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RE: [FT897] Re: Traveling/RV'ing whatever you want to call it.

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  • KD8CCX - Adam Filkins
    I have had a similar issue in the Campground that we frequent. We usually grab a space next to all the amenities, and my 897D operates wonderfully. I
    Message 1 of 22 , Nov 3, 2008
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      I have had a similar issue in the Campground that we frequent. We usually
      grab a space next to all the amenities, and my 897D operates wonderfully. I
      recently rented a cabin, and had all sorts of noise. I just ran off the
      battery in my car - like usual for short QSO's. What I found was that the
      transformers used in the boxes near some of the campsites were extremely
      noisy. I don't know if the hum you are getting is a 60cycle or not, but it
      may be worth checking into. The portion we usually stay in is a newer
      addition to the campground, with much better power delivery equipment, while
      the cabins have been placed in an older section. Just a thought, hope it
      helps.



      73's



      Adam Filkins

      KD8CCX

      www.W8AX.com

      146.860Mhz - Repeater



      -----Original Message-----
      From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
      sargern2
      Sent: Monday, November 03, 2008 12:53 PM
      To: FT897@yahoogroups.com
      Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.



      Let me update on the various responses and what I've done.
      The RV is a 30 foot trailer.
      I've hooked up a battery that is not connected to the RV in any
      fashion. I shut down everything, TV, satellite reciever, computer and
      it's power supply...noise still present.
      Shut down each circuit breaker one at a time, while on external
      battery...noise still present.
      Disconnected the AC park power...noise still present.
      Other folks stuff...well know it's not from antenna amplifiers as the
      ONLY way you get TV in this RV park is via satellite - no cable and
      the closest TV station is way over 70 miles away! TV antennas don't
      function.
      Repeated the AM radio "sniffer" again with same inconclusive results.
      My power supply...well it is a switching PS a Radio Shack 25 amp and
      I've been wondering about that also! But like I've said the noise
      remains even off the supply and all external power sources off and or
      disconnected.
      OK that should have answered most of the questions/ideas that have
      been put forth.
      So that kind of leaves the problem in the antenna, maybe! Guess I
      really need to figure a way to get the ends up and get that ladder
      line either up off the ground or some kind of coax feed in. Will
      check with the antenna manufacturer and see how short I can get away
      with trimming that ladder line without messing with the preformance.
      Keep the suggestions/ideas coming!
      73's

      Sarge





      [Non-text portions of this message have been removed]
    • kc3vo@aol.com
      Do you use an inverter on your RV? If so make sure to turn it completely off/disconnect the battery, as some inverters make heavy QRM, even when not running
      Message 2 of 22 , Nov 3, 2008
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        Do you use an inverter on your RV? If so make sure to turn it
        completely off/disconnect the battery, as some inverters make heavy
        QRM, even when not running any 120 volt loads. If the noise goes away
        when you disconnect the antenna, it is outside the radio!--73, KC3VO,
        Bob Curry


        -----Original Message-----
        From: sargern2 <ke5ovt@...>
        To: FT897@yahoogroups.com
        Sent: Mon, 3 Nov 2008 12:52 pm
        Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.



        Let me update on the various responses and what I've done.
        The RV is a 30 foot trailer.
        I've hooked up a battery that is not connected to the RV in any
        fashion. I shut down everything, TV, satellite reciever, computer and
        it's power supply...noise still present.
        Shut down each circuit breaker one at a time, while on external
        battery...noise still present.
        Disconnected the AC park power...noise still present.
        Other folks stuff...well know it's not from antenna amplifiers as the
        ONLY way you get TV in this RV park is via satellite - no cable and
        the closest TV station is way over 70 miles away! TV antennas don't
        function.
        Repeated the AM radio "sniffer" again with same inconclusive results.
        My power supply...well it is a switching PS a Radio Shack 25 amp and
        I've been wondering about that also! But like I've said the noise
        remains even off the supply and all external power sources off and or
        disconnected.
        OK that should have answered most of the questions/ideas that have
        been put forth.
        So that kind of leaves the problem in the antenna, maybe! Guess I
        really need to figure a way to get the ends up and get that ladder
        line either up off the ground or some kind of coax feed in. Will
        check with the antenna manufacturer and see how short I can get away
        with trimming that ladder line without messing with the preformance.
        Keep the suggestions/ideas coming!
        73's

