DX Engineering also has bio degradable staples which I have started using
because my radials are in my lawn. By the time they degrade the wire is well
into the lawn.
Bruce
In a message dated 4/7/2010 8:31:36 A.M. Pacific Daylight Time,
topband-request@contesting.com writes:
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than "Re: Contents of Topband digest..."
Today's Topics:
1. Re: Staples (W5UN)
2. Receiver Rankings (Charlie & Vivian Vaughan)
3. deterioration of RG-6 (Larry Pasman)
4. Re: deterioration of RG-6 (Herb Schoenbohm)
5. Re: Staples (w8uvz)
6. Re: deterioration of RG-6 (Guy Olinger K2AV)
7. Re: deterioration of RG-6 (Robin)
8. Coax for receive (Price Smith)
9. Re: deterioration of RG-6 (Missouri Guy)
10. DOUBLE DIAMOND (Mr. and Mrs. Magoo)
----------------------------------------------------------------------
Message: 1
Date: Tue, 06 Apr 2010 18:42:40 +0000
From: W5UN <w5un@wt.net>
Subject: Re: Topband: Staples
To: Topband@contesting.com
Message-ID: <20100406114242.C7E9D154@dm0201.mta.everyone.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Barb-less fence wire from McCoys Home building supply works very well
for this. Buy a quarter mile roll, and make thousands of staples any
length you need.
Dave, W5UN
------------------------------
Message: 2
Date: Tue, 6 Apr 2010 15:58:42 -0400
From: "Charlie & Vivian Vaughan" <vcm4@bellsouth.net>
Subject: Topband: Receiver Rankings
To: <topband@contesting.com>
Message-ID: <5025117B5F4A45C5837FD80B19CC86B8@yourze8cxvr8tt>
Content-Type: text/plain; charset="us-ascii"
The subjective receiver rankings were interesting. I would suggest a look
at the following link for another view of receiver rankings. The contrast
is somewhat interesting.
http://www.sherweng.com/table.html
Charlie K4UWH
------------------------------
Message: 3
Date: Tue, 6 Apr 2010 16:11:58 -0400
From: "Larry Pasman" <lrpmbt@comcast.net>
Subject: Topband: deterioration of RG-6
To: <topband@contesting.com>
Message-ID: <99AE49952E0C4FDFB75B1093B47D9607@ownerPC>
Content-Type: text/plain; charset="us-ascii"
Any coax or feedline is likely to get moisture in it. Aluminum turns to a
white powder and copper turns black. What is happening is temperature
changes from day to night. Each time temperature cools down the coax acts
like a big straw and sucks in moisture and can do so for several feet. If
the run is down hill water can make it all the way to the shack. If you
are
making a splice and cannot seal it very well is not use electrical tape.
Tape will only hold moisture in and not let it dry. Using "F" connectors
and
a double female will work if out in the open to allow drying. Simply mount
it on a small post above ground and put a flap of some sort over it. Taping
over connectors will only allow it to get wet and not dry.
------------------------------
Message: 4
Date: Tue, 06 Apr 2010 16:40:23 -0400
From: Herb Schoenbohm <herbs@vitelcom.net>
Subject: Re: Topband: deterioration of RG-6
To: n4zr@contesting.com
Cc: Topband@contesting.com
Message-ID: <4BBB9C37.1050204@vitelcom.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Pete Smith N4ZR wrote:
> I feed my 160m receiving antenna with about 300 feet of RG-6, which
> supplies power to an amplifier at the antenna. Recently, I started
> seeing an high-resistance short across the coax (~30-50 ohms). I took a
> junction apart and discovered evidence of current flowing across the
> double-female, as wellas some water in the connector. I changed it out,
> and also changed both connectors on the cable, and in the process
> discovered that the braid and the first foil (it is quad-shield) appear
> to be somewhat corroded (there is a powdery grey residue that comes
> out). I reconnected the junction, and within a few days both the short
> and the moisture were back. In checking out the problem, I have cut
> back a couple of feet on the cable, and the grey residue is still
evident.
>
> Is water ingress a known problem with RG-6? Any particular brand known
> to be better? If I'm going to replace the whole feedline I might as
> well do what I can.
>
>
Pete,
Yes some brands or off brands of RG-6 sucks up moisture like a sponge.
They are a foam product and.with diurnal sunlight heat and night time
cooling on the jacket laying out in the sun during the day, would IMHO
act as sort of a pump. You can mitigate this a bit with a cable that
has be flooded with a special sticky goo (flooding compound). I have
found out here that since VF and cable attenuation are not a big thing
that using good quality Belden RG-59 with a copper braid and solid
interconductor is a much better solution.
