Loading ...
Sorry, an error occurred while loading the content.
 

aluminium centre post

Expand Messages
  • chris_bridgehouse
    I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else
    Message 1 of 16 , Feb 20, 2013
      I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?

      Cheers,

      Chris, ZL1BR
    • landtrack@ymail.com
      Chris, I also want to do this to reduce the number of supports needed for my antennae. I would be interested to hear from others who have tried this. 73 de
      Message 2 of 16 , Feb 21, 2013
        Chris,

        I also want to do this to reduce the number of supports needed for my antennae. I would be interested to hear from others who have tried this.

        73 de Joe, WM9I

        --- In hex-beam@yahoogroups.com, "chris_bridgehouse" <chris_bridgehouse@...> wrote:
        >
        > I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?
        >
        > Cheers,
        >
        > Chris, ZL1BR
        >
      • MWØJZE Hexbeam
        Hi Chris, Does Leo actually state that you could place a VHF beam above the Hexbeam. I doubt if the post could handle the wind load on it with out any type of
        Message 3 of 16 , Feb 21, 2013
          Hi Chris,

          Does Leo actually state that you could place a VHF beam above the Hexbeam. I doubt if the post could handle the wind load on it with out any type of modification. When potential customers ask me if this is possible with my version I try to put them off.

          73's Ant MWØJZE

          UK Manufacturer Of The G3TXQ Broadband Hexbeam!

          www.g3txq-hexbeam.com

          Seach my log on line
          http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
          Eat, Sleep, Dream the ultimate DX Holiday!

          ----- Original Message -----
          From: "chris_bridgehouse" <chris_bridgehouse@...>
          To: hex-beam@yahoogroups.com
          Sent: Thursday, February 21, 2013 4:55:53 AM
          Subject: [hex-beam] aluminium centre post

          I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?

          Cheers,

          Chris, ZL1BR
        • Robert
          I m pretty sure that was one of the many questions that I asked Leo before I bought mine, and he said to put any antennas on the mast below the hexbeam, since
          Message 4 of 16 , Feb 21, 2013
            I'm pretty sure that was one of the many questions that I asked Leo
            before I bought mine, and he said to put any antennas on the mast below
            the hexbeam, since the center post wasn't designed for any kind of load.

            Robert Patty
            K4IDK

            On 2/21/2013 3:00 PM, MWØJZE Hexbeam wrote:
            >
            > Hi Chris,
            >
            > Does Leo actually state that you could place a VHF beam above the
            > Hexbeam. I doubt if the post could handle the wind load on it with out
            > any type of modification. When potential customers ask me if this is
            > possible with my version I try to put them off.
            >
            > 73's Ant MWØJZE
            >
            > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
            >
            > www.g3txq-hexbeam.com
            >
            > Seach my log on line
            > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
            > Eat, Sleep, Dream the ultimate DX Holiday!
            >
            > ----- Original Message -----
            > From: "chris_bridgehouse" chris_bridgehouse@...
            > <mailto:chris_bridgehouse%40yahoo.co.nz>>
            > To: hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>
            > Sent: Thursday, February 21, 2013 4:55:53 AM
            > Subject: [hex-beam] aluminium centre post
            >
            > I see that KX4O has used an aluminium centre post to allow support of
            > a vhf antenna above his hexbeam. I was thinking of doing the same
            > thing. has anybody else done this? Are there any potential problems?
            >
            > Cheers,
            >
            > Chris, ZL1BR
            >
            >



            [Non-text portions of this message have been removed]
          • Steve
            Chris, The reason for the aluminium centre post is that it forms the outer conductor of a coaxial band-interconnect transmission line. Apart from any
            Message 5 of 16 , Feb 21, 2013
              Chris,

              The reason for the aluminium centre post is that it forms the outer conductor of a coaxial band-interconnect transmission line. Apart from any mechanical issues, anything you bolt to it is then electrically connected to one side of all the driven elements!

