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RE: [FT897] Re: Grounding the FT-897

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  • D. F.
    In #2, the key phrase is largest possible wire running the shortest possible distance. Remember that ANY wire used for ANY purpose (computer cables, speaker
    Message 1 of 29 , Aug 3, 2009
      In #2, the key phrase is "largest possible wire running the shortest
      possible distance." Remember that ANY wire used for ANY purpose
      (computer cables, speaker wire, ground wires, etc) become resonant at
      certain frequencies the longer they get. A 50 foot run of ground wire,
      IMO, is WAY TOO LONG! If you can shorten it in anyway, it would be best.

      Dennis - N8BMB

      -----Original Message-----
      From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
      Lew Phelps K6LMP
      Sent: Monday, August 03, 2009 09:01
      To: FT897@yahoogroups.com
      Subject: Re: [FT897] Re: Grounding the FT-897


      I am not a licensed electrician, but for reasons not worth discussion
      here, I have become quite familiar with the residential portions of
      the National Electric Code, and done a lot of residential wiring work
      under the supervision of a licensed electrical contractor who held a
      PhD in electrical engineering.

      Between that background and what I have learned from ARRL publications
      and elsewhere about transmitter grounding, I offer the following:\

      1. Purely from an AC mains standpoint, the ground wire should be large
      enough to carry the entire current that can possibly flow through it
      if a dead short occurs within the equipment. If the circuit in
      question has a 20 amp circuit breaker, then the maximum current that
      could flow through the ground wire (before the breaker trips) is 20
      amps. For a 50 foot run, #12 wire is sufficient from an NEC
      viewpoint. The NEC specifically allows grounding the "third plug" of a
      socket to a cold water pipe, for example, if a "system groundd" wire
      is not available at that location (for example in an older house where
      the wiring is only two conductor). But that is not the "driving issue."

      2. From an RF grounding standpoint, it is desirable to have the
      largest possible wire size running the shortest possible distance
      between your shack and the ground stakes. Within the shack, best
      practice is a short (several feet) "grounding bar" of large diameter.
      I use a 2 foot section of 1.5" diameter copper plumbing pipe, drilled
      and tapped for 1/4-28 thread bolts, and all RF-carrying devices are
      grounded to that bar with 1" wide braided copper straps, 1 foot
      length. The grounding bar is connected to ground rods with 2/0
      stranded wire (0.3648" conductor diameter). The first ground rod is a
      5 foot run of 00 wire from the grounding bar, and there are four
      additional ground rods, spaced about 20 feet apart, connected in
      series to each other with 00 wire. The grounding rods are 1/2" copper
      rods, available at big box hardware and electrical supply stores. This
      is an adequate, but not great, RF grounding system.

      The general rules for RF grounding are (1) shortest possible run from
      station ground to earth ground, preferably less than 1/4 wavelength on
      the highest frequency you'll be transmitting on. (2) Use as large
      diameter conductor as possible -- either large wire or large flat
      braid (or you can use the braided copper wire shielding from large
      diameter coaxial cable.) (3) Make sure all connections are properly
      bonded (clamped) and if exposed to weather, protected from corrosion.
      I use GE Silicon Bathroom Sealant to protect all bonding joints.

      The reason you need much larger diameter wire for RF grounding is that
      inductive reactance increases with wire length, but decreases with
      conductor diameter. Large diameter conductors help to offset the
      inductive reactance of long ground wire runs. If a run of ground wire
      is 1/4 wave length, or any odd multiple of a quarter wave length, for
      the frequency being transmitted, it will be, in effect, a ground-
      reversal device. There will be zero voltage at the ground stake, but
      whatever RF voltage is "available" to the system (from the
      transmission line, typically) will be at a maximum at the other end of
      the ground wire -- your transmitter! If the ground run is not exactly
      1/4 wave length, you'll still have voltage at the transmitter end of
      the grounding system, proportional to the phase position of the signal
      on the ground wire. With the 100 watt output of an FT-897, RF voltages
      can be a problem from an equipment standpoint, but not likely to be
      lethal. With a full 1.5KW legal limit linear amplifier, you're talking
      about (under some circumstances) several thousand volts!

      A 50 foot ground wire run is a horrible solution, because it creates
      1/4 wave length multiples for so many frequencies. For example, it's
      very close to a perfect odd multiple of a quarter wavelength on 20,
      15, and 12 meters, and it's an EXACT odd multiple of quarter wave
      lengths on portions of the 10, 6, and 2 meter and 70 cm bands. If you
      change the length slightly, you just shift the worst problems to other
      frequencies.

      There is a detailed and very good discussion of the issue and possible
      fixes at http://www.radiowor <http://www.radioworks.com/nbgnd.html.>
      ks.com/nbgnd.html.

      In particular, if you really can't avoid a 50 foot run from the ground
      stake to your rig, don't bother running the ground wire. It will
      create more problems than you have without an RF ground. Your house
      lines will provide grounding for the 110/220 VAC house power, but
      you'll have to deal with the RF ground problem another way. Read his
      discussion of a counterpoise.

      As for your question about multiple grounds within a residential
      system, the NEC does not prohibit multiple grounds. They can cause
      problems from ground loop current, but that's an RF issue, not a house
      mains issue.

      73

      Lew K6LMP



      [Non-text portions of this message have been removed]
    • oldmayorkd5lbe
      From KD5LBE resending In normal soil ground rods should be 8 foot copper clad steel. All rods at your house should be tied together to equalize any major
      Message 2 of 29 , Aug 3, 2009
        From KD5LBE resending

        In normal soil ground rods should be 8 foot copper clad steel. All rods at your house should be tied together to equalize any major lightening strike (code). Putting a ground rod down is easy with almost no effort. You need at least a two foot clearance above the rod. Dig a small hole no more that a couple of inches deep where you want the rod to go. Pour some water in the whole. put the sharp end of the rod in the hole and start churning the rod. up and down. As the rod goes down add a little more water. This should get you down at least 6 feet if not seven. What ever you have left should drive in with little or no problem. I put in many a rod with Memphis Light Gas and Water and at my house. You can even impress your friends with how easy it is. This doesn't work in rock, frozen ground, or rocky soil. This all assumes that you are at ground level looking for a grounding location. If you can't do this be sure to first by HAM radio insurance from the ARRL, and second to disconnect your radio and antenna in bad weather and have a surge protector on the power cord, the best you can afford. Grounding RF and Electrical are serious business. I have a friend in a wheelchair for life because he didn't take it serious.