        Sarge


        ------------------------------------

        Yahoo! Groups Links
      • sargern2
        ... Bob well maybe we re getting somewhere!!! Disconnected the RV battery and it seems to have reduced the noise to what I d consider normal background
        Message 3 of 22 , Nov 3, 2008
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          --- In FT897@yahoogroups.com, kc3vo@... wrote:
          Bob well maybe we're getting somewhere!!! Disconnected the RV battery
          and it seems to have reduced the noise to what I'd consider "normal"
          background noise. BUT as with all things we shall see and time will
          tell!
          THANKS for that suggesetion!!
          Sarge


          >
          > Do you use an inverter on your RV? If so make sure to turn it
          > completely off/disconnect the battery, as some inverters make heavy
          > QRM, even when not running any 120 volt loads. If the noise goes
          away
          > when you disconnect the antenna, it is outside the radio!--73,
          KC3VO,
          > Bob Curry
          >
          >
          > -----Original Message-----
          > From: sargern2 <ke5ovt@...>
          > To: FT897@yahoogroups.com
          > Sent: Mon, 3 Nov 2008 12:52 pm
          > Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.
          >
          >
          >
          > Let me update on the various responses and what I've done.
          > The RV is a 30 foot trailer.
          > I've hooked up a battery that is not connected to the RV in any
          > fashion. I shut down everything, TV, satellite reciever, computer
          and
          > it's power supply...noise still present.
          > Shut down each circuit breaker one at a time, while on external
          > battery...noise still present.
          > Disconnected the AC park power...noise still present.
          > Other folks stuff...well know it's not from antenna amplifiers as
          the
          > ONLY way you get TV in this RV park is via satellite - no cable and
          > the closest TV station is way over 70 miles away! TV antennas don't
          > function.
          > Repeated the AM radio "sniffer" again with same inconclusive
          results.
          > My power supply...well it is a switching PS a Radio Shack 25 amp and
          > I've been wondering about that also! But like I've said the noise
          > remains even off the supply and all external power sources off and
          or
          > disconnected.
          > OK that should have answered most of the questions/ideas that have
          > been put forth.
          > So that kind of leaves the problem in the antenna, maybe! Guess I
          > really need to figure a way to get the ends up and get that ladder
          > line either up off the ground or some kind of coax feed in. Will
          > check with the antenna manufacturer and see how short I can get away
          > with trimming that ladder line without messing with the preformance.
          > Keep the suggestions/ideas coming!
          > 73's
          >
          > Sarge
          >
          >
          > ------------------------------------
          >
          > Yahoo! Groups Links
          >
        • P Grant
          Greetings from Ireland I m not familiar with the electrical requirements in the USofA ,so I cannot imagine what set up is the recommended............
          Message 4 of 22 , Nov 3, 2008
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            Greetings from Ireland
            I'm not familiar with the electrical requirements in the USofA ,so I cannot imagine what set up is
            the recommended............ probably changes in different States..............
            I have a friend who travels around Europe in his Camper (RV) and he asked me to have a look at an installation in a registered site local to me...
            The set up was very well installed, with separate (240Volt ) RCBO's for evry 2 stands. the complaint my friend had was severe TVI on his mains (240V ac) / 12VDC "portable" TV set. it worked FB on mains on a rabbits ears antenna, at his home QTH, but went wild on both mains and 12V dc on the campsite.
            I checked out everything for over an Hour to no result, and we drove back home the couple of miles.
            A few miles from home he stopped at a gas station, to fill the tank, I turned on the little TV and moved the rabbits ears around, and got a perfect picture on our local TV station. When he came back to the wheel, I said, there is no problem here !!.
            He said Yeah, its only at that F***** campsite... He often parked up there out of season, and had friends stay over at weekends if he had a full house....... SO we went back to the campsite to check again...... same problem,,, we moved further around the site and found a berth where there was no interference.
            The mains outlet box on this berth was different... It had no 12V DC outlet !!!
            So back to the original berth (beside the washrooms) opened the ABS casing housing the "electricks" and there it was....... a 20Amp SM power supply... which was running day and night when the Mains switch was ON..
            I fitted a waterproof 5amp switch on the outside of the ABS enclosure and enabled switching OFF the NOISE.
            He had never used the 12 volt plug in supply, but his portable TV was taking the hash in on the mains cable... or perhaps on the rabbits ears !!!
            Just wondering if something similar could be the cause.... did someone also mention an inverter before ???
            Hope you get it sorted for the touring season, best 73 de Peter EI4HX ei4hxperimental@...