              73,
              Steve G3TXQ



              --- In hex-beam@yahoogroups.com, "chris_bridgehouse" <chris_bridgehouse@...> wrote:
              >
              > I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?
              >
              > Cheers,
              >
              > Chris, ZL1BR
              >
            • chris_bridgehouse
              Hi all. It wasnt Leo. I saw a link online. I think its called hexbeam gets a spine or something where the guy used a 1.5 inch thickwalled aluminium post as his
              Message 6 of 16 , Feb 21, 2013
                Hi all. It wasnt Leo. I saw a link online. I think its called hexbeam gets a spine or something where the guy used a 1.5 inch thickwalled aluminium post as his centre post and had an insulated feeder post in front of it. The aluminium then supported a vhf yagi above the hexbeam.
                Chris

                --- In hex-beam@yahoogroups.com, Robert <paradude54@...> wrote:
                >
                > I'm pretty sure that was one of the many questions that I asked Leo
                > before I bought mine, and he said to put any antennas on the mast below
                > the hexbeam, since the center post wasn't designed for any kind of load.
                >
                > Robert Patty
                > K4IDK
                >
                > On 2/21/2013 3:00 PM, MWØJZE Hexbeam wrote:
                > >
                > > Hi Chris,
                > >
                > > Does Leo actually state that you could place a VHF beam above the
                > > Hexbeam. I doubt if the post could handle the wind load on it with out
                > > any type of modification. When potential customers ask me if this is
                > > possible with my version I try to put them off.
                > >
                > > 73's Ant MWØJZE
                > >
                > > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
                > >
                > > www.g3txq-hexbeam.com
                > >
                > > Seach my log on line
                > > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                > > Eat, Sleep, Dream the ultimate DX Holiday!
                > >
                > > ----- Original Message -----
                > > From: "chris_bridgehouse" chris_bridgehouse@...
                > > <mailto:chris_bridgehouse%40yahoo.co.nz>>
                > > To: hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>
                > > Sent: Thursday, February 21, 2013 4:55:53 AM
                > > Subject: [hex-beam] aluminium centre post
                > >
                > > I see that KX4O has used an aluminium centre post to allow support of
                > > a vhf antenna above his hexbeam. I was thinking of doing the same
                > > thing. has anybody else done this? Are there any potential problems?
                > >
                > > Cheers,
                > >
                > > Chris, ZL1BR
                > >
                > >
                >
                >
                >
                > [Non-text portions of this message have been removed]
                >
              • chris_bridgehouse
                Here is the link to what i was refering to. http://www.hamradio.me/antennas/hexbeam-gets-a-spine.html. Chris
                Message 7 of 16 , Feb 21, 2013
                  Here is the link to what i was refering to. http://www.hamradio.me/antennas/hexbeam-gets-a-spine.html.

                  Chris

                  --- In hex-beam@yahoogroups.com, "chris_bridgehouse" <chris_bridgehouse@...> wrote:
                  >
                  > Hi all. It wasnt Leo. I saw a link online. I think its called hexbeam gets a spine or something where the guy used a 1.5 inch thickwalled aluminium post as his centre post and had an insulated feeder post in front of it. The aluminium then supported a vhf yagi above the hexbeam.
                  > Chris
                  >
                  > --- In hex-beam@yahoogroups.com, Robert <paradude54@> wrote:
                  > >
                  > > I'm pretty sure that was one of the many questions that I asked Leo
                  > > before I bought mine, and he said to put any antennas on the mast below
                  > > the hexbeam, since the center post wasn't designed for any kind of load.
                  > >
                  > > Robert Patty
                  > > K4IDK
                  > >
                  > > On 2/21/2013 3:00 PM, MWØJZE Hexbeam wrote:
                  > > >
                  > > > Hi Chris,
                  > > >
                  > > > Does Leo actually state that you could place a VHF beam above the
                  > > > Hexbeam. I doubt if the post could handle the wind load on it with out
                  > > > any type of modification. When potential customers ask me if this is
                  > > > possible with my version I try to put them off.
                  > > >
                  > > > 73's Ant MWØJZE
                  > > >
                  > > > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
                  > > >
                  > > > www.g3txq-hexbeam.com
                  > > >
                  > > > Seach my log on line
                  > > > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                  > > > Eat, Sleep, Dream the ultimate DX Holiday!
                  > > >
                  > > > ----- Original Message -----
                  > > > From: "chris_bridgehouse" chris_bridgehouse@
                  > > > <mailto:chris_bridgehouse%40yahoo.co.nz>>
                  > > > To: hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>
                  > > > Sent: Thursday, February 21, 2013 4:55:53 AM
                  > > > Subject: [hex-beam] aluminium centre post
                  > > >
                  > > > I see that KX4O has used an aluminium centre post to allow support of
                  > > > a vhf antenna above his hexbeam. I was thinking of doing the same
                  > > > thing. has anybody else done this? Are there any potential problems?
                  > > >
                  > > > Cheers,
                  > > >
                  > > > Chris, ZL1BR
                  > > >
                  > > >
                  > >
                  > >
                  > >
                  > > [Non-text portions of this message have been removed]
                  > >
                  >
                • John Huggins
                  That s my hex beam. In my case I desired a much stronger backbone in my hexbeam for a variety of reasons. I used the 1/4 wall aluminum mast of 8 feet length.
                  Message 8 of 16 , Feb 21, 2013
                    That's my hex beam.