        --- In FT897@yahoogroups.com, "D. F." <n8bmb1@...> wrote:
        >
        > In #2, the key phrase is "largest possible wire running the shortest
        > possible distance." Remember that ANY wire used for ANY purpose
        > (computer cables, speaker wire, ground wires, etc) become resonant at
        > certain frequencies the longer they get. A 50 foot run of ground wire,
        > IMO, is WAY TOO LONG! If you can shorten it in anyway, it would be best.
        >
        > Dennis - N8BMB
        >
        > -----Original Message-----
        > From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
        > Lew Phelps K6LMP
        > Sent: Monday, August 03, 2009 09:01
        > To: FT897@yahoogroups.com
        > Subject: Re: [FT897] Re: Grounding the FT-897
        >
        >
        > I am not a licensed electrician, but for reasons not worth discussion
        > here, I have become quite familiar with the residential portions of
        > the National Electric Code, and done a lot of residential wiring work
        > under the supervision of a licensed electrical contractor who held a
        > PhD in electrical engineering.
        >
        > Between that background and what I have learned from ARRL publications
        > and elsewhere about transmitter grounding, I offer the following:\
        >
        > 1. Purely from an AC mains standpoint, the ground wire should be large
        > enough to carry the entire current that can possibly flow through it
        > if a dead short occurs within the equipment. If the circuit in
        > question has a 20 amp circuit breaker, then the maximum current that
        > could flow through the ground wire (before the breaker trips) is 20
        > amps. For a 50 foot run, #12 wire is sufficient from an NEC
        > viewpoint. The NEC specifically allows grounding the "third plug" of a
        > socket to a cold water pipe, for example, if a "system groundd" wire
        > is not available at that location (for example in an older house where
        > the wiring is only two conductor). But that is not the "driving issue."
        >
        > 2. From an RF grounding standpoint, it is desirable to have the
        > largest possible wire size running the shortest possible distance
        > between your shack and the ground stakes. Within the shack, best
        > practice is a short (several feet) "grounding bar" of large diameter.
        > I use a 2 foot section of 1.5" diameter copper plumbing pipe, drilled
        > and tapped for 1/4-28 thread bolts, and all RF-carrying devices are
        > grounded to that bar with 1" wide braided copper straps, 1 foot
        > length. The grounding bar is connected to ground rods with 2/0
        > stranded wire (0.3648" conductor diameter). The first ground rod is a
        > 5 foot run of 00 wire from the grounding bar, and there are four
        > additional ground rods, spaced about 20 feet apart, connected in
        > series to each other with 00 wire. The grounding rods are 1/2" copper
        > rods, available at big box hardware and electrical supply stores. This
        > is an adequate, but not great, RF grounding system.
        >
        > The general rules for RF grounding are (1) shortest possible run from
        > station ground to earth ground, preferably less than 1/4 wavelength on
        > the highest frequency you'll be transmitting on. (2) Use as large
        > diameter conductor as possible -- either large wire or large flat
        > braid (or you can use the braided copper wire shielding from large
        > diameter coaxial cable.) (3) Make sure all connections are properly
        > bonded (clamped) and if exposed to weather, protected from corrosion.
        > I use GE Silicon Bathroom Sealant to protect all bonding joints.
        >
        > The reason you need much larger diameter wire for RF grounding is that
        > inductive reactance increases with wire length, but decreases with
        > conductor diameter. Large diameter conductors help to offset the
        > inductive reactance of long ground wire runs. If a run of ground wire
        > is 1/4 wave length, or any odd multiple of a quarter wave length, for
        > the frequency being transmitted, it will be, in effect, a ground-
        > reversal device. There will be zero voltage at the ground stake, but
        > whatever RF voltage is "available" to the system (from the
        > transmission line, typically) will be at a maximum at the other end of
        > the ground wire -- your transmitter! If the ground run is not exactly
        > 1/4 wave length, you'll still have voltage at the transmitter end of
        > the grounding system, proportional to the phase position of the signal
        > on the ground wire. With the 100 watt output of an FT-897, RF voltages
        > can be a problem from an equipment standpoint, but not likely to be
        > lethal. With a full 1.5KW legal limit linear amplifier, you're talking
        > about (under some circumstances) several thousand volts!
        >
        > A 50 foot ground wire run is a horrible solution, because it creates
        > 1/4 wave length multiples for so many frequencies. For example, it's
        > very close to a perfect odd multiple of a quarter wavelength on 20,
        > 15, and 12 meters, and it's an EXACT odd multiple of quarter wave
        > lengths on portions of the 10, 6, and 2 meter and 70 cm bands. If you
        > change the length slightly, you just shift the worst problems to other
        > frequencies.
        >
        > There is a detailed and very good discussion of the issue and possible
        > fixes at http://www.radiowor <http://www.radioworks.com/nbgnd.html.>
        > ks.com/nbgnd.html.
        >
        > In particular, if you really can't avoid a 50 foot run from the ground
        > stake to your rig, don't bother running the ground wire. It will
        > create more problems than you have without an RF ground. Your house
        > lines will provide grounding for the 110/220 VAC house power, but
        > you'll have to deal with the RF ground problem another way. Read his
        > discussion of a counterpoise.
        >
        > As for your question about multiple grounds within a residential
        > system, the NEC does not prohibit multiple grounds. They can cause
        > problems from ground loop current, but that's an RF issue, not a house
        > mains issue.
        >
        > 73
        >
        > Lew K6LMP
        >
        >
        >
        > [Non-text portions of this message have been removed]
        >
      • kj4nts
        I could put a surface wire counterpoise in the crawl space under my office where the radio is located. If I did that, there would be only about a 5 or 6 foot
        Message 3 of 29 , Aug 3, 2009
          I could put a surface wire counterpoise in the crawl space under my office where the radio is located. If I did that, there would be only about a 5 or 6 foot run to the center point of the counterpoise.

          Assuming the counterpoise wires are laying on the dirt floor of the crawl space, how many wires would I need, and how long do they need to be. I want to be able to work 6 through 40 meters.

          If I install a wire counterpoise like this, is there any problem also connecting the earth ground connection to the central ground bar in my office?

          The attic antenna is an Alpha Delta DX-EE.

          --- In FT897@yahoogroups.com, "D. F." <n8bmb1@...> wrote:
          >
          > In #2, the key phrase is "largest possible wire running the shortest
          > possible distance." Remember that ANY wire used for ANY purpose
          > (computer cables, speaker wire, ground wires, etc) become resonant at
          > certain frequencies the longer they get. A 50 foot run of ground wire,
          > IMO, is WAY TOO LONG! If you can shorten it in anyway, it would be best.
          >
          > Dennis - N8BMB
          >
          > -----Original Message-----
          > From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
          > Lew Phelps K6LMP
          > Sent: Monday, August 03, 2009 09:01
          > To: FT897@yahoogroups.com
          > Subject: Re: [FT897] Re: Grounding the FT-897
          >
          >
          > I am not a licensed electrician, but for reasons not worth discussion
          > here, I have become quite familiar with the residential portions of
          > the National Electric Code, and done a lot of residential wiring work
          > under the supervision of a licensed electrical contractor who held a
          > PhD in electrical engineering.
          >
          > Between that background and what I have learned from ARRL publications
          > and elsewhere about transmitter grounding, I offer the following:\
          >
          > 1. Purely from an AC mains standpoint, the ground wire should be large
          > enough to carry the entire current that can possibly flow through it
          > if a dead short occurs within the equipment. If the circuit in
          > question has a 20 amp circuit breaker, then the maximum current that
          > could flow through the ground wire (before the breaker trips) is 20
          > amps. For a 50 foot run, #12 wire is sufficient from an NEC
          > viewpoint. The NEC specifically allows grounding the "third plug" of a
          > socket to a cold water pipe, for example, if a "system groundd" wire
          > is not available at that location (for example in an older house where
          > the wiring is only two conductor). But that is not the "driving issue."
          >
          > 2. From an RF grounding standpoint, it is desirable to have the
          > largest possible wire size running the shortest possible distance
          > between your shack and the ground stakes. Within the shack, best
          > practice is a short (several feet) "grounding bar" of large diameter.
          > I use a 2 foot section of 1.5" diameter copper plumbing pipe, drilled
          > and tapped for 1/4-28 thread bolts, and all RF-carrying devices are
          > grounded to that bar with 1" wide braided copper straps, 1 foot
          > length. The grounding bar is connected to ground rods with 2/0
          > stranded wire (0.3648" conductor diameter). The first ground rod is a
          > 5 foot run of 00 wire from the grounding bar, and there are four
          > additional ground rods, spaced about 20 feet apart, connected in
          > series to each other with 00 wire. The grounding rods are 1/2" copper
          > rods, available at big box hardware and electrical supply stores. This
          > is an adequate, but not great, RF grounding system.
          >
          > The general rules for RF grounding are (1) shortest possible run from
          > station ground to earth ground, preferably less than 1/4 wavelength on
          > the highest frequency you'll be transmitting on. (2) Use as large
          > diameter conductor as possible -- either large wire or large flat
          > braid (or you can use the braided copper wire shielding from large
          > diameter coaxial cable.) (3) Make sure all connections are properly
          > bonded (clamped) and if exposed to weather, protected from corrosion.
          > I use GE Silicon Bathroom Sealant to protect all bonding joints.
          >
          > The reason you need much larger diameter wire for RF grounding is that
          > inductive reactance increases with wire length, but decreases with
          > conductor diameter. Large diameter conductors help to offset the
          > inductive reactance of long ground wire runs. If a run of ground wire
          > is 1/4 wave length, or any odd multiple of a quarter wave length, for
          > the frequency being transmitted, it will be, in effect, a ground-
          > reversal device. There will be zero voltage at the ground stake, but
          > whatever RF voltage is "available" to the system (from the
          > transmission line, typically) will be at a maximum at the other end of
          > the ground wire -- your transmitter! If the ground run is not exactly
          > 1/4 wave length, you'll still have voltage at the transmitter end of
          > the grounding system, proportional to the phase position of the signal
          > on the ground wire. With the 100 watt output of an FT-897, RF voltages
          > can be a problem from an equipment standpoint, but not likely to be
          > lethal. With a full 1.5KW legal limit linear amplifier, you're talking
          > about (under some circumstances) several thousand volts!
          >
          > A 50 foot ground wire run is a horrible solution, because it creates
          > 1/4 wave length multiples for so many frequencies. For example, it's
          > very close to a perfect odd multiple of a quarter wavelength on 20,
          > 15, and 12 meters, and it's an EXACT odd multiple of quarter wave
          > lengths on portions of the 10, 6, and 2 meter and 70 cm bands. If you
          > change the length slightly, you just shift the worst problems to other
          > frequencies.
          >
          > There is a detailed and very good discussion of the issue and possible
          > fixes at http://www.radiowor <http://www.radioworks.com/nbgnd.html.>
          > ks.com/nbgnd.html.
          >
          > In particular, if you really can't avoid a 50 foot run from the ground
          > stake to your rig, don't bother running the ground wire. It will
          > create more problems than you have without an RF ground. Your house
          > lines will provide grounding for the 110/220 VAC house power, but
          > you'll have to deal with the RF ground problem another way. Read his
          > discussion of a counterpoise.
          >
          > As for your question about multiple grounds within a residential
          > system, the NEC does not prohibit multiple grounds. They can cause
          > problems from ground loop current, but that's an RF issue, not a house
          > mains issue.
          >
          > 73
          >
          > Lew K6LMP
          >
          >
          >
          > [Non-text portions of this message have been removed]
          >
        • D. F.
          The counterpoise NEEDS to be separate from your equipment ground. Again, because your counterpoise is a LONG wire that runs around the house, it is going to be
          Message 4 of 29 , Aug 3, 2009
            The counterpoise NEEDS to be separate from your equipment ground. Again,
            because your counterpoise is a LONG wire that runs around the house, it
            is going to be resonant at some HF frequencies and act like an antenna
            and if tied/connected to your equipment ground, it COULD pose rf
            problems.

