...and never run more than 200 Watts to an R7
It's like playing Russian Roulette...you are kust asking for trouble.
Have seen MANY R7s toasted - another terrible design for Hi Power from
Cushcraft
N6KI
On Sun, Sep 6, 2009 at 2:08 PM, Jeff Wilson <jjw5257@yahoo.ca> wrote:
> I just finished refurbishing my 1992 vintage R7 vertical.
> The tips offered by web posting by PA0FRI and EI7BA and VE6LB were very
> useful.
> Should find them with a Google search.
> Basically I replaced all the trap coil connecting screws with stainless, as
> most were corroded (copper/aluminum/steel = corrosion)
> Coated all connections with anti-ox compound and new shrinkwrap.
> Coated the top edge of the shrink wrap with liquid tape as I didn't have to
> good stuff with glue inside the shrink wrap.
>
> Also. recoated the fibreglass insulator base with 2 part resin as described
> by PA0FRI (on his R5 )
> and replaced the aluminum rivet with stainless steel bolts to get rid of
> any wobble.
> Don't drill a bolt thru the aluminum tubing as it will eventually crack
> there with the continuous wind flexing.
> You can feed a bolt up the inside of the tube by taping it to a long dowel
> or narrow piece of wood, until it lines up with the hole. Tricky, but not
> hard to do.
> Make sure the capacitors for each trap are water tight and not burned or
> deformed from high power op. See Gerry, VE6LB's post on this.
>
> Hope this helps,
> 73
> Jeff, VE3FRX
>
>
> ________________________________
> From: "towertalk-request@contesting.com" <towertalk-request@contesting.com
> >
> To: towertalk@contesting.com
> Sent: Saturday, September 5, 2009 3:00:37 PM
> Subject: TowerTalk Digest, Vol 81, Issue 11
>
> Send TowerTalk mailing list submissions to
> towertalk@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/towertalk
> or, via email, send a message with subject or body 'help' to
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>
> You can reach the person managing the list at
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>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of TowerTalk digest..."
>
>
> Today's Topics:
>
> 1. Re: finding aluminum tubing (Charlie Gallo)
> 2. Re: NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY (D.W. Fearn)
> 3. Re: finding aluminum tubing (Rob Atkinson)
> 4. Re: NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY (K1TTT)
> 5. R7 traps (Barry Fox)
> 6. Re: R7 traps (AI4WM Bill)
> 7. Re: CushCraft R7 Antenna Problem (AI4WM Bill)
> 8. Telrex 6M624 antenna (Mike & Becca Krzystyniak)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 4 Sep 2009 20:19:37 -0400
> From: Charlie Gallo <Charlie@TheGallos.com>
> Subject: Re: [TowerTalk] finding aluminum tubing
> To: "Joe Barnes" <n4jbk@bellsouth.net>
> Cc: towertalk@contesting.com
> Message-ID: <1895505755.20090904201937@TheGallos.com>
> Content-Type: text/plain; charset=us-ascii
>
>
>
> On 9/4/2009 Joe Barnes wrote:
>
> > Where oh where can I buy aluminum tubing to rebuild my telrex
> > 6m624's? I have 3 bent /broke elements and apparently bin laden has
> > all such tubing with him because no one knows where it is. any help would
> be appreciated. Joe N4JBK
>
> Depending on how much you need, and sizes, there is always Yarde Metals
>
> http://www.yarde.com/index.html
>
> No affiliation except buying some 6061 from them
>
>
> --
> 73 de KG2V
>
> For the Children - RKBA!
>
> My Website: http://www.thegallos.com
> My Blog: http://kg2v.blogspot.com
>
> Boycott shampoo!!! Demand REAL poo!
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 04 Sep 2009 20:40:08 -0400
> From: "D.W. Fearn" <dwfearn@dwfearn.com>
> Subject: Re: [TowerTalk] NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY
> To: towertalk@contesting.com
> Message-ID: <0KPH00H4A36YY392@vms173017.mailsrvcs.net>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
> I was using RG-174 as a shielded lead in a product we build and
> experienced exactly the same problem as Larry describes. This was
> from a brand-new, very expensive roll of Belden RG-174. This was to
> the grid of a tube, so even a very high resistance had an effect. We
> have changed to a Teflon-insulated coax and that solved the problem.