            ~~~~~oo

            [Non-text portions of this message have been removed]
          • kc3vo@aol.com
            Glad to help! Many of the under $1,000.00 DC to AC inverters have little RF suppression, I have very GOOD results with my 24 volt XANTREX SW4024 inverter, a
            Message 5 of 22 , Nov 3, 2008
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              Glad to help! Many of the under $1,000.00 DC to AC inverters have
              little RF suppression, I have very GOOD results with my 24 volt XANTREX
              SW4024 inverter, a 4,000 watt unit, and my VANNER 12 volt 1000 watt
              inverter-they seem to be "RF quiet"--These are both HEAVY units, with
              60 hz transformers. I used a "VECTOR" brand 1,200 watt lightweight
              unit, and it was RF noisy. Sometimes by adding feedthrough capacitors
              and ferrite cores at the inverter for all input and output leads, and
              mounting it all to a grounded metal plate, bolted to the vehicle
              chassis, you may reduce the interference.-Good luck&73, KC3VO-Bob.


              -----Original Message-----
              From: sargern2 <ke5ovt@...>
              To: FT897@yahoogroups.com
              Sent: Mon, 3 Nov 2008 1:49 pm
              Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.



              --- In FT897@yahoogroups.com, kc3vo@... wrote:
              Bob well maybe we're getting somewhere!!! Disconnected the RV battery
              and it seems to have reduced the noise to what I'd consider "normal"
              background noise. BUT as with all things we shall see and time will
              tell!
              THANKS for that suggesetion!!
              Sarge


              >
              > Do you use an inverter on your RV? If so make sure to turn it
              > completely off/disconnect the battery, as some inverters make heavy
              > QRM, even when not running any 120 volt loads. If the noise goes
              away
              > when you disconnect the antenna, it is outside the radio!--73,
              KC3VO,
              > Bob Curry
              >
              >
              > -----Original Message-----
              > From: sargern2 <ke5ovt@...>
              > To: FT897@yahoogroups.com
              > Sent: Mon, 3 Nov 2008 12:52 pm
              > Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.
              >
              >
              >
              > Let me update on the various responses and what I've done.
              > The RV is a 30 foot trailer.
              > I've hooked up a battery that is not connected to the RV in any
              > fashion. I shut down everything, TV, satellite reciever, computer
              and
              > it's power supply...noise still present.
              > Shut down each circuit breaker one at a time, while on external
              > battery...noise still present.
              > Disconnected the AC park power...noise still present.
              > Other folks stuff...well know it's not from antenna amplifiers as
              the
              > ONLY way you get TV in this RV park is via satellite - no cable and
              > the closest TV station is way over 70 miles away! TV antennas don't
              > function.
              > Repeated the AM radio "sniffer" again with same inconclusive
              results.
              > My power supply...well it is a switching PS a Radio Shack 25 amp and
              > I've been wondering about that also! But like I've said the noise
              > remains even off the supply and all external power sources off and
              or
              > disconnected.
              > OK that should have answered most of the questions/ideas that have
              > been put forth.
              > So that kind of leaves the problem in the antenna, maybe! Guess I
              > really need to figure a way to get the ends up and get that ladder
              > line either up off the ground or some kind of coax feed in. Will
              > check with the antenna manufacturer and see how short I can get away
              > with trimming that ladder line without messing with the preformance.
              > Keep the suggestions/ideas coming!
              > 73's
              >
              > Sarge
              >
              >
              > ------------------------------------
              >
              > Yahoo! Groups Links
              >



              ------------------------------------

              Yahoo! Groups Links
            • Dale Blanchard
              ... I have a 700 watt Vector , marine series, It is RF quiet. Dale
              Message 6 of 22 , Nov 3, 2008
              • 0 Attachment
                --- In FT897@yahoogroups.com, kc3vo@... wrote:
                >
                > Glad to help! Many of the under $1,000.00 DC to AC inverters have
                > little RF suppression, I have very GOOD results with my 24 volt XANTREX
                > SW4024 inverter, a 4,000 watt unit, and my VANNER 12 volt 1000 watt
                > inverter-they seem to be "RF quiet"--These are both HEAVY units, with
                > 60 hz transformers. I used a "VECTOR" brand 1,200 watt lightweight
                > unit, and it was RF noisy.