            The idea behind equipment grounding is twofold; one to reduce/eliminate
            rf getting into your equipment, and two, also to assist in
            reducing/eliminating damage to your equipment from lightning strikes.

            The first is why the wire should be as short as possible, the second is
            electricity travels the path of shortest and least resistance. So,
            having the shortest grounding wire, helps to ensure proper
            elimination/reduction of rf and electrical damage.

            Dennis - N8BMB

            -----Original Message-----
            From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
            kj4nts
            Sent: Monday, August 03, 2009 12:10
            To: FT897@yahoogroups.com
            Subject: [FT897] Re: Grounding the FT-897


            I could put a surface wire counterpoise in the crawl space under my
            office where the radio is located. If I did that, there would be only
            about a 5 or 6 foot run to the center point of the counterpoise.

            Assuming the counterpoise wires are laying on the dirt floor of the
            crawl space, how many wires would I need, and how long do they need to
            be. I want to be able to work 6 through 40 meters.

            If I install a wire counterpoise like this, is there any problem also
            connecting the earth ground connection to the central ground bar in my
            office?

            The attic antenna is an Alpha Delta DX-EE.

            --- In FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com, "D. F."
            <n8bmb1@...> wrote:
            >
            > In #2, the key phrase is "largest possible wire running the shortest
            > possible distance." Remember that ANY wire used for ANY purpose
            > (computer cables, speaker wire, ground wires, etc) become resonant at
            > certain frequencies the longer they get. A 50 foot run of ground wire,
            > IMO, is WAY TOO LONG! If you can shorten it in anyway, it would be
            best.
            >
            > Dennis - N8BMB
            >
            > -----Original Message-----
            > From: FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com
            [mailto:FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com] On
            Behalf Of
            > Lew Phelps K6LMP
            > Sent: Monday, August 03, 2009 09:01
            > To: FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com
            > Subject: Re: [FT897] Re: Grounding the FT-897
            >
            >
            > I am not a licensed electrician, but for reasons not worth discussion
            > here, I have become quite familiar with the residential portions of
            > the National Electric Code, and done a lot of residential wiring work
            > under the supervision of a licensed electrical contractor who held a
            > PhD in electrical engineering.
            >
            > Between that background and what I have learned from ARRL publications

            > and elsewhere about transmitter grounding, I offer the following:\
            >
            > 1. Purely from an AC mains standpoint, the ground wire should be large

            > enough to carry the entire current that can possibly flow through it
            > if a dead short occurs within the equipment. If the circuit in
            > question has a 20 amp circuit breaker, then the maximum current that
            > could flow through the ground wire (before the breaker trips) is 20
            > amps. For a 50 foot run, #12 wire is sufficient from an NEC
            > viewpoint. The NEC specifically allows grounding the "third plug" of a

            > socket to a cold water pipe, for example, if a "system groundd" wire
            > is not available at that location (for example in an older house where

            > the wiring is only two conductor). But that is not the "driving
            issue."
            >
            > 2. From an RF grounding standpoint, it is desirable to have the
            > largest possible wire size running the shortest possible distance
            > between your shack and the ground stakes. Within the shack, best
            > practice is a short (several feet) "grounding bar" of large diameter.
            > I use a 2 foot section of 1.5" diameter copper plumbing pipe, drilled
            > and tapped for 1/4-28 thread bolts, and all RF-carrying devices are
            > grounded to that bar with 1" wide braided copper straps, 1 foot
            > length. The grounding bar is connected to ground rods with 2/0
            > stranded wire (0.3648" conductor diameter). The first ground rod is a
            > 5 foot run of 00 wire from the grounding bar, and there are four
            > additional ground rods, spaced about 20 feet apart, connected in
            > series to each other with 00 wire. The grounding rods are 1/2" copper
            > rods, available at big box hardware and electrical supply stores. This

            > is an adequate, but not great, RF grounding system.
            >
            > The general rules for RF grounding are (1) shortest possible run from
            > station ground to earth ground, preferably less than 1/4 wavelength on

            > the highest frequency you'll be transmitting on. (2) Use as large
            > diameter conductor as possible -- either large wire or large flat
            > braid (or you can use the braided copper wire shielding from large
            > diameter coaxial cable.) (3) Make sure all connections are properly
            > bonded (clamped) and if exposed to weather, protected from corrosion.
            > I use GE Silicon Bathroom Sealant to protect all bonding joints.
            >
            > The reason you need much larger diameter wire for RF grounding is that

            > inductive reactance increases with wire length, but decreases with
            > conductor diameter. Large diameter conductors help to offset the
            > inductive reactance of long ground wire runs. If a run of ground wire
            > is 1/4 wave length, or any odd multiple of a quarter wave length, for
            > the frequency being transmitted, it will be, in effect, a ground-
            > reversal device. There will be zero voltage at the ground stake, but
            > whatever RF voltage is "available" to the system (from the
            > transmission line, typically) will be at a maximum at the other end of

            > the ground wire -- your transmitter! If the ground run is not exactly
            > 1/4 wave length, you'll still have voltage at the transmitter end of
            > the grounding system, proportional to the phase position of the signal

            > on the ground wire. With the 100 watt output of an FT-897, RF voltages

            > can be a problem from an equipment standpoint, but not likely to be
            > lethal. With a full 1.5KW legal limit linear amplifier, you're talking

            > about (under some circumstances) several thousand volts!
            >
            > A 50 foot ground wire run is a horrible solution, because it creates
            > 1/4 wave length multiples for so many frequencies. For example, it's
            > very close to a perfect odd multiple of a quarter wavelength on 20,
            > 15, and 12 meters, and it's an EXACT odd multiple of quarter wave
            > lengths on portions of the 10, 6, and 2 meter and 70 cm bands. If you
            > change the length slightly, you just shift the worst problems to other

            > frequencies.
            >
            > There is a detailed and very good discussion of the issue and possible

            > fixes at http://www.radiowor <http://www.radiowor
            <http://www.radioworks.com/nbgnd.html.> ks.com/nbgnd.html.>
            > ks.com/nbgnd.html.
            >
            > In particular, if you really can't avoid a 50 foot run from the ground

            > stake to your rig, don't bother running the ground wire. It will
            > create more problems than you have without an RF ground. Your house
            > lines will provide grounding for the 110/220 VAC house power, but
            > you'll have to deal with the RF ground problem another way. Read his
            > discussion of a counterpoise.
            >
            > As for your question about multiple grounds within a residential
            > system, the NEC does not prohibit multiple grounds. They can cause
            > problems from ground loop current, but that's an RF issue, not a house

            > mains issue.
            >
            > 73
            >
            > Lew K6LMP
            >
            >
            >
            > [Non-text portions of this message have been removed]
            >



            [Non-text portions of this message have been removed]
          • kj4nts
            I understand and agree with both of your points. However, short of moving to a different house, I have to live with the limitations of my home geometry. There
            Message 5 of 29 , Aug 3, 2009
              I understand and agree with both of your points. However, short of moving to a different house, I have to live with the limitations of my home geometry.

              There is no way to get from my office to the outside ground without a 50 foot run.

              An outside buried counterpose would be extremely difficult. We have many buried wires for sprinker systems, low and high voltage outside lighting, phone, alarm, and cable connections fanning out from the side of the house where the counterpoise would have to start. I can get between the wires to drive ground stakes, but if I start digging long trenches I am going to cut many wires. Also, even if I used an outside counterpoise, it would be a 50 foot run to get from the FT-897 to it.