In CATV Foam, where UHF attenuation is always a factor, without the
flooding compound inside the jacked it doesn't take long to get to the
point where the foil is pulverize to aluminum oxide contaminating the
cable run.. If as in your case you run DC for pre-amps and/or
switching through the cable to relay boxes and switching of reversible
Beverages...expect even quicker deterioration as some forms as
electrolysis is certain. I have seen running DC make the female F
connector center pin actually dissolve. Always look for as tarnish on
the center conductor where it exist the RG-6 F-connector. Scrapping it
with a knife will only make things worse in the long run as now you are
down to steel and rather than copper plated steel. In fact DC over the
cable made things so bad here I now use separate feedlines for even the
DXE-Reversible boxes. Yes termination of the unused port is important
but this is done back at the shack with a self terminating Dynair 12x1
Video Passive switcher from a former TV station.
Regular RG-6 connectors are not water proof either except except some
are available with and O ring and sealing gel from gel from MCM for a
few pennies more.. Even tape wrap and then butyl over that will help
at the connectors. But changing a connector and removing it is very
bothersome when the connector is covered with Butyl.
Even protecting the connectors will not stop cable deterioration if one
little gnaw from of a small rodent, a peck of a robin looking for a
worm, or pin hole opens, or anything opens the flood gate for ingress
of moisture along the run. Using inexpensive RG-6 is fine if you plan
to change it every 6 months or less. If you need some long term
protection than the expensive self sealing flooded heavy jacketed RG-6,
direct buried in the ground is the way to go. This keeps the rats, weed
wackers, and lawn mowers from destroying the quality of the cable. It
also provides some reduction in heat effect.
There is one positive thing about poor cable and that on TB is the last
place where it really shows up. I have had complete outer shield breaks
and still worked some nice DX. In some case a few db's of attenuation
are not all that noticeable. But the dissimilar metals can be the point
at which birdies and signal re-rectification can make weak signal
reception very difficult.
The MFJ analyzer will not tell you the story and may even present a
false positive reading if there is significant attenuation in the
cable. I found the best test is to measure the Beverage feed point
transformer, which is hopefully floating and not grounded, and based on
the cable length I get about 1.2 ohms center to shield at the shack. If
it starts to creep up then you may have some shield deterioration
offering cumulative resistance over the length.
Most of the TB activists I have spoken to about this expect to do a lot
of Beverage maintenance both in the spring when the thaw melts and then
again in the fall before the contest season begins. Actually it never
ends as if you can get past the thunderstorms there is plenty of
trans-equatorial DX available. Nice thing about replacing Beverages is
the mental impact in thinking that you are going to hear something now
you didn't or couldn't hear before. You could be right.
73
Herb Schoenbohm
------------------------------
Message: 5
Date: Tue, 6 Apr 2010 17:04:36 -0400
From: "w8uvz" <w8uvz@voyager.net>
Subject: Re: Topband: Staples
To: "W5UN" <w5un@wt.net>
Cc: Topband@contesting.com
Message-ID: <003801cad5cc$c4c3a040$6501a8c0@GET>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
And it makes great beverage wire too, rite Dave?
We buy it locally from Tractor Supply.
73 George W8UVZ
> Barb-less fence wire from McCoys Home building supply works very well
> for this. Buy a quarter mile roll, and make thousands of staples any
> length you need.
>
> Dave, W5UN
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
------------------------------
Message: 6
Date: Tue, 6 Apr 2010 20:03:21 -0400
From: Guy Olinger K2AV <olinger@bellsouth.net>
Subject: Re: Topband: deterioration of RG-6
To: n4zr@contesting.com
Cc: Topband@contesting.com
Message-ID:
<q2x46f338981004061703zac77e915ha78d104aa47e1acc@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I would have to call this the true colors of RG6, given enough time.
I have had that problem with years old TV & SAT leads around here, and
am going to flooded RG6 on anything new, to prevent just what you
describe. The oxidation is capable of creating impedance anomalies at
TV frequencies and extra loss at MF. In one aged case after the
jacket was removed for inspection, just a mild flex of the remainder
split the foil, which clearly had become brittle.
My best guess is that the braid creates an ingress path that breathes
and contributes to condensation after time.
Splices and connections on regular RG6 need to be vapor sealed ala
RG8, etc to prevent what is otherwise an inevitable process. Better
choice is to use cable and connectors intended for burying, and the
spec'd tools to crimp them.
73, Guy.
On Tue, Apr 6, 2010 at 8:18 AM, Pete Smith N4ZR <n4zr@contesting.com>
wrote:
> I feed my 160m receiving antenna with about 300 feet of RG-6, which
> supplies power to an amplifier at the antenna. ?Recently, I started
> seeing an high-resistance short across the coax (~30-50 ohms). ?I took a
> junction apart and discovered evidence of current flowing across the
> double-female, as wellas some water in the connector. ?I changed it out,
> and also changed both connectors on the cable, and in the process
> discovered that the braid and the first foil (it is quad-shield) appear
> to be somewhat corroded (there is a powdery grey residue that comes
> out). ?I reconnected the junction, and within a few days both the short
> and the moisture were back. ?In checking out the problem, I have cut
> back a couple of feet on the cable, and the grey residue is still
evident.