>
> Doug K3KW
>
>
>
>
>
> >Date: Fri, 4 Sep 2009 06:55:15 -0400
> >From: "Larry - K7SV" <k7sv@comcast.net>
> >Subject: [TowerTalk] NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY
> >To: <towertalk@contesting.com>
> >
> >Some of you may remember my posting about our experience with beverages
> >using plastic boxes to house matching transformers. The black plastic
> boxes
> >turned out to be conductive which obviously led to a lot of head
> scratching.
> >
> >Well, I've been working a small project using RG-174. I kept finding
> shorts
> >after putting connectors on the ends. Nothing was making sense so it got
> to
> >the point that I cut a foot long piece of the stuff, stripped back about
> an
> >inch of the outer insulated jacket at both ends and pushed the shield away
> >from the ends. I then took resistance measurements between the shield and
> >the ends (didn't strip back the inner insulation, just stuck the meter
> probe
> >in the end). So I'm still seeing resistance between the shield and the
> >center conductor.
> >
> >On a whim I connected a meter probe to the inner "insulation" at both ends
> >of the piece. Sure enough it was a conductive material. I picked up a
> couple
> >hundred feet of this stuff from Mendelson's at Dayton a few years ago. As
> it
> >turns out construction consists of an insulated black outer jacket,
> stranded
> >copper shield, a black conductive material, a light opaque insulation and
> >then the stranded copper inner conductor.
> >
> >My problem obviously existed anywhere that the inner black "insulated"
> >material was touching the shield.
> >
> >This is the first time I've experienced something like this with RG-174.
> >Actually as I think about it, the stuff must have really great isolation
> >between the center conductor and the braid! I don't think this is typical
> >RG-174!
> >
> >73 de Lar K7SV
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 4 Sep 2009 19:40:22 -0500
> From: Rob Atkinson <ranchorobbo@gmail.com>
> Subject: Re: [TowerTalk] finding aluminum tubing
> To: towertalk@contesting.com
> Message-ID:
> <d2bb1cb80909041740i7709d808qa67ad818a21871b1@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Jorge:
>
> It's not my intent to get into a "testimonial war" so I'll freely
> state that I have ordered from DX Engineering before, and the
> cardboard box they used to ship my purchase in was of the best
> quality. The radial plate is a very nice radial plate too and still
> works great with my 101 radials out in back.
>
> I don't know who will pick up the phone at DXE when you call, but if
> you call Penninger Radio a live mechanical engineer will answer the
> phone during business hours (no machines and menus) and advise you on
> a purchase based on his experience with forces on structures,
> performing calculations on the spot as you give him your
> specifications. This is the only ham vendor I know of where after a
> minute on the phone the guy is giving me the bending moment on a ten
> foot mast at the top of a four foot quad mount for a 3 sq. foot wind
> load at the top in a 70 mph wind and advising me on what o.d. and wall
> thickness to use.
>
> And I just purchased a 50 foot crank up aluminum mast from him in
> which he did the whole design and put it all together for me and
> guaranteed that if it didn't stay up he'd fix it until it does. (It's
> staying up FB). But I'm sure everyone else has a fine product and
> good luck with them.
>
> 73
>
> Rob K5UJ
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 05 Sep 2009 10:39:22 +0000
> From: "K1TTT" <K1TTT@ARRL.NET>
> Subject: Re: [TowerTalk] NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY
> To: <towertalk@contesting.com>
> Message-ID: <9FBD7A0210844B22A93ABA93284EA6FE@k1tttibm>
> Content-Type: text/plain; charset=US-ASCII
>
> This sounded odd so I pulled out my belden catalog... and sure enough,
> right
> at the beginning of the coaxial cable section are these 3 'low noise'
> cables.
>
> 174/u type 8239 description: bare copper covered steel conductor,
> polyethylene insulation, conductive layer, tinned copper braid shield,
> black
> pvc jacket.
>
> 58/u type 9223 description: tinned copper conductor, conductive layer,
> polyethylene insulation, duobond II tinned copper braid shield, black pvc
> jacket.
>
> 59/u type 9224 description: bare copper covered steel conductor,
> polyethylene insulation, conductive layer, tinned copper braid shield,
> black
> pvc jacket.
>
> Note that these are separate from the 'normal' 174/u mil-c-17d 8216 cable,
> and the common 58/u and 59/u entries. Unfortunately this is common with
> the
> 'rg' numbering system, there are often many manufacture variations on
> those.
> with belden you must check the 4 digit cable type to know exactly what you
> have.
