I (or my team) is in charge of about 4000 towers in the SE. They have from 1
to 15 carriers
on the towers depending on the tower. Not one (yes, not one) has anything
but a copper buss bar
that the polys are mounted to. Bottom of the tower, hardline grounded to
copper bus. Next buss
the polys are mounted to just before the equipment, copper buss.
When the thefts started, some went to aluminum but went back to copper and
installed a box over
it or covered is with a spray can of undercoat to stop the theft. They went
back to copper as
they couldn't get under 5 ohms needed for the specs.
I have 4 buss bars here between my two towers and use all copper.
73 Dave n4zkf
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of rurie@mywdo.com
Sent: Friday, June 12, 2009 6:17 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to SPGP
All this discussion concerning how to mount the polyphaser
to the SPG. If aluminum is so bad, why is the body and
the
mounting tab made of it? Follow the instructions provided
with the item, or, check out their website as there are
numerous
articles concerning this subject. At my comm sites, I
generally have them mounted on an AL plate with no issues.
Properly
protected from the elements, dissimilar corrosion can be
eliminated.
73,
Robb N0RU
On Fri, 12 Jun 2009 12:00:30 -0700
towertalk-request@contesting.com wrote:
> Send TowerTalk mailing list submissions to
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> Today's Topics:
>
> 1. Re: Mounting Polyphaser IS-RCT to SPGP (Dick Green)
> 2. Re: Mounting Polyphaser IS-RCT to SPGP (Michael Fox
>- N6MEF)
> 3. Re: Mounting Polyphaser IS-RCT to SPGP (jimlux)
> 4. Re: Mounting Polyphaser IS-RCT to SPGP (John
>Kemker)
> 5. Re: Vacuum variable / inductor ratings for shunt
>fed tower
> (Rick Karlquist)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 12 Jun 2009 02:05:14 -0400
>From: Dick Green <dick@mailgreen.us>
> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>SPGP
> To: John Kemker <john@kemker.org>, Peter Dougherty
><w2irt@verizon.net>
> Cc: "TowerTalk@contesting.com"
><TowerTalk@contesting.com>
> Message-ID:
>
<6AA81205DA0C6448BBE5463F4401DBF2010238E994C2@VMBX115.ihostexchange.net>
>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Why do you advise against an aluminum ground plate? Are
>you only against outdoor use or indoor as well? I have a
>pair of Hoffmann metal utility cabinets with aluminum
>grounding plates inside. They seem to be fine and haven't
>corroded a bit.
>
> 73, Dick WC1M
>
>> -----Original Message-----
>> From: John Kemker [mailto:john@kemker.org]
>> Sent: Thursday, June 11, 2009 11:47 PM
>> To: Peter Dougherty
>> Cc: TowerTalk@contesting.com
>> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>>SPGP
>>
>> The ICE might be a better solution, in any case.
>> However, to each their
>> own.
>>
>> I'd advise against the aluminum and seriously check out
>> www.georgiacopper.com for their copper plates. VERY
>>reasonable prices
>> for 12"x12" sheets and straps. I just got two in the
>>mail that I'll be
>> mounting for the tower base. It cost less than the
>>great eBay deal I
>> got on a PolyPhaser copper plate mounted on MDF I
>>purchased a few years
>> ago. As in five times less money. (I spent $45 before
>>shipping on the
>> PolyPhaser plate. I spent $9 before shipping on the
>>GA-Copper plate.)
>> They also sell the wide copper straps for grounding and
>>the copper
>> anti-oxidant grease, as well. All in all, good deals on
>>good product.
>>
>> Peter Dougherty wrote:
>> > My Round Tuit finally arrived and I'm hoping to have
>>my single-point entry
>> > panel finished in a couple of weeks. What I'm trying
>>to figure out the
>> > proper way of mounting the Polyphaser IS-RCT
>>(8-terminal rotor control
>> > protector) to the panel. It's a solid box with a ?"-20
>>one-inch stud coming
>> > out the top and there are no mounting flanges on the
>>box. My original plan
>> > was an 18 x 24" copper or aluminum plate to which all
>>the suppressors would
>> > be mounted, and 2" strapping to the bonded system. The
>>thing of it is, none
>> > of the polyphaser devices are made for panel
>>mounting-neither these IS-RCT
>> > boxes or the high-power coax supressors, which are
>>bulkhead-mount only.