                    In my case I desired a much stronger backbone in my hexbeam for a
                    variety of reasons. I used the 1/4" wall aluminum mast of 8 feet
                    length. The other reason was to put a VHF beam above the hex. I did
                    quite a bit of modeling to ensure that little 4 element 2m beam would
                    not present difficulties. It doesn't appear to cause trouble.

                    As for the feed structure, it is a traditional multi-coax piece
                    approach, but not directly against the metal mast. Instead I have it
                    mounted on that parallel fiberglass tube connected with the DX
                    Engineering resin blocks. Yes, this offsets things just a bit, but not
                    by much. The hex strings up pretty much the same.

                    If you choose to have a metal mast like me, you will need a compatible
                    feed system a bit different from the typical style. Some time back I
                    looked seriously at the DX Engineering feed system. I modeled the
                    parallel flat plates in FDTD and find the fields are well contained
                    between the plates suggesting the DXE feed will play well mounting
                    directly to the metal mast. I've not had the guts to lay out the big
                    coin to test this theory though.

                    All that said, I am designing a completely different feed system for
                    this hex once I get it all back together (the fiberglass spreaders
                    failed from sunlight/weather damage :( - will paint them next time for
                    sure).

                    I'm an antenna freak so I enjoy fiddling with great antennas like the
                    BBHB making it fit my style.

                    The big metal mast hexbeam idea seems to be an eccentric solution not
                    suitable for the needs of most hexbeam users. It is very very sturdy.
                    The metal mast is a keeper for me.

                    John, kx4o

                    On 2/21/13 7:53 PM, chris_bridgehouse wrote:
                    >
                    > Here is the link to what i was refering to.
                    > http://www.hamradio.me/antennas/hexbeam-gets-a-spine.html.
                    >
                    > Chris
                    >
                    > --- In hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>,
                    > "chris_bridgehouse" wrote:
                    > >
                    > > Hi all. It wasnt Leo. I saw a link online. I think its called
                    > hexbeam gets a spine or something where the guy used a 1.5 inch
                    > thickwalled aluminium post as his centre post and had an insulated
                    > feeder post in front of it. The aluminium then supported a vhf yagi
                    > above the hexbeam.
                    > > Chris
                    > >
                    > > --- In hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>,
                    > Robert wrote:
                    > > >
                    > > > I'm pretty sure that was one of the many questions that I asked Leo
                    > > > before I bought mine, and he said to put any antennas on the mast
                    > below
                    > > > the hexbeam, since the center post wasn't designed for any kind of
                    > load.
                    > > >
                    > > > Robert Patty
                    > > > K4IDK
                    > > >
                    > > > On 2/21/2013 3:00 PM, MWÃ~JZE Hexbeam wrote:
                    > > > >
                    > > > > Hi Chris,
                    > > > >
                    > > > > Does Leo actually state that you could place a VHF beam above the
                    > > > > Hexbeam. I doubt if the post could handle the wind load on it
                    > with out
                    > > > > any type of modification. When potential customers ask me if
                    > this is
                    > > > > possible with my version I try to put them off.
                    > > > >
                    > > > > 73's Ant MWÃ~JZE
                    > > > >
                    > > > > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
                    > > > >
                    > > > > www.g3txq-hexbeam.com
                    > > > >
                    > > > > Seach my log on line
                    > > > > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                    > > > > Eat, Sleep, Dream the ultimate DX Holiday!
                    > > > >
                    > > > > ----- Original Message -----
                    > > > > From: "chris_bridgehouse" chris_bridgehouse@
                    > > > > >
                    > > > > To: hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>
                    > > > > Sent: Thursday, February 21, 2013 4:55:53 AM
                    > > > > Subject: [hex-beam] aluminium centre post
                    > > > >
                    > > > > I see that KX4O has used an aluminium centre post to allow
                    > support of
                    > > > > a vhf antenna above his hexbeam. I was thinking of doing the same
                    > > > > thing. has anybody else done this? Are there any potential problems?
                    > > > >
                    > > > > Cheers,
                    > > > >
                    > > > > Chris, ZL1BR
                    > > > >
                    > > > >
                    > > >
                    > > >
                    > > >
                    > > > [Non-text portions of this message have been removed]
                    > > >
                    > >
                    >
                    >