>
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>
>
> > -----Original Message-----
> > From: D.W. Fearn [mailto:dwfearn@dwfearn.com]
> > Sent: Saturday, September 05, 2009 00:40
> > To: towertalk@contesting.com
> > Subject: Re: [TowerTalk] NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY
> >
> > I was using RG-174 as a shielded lead in a product we build and
> > experienced exactly the same problem as Larry describes. This was
> > from a brand-new, very expensive roll of Belden RG-174. This was to
> > the grid of a tube, so even a very high resistance had an effect. We
> > have changed to a Teflon-insulated coax and that solved the problem.
> >
> > Doug K3KW
> >
> >
> >
> >
> >
> > >Date: Fri, 4 Sep 2009 06:55:15 -0400
> > >From: "Larry - K7SV" <k7sv@comcast.net>
> > >Subject: [TowerTalk] NON-INSULLATION STRIKES AGAIN! RG174 ANOMALLY
> > >To: <towertalk@contesting.com>
> > >
> > >Some of you may remember my posting about our experience with beverages
> > >using plastic boxes to house matching transformers. The black plastic
> > boxes
> > >turned out to be conductive which obviously led to a lot of head
> > scratching.
> > >
> > >Well, I've been working a small project using RG-174. I kept finding
> > shorts
> > >after putting connectors on the ends. Nothing was making sense so it got
> > to
> > >the point that I cut a foot long piece of the stuff, stripped back about
> > an
> > >inch of the outer insulated jacket at both ends and pushed the shield
> > away
> > >from the ends. I then took resistance measurements between the shield
> and
> > >the ends (didn't strip back the inner insulation, just stuck the meter
> > probe
> > >in the end). So I'm still seeing resistance between the shield and the
> > >center conductor.
> > >
> > >On a whim I connected a meter probe to the inner "insulation" at both
> > ends
> > >of the piece. Sure enough it was a conductive material. I picked up a
> > couple
> > >hundred feet of this stuff from Mendelson's at Dayton a few years ago.
> As
> > it
> > >turns out construction consists of an insulated black outer jacket,
> > stranded
> > >copper shield, a black conductive material, a light opaque insulation
> and
> > >then the stranded copper inner conductor.
> > >
> > >My problem obviously existed anywhere that the inner black "insulated"
> > >material was touching the shield.
> > >
> > >This is the first time I've experienced something like this with RG-174.
> > >Actually as I think about it, the stuff must have really great isolation
> > >between the center conductor and the braid! I don't think this is
> typical
> > >RG-174!
> > >
> > >73 de Lar K7SV
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sat, 5 Sep 2009 07:37:04 -0400
> From: "Barry Fox" <foxbw@comcast.net>
> Subject: [TowerTalk] R7 traps
> To: <towertalk@contesting.com>
> Message-ID: <PIEAJOGJKIOKMDLBKGKGGEHJCNAA.foxbw@comcast.net>
> Content-Type: text/plain; charset="iso-8859-1"
>
> I'm no antenna designer, but it seems to me that if the trap capacitor
> clamps were swapped such that the center rod were at the bottom, no
> water could then enter. Would that work?
> Barry - W1HFN
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sat, 5 Sep 2009 08:07:33 -0700 (PDT)
> From: AI4WM Bill <ai4wm@yahoo.com>
> Subject: Re: [TowerTalk] R7 traps
> To: towertalk@contesting.com, Barry Fox <foxbw@comcast.net>
> Message-ID: <320837.15414.qm@web57905.mail.re3.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> These traps have caps on the end opposite the piston.? IF the cap is good
> it will keep water out.? The same for the heat shrink integrity for the
> piston end.? The original heat shrink has a liner that melts when the heat
> shrink is heated.? This makes a water tight seal IF the heat shrink was
> correctly heated and correctly shrunk (as it was from the factory).?
>
> Over time the heat shrink can deteriorate from being out in all kinds of
> weather.? If someone replaced the heatshrink with the regular heatshrink or
> used some other method of repair water can enter the capacitors.? In this
> case the capacitor must be taken apart and cleaned.? There are 2 good
> websites that detail this, just google R5 or R7 traps or trap repair.? There
> are cross links to the sites from several amateur radio sites also.? Here is
> one of the sites:
>
> http://www.iol.ie/~bravo/r7_vertical.htm<http://www.iol.ie/%7Ebravo/r7_vertical.htm>
>
> The capacitors are plain old coaxial capacitors and there is no electrical
> reason to have piston up or piston down.? The constraint comes with how the
> capacitor will interfere with the trap below it or above it.
>
> The problem would be if the brackets move and you end up with a different
> capacitance thus changing the frequency.
>
> I?
