80% is the "standard." There is nothing magic about that distance.
Actually, farther away guying is better structurally, but there is a point
of diminishing returns.
It is possible to guy closer, as is often done with taller towers or on
sites that don't have enough room for 80% (or more). Engineering these
calculations is something Rohn used to offer, with their engineers. I
talked to them about it some years back concerning a Nextel tower that was
going in on my property, which I wanted to put way back in the far back
"pointy" corner of my property. It was a Rohn 80. You can guy closer and
make up for it with heavier guy cable and higher guy tension. I suppose at
some point this would mean huskier tower and larger base foundation too, to
withstand the additional downward forces.
Hams often want to guy as far out as possible (e.g. 80%) because then the
guys get in the way less of sidemounted antennas up and down the tower.
73 - Rich, KE3Q
----- Original Message -----
From: "Jess (AI9L)" <ai9l@core.com>
To: <towertalk@contesting.com>
Sent: Saturday, December 11, 2004 1:39 PM
Subject: [TowerTalk] Re: TowerTalk Digest, Vol 24, Issue 36
> I believe the % of tower length is 80 % with rohn tower
> ----- Original Message -----
> From: <towertalk-request@contesting.com>
> To: <towertalk@contesting.com>
> Sent: Saturday, December 11, 2004 11:00 AM
> Subject: TowerTalk Digest, Vol 24, Issue 36
>
>
> > 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
> > towertalk-request@contesting.com
> >
> > You can reach the person managing the list at
> > towertalk-owner@contesting.com
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of TowerTalk digest..."
> >
> >
> > Today's Topics:
> >
> > 1. Guy anchor distance from tower base? (SJ W3TX)
> > 2. RE: Guy anchor distance from tower base? (David Robbins K1TTT)
> > 3. RE: ICE 419A Combination Bandpass Filter 10M Section Blown
> > (Tony Kazmakites)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sat, 11 Dec 2004 07:14:42 -0500
> > From: "SJ W3TX" <superberthaguy@adelphia.net>
> > Subject: [TowerTalk] Guy anchor distance from tower base?
> > To: <TowerTalk@contesting.com>
> > Message-ID: <001501c4df7a$fe97ec70$6401a8c0@PC988720711140>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > I read the TIA-222 document, but it doesn't specify the recommended
> > distance
> > between the tower base and guy anchors (as a percent of tower height).
> > I
> > may end up using 4 guy wire directions to allow me to place the tower
> > base
> > closer to my setback (so the towers can be further apart).
> >
> > What is the standard % for:
> >
> > 3 guy wire directions (guys spaced 120 degrees)?
> >
> > 4 guy wire directions (guys spaced 90 degrees)?
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Sat, 11 Dec 2004 12:29:27 -0000
> > From: "David Robbins K1TTT" <k1ttt@arrl.net>
> > Subject: RE: [TowerTalk] Guy anchor distance from tower base?
> > To: "reflector -tower" <towertalk@contesting.com>
> > Message-ID: <000401c4df7d$0ec7d5e0$0800a8c0@k1tttibm>
> > Content-Type: text/plain; charset="us-ascii"
> >
> > Tia-222 can't calculate things like that because those types of
> > calculations
> > are up to the manufacturer and engineer designing the system.
> > Manufacturers
> > like rohn do sets of generic designs for 'standard' installations that
> > assume flat land, some max wind speed, and specify max wind and weight
> > loading... but those designs are only for specific tower configurations
> > and
> > can't cover all circumstances either. To get a safe design, especially
> > when
> > you are trying to do something odd like guying a triangular tower to 4
> > anchors, you must get a qualified engineer to design and approve it.
> >
> > That said and noting that I am not a qualified engineer for this type of
> > stuff... just by geometric considerations you can put a tower closer to
> > something with 3 guy points than 4, assuming the location of the guy
> > points
> > are on the setback line and are the same distance from the base of the
> > tower. I would not expect the distance out from the base of the tower
> > to
> > change much for 4 guy points vs 3, it is the distance out that
> > determines
> > the angle to the tower and the side force exerted... and it is the side
> > force that keeps the tower upright. Move the buy points in and they
> > pull
> > down more than out which does not help keep the tower straight up.
> >
> >
> > 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: towertalk-bounces@contesting.com [mailto:towertalk-
> >> bounces@contesting.com] On Behalf Of SJ W3TX
> >> Sent: Saturday, December 11, 2004 12:15
> >> To: TowerTalk@contesting.com
> >> Subject: [TowerTalk] Guy anchor distance from tower base?
> >>
> >> I read the TIA-222 document, but it doesn't specify the recommended
> >> distance
> >> between the tower base and guy anchors (as a percent of tower height).
> >> I
> >> may end up using 4 guy wire directions to allow me to place the tower
> >> base
> >> closer to my setback (so the towers can be further apart).
> >>
> >> What is the standard % for:
> >>
> >> 3 guy wire directions (guys spaced 120 degrees)?