>
> Is water ingress a known problem with RG-6? ?Any particular brand known
> to be better? ?If I'm going to replace the whole feedline I might as
> well do what I can.
>
> --
> 73, Pete N4ZR
>
> The World Contest Station Database, updated daily at
www.conteststations.com
> The Reverse Beacon Network at http://reversebeacon.net, blog at
reversebeacon.blogspot.com
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
------------------------------
Message: 7
Date: Tue, 6 Apr 2010 19:04:48 -0700
From: "Robin" <wb6tza@socal.rr.com>
Subject: Re: Topband: deterioration of RG-6
To: "160" <Topband@contesting.com>
Message-ID: <DC41D88B59D1479ABB587626ED92A256@HPMEDIA7650>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Use flooded cable- its air spaces are flooded with goo that does pretty
well at keeping water out. Flooded cable is available from many
suppliers - quad shield flooded cable is pretty standard for the cable TV
folks. If a section of the line gets damaged, the goo will mostly keep the
water from wicking along the cable and killing the whole run
check with whatever supplier you use, or do a search for flooded RG-6 &
pick the best price for you
DO use the correct connectors
73
Robin, WA6CDR
----- Original Message -----
From: "Larry Pasman" <lrpmbt@comcast.net>
To: <topband@contesting.com>
Sent: Tuesday, April 06, 2010 13:11
Subject: Topband: deterioration of RG-6
> Any coax or feedline is likely to get moisture in it. Aluminum turns to a
> white powder and copper turns black. What is happening is temperature
> changes from day to night. Each time temperature cools down the coax
acts
> like a big straw and sucks in moisture and can do so for several feet. If
> the run is down hill water can make it all the way to the shack. If you
> are
> making a splice and cannot seal it very well is not use electrical tape.
> Tape will only hold moisture in and not let it dry. Using "F" connectors
> and
> a double female will work if out in the open to allow drying. Simply
> mount
> it on a small post above ground and put a flap of some sort over it.
> Taping
> over connectors will only allow it to get wet and not dry.
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
------------------------------
Message: 8
Date: Tue, 6 Apr 2010 23:28:35 -0500
From: "Price Smith" <w0rihps@sbcglobal.net>
Subject: Topband: Coax for receive
To: <topband@contesting.com>
Message-ID: <963B6D165EDE4FF78F2AC6F3E877C069@haroldfd2f6007>
Content-Type: text/plain; charset="iso-8859-1"
If one would look a one of the well known auction sites, you can find
Alpha RG-58A.
I am sure that the 1000ft roll will go for a very cheap price.
As Herb said, RG-6 quality is very good to terrible
73...Price W?RI
------------------------------
Message: 9
Date: Wed, 7 Apr 2010 04:59:58 +0000
From: Missouri Guy <n0tt1@juno.com>
Subject: Re: Topband: deterioration of RG-6
To: n4zr@contesting.com,topband@contesting.com
Message-ID: <20100407.050653.3360.1.N0TT1@juno.com>
Content-Type: text/plain; charset=us-ascii
Hi Pete,
> Is water ingress a known problem with RG-6? Any particular brand
> known to be better?
"Regular" RG6 will wick water into the shield and eventually ruin the
coax. Use only the "flooded" type outdoors. Read more below.
In my experience, the brand of RG6 doesn't particularly matter. I
bought all of mine on "the bay" in 1000' spools. All of it was
quality USA-made, specifically for direct-bury.
I have quite a few feet of RG6, all buried, for my 9-circle RX array.
No water problems. I took the advice of the guys on this reflector
and purchased nothing but "flooded" RG6....it's got a sticky-gooey
stuff imbedded in the shields (wrapped AL foil and a single braid
over that) so water won't wick it's way in. I also use
Thomas & Betts "Snap 'n Seal" F-connectors that have a
built-in O-ring. Even with those, I keep the connectors
totally out of direct rain exposure.
73,
Charlie, N0TT
------------------------------
Message: 10
Date: Wed, 7 Apr 2010 07:34:45 -0400
From: "Mr. and Mrs. Magoo" <magoo@isp.ca>
Subject: Topband: DOUBLE DIAMOND
To: <topband@contesting.com>
Message-ID: <B0C5F81DCC944D64B7A70347AEC7CC02@MCHUGHU64FGOY>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Has anyone who built one of these experienced any loss in performance due
to
proximity of metallic objects such as hydro lines, wire fences or such?
Those I have seen described have been built totally in the clear and far
away from the above objects.
Bill, VE3NH
------------------------------
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End of Topband Digest, Vol 88, Issue 8
**************************************
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|