              So, an alternative is to lay wires on the dirt floor in the crawl space under my office and try to form a counterpoise that way. But if I do that for an RF ground, I would still like to have a connection from the FT-897 to a good earth ground for lightining and general safety reasons.

              If it helps, I can lay the 50 foot wire running to the ground rod directly on the dirt floor. Maybe the close proximity to the ground would add RF grounding to the long ground wire.

              If I construct a radial counterpoise in the crawl space, how long do the radials need to be to handle 6-40 meters? And how many radials are needed?

              --- In FT897@yahoogroups.com, "D. F." <n8bmb1@...> wrote:
              >
              > The counterpoise NEEDS to be separate from your equipment ground. Again,
              > because your counterpoise is a LONG wire that runs around the house, it
              > is going to be resonant at some HF frequencies and act like an antenna
              > and if tied/connected to your equipment ground, it COULD pose rf
              > problems.
              >
              > The idea behind equipment grounding is twofold; one to reduce/eliminate
              > rf getting into your equipment, and two, also to assist in
              > reducing/eliminating damage to your equipment from lightning strikes.
              >
              > The first is why the wire should be as short as possible, the second is
              > electricity travels the path of shortest and least resistance. So,
              > having the shortest grounding wire, helps to ensure proper
              > elimination/reduction of rf and electrical damage.
              >
              > Dennis - N8BMB
              >
              > -----Original Message-----
              > From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
              > kj4nts
              > Sent: Monday, August 03, 2009 12:10
              > To: FT897@yahoogroups.com
              > Subject: [FT897] Re: Grounding the FT-897
              >
              >
              > I could put a surface wire counterpoise in the crawl space under my
              > office where the radio is located. If I did that, there would be only
              > about a 5 or 6 foot run to the center point of the counterpoise.
              >
              > Assuming the counterpoise wires are laying on the dirt floor of the
              > crawl space, how many wires would I need, and how long do they need to
              > be. I want to be able to work 6 through 40 meters.
              >
              > If I install a wire counterpoise like this, is there any problem also
              > connecting the earth ground connection to the central ground bar in my
              > office?
              >
              > The attic antenna is an Alpha Delta DX-EE.
              >
              > --- In FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com, "D. F."
              > <n8bmb1@> wrote:
              > >
              > > In #2, the key phrase is "largest possible wire running the shortest
              > > possible distance." Remember that ANY wire used for ANY purpose
              > > (computer cables, speaker wire, ground wires, etc) become resonant at
              > > certain frequencies the longer they get. A 50 foot run of ground wire,
              > > IMO, is WAY TOO LONG! If you can shorten it in anyway, it would be
              > best.
              > >
              > > Dennis - N8BMB
              > >
              > > -----Original Message-----
              > > From: FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com
              > [mailto:FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com] On
              > Behalf Of
              > > Lew Phelps K6LMP
              > > Sent: Monday, August 03, 2009 09:01
              > > To: FT897@yahoogroups. <mailto:FT897%40yahoogroups.com> com
              > > Subject: Re: [FT897] Re: Grounding the FT-897
              > >
              > >
              > > I am not a licensed electrician, but for reasons not worth discussion
              > > here, I have become quite familiar with the residential portions of
              > > the National Electric Code, and done a lot of residential wiring work
              > > under the supervision of a licensed electrical contractor who held a
              > > PhD in electrical engineering.
              > >
              > > Between that background and what I have learned from ARRL publications
              >
              > > and elsewhere about transmitter grounding, I offer the following:\
              > >
              > > 1. Purely from an AC mains standpoint, the ground wire should be large
              >
              > > enough to carry the entire current that can possibly flow through it
              > > if a dead short occurs within the equipment. If the circuit in
              > > question has a 20 amp circuit breaker, then the maximum current that
              > > could flow through the ground wire (before the breaker trips) is 20
              > > amps. For a 50 foot run, #12 wire is sufficient from an NEC
              > > viewpoint. The NEC specifically allows grounding the "third plug" of a
              >
              > > socket to a cold water pipe, for example, if a "system groundd" wire
              > > is not available at that location (for example in an older house where
              >
              > > the wiring is only two conductor). But that is not the "driving
              > issue."
              > >
              > > 2. From an RF grounding standpoint, it is desirable to have the
              > > largest possible wire size running the shortest possible distance
              > > between your shack and the ground stakes. Within the shack, best
              > > practice is a short (several feet) "grounding bar" of large diameter.
              > > I use a 2 foot section of 1.5" diameter copper plumbing pipe, drilled
              > > and tapped for 1/4-28 thread bolts, and all RF-carrying devices are
              > > grounded to that bar with 1" wide braided copper straps, 1 foot
              > > length. The grounding bar is connected to ground rods with 2/0
              > > stranded wire (0.3648" conductor diameter). The first ground rod is a
              > > 5 foot run of 00 wire from the grounding bar, and there are four
              > > additional ground rods, spaced about 20 feet apart, connected in
              > > series to each other with 00 wire. The grounding rods are 1/2" copper
              > > rods, available at big box hardware and electrical supply stores. This
              >
              > > is an adequate, but not great, RF grounding system.
              > >
              > > The general rules for RF grounding are (1) shortest possible run from
              > > station ground to earth ground, preferably less than 1/4 wavelength on
              >
              > > the highest frequency you'll be transmitting on. (2) Use as large
              > > diameter conductor as possible -- either large wire or large flat
              > > braid (or you can use the braided copper wire shielding from large
              > > diameter coaxial cable.) (3) Make sure all connections are properly
              > > bonded (clamped) and if exposed to weather, protected from corrosion.
              > > I use GE Silicon Bathroom Sealant to protect all bonding joints.
              > >
              > > The reason you need much larger diameter wire for RF grounding is that
              >
              > > inductive reactance increases with wire length, but decreases with
              > > conductor diameter. Large diameter conductors help to offset the
              > > inductive reactance of long ground wire runs. If a run of ground wire
              > > is 1/4 wave length, or any odd multiple of a quarter wave length, for
              > > the frequency being transmitted, it will be, in effect, a ground-
              > > reversal device. There will be zero voltage at the ground stake, but
              > > whatever RF voltage is "available" to the system (from the
              > > transmission line, typically) will be at a maximum at the other end of
              >
              > > the ground wire -- your transmitter! If the ground run is not exactly
              > > 1/4 wave length, you'll still have voltage at the transmitter end of
              > > the grounding system, proportional to the phase position of the signal
              >
              > > on the ground wire. With the 100 watt output of an FT-897, RF voltages
              >
              > > can be a problem from an equipment standpoint, but not likely to be
              > > lethal. With a full 1.5KW legal limit linear amplifier, you're talking
              >
              > > about (under some circumstances) several thousand volts!
              > >
              > > A 50 foot ground wire run is a horrible solution, because it creates
              > > 1/4 wave length multiples for so many frequencies. For example, it's
              > > very close to a perfect odd multiple of a quarter wavelength on 20,
              > > 15, and 12 meters, and it's an EXACT odd multiple of quarter wave
              > > lengths on portions of the 10, 6, and 2 meter and 70 cm bands. If you
              > > change the length slightly, you just shift the worst problems to other
              >
              > > frequencies.
              > >
              > > There is a detailed and very good discussion of the issue and possible
              >
              > > fixes at http://www.radiowor <http://www.radiowor
              > <http://www.radioworks.com/nbgnd.html.> ks.com/nbgnd.html.>
              > > ks.com/nbgnd.html.
              > >
              > > In particular, if you really can't avoid a 50 foot run from the ground
              >
              > > stake to your rig, don't bother running the ground wire. It will
              > > create more problems than you have without an RF ground. Your house
              > > lines will provide grounding for the 110/220 VAC house power, but
              > > you'll have to deal with the RF ground problem another way. Read his
              > > discussion of a counterpoise.
              > >
              > > As for your question about multiple grounds within a residential
              > > system, the NEC does not prohibit multiple grounds. They can cause
              > > problems from ground loop current, but that's an RF issue, not a house
              >
              > > mains issue.
              > >
              > > 73
              > >
              > > Lew K6LMP
              > >
              > >
              > >
              > > [Non-text portions of this message have been removed]
              > >
              >
              >
              >
              > [Non-text portions of this message have been removed]
              >
            • Lew Phelps K6LMP
              I completely concur with Dennis that a 50 foot ground wire is far too long for RF purposes. The goal is to use as short as possible a ground wire between the
              Message 6 of 29 , Aug 3, 2009
                I completely concur with Dennis that a 50 foot ground wire is far too
                long for RF purposes. The goal is to use as short as possible a ground
                wire between the shack and the rig, knowing that the longer the wire,
                the more ham-band frequencies will be 1/4 wave resonant. Shortening
                the wire is far more significant than increasing its diameter.