>> >
>> > I'm really stumped here and I think I may just end up
>>selling these and
>> > getting ICE devices instead. Any suggestions?
>> >
>> > Also, would I be just as well to get aluminum sheeting
>>for the SPGP, then
>> > using copper strap with a thick layer of NoAlox where
>>the strap meets the
>> > plate? Would I run into problems if I ran two 2"-wide
>>by foot-long buses
>> > tied together by 2" strapping or is it better to go
>>with a single large
>> > plate instead?
>> >
>> > Thanks in advance.
>> >
>> > -----------------------------------
>> >
>> > Regards,
>> >
>> > Peter,
>> > W2IRT
>> >
>> --
>> --JohnK
>> 73 de W5NNH
>> 10X 75371/M&M 117/SMIRK 6185/Six Club 285/TRA
>>2499/Norcross 228 F&AM
>>
>>
>>
>>
>> ---
>> avast! Antivirus: Outbound message clean.
>> Virus Database (VPS): 090611-0, 06/11/2009
>> Tested on: 6/11/2009 11:47:24 PM
>> avast! - copyright (c) 1988-2009 ALWIL Software.
>> http://www.avast.com
>>
>>
>>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 12 Jun 2009 05:09:59 -0700
>From: "Michael Fox - N6MEF" <n6mef@mefox.org>
> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>SPGP
> To: <towertalk@contesting.com>
> Message-ID: <030801c9eb56$b5933c90$20b9b5b0$@org>
> Content-Type: text/plain; charset="us-ascii"
>
> I have a similar situation to yours, but it's
>intentional.
>
> My outdoor NEMA boxes have an aluminum plate that mounts
>to the back of the
> box. But I wanted a bulkhead for mounting the
>suppressors so the cables
> could enter one side, pass through the bulkhead and exit
>the other side.
> (BTW, Polyphase does make flange-mount, but the bulkhead
>approach let's you
> pack them in more densely.)
>
> So I made the bulkhead out of aluminum and then mounted
>it at a right angle
> to the back plate using some pieces of 1-inch aluminum
>angle from Home
> Depot.
>
>For the IS-RCT, I secured a small piece of 1-inch
>aluminum angle the main
> plate. The bolt from the IS-RCT then goes through the
>angle and the IS-RCT
> is essentially flat against the back plate. (It's not
>exactly flat because
> the grounding bolt in the IS-RCT is at a small angle,
>but it works fine).
>
> Michael - N6MEF
>
>
>> -----Original Message-----
>> ------------------------------
>>
>> Message: 3
>> Date: Thu, 11 Jun 2009 22:11:40 -0400
>> From: "Peter Dougherty" <w2irt@verizon.net>
>> Subject: [TowerTalk] Mounting Polyphaser IS-RCT to SPGP
>> To: <TowerTalk@contesting.com>
>> Message-ID: <005b01c9eb03$1fe154a0$5fa3fde0$@net>
>> Content-Type: TEXT/PLAIN
>>
>> My Round Tuit finally arrived and Im hoping to have my
>>single-point
>> entry
>> panel finished in a couple of weeks. What Im trying to
>>figure out the
>> proper way of mounting the Polyphaser IS-RCT (8-terminal
>>rotor control
>> protector) to the panel. Its a solid box with a <-20
>>one-inch stud
>> coming
>> out the top and there are no mounting flanges on the
>>box. My original
>> plan
>> was an 18 x 24 copper or aluminum plate to which all
>>the suppressors
>> would
>> be mounted, and 2 strapping to the bonded system. The
>>thing of it is,
>> none
>> of the polyphaser devices are made for panel
>>mountingneither these IS-
>> RCT
>> boxes or the high-power coax supressors, which are
>>bulkhead-mount only.
>>
>> Im really stumped here and I think I may just end up
>>selling these and
>> getting ICE devices instead. Any suggestions?