                I have a 700 watt Vector , marine series, It is RF quiet.
                Dale
              • sargern2
                Well as I said in the original post this is a rented trailer so.... Well discovered something interesting! The entire roll-out in the living room is some
                Message 7 of 22 , Nov 3, 2008
                • 0 Attachment
                  Well as I said in the original post this is a rented trailer so....
                  Well discovered something interesting! The entire "roll-out" in the
                  living room is some type of plastic!!! So theladder line is loosely
                  coiled and is lying on top of the roll out and the SWR has not changed
                  still tunes to 1:1 on all bands. Also that seems to have lowered the
                  noise level a little bet more. Seems like all this is coming together!
                  THANKS gang!!
                  73's
                  Sarge
                • kav
                  Hello. Unfortuneately the ladder line has to stay. Only if you don t have any side cutters The antenna is a Cobra Ultralite Junior and that is the way
                  Message 8 of 22 , Nov 15, 2008
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                    Hello.

                    ""Unfortuneately the ladder line has to stay."" ""

                    Only if you don't have any side cutters



                    ""The antenna is a Cobra Ultralite Junior and that is the way it is""
                    ""designed and manufactured""

                    You're a radio ham aren't you? Modify it!

                    Sorry if that sounds sarcastic, it isn't meant to be. Its just that
                    ribbon type feeders, even the better quality windowed type, are a
                    right royal pain in the socket if you don't have the ideal qth.

                    A few years ago I was introduced to 75ohm twin feeder. I had the low
                    power type, ie it would only handle about 400w. It is smaller than
                    RG58 coax, extremely robust, almost immune to interference pick up,
                    very easy to work with, almost invisible to narky neighbours and a
                    trapped dipole fed with it via a 1:1 balun was easily matched to all
                    bands by a typical 3:1 internal tuner.

                    The biggest benefit is that you can twist it, bend it loop it up, oh
                    yes, and you can tape it directly to a metal support mast if you want.
                    Or in other words you could get yours off the ground by lying it on
                    or even wrapping it round your RV and it wouldn't make a hapeth of
                    difference to the performance.

                    I cannot understand why more people don't use it. Unfortunately the
                    best I can fit in this property is a coax fed SGC tuned short single
                    wire L but if I ever get enough estate to rig balanced antennas again
                    it would never occur to me to use anything other than 75ohm twin.


                    As for the interference, you say you heard nothing on an AM receiver
                    but can you wander the sight with the 897? It may be the set itself
                    which is prone. Or maybe you could knock up a small loop test antenna
                    which you can use to try and DF the noise. If you can null it out
                    with a small test antenna, consider building a transmitting loop then
                    you could null it out permanently.

                    Just a few out loud thoughts.


                    Regards
                  • capbrian
                    It is curious that all modern radios assume that the transmit antenna will also be the rx antenna. Using different ones for each purpose can have advantages
                    Message 9 of 22 , Nov 15, 2008
                    • 0 Attachment
                      It is curious that all modern radios assume that the transmit antenna will also be the rx antenna. Using different ones for each purpose can have advantages but I know of no readily available RF operated change-over relay kit.

                      The man under discussion could have a small loop turned permanently to null out his noise for Rx. but use his existing one to get his signal out.

                      A small antenna in a quiet place for reception can be better than a larger one with higher signal level but from many sources at once.

                      Bryan G3GVB


                      --- On Sat, 11/15/08, kav <smartlock.pro@...> wrote:

                      > From: kav <smartlock.pro@...>
                      > Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.
                      > To: FT897@yahoogroups.com
                      > Date: Saturday, November 15, 2008, 8:08 PM
                      > Hello.
                      >
                      > ""Unfortuneately the ladder line has to
                      > stay."" ""
                      >
                      > Only if you don't have any side cutters
                      >
                      >
                      >
                      > ""The antenna is a Cobra Ultralite Junior and
                      > that is the way it is""
                      > ""designed and manufactured""
                      >
                      > You're a radio ham aren't you? Modify it!
                      >
                      > Sorry if that sounds sarcastic, it isn't meant to be.
                      > Its just that
                      > ribbon type feeders, even the better quality windowed type,
                      > are a
                      > right royal pain in the socket if you don't have the
                      > ideal qth.
                      >
                      > A few years ago I was introduced to 75ohm twin feeder. I
                      > had the low
                      > power type, ie it would only handle about 400w. It is
                      > smaller than
                      > RG58 coax, extremely robust, almost immune to interference
                      > pick up,
                      > very easy to work with, almost invisible to narky
                      > neighbours and a
                      > trapped dipole fed with it via a 1:1 balun was easily
                      > matched to all
                      > bands by a typical 3:1 internal tuner.
                      >
                      > The biggest benefit is that you can twist it, bend it loop
                      > it up, oh
                      > yes, and you can tape it directly to a metal support mast
                      > if you want.
                      > Or in other words you could get yours off the ground by
                      > lying it on
                      > or even wrapping it round your RV and it wouldn't make
                      > a hapeth of
                      > difference to the performance.
                      >
                      > I cannot understand why more people don't use it.
                      > Unfortunately the
                      > best I can fit in this property is a coax fed SGC tuned
                      > short single
                      > wire L but if I ever get enough estate to rig balanced
                      > antennas again
                      > it would never occur to me to use anything other than 75ohm
                      > twin.
                      >
                      >
                      > As for the interference, you say you heard nothing on an AM
                      > receiver
                      > but can you wander the sight with the 897? It may be the
                      > set itself
                      > which is prone. Or maybe you could knock up a small loop
                      > test antenna
                      > which you can use to try and DF the noise. If you can null
                      > it out
                      > with a small test antenna, consider building a transmitting
                      > loop then
                      > you could null it out permanently.
                      >
                      > Just a few out loud thoughts.
                      >
                      >
                      > Regards
                      >
                      >
                      >
                      > ------------------------------------
                      >
                      > Yahoo! Groups Links
                      >
                      >
                      >
                    • P Grant
                      Hi Bryan, I think a lot of the old chrystal type PMR Pye and storno radios had RF sensing relays... Check out a junker. de Peter EI4HX _._
                      Message 10 of 22 , Nov 15, 2008
                      • 0 Attachment
                        Hi Bryan,
                        I think a lot of the old chrystal type PMR Pye and storno
                        radios had RF sensing relays...
                        Check out a junker.
                        de Peter EI4HX _._ ei4hxperimental@...
                        ~~~o.
                        ----- Original Message -----
                        From: capbrian
                        To: FT897@yahoogroups.com
                        Sent: Saturday, November 15, 2008 8:41 PM
                        Subject: Re: [FT897] Re: Traveling/RV'ing whatever you want to call it.


                        It is curious that all modern radios assume that the transmit antenna will also be the rx antenna. Using different ones for each purpose can have advantages but I know of no readily available RF operated change-over relay kit.

                        The man under discussion could have a small loop turned permanently to null out his noise for Rx. but use his existing one to get his signal out.

                        A small antenna in a quiet place for reception can be better than a larger one with higher signal level but from many sources at once.

                        Bryan G3GVB

                        --- On Sat, 11/15/08, kav <smartlock.pro@...> wrote:

                        > From: kav <smartlock.pro@...>
                        > Subject: [FT897] Re: Traveling/RV'ing whatever you want to call it.
                        > To: FT897@yahoogroups.com
                        > Date: Saturday, November 15, 2008, 8:08 PM
                        > Hello.
                        >
                        > ""Unfortuneately the ladder line has to
                        > stay."" ""
                        >
                        > Only if you don't have any side cutters
                        >
                        >
                        >
                        > ""The antenna is a Cobra Ultralite Junior and
                        > that is the way it is""
                        > ""designed and manufactured""
                        >
                        > You're a radio ham aren't you? Modify it!
                        >
                        > Sorry if that sounds sarcastic, it isn't meant to be.
                        > Its just that
                        > ribbon type feeders, even the better quality windowed type,
                        > are a
                        > right royal pain in the socket if you don't have the
                        > ideal qth.
                        >
                        > A few years ago I was introduced to 75ohm twin feeder. I
                        > had the low
                        > power type, ie it would only handle about 400w. It is
                        > smaller than
                        > RG58 coax, extremely robust, almost immune to interference
                        > pick up,
                        > very easy to work with, almost invisible to narky
                        > neighbours and a
                        > trapped dipole fed with it via a 1:1 balun was easily
                        > matched to all
                        > bands by a typical 3:1 internal tuner.
                        >
                        > The biggest benefit is that you can twist it, bend it loop
                        > it up, oh
                        > yes, and you can tape it directly to a metal support mast
                        > if you want.
                        > Or in other words you could get yours off the ground by
                        > lying it on
                        > or even wrapping it round your RV and it wouldn't make
                        > a hapeth of
                        > difference to the performance.
                        >
                        > I cannot understand why more people don't use it.
                        > Unfortunately the
                        > best I can fit in this property is a coax fed SGC tuned
                        > short single
                        > wire L but if I ever get enough estate to rig balanced
                        > antennas again
                        > it would never occur to me to use anything other than 75ohm
                        > twin.
                        >
                        >
                        > As for the interference, you say you heard nothing on an AM
                        > receiver
                        > but can you wander the sight with the 897? It may be the
                        > set itself
                        > which is prone. Or maybe you could knock up a small loop
                        > test antenna
                        > which you can use to try and DF the noise. If you can null
                        > it out
                        > with a small test antenna, consider building a transmitting
                        > loop then
                        > you could null it out permanently.
                        >
                        > Just a few out loud thoughts.
                        >
                        >
                        > Regards
                        >
                        >
                        >
                        > ------------------------------------
                        >
                        > Yahoo! Groups Links
                        >
                        >
                        >





