corporation. They needed a cost effective coax for installing mobile 
antennas in automobiles that wouldn't melt if placed near catalytic 
converters etc. Cushcraft marketed it as "Ultra Link" coax. Ultra 
Link, as I recall, is about the diameter of RG58. It uses PTFE 
(instead of teflon) dielectric. The dielectric is first covered by a 
foil shield which in turn is covered by a regular braided shield  but 
with a polyethylene outer jacket. It can easily handle amateur high 
power levels. Furthermore, Ultra Link coax should be widely available 
through distributors of mobile products such as Tessco and the like 
and should be very reasonable in price versus RG141 or RG303.

The W1JR current balun was mainly intended for 20-10 Meters and only 
had 12 turns of coax but did have sufficient impedance to work from 
80 meters through 6 meters. I later tried stacking (placing two 
toroid on top of each other) and that balun with 12 turns of RG303 
coax has sufficient impedance to go down to  160 meters. I see that 
Array Solutions (WX0B) markets both types of the W1JR balun. I am in 
no way involved financially with this design although I tested them 
for Jay and they worked great. Jay used a neat layout by closely and 
tightly wrapping the coax which improves the upper frequency limits. 
One of the stacked (2 toroid) baluns using 2.4" OD 61 material is 
used on my 160/80 meter G5RV dipole and easily handles 1500 Watts 
even with poor VSWR (a characteristic of the G5RV dipole). The beauty 
of this type of toroid balun is that it is compact, has a good high 
frequency response, has low loss and the cross over winding keeps the 
input and output separate simplifying isolation and connection to the 
outside world. The W1JR balun is arguably the widest distributed 
balun to date having been used in every R5, R6, R7and R8 Cushcraft 
antenna with over 100,000 antennas sold! Cushcraft used RG303 coax 
for that balun. Cushcraft uses a 4:1 balun with Ultra Link coax in 
the 17B2 and 13B2 VHF high power Yagis.

Soon after the W1JR balun article was published, several individuals 
published articles on the same balun but adding a tertiary wire. This 
in effect made it a voltage balun, a poor choice indeed. Shortly 
thereafter, W7EL wrote a paper (see ARRL Antenna Compendium, Volume 
1) to correct the errors and pointed out the differences between the 
current and voltage type baluns. Thus a great mystery was solved ands 
two new terms (current baluns and voltage baluns) became widely used 
in amateur radio.

Since then, the W2DU in line coax balun has become popular due to its 
ease in construction. It uses 50 to 100 ferrite beads with type 73 
material. It turns out that this ferrite material has a high loss and 
low resistivity in the HF frequency range. The beads W2DU chose had a 
small inside and outside diameter so the outer jacket of RG141 coax 
had to be removed to insert the coax into the bead. Due to the losses 
and small size of these beads, the W2DU balun can get quite hot with 
high power and in one documented case (Common Mode Chokes by W1HIS) 
started an attic fire!

More recent W2DU type balun designs have emerged (Exploring the 1:1 
Current Choke Balun by W0IYH in June 1997 QEX). Basically W0IYH used 
larger diameter and longer length ferrite beads with lower loss type 
43 ferrite material. This approach seems to improve the 
aforementioned problems and less chance of IMD. It uses a 36" string 
of ferrite beads! For some time now, I had also been using 30 of a 
similar bead (see below) for my HF line decouplers.

I used similar ferrite beads to W0IYH in my commercial antennas 
starting in 1992. The beads are 1.125" long, 0.562" OD with a .250" 
ID with Fair-Rite 43 material. Three of these beads in a string 
covered with a heat shrink tubing with a flooding agent worked great 
for 1:1 baluns from 100 MHz through 1000 MHz. For my commercial 
antennas in the 40-100 MHz spectrum, we used 5 of these beads. At 50 
MHz 5 beads in a string measured over 1000 Ohms and over 500 Ohms at 
28 MHz on a Hewlett Packard 8753C network analyzer. I believe that 
Amidon part number FB-43-5621 is a very available equivalent. RG58 
was used for 100 Watts and less with RG303 for higher power antennas. 
This was obviously an economical choice for ease in manufacturing.

Some amateurs don't want to use the smaller RG303 coax and .562" OD 
beads since it requires another set of connectors to be compatible 
with RG213. Therefore, I also tested some 1" OD ferrite beads about 
1.125" long with 43 material and a 0.500" ID. Five (5) of these beads 
in a string measured about 500 Ohms at 28 MHz and 900 Ohms at 50 MHz 
and would be OK if threaded on to RG213 coax before connector 
installation. These beads should be equivalent to Amidon part number 
FB-43-1020.

Recently type 31 material has become available from Fair-Rite. K9YC 
has mentioned this in his paper on "Understanding and Solving RF 
Interference Problems." This material has a higher permeability (1500 
versus 850 for 43 material) and thus probably greater loss but should 
be better at the lower frequencies than 43 material. I recently 
acquired a batch of 1" OD 31 material beads similar to the ones just 
mentioned. Five (5) of them in a string measured about 750 Ohms at 28 
MHz and 1,000 Ohms at 50 MHz. I don't know if they are available yet 
from the typical amateur suppliers.

Finally, several have mentioned the use of clamp on beads. These are 
OK but must be properly chosen for size, material, permeability etc. 
I don't have any here to test. I would be worried that they stay 
closed and that the outside wrapper keep them tightly bound. 
Obviously clamp on beads are great if added to an already installed 
antenna etc. Exposure to sunlight may deteriorate the clamping shell 
so attention must be paid to installation. Also, they are probably 
more expensive and require some special mounting.