                The only purpose of a larger diameter wire is to reduce the inductive
                reactance for whatever length of wire you are running, but larger wire
                is not a substitute for a short wire run.

                A calculator is available online at http://www.consultrsr.com/resources/eis/induct5.htm
                to calculate the inductive reactance of a straight piece of wire of
                a given diameter and length. To take two examples, #14 wire has a
                diameter of 1.62814 mm. A run of 15 meters (appx. 50 feet) has an
                inductance of about 29.2 µH. Changing the diameter to 2/0 wire (9.25
                mm diameter) reduces the inductance to 26 µH -- a little help, but not
                much.

                On the other hand, a 1.5 meter (10 times shorter) run of #14 wire
                possesses inductance of about 2.2 µH, and a 1.5 meter run of 2/0 wire
                only 1.7 µH. Thus, a 50-foot run of #14 wire will have 13 times as
                much inductance as a 5 foot run of #14 wire, and 17 times as much as a
                5 foot run of #00 wire, which means the longer wire has the potential
                to create up to 17 times as much voltage at the rig as the shorter
                wire, not even counting quarter-wave issues. The increase in
                inductance is not a linear function of wire length. The formula is :



                In this equation, L is the inductance in nH (10-9 henry), l is the
                length and d is the diameter of the wire/rod (both in cm). µ is the
                permeability of the material (=1.0, except for iron and other
                ferromagnetic materials).

                You can work through the formula if you wish, but a simple
                demonstration with the online calculator shows the effect. Holding all
                other factor equal, here are the inductance numbers for #14 wire at
                various lengths:

                1 meter = 1.4 µH
                10 meters = 18.7 µH (10 times length gives 13.4 times inductance)
                15 meters = 29.3 µH (15 times length gives 21 times inductance) (this
                is your 50 foot wire)
                100 meters = 233 µH (ten times length gives 12.5 times inductance and
                100 times length gives 166 times inductance)

                changing the wire size to #00 provides a little relief:
                1 meter = 1.06 µH
                10 meters = 15.2 µH
                100 meters = 197.6 µH

                As you can see, wire length is VASTLY more significant than wire
                diameter.

                To compound the problem, inductive reactance as a direct function of
                frequency. (the formula is



                This says that if you quadruple the frequency, inductive reactance
                increases fourfold, Thus, RF energy imposed onto the ground wire at 28
                mHz will encounter 4 times the inductive reactance as energy at 7
                mHz. This means that (setting quarter wave resonance issues aside)
                you'll get four times as much voltage drop over the wire and four
                times as much voltage at the rig on 10 meters as you would on 40
                meters.

                The problem is compounded by the higher probability that a longer
                ground wire will be quarter -wave resonant as you move to higher
                bands. Voltage at the rig is maximized at quarter-wave resonance or
                odd multiples thereof. a five-foot wire is fairly close to quarter-
                wave resonance on the six meter band, and the third multiple on 2
                meters. Hmmm. I should look carefully at my setup. A wire run of
                either 4 feet or 6 feet would move the resonance points outside of ham
                bands. I think the distance of the ground stake above ground counts,
                so my 5 feet of 00 wire plus a foot of ground stake is less
                problematic than 5 feet between the rig and ground itself. Dennis, do
                you concur?

                All of which is intended to reinforce the point that -- as Dennis said
                and I agree -- a 50 foot run of ground wire is 'way too long.

                Dennis is also correct that the NEC says that in general, all
                grounding rods should be tied together, but the NEC does make some
                exceptions. Best practice is to tie them all together.

                And yes, I have lightning arrestors build into the antenna system to
                carry the energy from lightning strikes on the antenna directly to
                ground. Living in Southern California, where we almost never have
                lightning, I forgot to mention that issue, but it's of real concern in
                most parts of the country.


                Lew K6LMP

                On Aug 3, 2009, at 9:20 AM, oldmayorkd5lbe wrote:
                >
                > [snip] A 50 foot run of ground wire, IMO, is WAY TOO LONG! If you
                > can shorten it in anyway, it would be best.
                > >
                > > Dennis - N8BMB
                > >
                >


                [Non-text portions of this message have been removed]
              • Lew Phelps K6LMP
                The short answer for counterpoise construction is a separate wire cut to 1/4 wavelength or slightly longer for each band on which you re operating. They can be
                Message 7 of 29 , Aug 3, 2009
                  The short answer for counterpoise construction is a separate wire cut
                  to 1/4 wavelength or slightly longer for each band on which you're
                  operating. They can be run around the edge of a room, under carpets,
                  or in a crawl space, parallel with each other so long as they are not
                  actually touching each other (or are insulated). You can get by with
                  eliminating a few wires, because (for example) 80 meters is the third
                  multiple of 30 meters, and 40 a multiple of 15 meters.

                  Lew K6LMP

                  On Aug 3, 2009, at 10:47 AM, kj4nts wrote:
                  >
                  > If I construct a radial counterpoise in the crawl space, how long do
                  > the radials need to be to handle 6-40 meters? And how many radials
                  > are needed?
                  >
                  > -


                  [Non-text portions of this message have been removed]
                • af6cm_yahoo@myfastmail.com
                  KJ4NTS, I don t think that you need a *counterpoise* at all, because you are using an Alpha Delta DX-EE, which is a fan dipole. Dipoles are balanced.
                  Message 8 of 29 , Aug 3, 2009
                    KJ4NTS,

                    I don't think that you need a *counterpoise* at all, because you are
                    using an Alpha Delta DX-EE, which is a fan dipole. Dipoles are
                    balanced. Counterpoises are used with monopole (vertical) antennas to
                    provide the other half of the antenna, in effect.

                    Do you have high resistivity soil? If so, you may want to put radials
                    down to improve ground return. I would not call this a counterpoise. In
                    this case the radials would connect to (RF) ground. These should not be
                    buried, just at ground level. They can even be stapled to the lawn or
                    soil.

                    If your antenna is not working well, you want to move it out of the
                    attic, if possible, and up a half wavelength above everything. That is
                    the ideal. In reality, you can only do your best.

                    Do make sure your station is safe. This includes lightning protection
                    and making sure RF levels are safe in your home (and your neighbors').
                    Since there is a '4' in your call, you probably need lightning
                    protection. I have done this, even though we don't get many
                    thunderstorms here.

                    Rob
                    AF6CM
                  • D. F.
                    Just a few more thoughts from reading posts – counterpoise does no good if it is buried! RF cannot penetrate the ground! Burying your counterpoise defeats
                    Message 9 of 29 , Aug 3, 2009
                      Just a few more thoughts from reading posts – counterpoise does no good
                      if it is buried! RF cannot penetrate the ground! Burying your
                      counterpoise defeats the purpose of having it. It is like a shunt, it
                      is supposed to pick up “stray” RF (so to speak) and remove it from
                      “inside” the loop “shunting” it to ground and away from electronics.

                      Your counterpoise should be around the OUTSIDE of your home, around the
                      foundation, if you want it to work the way it should. Under the home is
                      defeating the purpose again. Laying it on the ground is ok, but if you
                      could prop it about an inch off the ground helps.

                      For those who may live in a mobile home (ANY YEAR) – IT MAKES NO
                      DIFFERENCE!!! The home STILL NEEDS that counterpoise!

                      My grounds have always been #10 or #8 SOLID WIRE run from the strap on
                      the back of my home built radio shelving (all wood) to the outside
                      ground rod directly under the window from my shack. The run was about 12
                      feet (a little longer than I wanted, but, like was stated, gotta make
                      the shortest run).

                      Remember that the longer your wire, you are creating an antenna that
                      will be resonant SOMEWHERE! If for HF, try to stay under 15 feet for
                      best results. However, as I stated before, the shorter the wire, the
                      better.

                      Because I do not know what type of housing you are in (Actual house,
                      condo, apartment, etc), couldn’t you put your shack closer to an
                      exterior wall that would help shorten your run of wire? How about the
                      basement?

                      Now, that said, you can try this: Take some RG-8 and use the center
                      conductor for your ground. Take the shielding and use that to “ground”
                      the ground. The shield should trap stray RF and remove it from the
                      center ground. YES, both center and shield must be separately grounded.
                      When you fray the ends, DO NOT go more than a few inches up from the
                      ends of the coax! That may work for a “long” run and help keep RF at
                      bay!

                      As far as the rod is concerned, A few inches high is good enough. By “a
                      few” I mean 2 to 6 inches. The majority of the rod should be in the
                      ground to maximize dispersal. You only really need 2 to 4 inches to
                      connect the ground wire to the rod, so having a foot or two out of the
                      ground is a waste, IMO.

                      Hope this helps!