                    [Non-text portions of this message have been removed]
                  • MWØJZE Hexbeam
                    Good point Steve, I was only thinking mechanicly! 73 s Ant MWØJZE UK Manufacturer Of The G3TXQ Broadband Hexbeam! www.g3txq-hexbeam.com Seach my log on line
                    Message 9 of 16 , Feb 22, 2013
                      Good point Steve,

                      I was only thinking mechanicly!

                      73's Ant MWØJZE

                      UK Manufacturer Of The G3TXQ Broadband Hexbeam!

                      www.g3txq-hexbeam.com

                      Seach my log on line
                      http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                      Eat, Sleep, Dream the ultimate DX Holiday!

                      ----- Original Message -----
                      From: "Steve" <steve@...>
                      To: hex-beam@yahoogroups.com
                      Sent: Thursday, 21 February, 2013 9:34:51 PM
                      Subject: [hex-beam] Re: aluminium centre post

                      Chris,

                      The reason for the aluminium centre post is that it forms the outer conductor of a coaxial band-interconnect transmission line. Apart from any mechanical issues, anything you bolt to it is then electrically connected to one side of all the driven elements!

                      73,
                      Steve G3TXQ



                      --- In hex-beam@yahoogroups.com, "chris_bridgehouse" <chris_bridgehouse@...> wrote:
                      >
                      > I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?
                      >
                      > Cheers,
                      >
                      > Chris, ZL1BR
                      >
                    • Rob
                      The question remains: is this a problem? 73, AL7AW.
                      Message 10 of 16 , Feb 22, 2013
                        The question remains: is this a problem? 73, AL7AW.


                        --- In hex-beam@yahoogroups.com, MWØJZE Hexbeam <mw0jze@...> wrote:
                        >
                        > Good point Steve,
                        >
                        > I was only thinking mechanicly!
                        >
                        > 73's Ant MWØJZE
                        >
                        > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
                        >
                        > www.g3txq-hexbeam.com
                        >
                        > Seach my log on line
                        > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                        > Eat, Sleep, Dream the ultimate DX Holiday!
                        >
                        > ----- Original Message -----
                        > From: "Steve" <steve@...>
                        > To: hex-beam@yahoogroups.com
                        > Sent: Thursday, 21 February, 2013 9:34:51 PM
                        > Subject: [hex-beam] Re: aluminium centre post
                        >
                        > Chris,
                        >
                        > The reason for the aluminium centre post is that it forms the outer conductor of a coaxial band-interconnect transmission line. Apart from any mechanical issues, anything you bolt to it is then electrically connected to one side of all the driven elements!
                        >
                        > 73,
                        > Steve G3TXQ
                        >
                        >
                        >
                        > --- In hex-beam@yahoogroups.com, "chris_bridgehouse" <chris_bridgehouse@> wrote:
                        > >
                        > > I see that KX4O has used an aluminium centre post to allow support of a vhf antenna above his hexbeam. I was thinking of doing the same thing. has anybody else done this? Are there any potential problems?
                        > >
                        > > Cheers,
                        > >
                        > > Chris, ZL1BR
                        > >
                        >
                      • T.H. Bauer
                        When I was considering Leo s design I had asked about using the Hex s center support for doing the same thing. He recommended against doing so because the post
                        Message 11 of 16 , Feb 22, 2013
                          When I was considering Leo's design I had asked about using the Hex's
                          center support for doing the same thing. He recommended against doing so
                          because the post would not have sufficient structural strength for mounting
                          a VHF Yagi. I wouldn't even do it with Ant's design, even though his center
                          post is more rigidly secured.