So, just as amateurs chose their ideal antenna based on their 
individual needs, cost, performance, XYL etc. etc. (and every ones 
choice is different!), the same goes for baluns. Hopefully the above 
information will be informative and complete enough to assist you in 
choosing the perfect fit for your application.

73,

Joe, W1JR



At 06:15 PM 7/26/2007, n7ka@comcast.net wrote:
>WOW.
>
>At the risk of getting flamed to death, here goes.  Actually, there 
>is NO risk as I know it will happen.
>
>I asked for assistance from those who have gone before and could 
>help to inform me if I was headed in the correct direction for a 
>commom mode choke for a 6M antenna project.  I have read I NEED to have
one.
>
>I received 1 straight forward comment that said they were using 
>something and was having NO problems.  It worked OK.  TYhanks.
>
>Another answer was to look at the Jim, K9YC, tutorial for info.  I 
>plan  to do that so see if a little knowledge will sink into my 
>retired brain.  Also,thanks
>
>I have been wearing out my mouse deleting messages that went into 
>another galaxy.
>
>IS IT TIME TO HAVE 2 RELECTORS, 1 FOR THE PRACTICAL HOME BUILDER WHO 
>ASKS FOR IDEAS AND 1 FOR THE THEORITICAL ENGINEER TO DISCUSS THE 
>MERIT OF 0.01 dBi?
>
>I do not own the $30,000 (more or less) worth of test equipment 
>needed, so some say, just to make a working choke that might cost 
>all of $15.00 to build.  Nor do I want to own it.  And if I go back 
>a number of years I would not think of having anything except 
>TEKTRONIX (I worked for then in the 60/70s) equipment in my 
>home.though they did not build every kind of test equipment.  HP 
>built stuff TEKdid not anad we should have all said thanks to thenm 
>and others who made test equipment of various types. (Lets see, 
>where is my FLUKE DMM, SIMPSON 260, and my TRIPLETT  VOM?)
>
>I am glad progress has been made in equipment and ideas but think 
>about those of us who go at this hobby from a practical 
>approach.   We do not need to understand  the intricate details of 
>something to use it or build it.  Yes, its nice to learn 
>"something"as we go but!"
>
>If I had to know the REASON in detail before a situation occurs I 
>would have to delve deep into propagation to understand why I worked 
>S5 on 6M  in June at the bottom of the solar cycle, hey with 5el and 
>100W from NM guess thats NOT TO SHABBY.  I do not know how it 
>happened, but the QSL card I received proved it did happen and thats 
>good enough for me.  Yes, I did learn a little from it and will be 
>applying that knowledge in the future, so all is not lost.  I also 
>learned I needed an amp to help overcome the noise level at the 
>other end; S5 was not the only station I heard, just the only one I worked.
>
>Now back to the practical side of this hobby and my DELETE button on 
>the mouse will probably get overtime work for a few days.
>
>I acknowledge those learned folks who can delve into and understand 
>all of the theory; more power to you.  We so called practical 
>dummies can benefit when something practical comes from the theory, 
>and we thank you.
>
>Thanks to those who did provide ON SUBJECT comments to my query.
>
>Now to refill my drink container with more NM SUN brewed iced tea 
>and grease the mouse keys.
>
>Arne N7KA
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk



------------------------------

Message: 6
Date: Fri, 27 Jul 2007 13:36:43 -0700
From: Bill Turner <dezrat@copper.net>
Subject: Re: [TowerTalk] What rebar is made is
To: towertalk@contesting.com
Message-ID: <bnlka3lvk17jqn7kbctj5ji38hu1muvot9@4ax.com>
Content-Type: text/plain; charset=us-ascii

ORIGINAL MESSAGE:

On Fri, 27 Jul 2007 12:39:15 -0700 (PDT), "Rick Karlquist"
<richard@karlquist.com> wrote:

>Answer:  guns :-)
>
>All the recent discussion on rebar came to mind yesterday while
>I was watching a show on the History Channel about what happens
>to guns confiscated by the police.  It turns out that the LA police
>take seized guns no longer needed for legal purposes and send
>them by the truckload to a nearby foundry.  There they go into
>an arc furnace where they are melted down, and after a series of
>steps explained on the TV show, eventually emerge as REBAR.
>The TV show has the foundry owner proudly listing some of the
>famous structures that are rebarred courtesy of his foundry,
>and the LA police.  I guess the specification on rebar must
>go something like:  mostly iron, with some other stuff.  Kind of
>like sausage; don't ask too many questions.

------------ REPLY FOLLOWS ------------

The quantity of guns melted down vs the quantity of rebar produced
annually would suggest that gun metal is a very small percentage.

It was a good program, however.

Bill W6WRT


------------------------------

Message: 7
Date: Fri, 27 Jul 2007 13:42:18 -0700 (PDT)
From: Hector Garcia XE2K <j_hector_garcia@sbcglobal.net>
Subject: [TowerTalk] m2 6M7   SWR change with rain
To: Tower Talk <towertalk@contesting.com>
Message-ID: <675740.34799.qm@web83509.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Hi guys:

A friend   just install the 6M7 in his  office tower 
and he report that his antena in the last rains the
swr change from the perfect 50.125 1:1  to 49.9 1:1
when the antena is WET , just dry and the SWR back  to
50.125

I have a 6M7JHV in the box to be installed  at 150ft
and really i will like to know if adding some clear
spray or paint to the driven will reduce or eliminate
that problem of SWR change when WET.

any solve the problem ?  any solution  avaliable

or just live with that ?


Hector 

Hector Garcia XE2K / XF1K
   Mexicali B.C  DM22fp
P.O.Box 73 
El Centro CA 92244-0073
USA
http:// www.xe2k.net
http://www.dxxe.org


------------------------------

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End of TowerTalk Digest, Vol 55, Issue 138
******************************************


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