> >>
> >> 4 guy wire directions (guys spaced 90 degrees)?
> >>
> >>
> >> _______________________________________________
> >>
> >> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> >> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> >> any questions and ask for Sherman, W2FLA.
> >>
> >> _______________________________________________
> >> TowerTalk mailing list
> >> TowerTalk@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Fri, 10 Dec 2004 17:01:21 -0500
> > From: "Tony Kazmakites" <tony.kazmakites@verizon.net>
> > Subject: RE: [TowerTalk] ICE 419A Combination Bandpass Filter 10M
> > Section Blown
> > To: "'David Hachadorian'" <K6LL@adelphia.net>, "'Towertalk Reflector'"
> > <towertalk@contesting.com>
> > Message-ID: <000801c4df03$c9b56220$6401a8c0@MT001825LT>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > I had a set of ICE bandpass filters that never saw more than 100w - used
> > them on my Icom 751A to drive an amp. After I had used them for a few
> > years
> > I checked for insertion loss and passband. Some had changed. When I
> > opened
> > up the ones that had changed I could see some caps that were blackened
> > and
> > they had a burnt smell. That's when I bought a set of W3NQN filters.
> > 73,
> > N2TK, Tony
> >
> >
> >
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com]On Behalf Of David Hachadorian
> > Sent: Friday, December 10, 2004 4:20 PM
> > To: Towertalk Reflector
> > Subject: Re: [TowerTalk] ICE 419A Combination Bandpass Filter 10M
> > Section
> > Blown
> >
> >
> > ----- Original Message -----
> > From: "Keith Dutson" <kjdutson@earthlink.net>
> > To: "TowerTalk" <towertalk@contesting.com>
> > Sent: Friday, December 10, 2004 12:39 PM
> > Subject: [TowerTalk] ICE 419A Combination Bandpass
> > Filter 10M Section Blown
> >
> >
> >> Subject says it all. VSWR went to 5 at some point
> >> during operation of
> >> VP8WWW. The filter box was set to 10 meters and
> >> connected to a trapped
> >> vertical and Kenwood 480HX. Transceiver was set to
> >> 200 watts CW on 10
> >> meters. We were using two boxes and switched them.
> >> About an hour later the
> >> second box did the same thing.
> >>
> >> I read the manual. It states the unit is rated at
> >> 200 watts. I am guessing
> >> that is for SSB rather than CW. Anyone else
> >> experience this problem?
> >>
> >> Each filter section apparently consists of a simple
> >> coil and two caps in T
> >> configuration. This is only an observation as I do
> >> not have a schematic. I
> >> would like to beef up the capacity and assume this
> >> might be done with higher
> >> voltage caps.
> >>
> >> Keith NM5G
> > -------------------------------
> >
> > A friend of mine has the ICE filters, and I have helped
> > him change bad 10 meter capacitors twice now. At least
> > one other person has publicly complained of the same
> > thing. The factory guys say they have never heard of
> > such a problem. They did supply the replacement caps
> > for free, but it took a few weeks to get them, and by
> > then we had already purchased the replacement caps from
> > Mouser. The cap that failed both times was in the leg
> > that runs to ground on the rig side, not the antenna
> > side. This leg is a parallel combinaton of two caps.
> > The cap did not blow completely, rather it just made a
> > significant change in value. If you separate them you
> > can use an impedance measuring device, such as an
> > antenna analyzer, to figure out which one has changed.
> > The capacitor values are all different for the various
> > bands, but a typical Mouser part number would be
> > 5982-19-500V270 for the 270 pF. The Mouser catalog does
> > have some 1000V micas, but the selection of values is
> > quite limited. You could switch to a parallel/series
> > combination of four 500V caps, at least in this leg.
> >
> > Another thing I don't like about the ICE Filters is
> > that the signal path goes through 12 normally-closed
> > relay contacts. In my friend's units, he experiences
> > occasional signal dropout on receive. As soon as he
> > sends one 50 watt "dit" through the filter, the film on
> > the relay contacts is penetrated, and the receive
> > signals reappear. The factory guys say they have never
> > heard of that one, either.
> >
> > Just pull the cover off the filter, and you will see
> >how it is built. At least it is easy to work on. We've
> > had the covers off my friend's unit so much that now we
> > just have to whistle, and the screws unscrew
> > themselves. After you change the caps, just squeeze the
> > 10 meter coil/bend cap leads for min swr. We keep a
> > rubber glove handy for this purpose, to avoid rf burns,
> > and to avoid affecting the swr. Make final adjustment
> > with the cover on as far as you can get it, and still
> > be able to reach in. We can change these caps in about
> > ten minutes now. It looks like a Wood brothers' pit
> > stop.
> >
> >
> > Dave Hachadorian, K6LL
> > Yuma, AZ
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> > any
> > questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > 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 24, Issue 36
> > *****************************************
> >
> >
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
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