                      Dennis - N8BMB

                      -----Original Message-----
                      From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
                      Lew Phelps K6LMP
                      Sent: Monday, August 03, 2009 13:03
                      To: FT897@yahoogroups.com
                      Subject: Re: [FT897] Re: Grounding the FT-897


                      I completely concur with Dennis that a 50 foot ground wire is far too
                      long for RF purposes. The goal is to use as short as possible a ground
                      wire between the shack and the rig, knowing that the longer the wire,
                      the more ham-band frequencies will be 1/4 wave resonant. Shortening
                      the wire is far more significant than increasing its diameter.

                      The only purpose of a larger diameter wire is to reduce the inductive
                      reactance for whatever length of wire you are running, but larger wire
                      is not a substitute for a short wire run.

                      A calculator is available online at http://www.consultr
                      <http://www.consultrsr.com/resources/eis/induct5.htm>
                      sr.com/resources/eis/induct5.htm
                      to calculate the inductive reactance of a straight piece of wire of
                      a given diameter and length. To take two examples, #14 wire has a
                      diameter of 1.62814 mm. A run of 15 meters (appx. 50 feet) has an
                      inductance of about 29.2 µH. Changing the diameter to 2/0 wire (9.25
                      mm diameter) reduces the inductance to 26 µH -- a little help, but not
                      much.

                      On the other hand, a 1.5 meter (10 times shorter) run of #14 wire
                      possesses inductance of about 2.2 µH, and a 1.5 meter run of 2/0 wire
                      only 1.7 µH. Thus, a 50-foot run of #14 wire will have 13 times as
                      much inductance as a 5 foot run of #14 wire, and 17 times as much as a
                      5 foot run of #00 wire, which means the longer wire has the potential
                      to create up to 17 times as much voltage at the rig as the shorter
                      wire, not even counting quarter-wave issues. The increase in
                      inductance is not a linear function of wire length. The formula is :

                      In this equation, L is the inductance in nH (10-9 henry), l is the
                      length and d is the diameter of the wire/rod (both in cm). µ is the
                      permeability of the material (=1.0, except for iron and other
                      ferromagnetic materials).

                      You can work through the formula if you wish, but a simple
                      demonstration with the online calculator shows the effect. Holding all
                      other factor equal, here are the inductance numbers for #14 wire at
                      various lengths:

                      1 meter = 1.4 µH
                      10 meters = 18.7 µH (10 times length gives 13.4 times inductance)
                      15 meters = 29.3 µH (15 times length gives 21 times inductance) (this
                      is your 50 foot wire)
                      100 meters = 233 µH (ten times length gives 12.5 times inductance and
                      100 times length gives 166 times inductance)

                      changing the wire size to #00 provides a little relief:
                      1 meter = 1.06 µH
                      10 meters = 15.2 µH
                      100 meters = 197.6 µH

                      As you can see, wire length is VASTLY more significant than wire
                      diameter.

                      To compound the problem, inductive reactance as a direct function of
                      frequency. (the formula is

                      This says that if you quadruple the frequency, inductive reactance
                      increases fourfold, Thus, RF energy imposed onto the ground wire at 28
                      mHz will encounter 4 times the inductive reactance as energy at 7
                      mHz. This means that (setting quarter wave resonance issues aside)
                      you'll get four times as much voltage drop over the wire and four
                      times as much voltage at the rig on 10 meters as you would on 40
                      meters.

                      The problem is compounded by the higher probability that a longer
                      ground wire will be quarter -wave resonant as you move to higher
                      bands. Voltage at the rig is maximized at quarter-wave resonance or
                      odd multiples thereof. a five-foot wire is fairly close to quarter-
                      wave resonance on the six meter band, and the third multiple on 2
                      meters. Hmmm. I should look carefully at my setup. A wire run of
                      either 4 feet or 6 feet would move the resonance points outside of ham
                      bands. I think the distance of the ground stake above ground counts,
                      so my 5 feet of 00 wire plus a foot of ground stake is less
                      problematic than 5 feet between the rig and ground itself. Dennis, do
                      you concur?

                      All of which is intended to reinforce the point that -- as Dennis said
                      and I agree -- a 50 foot run of ground wire is 'way too long.

                      Dennis is also correct that the NEC says that in general, all
                      grounding rods should be tied together, but the NEC does make some
                      exceptions. Best practice is to tie them all together.

                      And yes, I have lightning arrestors build into the antenna system to
                      carry the energy from lightning strikes on the antenna directly to
                      ground. Living in Southern California, where we almost never have
                      lightning, I forgot to mention that issue, but it's of real concern in
                      most parts of the country.

                      Lew K6LMP

                      On Aug 3, 2009, at 9:20 AM, oldmayorkd5lbe wrote:
                      >
                      > [snip] A 50 foot run of ground wire, IMO, is WAY TOO LONG! If you
                      > can shorten it in anyway, it would be best.
                      > >
                      > > Dennis - N8BMB
                      > >
                      >

                      [Non-text portions of this message have been removed]



                      [Non-text portions of this message have been removed]
                    • Charles Scott
                      Dennis: I m going to disagree with you in some ways, but do respect your comments. This has to be one of the most difficult areas of the technology for Hams
                      Message 10 of 29 , Aug 3, 2009
                        Dennis:

                        I'm going to disagree with you in some ways, but do respect your
                        comments. This has to be one of the most difficult areas of the
                        technology for Hams and there's so much conflicting information out
                        there I don't know how anyone can make sense of it all. So, I'm sure
                        some of my comments are also not going to ring true with many people on
                        the list.

                        First off. I had a sign at Dayton this year that eventually was mostly
                        erased by the rain (perhaps that should have been a clue). It said "When
                        is a Ground Not a Ground?" The answer to that, of course, is "When
                        there's current!". I think it's helpful for everyone to keep that in
                        mind and that this incontrovertible fact should guide us when we're
                        talking about what is commonly termed an "RF Ground". In essence, there
                        is no such thing, so we need to accept that and look at how we can deal
                        with stray RF issues.

                        The other thing is that your antenna includes anything attached to it
                        that conducts RF or is close enough for some significant energy to be
                        coupled into it. I believe it's important to keep this in mind and make
                        a conscience decision as to what you want to be part of your antenna and
                        what you don't want to be part of your antenna. Once you make that
                        decision, everything else should be configured to NOT conduct RF or at
                        least to have minimal RF coupled into it.

                        The direction I'm headed with this is that if you decide that your
                        transmission line, your radio equipment, and your house wiring is not
                        part of your antenna, then handle that accordingly. This means measures
                        to avoid the RF being coupled into those conductors or being conducted
                        by them. If you accept that you can't simply drain stray RF to some
                        magical ground point, and that you can only minimize the effect of it at
                        some location (i.e. using one of the tuneable ground devices), then
                        nearly all such "RF Ground" measures become moot. This is because it
                        doesn't matter what you do, it will be a totally different situation at
                        another frequency and you'll be chasing it again later. The alternative
                        of avoiding the RF in the first place starts to make more sense.

                        I also want to take the opportunity to differ with you on buried
                        counterpoises (actually part of your antenna). The earth is not simply
                        impenetrable by RF. If it were, many large MF an HF broadcast sites
                        wouldn't have buried counterpoises. That's a whole other discussion though.

                        Chuck - N8DNX



                        D. F. wrote:
                        > Just a few more thoughts from reading posts – counterpoise does no good
                        > if it is buried! RF cannot penetrate the ground! Burying your
                        > counterpoise defeats the purpose of having it. It is like a shunt, it
                        > is supposed to pick up “stray” RF (so to speak) and remove it from
                        > “inside” the loop “shunting” it to ground and away from electronics.
                        >
                        > Your counterpoise should be around the OUTSIDE of your home, around the
                        > foundation, if you want it to work the way it should. Under the home is
                        > defeating the purpose again. Laying it on the ground is ok, but if you
                        > could prop it about an inch off the ground helps.
                        >
                        > For those who may live in a mobile home (ANY YEAR) – IT MAKES NO
                        > DIFFERENCE!!! The home STILL NEEDS that counterpoise!
                        >
                        > My grounds have always been #10 or #8 SOLID WIRE run from the strap on
                        > the back of my home built radio shelving (all wood) to the outside
                        > ground rod directly under the window from my shack. The run was about 12
                        > feet (a little longer than I wanted, but, like was stated, gotta make
                        > the shortest run).
                        >
                        > Remember that the longer your wire, you are creating an antenna that
                        > will be resonant SOMEWHERE! If for HF, try to stay under 15 feet for
                        > best results. However, as I stated before, the shorter the wire, the
                        > better.
                        >
                        > Because I do not know what type of housing you are in (Actual house,
                        > condo, apartment, etc), couldn’t you put your shack closer to an
                        > exterior wall that would help shorten your run of wire? How about the
                        > basement?
                        >
                        > Now, that said, you can try this: Take some RG-8 and use the center
                        > conductor for your ground. Take the shielding and use that to “ground”
                        > the ground. The shield should trap stray RF and remove it from the
                        > center ground. YES, both center and shield must be separately grounded.
                        > When you fray the ends, DO NOT go more than a few inches up from the
                        > ends of the coax! That may work for a “long” run and help keep RF at
                        > bay!
                        >
                        > As far as the rod is concerned, A few inches high is good enough. By “a
                        > few” I mean 2 to 6 inches. The majority of the rod should be in the
                        > ground to maximize dispersal. You only really need 2 to 4 inches to
                        > connect the ground wire to the rod, so having a foot or two out of the
                        > ground is a waste, IMO.
                        >
                        > Hope this helps!
                        >
                        > Dennis - N8BMB
                        >
                        >
                      • Jim C
                        Youy need to read this article. COunterpoise works with dipoles too http://www.hamuniverse.com/grounding.html Here is part of what Bill says in that article,
                        Message 11 of 29 , Aug 3, 2009
                          Youy need to read this article. COunterpoise works with dipoles too