                          I wanted to mount my 2M Yagi vertically polarized, so I tried doing so
                          below the Hex. That created an entirely different set of problems for the
                          rotator. If you're thinking 6M horizontal below the Hex, you'll run into
                          the same issues due to the spacing needed. 2M horizontal below the Hex *
                          might* work with a sufficiently robust rotator.


                          73
                          ---
                          Ted WA3AER


                          [Non-text portions of this message have been removed]
                        • Steve
                          If you are asking is it a problem to connect a mast and another antenna to one side of a balanced wire beam like the hexbeam? , the answer is Yes . 73, Steve
                          Message 12 of 16 , Feb 22, 2013
                            If you are asking "is it a problem to connect a mast and another antenna to one side of a balanced wire beam like the hexbeam?", the answer is "Yes".

                            73,
                            Steve G3TXQ


                            --- In hex-beam@yahoogroups.com, "Rob" <robmm76@...> wrote:
                            >
                            >
                            > The question remains: is this a problem? 73, AL7AW.
                            >
                            >
                          • chris_bridgehouse
                            Hi all. I seem to have created some confusion. My question was regarding using a setup like John Huggins and NOT Leo`s coaxial centre post. No part of the
                            Message 13 of 16 , Feb 22, 2013
                              Hi all. I seem to have created some confusion. My question was regarding using a setup like John Huggins and NOT Leo`s coaxial centre post. No part of the centre post is/ would be connected to either side of the antenna.
                              The feeders would still be insulated from the centre post on nylon support/standoffs. My main concern was "would the hexbeam performance be compromised if it had a metal post running up the centre of it that wasn`t part of the feed system?

                              Sorry if i wasn`t clear enough with my original question.

                              Chris, ZL1BR

                              --- In hex-beam@yahoogroups.com, "Steve" <steve@...> wrote:
                              >
                              > If you are asking "is it a problem to connect a mast and another antenna to one side of a balanced wire beam like the hexbeam?", the answer is "Yes".
                              >
                              > 73,
                              > Steve G3TXQ
                              >
                              >
                              > --- In hex-beam@yahoogroups.com, "Rob" <robmm76@> wrote:
                              > >
                              > >
                              > > The question remains: is this a problem? 73, AL7AW.
                              > >
                              > >
                              >
                            • chris_bridgehouse
                              Thanks for the PM John. Chris
                              Message 14 of 16 , Feb 22, 2013
                                Thanks for the PM John.