> have an AP8A that is very similar to the R7.? I have resonated these
> on the bench and find no difference with the direction of mounting the
> capacitor since this was my thought on one
> that was missing an end cap.? However I have found a cap and did not
> reverse the capacitor mounting.
>
> 73,
>
> Bill
>
> AI4WM
>
> --- On Sat, 9/5/09, Barry Fox <foxbw@comcast.net> wrote:
>
> From: Barry Fox <foxbw@comcast.net>
> Subject: [TowerTalk] R7 traps
> To: towertalk@contesting.com
> Date: Saturday, September 5, 2009, 7:37 AM
>
> I'm no antenna designer, but it seems to me that if the trap capacitor
> clamps were swapped such that the center rod were at the bottom, no
> water could then enter.? Would that work?
> Barry - W1HFN
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sat, 5 Sep 2009 08:22:42 -0700 (PDT)
> From: AI4WM Bill <ai4wm@yahoo.com>
> Subject: Re: [TowerTalk] CushCraft R7 Antenna Problem
> To: towertalk@contesting.com, Ray <rayn6vr@cableone.net>
> Message-ID: <209003.22758.qm@web57905.mail.re3.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> One thing I forgot...
> When I installed my (bought it used) AP8A it would not resonate on 20M 30M
> was also off.
>
> I decided to check trap frequencies and found 17 off.? I took this trap
> apart (even though the 20M cap was in need of repair) and found corroded
> connections where the coil connects to the tubing.?
>
> 73,
>
> Bill
>
> AI4WM
>
> --- On Fri, 9/4/09, Ray <rayn6vr@cableone.net> wrote:
>
> From: Ray <rayn6vr@cableone.net>
> Subject: [TowerTalk] CushCraft R7 Antenna Problem
> To: towertalk@contesting.com
> Date: Friday, September 4, 2009, 12:41 PM
>
> Recently I tried running about 600 - 700 watts to my old reliable Cushcraft
> R7 vertical. Everything went fine on 20m, but when I went to 40m the SWR
> became erratic, then jump to a very high level and stayed there (more than
> 6
> - 8:1). The RX is also quite numb on 40m. The same high SWR is on 30m too.
> 20m is still has a good low SWR.
>
>
>
> It seems that there is an open or something bad at the 30m joint or coil,
> but a visual inspection and ohm meter check show every think OK. I have not
> yet opened the matching box at the base. I did remove the heat shrink at
> the
> 30m coil connects, but those connects are fine with no burn spots along the
> coil.
>
>
>
> Any ideas or suggests as to how to track down the problem? Sometime today
> or
> tmw, I will look inside the matching box to see what I can find. But if
> anyone as any experience or suggests, please let me know.
>
>
>
> Ray, N6VR
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Sat, 5 Sep 2009 13:48:55 -0500
> From: "Mike & Becca Krzystyniak" <k9mk@flash.net>
> Subject: [TowerTalk] Telrex 6M624 antenna
> To: "'Joe Barnes'" <n4jbk@bellsouth.net>
> Cc: towertalk@contesting.com
> Message-ID: <002201ca2e59$859238c0$90b6aa40$@net>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Joe,
>
> I inherited a Telrex 6M624 from an Elmer friend. It is in pieces and
> like yours needs a little refurbishing. More importantly I'm looking for
> any documentation on assembly for this antenna. Might you have a manual or
> Telrex assembly documentation for yours?
>
> Thanks...
>
> Mike K9MK/5
>
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Charlie Gallo
> Sent: Friday, September 04, 2009 7:20 PM
> To: Joe Barnes
> Cc: towertalk@contesting.com
> Subject: Re: [TowerTalk] finding aluminum tubing
>
>
>
> On 9/4/2009 Joe Barnes wrote:
>
> > Where oh where can I buy aluminum tubing to rebuild my telrex
> > 6m624's? I have 3 bent /broke elements and apparently bin laden has
> > all such tubing with him because no one knows where it is. any help would
> be appreciated. Joe N4JBK
>
> Depending on how much you need, and sizes, there is always Yarde Metals
>
> http://www.yarde.com/index.html
>
> No affiliation except buying some 6061 from them
>
>
> --
> 73 de KG2V
>
> For the Children - RKBA!
>
> My Website: http://www.thegallos.com
> My Blog: http://kg2v.blogspot.com
>
> Boycott shampoo!!! Demand REAL poo!
>
> _______________________________________________
>
>
>
> _______________________________________________
> 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
>
>
> End of TowerTalk Digest, Vol 81, Issue 11
> *****************************************
>
>
>
> __________________________________________________________________
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