                          http://www.hamuniverse.com/grounding.html


                          Here is part of what Bill says in that article, but go to the website
                          and read the whole thing

                          Years ago I installed a long wire antenna that was about 250 feet long
                          and about 50 feet in the air. This should work fantastic you say. I
                          had three ground rods outside window of shack with single ott solid
                          copper ground wire direct to tuner. Ground wire length was only six
                          feet. All three rods were spaced about eight feet apart with
                          connecting bare wire interconnecting them....in other words, a really
                          good surge ground. What I did not realize at that time was how lousy my
                          RF ground was. We could not tune the antenna on most frequencies and we
                          kept getting zapped from the radio or microphone when we transmitted.
                          Also, our signal reports were lousy. SO, after consulting some experts,
                          I added 250 feet of counterpoise around the building consisting of some
                          bare 6 gauge copper wire I had. The radio was on while I rolled it out
                          and a friend was listening to the broadcast on 40 meters, (OK it was
                          night time---best time to do antenna work right!) Anyway he reported
                          the broadcast was only about S 4-5 on meter. As I rolled out the
                          counterpoise it rose to 40 over S9 and came in much clearer. We were
                          able to tune everything easily now and SWR was rock stable. When we did
                          a signal test, the station we had talked to before accused us of running
                          a contest amplifier. We could not convince them it was only 100 watts,
                          same as before and the same antenna!


                          af6cm_yahoo@... wrote:
                          >
                          >
                          > KJ4NTS,
                          >
                          > I don't think that you need a *counterpoise* at all, because you are
                          > using an Alpha Delta DX-EE, which is a fan dipole. Dipoles are
                          > balanced. Counterpoises are used with monopole (vertical) antennas to
                          > provide the other half of the antenna, in effect.
                          >
                        • Charles Scott
                          Jim: You do realize that these are very different situations. In the case of the DX-EE, it is the entire antenna, or should be. In the case of the long wire,
                          Message 12 of 29 , Aug 3, 2009
                            Jim:

                            You do realize that these are very different situations. In the case of
                            the DX-EE, it is the entire antenna, or should be. In the case of the
                            long wire, that is only 1/2 of the antenna (presumably end-fed) and does
                            require the ground, counterpoise, or whatever you want to call it to be
                            a complete antenna. In that case, the counterpoise was clearly
                            inadequate until it he added more wire. Applying that story to the DX-EE
                            would require disconnecting nearly half of the antenna, then comparing
                            results with that part added back in.

                            Chuck - N8DNX


                            Jim C wrote:
                            > Youy need to read this article. COunterpoise works with dipoles too
                            >
                            > http://www.hamuniverse.com/grounding.html
                            >
                            >
                            > Here is part of what Bill says in that article, but go to the website
                            > and read the whole thing
                            >
                            > Years ago I installed a long wire antenna that was about 250 feet long
                            > and about 50 feet in the air. This should work fantastic you say. I
                            > ...
                            >
                            > af6cm_yahoo@... wrote:
                            >
                            >>
                            >> KJ4NTS,
                            >>
                            >> I don't think that you need a *counterpoise* at all, because you are
                            >> using an Alpha Delta DX-EE, which is a fan dipole. Dipoles are
                            >> balanced. Counterpoises are used with monopole (vertical) antennas to
                            >> provide the other half of the antenna, in effect.
                            >>
                            >>
                          • Jim
                            To Me, A ground is a ground at the resonant frequency AT the SET. A counterpoise has to be elevated as it is a tuned length. If a counterpoise is 1/4 wave long
                            Message 13 of 29 , Aug 4, 2009
                              To Me, A ground is a ground at the resonant frequency AT the SET. A counterpoise has to be elevated as it is a tuned length.
                              If a counterpoise is 1/4 wave long (tuned) then the nearby connection to the rig is at a current high or max.
                              If you let the far end of a counterpoise get grounded, then the near end reverts to a voltage max and your rig is at high SWR condition . At this point the microphone can be RF hot and your lips get sparked --------Ouch! RF burns can take months to heal and into the bargain you have to explain why your lips look as if someone else bit them.
                              On 10 meters, an 8 ft GROUND wire (grounded at the far end) is actually putting the rig at a voltage peak and the SWR is high.
                              The only effective "ground" in this case is to have multiple lengths to different points otherwise have an elevated tuned counterpoise that is tuned by observing the SWR. Now if the Counterpoise is a 1/2 wave long the far end SHOULD be grounded. People who drag a so-called counterpoise behind them as they operate "Pedestrain " deserve to have it stomped upon.
                              Jim VE3DDY
                            • Charles Scott
                              Jim: I think you miss the point. Your rig and your transmission lines should NOT BE PART OF THE ANTENNA SYSTEM. You need to look at isolating RF from anything
                              Message 14 of 29 , Aug 4, 2009
                                Jim:

                                I think you miss the point. Your rig and your transmission lines should
                                NOT BE PART OF THE ANTENNA SYSTEM. You need to look at isolating RF from
                                anything but what you decide is your antenna system.

                                Chuck

                                Jim wrote:
                                > To Me, A ground is a ground at the resonant frequency AT the SET. A counterpoise has to be elevated as it is a tuned length.
                                > If a counterpoise is 1/4 wave long (tuned) then the nearby connection to the rig is at a current high or max.
                                > If you let the far end of a counterpoise get grounded, then the near end reverts to a voltage max and your rig is at high SWR condition . At this point the microphone can be RF hot and your lips get sparked --------Ouch! RF burns can take months to heal and into the bargain you have to explain why your lips look as if someone else bit them.
                                > On 10 meters, an 8 ft GROUND wire (grounded at the far end) is actually putting the rig at a voltage peak and the SWR is high.
                                > The only effective "ground" in this case is to have multiple lengths to different points otherwise have an elevated tuned counterpoise that is tuned by observing the SWR. Now if the Counterpoise is a 1/2 wave long the far end SHOULD be grounded. People who drag a so-called counterpoise behind them as they operate "Pedestrain " deserve to have it stomped upon.
                                > Jim VE3DDY
                                >
                                >
                              • Jim C
                                The counterpoise doesn t really have to be resonant and it will still work
                                Message 15 of 29 , Aug 4, 2009
                                  The counterpoise doesn't really have to be resonant and it will still work

                                  Jim wrote:
                                  >
                                  > i._,___
                                • af6cm_yahoo@myfastmail.com
                                  Jim, Thanks for the pointer to the article. It s an interesting article. The article is about a long wire antenna, which is a monopole, not a dipole. Rob
                                  Message 16 of 29 , Aug 4, 2009
                                    Jim,

                                    Thanks for the pointer to the article. It's an interesting
                                    article.

                                    The article is about a long wire antenna, which is a monopole,
                                    not a dipole.