                                Chris

                                --- In hex-beam@yahoogroups.com, John Huggins <john@...> wrote:
                                >
                                > That's my hex beam.
                                >
                                > In my case I desired a much stronger backbone in my hexbeam for a
                                > variety of reasons. I used the 1/4" wall aluminum mast of 8 feet
                                > length. The other reason was to put a VHF beam above the hex. I did
                                > quite a bit of modeling to ensure that little 4 element 2m beam would
                                > not present difficulties. It doesn't appear to cause trouble.
                                >
                                > As for the feed structure, it is a traditional multi-coax piece
                                > approach, but not directly against the metal mast. Instead I have it
                                > mounted on that parallel fiberglass tube connected with the DX
                                > Engineering resin blocks. Yes, this offsets things just a bit, but not
                                > by much. The hex strings up pretty much the same.
                                >
                                > If you choose to have a metal mast like me, you will need a compatible
                                > feed system a bit different from the typical style. Some time back I
                                > looked seriously at the DX Engineering feed system. I modeled the
                                > parallel flat plates in FDTD and find the fields are well contained
                                > between the plates suggesting the DXE feed will play well mounting
                                > directly to the metal mast. I've not had the guts to lay out the big
                                > coin to test this theory though.
                                >
                                > All that said, I am designing a completely different feed system for
                                > this hex once I get it all back together (the fiberglass spreaders
                                > failed from sunlight/weather damage :( - will paint them next time for
                                > sure).
                                >
                                > I'm an antenna freak so I enjoy fiddling with great antennas like the
                                > BBHB making it fit my style.
                                >
                                > The big metal mast hexbeam idea seems to be an eccentric solution not
                                > suitable for the needs of most hexbeam users. It is very very sturdy.
                                > The metal mast is a keeper for me.
                                >
                                > John, kx4o
                                >
                                > On 2/21/13 7:53 PM, chris_bridgehouse wrote:
                                > >
                                > > Here is the link to what i was refering to.
                                > > http://www.hamradio.me/antennas/hexbeam-gets-a-spine.html.
                                > >
                                > > Chris
                                > >
                                > > --- In hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>,
                                > > "chris_bridgehouse" wrote:
                                > > >
                                > > > Hi all. It wasnt Leo. I saw a link online. I think its called
                                > > hexbeam gets a spine or something where the guy used a 1.5 inch
                                > > thickwalled aluminium post as his centre post and had an insulated
                                > > feeder post in front of it. The aluminium then supported a vhf yagi
                                > > above the hexbeam.
                                > > > Chris
                                > > >
                                > > > --- In hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>,
                                > > Robert wrote:
                                > > > >
                                > > > > I'm pretty sure that was one of the many questions that I asked Leo
                                > > > > before I bought mine, and he said to put any antennas on the mast
                                > > below
                                > > > > the hexbeam, since the center post wasn't designed for any kind of
                                > > load.
                                > > > >
                                > > > > Robert Patty
                                > > > > K4IDK
                                > > > >
                                > > > > On 2/21/2013 3:00 PM, MWÃ~JZE Hexbeam wrote:
                                > > > > >
                                > > > > > Hi Chris,
                                > > > > >
                                > > > > > Does Leo actually state that you could place a VHF beam above the
                                > > > > > Hexbeam. I doubt if the post could handle the wind load on it
                                > > with out
                                > > > > > any type of modification. When potential customers ask me if
                                > > this is
                                > > > > > possible with my version I try to put them off.
                                > > > > >
                                > > > > > 73's Ant MWÃ~JZE
                                > > > > >
                                > > > > > UK Manufacturer Of The G3TXQ Broadband Hexbeam!
                                > > > > >
                                > > > > > www.g3txq-hexbeam.com
                                > > > > >
                                > > > > > Seach my log on line
                                > > > > > http://www.clublog.org/logsearch.php?log=MW0JZE&iframe=1
                                > > > > > Eat, Sleep, Dream the ultimate DX Holiday!
                                > > > > >
                                > > > > > ----- Original Message -----
                                > > > > > From: "chris_bridgehouse" chris_bridgehouse@
                                > > > > > >
                                > > > > > To: hex-beam@yahoogroups.com <mailto:hex-beam%40yahoogroups.com>
                                > > > > > Sent: Thursday, February 21, 2013 4:55:53 AM
                                > > > > > Subject: [hex-beam] aluminium centre post
                                > > > > >
                                > > > > > I see that KX4O has used an aluminium centre post to allow
                                > > support of
                                > > > > > a vhf antenna above his hexbeam. I was thinking of doing the same
                                > > > > > thing. has anybody else done this? Are there any potential problems?
                                > > > > >
                                > > > > > Cheers,
                                > > > > >
                                > > > > > Chris, ZL1BR
                                > > > > >
                                > > > > >
                                > > > >
                                > > > >
                                > > > >
                                > > > > [Non-text portions of this message have been removed]
                                > > > >
                                > > >
                                > >
                                > >
                                >
                                >
                                >
                                > [Non-text portions of this message have been removed]
                                >
                              • Chris Wilson
                                ... 18/05/2013 01:02 Would the DX Engineering hex beam, in its standard, purchased form, allow the easy installation of a longer stub mast? I want a VHF
                                Message 15 of 16 , May 17, 2013
                                  >
                                  > That's my hex beam.

                                  > In my case I desired a much stronger backbone in my hexbeam for a
                                  > variety of reasons. I used the 1/4" wall aluminum mast of 8 feet
                                  > length. The other reason was to put a VHF beam above the hex. I did
                                  > quite a bit of modeling to ensure that little 4 element 2m beam would
                                  > not present difficulties. It doesn't appear to cause trouble.

                                  > As for the feed structure, it is a traditional multi-coax piece
                                  > approach, but not directly against the metal mast. Instead I have it
                                  > mounted on that parallel fiberglass tube connected with the DX
                                  > Engineering resin blocks. Yes, this offsets things just a bit, but not
                                  > by much. The hex strings up pretty much the same.