                        [Non-text portions of this message have been removed]
                      • kc3vo@aol.com
                        RF Sensed relays, amplifier switching, etc are popular on CB (Childrens Band/Citizens Band AM/FM Radio) , but not appropriate for use with HAM, or AMATEUR
                        Message 11 of 22 , Nov 15, 2008
                        • 0 Attachment
                          "RF Sensed" relays, amplifier switching, etc are popular on "CB (Childrens
                          Band/Citizens Band AM/FM Radio) , but not appropriate for use with HAM, or
                          AMATEUR radio SSB radios!--WHY? When operating a SSB radio, there is essentially
                          NO RF until and unless an audio modulating signal is applied, as any amateur
                          with the technical skills/knowledge expected of an HF licensed radio operator
                          SHOULD posses! This means that RF sensing/switching will result in delayed
                          switching, and the switching ill occur AFTER the radio has begun transmitting,
                          resulting in dropping the first part of the voice, and swtching the power
                          while transmitting, (Especially at over 10 watts or so) can cause SWR spikes
                          and damaged relays and/or radios. Switching should be performed/activated by a
                          direct command from the radio, usually a D.C. voltage or internal, radio
                          provided, path to ground.---73, KC3VO-Bob Curry
                          **************You Rock! One month of free movies delivered by mail from
                          blockbuster.com
                          (http://pr.atwola.com/promoclk/100000075x1212639737x1200784900/aol?redir=https://www.blockbuster.com/signup/y/reg/p.26978/r.email_footer)


                          [Non-text portions of this message have been removed]
                        • Charles Scott
                          Bob: I d agree with you in general that permitting relays to switch while hot with any reasonable RF is probably not advisable. As a practical matter, many
                          Message 12 of 22 , Nov 15, 2008
                          • 0 Attachment
                            Bob:

                            I'd agree with you in general that permitting relays to switch while hot
                            with any reasonable RF is probably not advisable. As a practical matter,
                            many good Ham grade and even commercial grade mobile amplifiers can do
                            RF sensed switching and actually do it quite well. The better ones do
                            have a means to provide a very short-term load to the transmitter before
                            fully switching to transmit mode, but most don't. Even still, the short
                            reflected power transient is really not a problem for the transmitter
                            unless there's some type of sensing or switching failure.

                            Also, some of these amps have switching drop-out delay that can be
                            extended longer for SSB/CW modes as well as selectable sensing modes for
                            FM vs SSB/CW. As long as the timeout is long enough to keep the amp from
                            switching back out between words, there's very little practical impact
                            on communications.

                            Again, however, I do agree that if at all possible switching should be
                            by direct control, or better by sequencing.

                            Chuck - N8DNX



                            kc3vo@... wrote:
                            > "RF Sensed" relays, amplifier switching, etc are popular on "CB (Childrens
                            > Band/Citizens Band AM/FM Radio) , but not appropriate for use with HAM, or
                            > AMATEUR radio SSB radios!--WHY? When operating a SSB radio, there is essentially
                            > NO RF until and unless an audio modulating signal is applied, as any amateur
                            > with the technical skills/knowledge expected of an HF licensed radio operator
                            > SHOULD posses! This means that RF sensing/switching will result in delayed
                            > switching, and the switching ill occur AFTER the radio has begun transmitting,
                            > resulting in dropping the first part of the voice, and swtching the power
                            > while transmitting, (Especially at over 10 watts or so) can cause SWR spikes
                            > and damaged relays and/or radios. Switching should be performed/activated by a
                            > direct command from the radio, usually a D.C. voltage or internal, radio
                            > provided, path to ground.---73, KC3VO-Bob Curry
                            >
                            >
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