                                    Rob
                                    AF6CM


                                    On Mon, 03 Aug 2009 18:43 -0400, "Jim C" <liteways@...>
                                    wrote:


                                    Youy need to read this article. COunterpoise works with dipoles
                                    too
                                    http://www.hamuniverse.com/grounding.html
                                    Here is part of what Bill says in that article, but go to the
                                    website
                                    and read the whole thing
                                    Years ago I installed a long wire antenna that was about 250 feet
                                    long
                                    and about 50 feet in the air.
                                    <SNIP>

                                    af6cm_yahoo@... wrote:
                                    >
                                    >
                                    > KJ4NTS,
                                    >
                                    > I don't think that you need a *counterpoise* at all, because
                                    you are
                                    > using an Alpha Delta DX-EE, which is a fan dipole. Dipoles are
                                    > balanced. Counterpoises are used with monopole (vertical)
                                    antennas to
                                    > provide the other half of the antenna, in effect.
                                  • Jim
                                    I once served in a foreign military. We used portable HF for a lot of field work and the radio operator had either a small hip style rig similar to the 817 or
                                    Message 17 of 29 , Aug 5, 2009
                                      I once served in a foreign military.
                                      We used portable HF for a lot of field work and the radio operator had either a small hip style rig similar to the 817 or a RAcal 931.
                                      Instead of a counterpoise, the set had a piece of fly screen wire about 6" X 10" and enclosed in a piece of canvass which he tucked in his belt or put in his back pocket. The screen was connected to the Ground stud of the rig via a short wire. The screen acted as a plate of a capacitor and coupled the set to the operator who I suppose acted as a ground plane.
                                      When the operator would get too far off frequency, SWR would increase and the screen would ZAPP the guy in the rear and remind him to retune.
                                      It was understood NOT to put the screen under your belt in the front of your pants.
                                      This idea was patented by Racal Electronics so it must have some desrability. Operators claimed longer ground wave distances for contacts. I still have one of these in my junk box. If anyone wants a picture, ask.
                                      Jim VE3DDY
                                    • kav
                                      ... Hello I read your original post and assumed that, like me, you were on an upper floor hence inconveniently far from the nearest ground, by which I mean
                                      Message 18 of 29 , Aug 5, 2009
                                        --- In FT897@yahoogroups.com, "kj4nts" <philsherrod@...> wrote:
                                        >
                                        > I could put a surface wire counterpoise in the crawl space under my office where the radio is located. If I did that, there would be only about a 5 or 6 foot run to the center point of the counterpoise. Assuming the counterpoise wires are laying on the dirt floor of the crawl space,how many wires would I need, and how long do they need to be.



                                        Hello

                                        I read your original post and assumed that, like me, you were on an upper floor hence inconveniently far from the nearest ground, by which I mean soil,substrate,planets crust etc.

                                        Then I read all the rsponses from the many members, all of whom made perfect sense. All of whom I believe to be correct in various different scenarios. Some of which I have used myself with varying degrees of success. It always amazes me the ammount of knowledge combined in these groups and many of my problems have been solved this way. A news group often gets across what a book just can't.

                                        Then I read the part of your post at the head of this message and wondered if we'd all missed a tiny possibility.

                                        Now if I'm reading it correctly, your radio is in a ground floor office. That office floor is but 3 feet above the "dirt floor of the crawl space" (ie the substrate beneath your house).

                                        Or to put it another way you have not a 50 foot but a 6 foot run to the nearest possible earth point. Drill, lift, ease asside or just plain vaporise that office floor and knock in some earth rods.

                                        Or have I read it wrong? Unless that "dirt floor of the crawl space" is actually atop one of those dreadful one piece concrete rafts that modern builders love so much then you don't got no excuse. Get drilling.


                                        Regards
                                      • KONI
                                        Jim please send me the picture juergen, dg8fdd ... From: Jim To: FT897@yahoogroups.com Sent: Wednesday, August 05, 2009 6:29 PM Subject: [FT897] Re: Grounding
                                        Message 19 of 29 , Aug 5, 2009
                                          Jim please send me the picture
                                          juergen, dg8fdd

                                          ----- Original Message -----
                                          From: Jim
                                          To: FT897@yahoogroups.com
                                          Sent: Wednesday, August 05, 2009 6:29 PM
                                          Subject: [FT897] Re: Grounding the FT-897


                                          I once served in a foreign military.
                                          We used portable HF for a lot of field work and the radio operator had either a small hip style rig similar to the 817 or a RAcal 931.
                                          Instead of a counterpoise, the set had a piece of fly screen wire about 6" X 10" and enclosed in a piece of canvass which he tucked in his belt or put in his back pocket. The screen was connected to the Ground stud of the rig via a short wire. The screen acted as a plate of a capacitor and coupled the set to the operator who I suppose acted as a ground plane.
                                          When the operator would get too far off frequency, SWR would increase and the screen would ZAPP the guy in the rear and remind him to retune.
                                          It was understood NOT to put the screen under your belt in the front of your pants.
                                          This idea was patented by Racal Electronics so it must have some desrability. Operators claimed longer ground wave distances for contacts. I still have one of these in my junk box. If anyone wants a picture, ask.
                                          Jim VE3DDY





                                          [Non-text portions of this message have been removed]
                                        • Edward Thorpe
                                          I used a variation on this in one of my QTH. I applied brick layer s copper flashing to the below grade, inside surface of all exterior concrete walls in my
                                          Message 20 of 29 , Aug 5, 2009
                                            I used a variation on this in one of my QTH. I applied brick layer's
                                            copper flashing to the below grade, inside surface of all exterior
                                            concrete walls in my ham shack. It produced a capacitive path with 1
                                            ohm reactance (as I measured it) to ground at 3 mhz. It behaved
                                            almost as a Faraday shield in the shack and I never had RF in the
                                            shack after that.
                                            -----
                                            Ted Thorpe, VE3HPL

                                            On 5-Aug-09, at 12:29 PM, Jim wrote:

                                            > I once served in a foreign military.
                                            > We used portable HF for a lot of field work and the radio operator
                                            > had either a small hip style rig similar to the 817 or a RAcal 931.
                                            > Instead of a counterpoise, the set had a piece of fly screen wire
                                            > about 6" X 10" and enclosed in a piece of canvass which he tucked in
                                            > his belt or put in his back pocket. The screen was connected to the
                                            > Ground stud of the rig via a short wire. The screen acted as a plate
                                            > of a capacitor and coupled the set to the operator who I suppose
                                            > acted as a ground plane.
                                            > When the operator would get too far off frequency, SWR would
                                            > increase and the screen would ZAPP the guy in the rear and remind
                                            > him to retune.
                                            > It was understood NOT to put the screen under your belt in the front
                                            > of your pants.
                                            > This idea was patented by Racal Electronics so it must have some
                                            > desrability. Operators claimed longer ground wave distances for
                                            > contacts. I still have one of these in my junk box. If anyone wants
                                            > a picture, ask.
                                            > Jim VE3DDY
                                            >
                                            >
                                            > _



                                            [Non-text portions of this message have been removed]
                                          • jcjglt
                                            Like you my QTH is on the last floor (4th floor) of a building. I intend to use a mobile antenna (Hustler) with the metal parts of my balconny as counterpoise.
                                            Message 21 of 29 , Aug 5, 2009
                                              Like you my QTH is on the last floor (4th floor) of a building. I intend to use a mobile antenna (Hustler) with the metal parts of my balconny as counterpoise. About the grounding of my brand new FT897D what would be your suggestions as I can't direct a grounding wire to the ground (too high) and the co-owners of the building would not agree and I do not want also to disturb them with QRM.
                                              Regards to all and many thanks for this very interesting link.
                                              jcjglt (FK8IH)
                                            • Jim C
                                              So I guess to tune it he looked a pictures in Playboy Magazine? Jim VE3DDY wrote: Posted by: Jim portdoverbells@hotmail.com
                                              Message 22 of 29 , Aug 6, 2009
                                                So I guess to tune it he looked a pictures in Playboy Magazine?


                                                Jim VE3DDY wrote:


                                                Posted by: "Jim" portdoverbells@...
                                                <mailto:portdoverbells@...?Subject=%20Re%3A%20Grounding%20the%20FT-897>
                                                bambazonke01 <http://profiles.yahoo.com/bambazonke01>


                                                Wed Aug 5, 2009 9:30 am (PDT)

                                                I once served in a foreign military.
                                                We used portable HF for a lot of field work and the radio operator had
                                                either a small hip style rig similar to the 817 or a RAcal 931.
                                                Instead of a counterpoise, the set had a piece of fly screen wire about
                                                6" X 10" and enclosed in a piece of canvass which he tucked in his belt
                                                or put in his back pocket. The screen was connected to the Ground stud
                                                of the rig via a short wire. The screen acted as a plate of a capacitor
                                                and coupled the set to the operator who I suppose acted as a ground plane.
                                                When the operator would get too far off frequency, SWR would increase
                                                and the screen would ZAPP the guy in the rear and remind him to retune.
                                                It was understood NOT to put the screen under your belt in the front of
                                                your pants.
                                                This idea was patented by Racal Electronics so it must have some
                                                desrability. Operators claimed longer ground wave distances for
                                                contacts. I still have one of these in my junk box. If anyone wants a
                                                picture, ask.
                                                Jim VE3DDY
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