                                  > If you choose to have a metal mast like me, you will need a compatible
                                  > feed system a bit different from the typical style. Some time back I
                                  > looked seriously at the DX Engineering feed system. I modeled the
                                  > parallel flat plates in FDTD and find the fields are well contained
                                  > between the plates suggesting the DXE feed will play well mounting
                                  > directly to the metal mast. I've not had the guts to lay out the big
                                  > coin to test this theory though.

                                  > All that said, I am designing a completely different feed system for
                                  > this hex once I get it all back together (the fiberglass spreaders
                                  > failed from sunlight/weather damage - will paint them next time for
                                  > sure).

                                  > I'm an antenna freak so I enjoy fiddling with great antennas like the
                                  > BBHB making it fit my style.

                                  > The big metal mast hexbeam idea seems to be an eccentric solution not
                                  > suitable for the needs of most hexbeam users. It is very very sturdy.
                                  > The metal mast is a keeper for me.

                                  > John, kx4o



                                  18/05/2013 01:02

                                  Would the DX Engineering hex beam, in its standard, purchased form,
                                  allow the easy installation of a longer stub mast? I want a VHF
                                  vertical (2 meter) antenna above the hex, and maybe a VHF Yagi, as
                                  well. I only realised at the last moment such a set up was fraught
                                  with potential issues, like feeding the hex elements. Do you have any
                                  photos of your set up John, that you might be willing to share?
                                  Thanks. My direct e-mail is chris@...

                                  --
                                  Best Regards,
                                  Chris Wilson.
                                • John Huggins
                                  ... Chris, The vertical antenna and, with caution, a very small VHF beam should play well above the hex. The key is the compatibility of the various hex feed
                                  Message 16 of 16 , May 18, 2013
                                    On 5/17/13 8:05 PM, Chris Wilson wrote:
                                    >
                                    >
                                    > > The big metal mast hexbeam idea seems to be an eccentric solution not
                                    > > suitable for the needs of most hexbeam users. It is very very sturdy.
                                    > > The metal mast is a keeper for me.
                                    >
                                    > > John, kx4o
                                    >
                                    > 18/05/2013 01:02
                                    >
                                    > Would the DX Engineering hex beam, in its standard, purchased form,
                                    > allow the easy installation of a longer stub mast? I want a VHF
                                    > vertical (2 meter) antenna above the hex, and maybe a VHF Yagi, as
                                    > well. I only realised at the last moment such a set up was fraught
                                    > with potential issues, like feeding the hex elements.
                                    >
                                    Chris,

                                    The vertical antenna and, with caution, a "very small" VHF beam should
                                    play well above the hex.

                                    The key is the compatibility of the various hex feed systems with a
                                    strong central mast. Some hex vendors incorporate the feedline into a
                                    conductive and sturdy central mast. Others offset the feed line from
                                    the central mast. The latter approach is what you want if you desire to
                                    lengthen the center mast.

                                    The DXE feed system uses two flat and parallel strips (plates?)
                                    separated by a thin dielectric material ultimately and hopefully
                                    resulting in a 50 ohm balanced feed line. As you know this straps to
                                    the central mast which, in the DXE case, is a non-conductive pole.

                                    The question becomes if this DXE feed system will play well if attached
                                    to a conductive center mast. I simulated this in a full up
                                    electro-magnetic package. This showed me the fields were well contained
                                    between the plates and a bit out the sides. There were some fields
                                    everywhere of course, but the DXE approach seems to do a good job of
                                    keeping almost all the fields tight. Thus, I would have no problem
                                    "trying" the DXE system with its parallel transmission line strapped to
                                    a conductive metal mast.
                                    >
                                    > Do you have any
                                    > photos of your set up John, that you might be willing to share?
                                    >
                                    Here is my article concerning my use of a metal mast through the DXE hub...

                                    http://www.hamradio.me/antennas/hexbeam-gets-a-spine.html

                                    ...including some pics.

                                    As I currently use the traditional coax cable approach, I mount them on
                                    an offset parallel non-conductive pole.

                                    John, kx4o




                                    [Non-text portions of this message have been removed]
                                  Your message has been successfully submitted and would be delivered to recipients shortly.