>>
>> Also, would I be just as well to get aluminum sheeting
>>for the SPGP,
>> then
>> using copper strap with a thick layer of NoAlox where
>>the strap meets
>> the
>> plate? Would I run into problems if I ran two 2-wide by
>>foot-long
>> buses
>> tied together by 2 strapping or is it better to go with
>>a single large
>> plate instead?
>>
>> Thanks in advance.
>>
>> -----------------------------------
>>
>> Regards,
>>
>> Peter,
>> W2IRT
>>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 12 Jun 2009 06:25:47 -0700
>From: jimlux <jimlux@earthlink.net>
> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>SPGP
> To: Dick Green <dick@mailgreen.us>
> Cc: Peter Dougherty
><w2irt@verizon.net>, "TowerTalk@contesting.com"
> <TowerTalk@contesting.com>, John Kemker
><john@kemker.org>
> Message-ID: <4A32575B.3020707@earthlink.net>
> Content-Type: text/plain; charset=ISO-8859-1;
>format=flowed
>
> Dick Green wrote:
>> Why do you advise against an aluminum ground plate? Are
>>you only against outdoor use or indoor as well? I have a
>>pair of Hoffmann metal utility cabinets with aluminum
>>grounding plates inside. They seem to be fine and haven't
>>corroded a bit.
>>
>> 73, Dick WC1M
>>
>>> -----Original Message-----
>>> From: John Kemker [mailto:john@kemker.org]
>>> Sent: Thursday, June 11, 2009 11:47 PM
>>> To: Peter Dougherty
>>> Cc: TowerTalk@contesting.com
>>> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>>>SPGP
>>>
>>> The ICE might be a better solution, in any case.
>>> However, to each their
>>> own.
>>>
>>> I'd advise against the aluminum and seriously check out
>>> www.georgiacopper.com for their copper plates. VERY
>>>reasonable prices
>>> for 12"x12" sheets and straps. I just got two in the
>>>mail that I'll be
>>
>
>
> I was wondering the same. Aluminum is almost the same
>conductivity as
> copper and much cheaper and easier to machine. For the
>same money, one
> can probably get thicker aluminum (better mechanical
>properties..)
>
> One advantage of copper is that you can solder to it
>(although soldering
> to a big sheet is challenging from a heat standpoint),
>but bolted
> connections to aluminum work pretty well, especially if
>you use one of
> the goops designed for the purpose.
>
>
> ------------------------------
>
> Message: 4
> Date: Fri, 12 Jun 2009 12:26:30 -0400
>From: John Kemker <john@kemker.org>
> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>SPGP
> To: jimlux <jimlux@earthlink.net>
> Cc: Peter Dougherty
><w2irt@verizon.net>, "TowerTalk@contesting.com"
> <TowerTalk@contesting.com>, Dick Green
><dick@mailgreen.us>
> Message-ID: <4A3281B6.3060701@kemker.org>
> Content-Type: text/plain; charset=ISO-8859-1;
>format=flowed
>
> Aluminum has 60% of the conductivity of copper. That's
>not "almost the
> same." In order to get the equivalent conductivity out
>of aluminum, you
> have to make it thicker, which isn't always the best
>choice, based upon
> the skin effect of lightning conduction. For good
>mechanical
> properties, screw your copper to MDF and utilize that
>material's
> mechanical properties. That's what PolyPhaser does.
> That's what is
> recommended by I.C.E. as well. Engineers who design
>lightning
> protection systems for large installations generally
>recommend copper
> ground plates, not aluminum, for that very reason.
>
> Of course, not every engineer designing lightning
>protection systems is
> going to specify copper for ground plates. Also,
>there's lots of people
> out there using aluminum who have not had problems with
>lightning. This
> is just my opinion, based upon the information available
>to me. Make
> your own decision.
>
> jimlux wrote:
>> Dick Green wrote:
>>
>>> Why do you advise against an aluminum ground plate? Are
>>>you only against outdoor use or indoor as well? I have a
>>>pair of Hoffmann metal utility cabinets with aluminum
>>>grounding plates inside. They seem to be fine and haven't
>>>corroded a bit.
>>>
>>> 73, Dick WC1M
>>>
>>>
>>>> -----Original Message-----
>>>> From: John Kemker [mailto:john@kemker.org]
>>>> Sent: Thursday, June 11, 2009 11:47 PM
>>>> To: Peter Dougherty
>>>> Cc: TowerTalk@contesting.com
>>>> Subject: Re: [TowerTalk] Mounting Polyphaser IS-RCT to
>>>>SPGP
>>>>
>>>> The ICE might be a better solution, in any case.
>>>> However, to each their
>>>> own.
>>>>
>>>> I'd advise against the aluminum and seriously check out
>>>> www.georgiacopper.com for their copper plates. VERY
>>>>reasonable prices
>>>> for 12"x12" sheets and straps. I just got two in the
>>>>mail that I'll be
>>>>
>>
>>
>> I was wondering the same. Aluminum is almost the same
>>conductivity as
>> copper and much cheaper and easier to machine. For the
>>same money, one
>> can probably get thicker aluminum (better mechanical
>>properties..)
>>
>> One advantage of copper is that you can solder to it
>>(although soldering
>> to a big sheet is challenging from a heat standpoint),
>>but bolted
>> connections to aluminum work pretty well, especially if
>>you use one of
>> the goops designed for the purpose.
>>
>
>
> --
> --JohnK
> 73 de W5NNH
> 10X 75371/M&M 117/SMIRK 6185/Six Club 285/TRA
>2499/Norcross 228 F&AM
>
>
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 090611-0, 06/11/2009
> Tested on: 6/12/2009 12:26:31 PM
> avast! - copyright (c) 1988-2009 ALWIL Software.
> http://www.avast.com
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Fri, 12 Jun 2009 11:52:48 -0700 (PDT)
>From: "Rick Karlquist" <richard@karlquist.com>
> Subject: Re: [TowerTalk] Vacuum variable / inductor
>ratings for shunt
> fed tower
> To: "K4SAV" <RadioIR@charter.net>
> Cc: towertalk@contesting.com
> Message-ID:
> <9fc0f93a86055de0cc85b92236246e3b.squirrel@webmail.sonic.net>
> Content-Type: text/plain;charset=iso-8859-1
>
> K4SAV wrote:
>> The balun is an unusual design. It's a combo 22 to 50
>>ohm unun plus a
>> common mode choke. Most people say that won't work.
>> However if you
>> look at what they did it almost makes sense. The unun
>>part is tri-filar
>> wound which produces very little core flux. They only
>>used about half
>> the core for this. So if it produces little core flux
>>then it shouldn't
>> affect the other part of the core. So they took the the
>>coax that hooks
>> to the unun and used the other part of the core to wind
>>a choke. That
>> is the part that is questionable in my mind. The choke
>>will produce
>> core flux. So shouldn't that couple back the the unun?
>> Apparently this
>> arrangement works or so they claim. I just don't know
>>how well it
>> works. I was hoping you had measured it.
>>
>> Jerry, K4SAV
>
> It's that old gag: it depends on what you mean by
>"works".
>
> It will work in terms of operating the SteppIR whether
>it is a voltage
> balun or a current balun. So that fact that it works
>for that
> purpose doesn't shed any light on whether it will work
>for top loading
> a shunt fed tower.
>
> I don't agree with some of your analysis. The unun
>certainly produces
> core flux at the lower frequencies. Below 7 MHz, the
>MonstIR balun
> goes south due to insufficient magnetizing inductance,
>according
> to my measurements. On 160 meters, the capacitive
>reactance of
> a 40 meter element as a top hat is about 300 ohms
>(measured). For
> a SteppIR 20 meter element, double this. Even if the
>SteppIR balun
> acted as a common mode choke on 20 meters and up, it
>would have
> relatively low impedance on 160 meters, and shouldn't
>amount to
> much in series with 600 ohms.
>
> I can't measure this now because all 3 of my SteppIR
>band antennas
> are on the tops of towers :-).
>
> Rick N6RK
>
>
>
> ------------------------------
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> End of TowerTalk Digest, Vol 78, Issue 39
> *****************************************
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